1
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Fu M, Critchley K. Inkjet printing of heavy-metal-free quantum dots-based devices: a review. NANOTECHNOLOGY 2024; 35:302002. [PMID: 38640903 DOI: 10.1088/1361-6528/ad40b3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 04/19/2024] [Indexed: 04/21/2024]
Abstract
Inkjet printing (IJP) has become a versatile, cost-effective technology for fabricating organic and hybrid electronic devices. Heavy-metal-based quantum dots (HM QDs) play a significant role in these inkjet-printed devices due to their excellent optoelectrical properties. Despite their utility, the intrinsic toxicity of HM QDs limits their applications in commercial products. To address this limitation, developing alternative HM-free quantum dots (HMF QDs) that have equivalent optoelectronic properties to HM QD is a promising approach to reduce toxicity and environmental impact. This article comprehensively reviews HMF QD-based devices fabricated using IJP methods. The discussion includes the basics of IJP technology, the formulation of printable HMF QD inks, and solutions to the coffee ring effect. Additionally, this review briefly explores the performance of typical state-of-the-art HMF QDs and cutting-edge characterization techniques for QD inks and printed QD films. The performance of printed devices based on HMF QDs is discussed and compared with those fabricated by other techniques. In the conclusion, the persisting challenges are identified, and perspectives on potential avenues for further progress in this rapidly developing research field are provided.
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Affiliation(s)
- Min Fu
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Kevin Critchley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
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2
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Cao K, Yu B, Huang F, Pan Q, Wang J, Ning J, Zheng K, Pullerits T, Tian J. Constructing ZnTe Spherical Quantum Well for Efficient Light Emission. NANO LETTERS 2024; 24:5238-5245. [PMID: 38629707 DOI: 10.1021/acs.nanolett.4c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
ZnTe colloidal semiconductor nanocrystals (NCs) have shown promise for light-emitting diodes (LEDs) and displays, because they are free from toxic heavy metals (Cd). However, so far, their low photoluminescence (PL) efficiency (∼30%) has hindered their applications. Herein, we devised a novel structure of ZnTe NCs with the configuration of ZnSe (core)/ZnTe (spherical quantum well, SQW)/ZnSe (shell). The inner layer ZnTe was grown at the surface of ZnSe core with avoiding using highly active and high-risk Zn sources. Due to the formation of coherently strained heterostructure which reduced the lattice mismatch, and the thermodynamic growth of ZnTe, the surface or interface defects were suppressed. A high PL efficiency of >60% was obtained for the green light-emitting ZnSe/ZnTe/ZnSe SQWs after ZnS outer layer passivation, which is the highest value for colloidal ZnTe-based NCs. This work paves the way for the development of novel semiconductor NCs for luminescent and display applications.
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Affiliation(s)
- Kequan Cao
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Binbin Yu
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Fei Huang
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Qinying Pan
- Chemical Physics and NanoLund, Lund University, 22100 Lund, Sweden
| | - Junfeng Wang
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Jiajia Ning
- College of Physics, Jilin University, Changchun 130012, People's Republic of China
| | - Kaibo Zheng
- Chemical Physics and NanoLund, Lund University, 22100 Lund, Sweden
| | - Tõnu Pullerits
- Chemical Physics and NanoLund, Lund University, 22100 Lund, Sweden
| | - Jianjun Tian
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
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3
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Wang Z, Tang J, Han J, Xia J, Ma T, Chen XW. Bright Nonblinking Photoluminescence with Blinking Lifetime from a Nanocavity-Coupled Quantum Dot. NANO LETTERS 2024; 24:1761-1768. [PMID: 38261791 DOI: 10.1021/acs.nanolett.3c04661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Colloidal quantum dots (QDs) are excellent luminescent nanomaterials for many optoelectronic applications. However, photoluminescence blinking has limited their practical use. Coupling QDs to plasmonic nanostructures shows potential in suppressing blinking. However, the underlying mechanism remains unclear and debated, hampering the development of bright nonblinking dots. Here, by deterministically coupling a QD to a plasmonic nanocavity, we clarify the mechanism and demonstrate unprecedented single-QD brightness. In particular, we report for the first time that a blinking QD could obtain nonblinking photoluminescence with a blinking lifetime through coupling to the nanocavity. We show that the plasmon-enhanced radiative decay outcompetes the nonradiative Auger process, enabling similar quantum yields for charged and neutral excitons in the same dot. Meanwhile, we demonstrate a record photon detection rate of 17 MHz from a colloidal QD, indicating an experimental photon generation rate of more than 500 MHz. These findings pave the way for ultrabright nonblinking QDs, benefiting diverse QD-based applications.
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Affiliation(s)
- Zhiyuan Wang
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Jianwei Tang
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
- Wuhan Institute of Quantum Technology, Wuhan 430206, P. R. China
| | - Jiahao Han
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Juan Xia
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Tianzi Ma
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Xue-Wen Chen
- School of Physics, Wuhan National Laboratory for Optoelectronics, Institute for Quantum Science and Engineering and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
- Wuhan Institute of Quantum Technology, Wuhan 430206, P. R. China
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4
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Fu W, Yin J, Cao H, Zhou Z, Zhang J, Fu J, Warner JH, Wang C, Jia X, Greaves GN, Cheetham AK. Non-Blinking Luminescence from Charged Single Graphene Quantum Dots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2304074. [PMID: 37395476 DOI: 10.1002/adma.202304074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/24/2023] [Accepted: 06/26/2023] [Indexed: 07/04/2023]
Abstract
Photoluminescence blinking behavior from single quantum dots under steady illumination is an important but controversial topic. Its occurrence has impeded the use of single quantum dots in bioimaging. Different mechanisms have been proposed to account for it, although controversial, the most important of which is the non-radiative Auger recombination mechanism whereby photocharging of quantum dots can lead to the blinking phenomenon. Here, the singly charged trion, which maintains photon emission, including radiative recombination and non-radiative Auger recombination, leads to fluorescence non-blinking which is observed in photocharged single graphene quantum dots (GQDs). This phenomenon can be explained in terms of different energy levels in the GQDs, caused by various oxygen-containing functional groups in the single GQDs. The suppressed blinking is due to the filling of trap sites owing to a Coulomb blockade. These results provide a profound understanding of the special optical properties of GQDs, affording a reference for further in-depth research.
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Affiliation(s)
- Wei Fu
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jiefu Yin
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Huaqiang Cao
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhongfu Zhou
- State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072, China
| | - Junying Zhang
- School of Physics, Beihang University, Beijing, 100191, China
| | - Jingjing Fu
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Jamie H Warner
- Department of Mechanical Engineering, The University of Texas at Austin, 204 East Dean Keeton Street, Austin, TX, 78712, USA
| | - Cheng Wang
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xiaofang Jia
- School of Physics, Beihang University, Beijing, 100191, China
| | - G Neville Greaves
- Department of Physics, Aberystwyth University, Aberystwyth, SY23 3BZ, UK
- Department of Materials Science and Metallurgy, The University of Cambridge, Cambridge, CB3 0FS, UK
| | - Anthony K Cheetham
- Department of Materials Science and Metallurgy, The University of Cambridge, Cambridge, CB3 0FS, UK
- Materials Research Laboratory, University of California, Santa Barbara, CA, 93106, USA
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5
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Chandrasiri HB, Jing H, Perera T, Hu YS, Snee PT. Fluorescence Intermittency of Quantum Dot-Organic Dye Conjugates: Implications for Alternative Energy and Biological Imaging. J Phys Chem Lett 2023; 14:3621-3626. [PMID: 37023397 DOI: 10.1021/acs.jpclett.3c00076] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Quantum dot (QD)-organic dye couple chromophores are topical due to their applications in biology, catalysis, and energy. The maximization of energy transfer efficiency can be guided by the underlying Förster or Dexter mechanisms; however, the impact of fluorescence intermittency must also be considered. Here we demonstrate that the average ⟨ton⟩ and ⟨toff⟩ times of dye acceptors in coupled QD-dye chromophores are substantially affected by the donors' blinking behavior. With regard to biological imaging, this effect beneficially minimizes the photobleaching of the acceptor dye. The implications for alternative energy are less encouraging as the acceptors' capacity to store energy, using ⟨ton⟩/⟨toff⟩ as a metric, was reduced by as much as ∼95%. These detrimental effects can be mitigated by suppressing QD blinking via surface treatment. This study also demonstrates several instances of the nonconformity of QD blinking dynamics to a power law distribution, as a robust examination of the off times reveals log-normal behavior that is consistent with the Albery model.
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Affiliation(s)
- Hashini B Chandrasiri
- Department of Chemistry, College of Liberal Arts & Sciences, University of Illinois, Chicago, Chicago, Illinois 60607-7061, United States
| | - Haoran Jing
- Department of Chemistry, College of Liberal Arts & Sciences, University of Illinois, Chicago, Chicago, Illinois 60607-7061, United States
| | - Thilini Perera
- Department of Chemistry, College of Liberal Arts & Sciences, University of Illinois, Chicago, Chicago, Illinois 60607-7061, United States
| | - Ying S Hu
- Department of Chemistry, College of Liberal Arts & Sciences, University of Illinois, Chicago, Chicago, Illinois 60607-7061, United States
| | - Preston T Snee
- Department of Chemistry, College of Liberal Arts & Sciences, University of Illinois, Chicago, Chicago, Illinois 60607-7061, United States
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6
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Ghosh S, Ross U, Chizhik AM, Kuo Y, Jeong BG, Bae WK, Park K, Li J, Oron D, Weiss S, Enderlein J, Chizhik AI. Excitation Intensity-Dependent Quantum Yield of Semiconductor Nanocrystals. J Phys Chem Lett 2023; 14:2702-2707. [PMID: 36892266 PMCID: PMC10026174 DOI: 10.1021/acs.jpclett.3c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
One of the key phenomena that determine the fluorescence of nanocrystals is the nonradiative Auger-Meitner recombination of excitons. This nonradiative rate affects the nanocrystals' fluorescence intensity, excited state lifetime, and quantum yield. Whereas most of the above properties can be directly measured, the quantum yield is the most difficult to assess. Here we place semiconductor nanocrystals inside a tunable plasmonic nanocavity with subwavelength spacing and modulate their radiative de-excitation rate by changing the cavity size. This allows us to determine absolute values of their fluorescence quantum yield under specific excitation conditions. Moreover, as expected considering the enhanced Auger-Meitner rate for higher multiple excited states, increasing the excitation rate reduces the quantum yield of the nanocrystals.
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Affiliation(s)
- Subhabrata Ghosh
- Third Institute
of Physics − Biophysics, Georg August
University Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
| | - Ulrich Ross
- IV. Physical
Institute - Solids and Nanostructures, Georg
August University Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
| | - Anna M. Chizhik
- Third Institute
of Physics − Biophysics, Georg August
University Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
| | - Yung Kuo
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los Angeles, California 90095, United States
| | - Byeong Guk Jeong
- School of
Chemical and Biomolecular Engineering, Pusan
National University, Busan 46241, Republic
of Korea
| | - Wan Ki Bae
- SKKU Advanced
Institute of Nanotechnology (SAINT), Sungkyunkwan
University, Suwon 16419, Republic
of Korea
| | - Kyoungwon Park
- Korea Electronics
Technology Institute, Seongnam-si, Gyeonggi-do 13509, Republic of Korea
| | - Jack Li
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los Angeles, California 90095, United States
| | - Dan Oron
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shimon Weiss
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California
Los Angeles, Los Angeles, California 90095, United States
- Department
of Physiology, University of California
Los Angeles, Los Angeles, California 90095, United States
- Department
of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Jörg Enderlein
- Third Institute
of Physics − Biophysics, Georg August
University Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
- Cluster
of Excellence “Multiscale Bioimaging: from Molecular Machines
to Networks of Excitable Cells,” (MBExC), Georg August University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Alexey I. Chizhik
- Third Institute
of Physics − Biophysics, Georg August
University Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
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7
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Lu S, Morrow DJ, Li Z, Guo C, Yu X, Wang H, Schultz JD, O'Connor JP, Jin N, Fang F, Wang W, Cui R, Chen O, Su C, Wasielewski MR, Ma X, Li X. Encapsulating Semiconductor Quantum Dots in Supramolecular Cages Enables Ultrafast Guest-Host Electron and Vibrational Energy Transfer. J Am Chem Soc 2023; 145:5191-5202. [PMID: 36745391 DOI: 10.1021/jacs.2c11981] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the field of supramolecular chemistry, host-guest systems have been extensively explored to encapsulate a wide range of substrates, owing to emerging functionalities in nanoconfined space that cannot be achieved in dilute solutions. However, host-guest chemistry is still limited to encapsulation of small guests. Herein, we construct a water-soluble metallo-supramolecular hexagonal prism with a large hydrophobic cavity by anchoring multiple polyethylene glycol chains onto the building blocks. Then, assembled prisms are able to encapsulate quantum dots (QDs) with diameters of less than 5.0 nm. Furthermore, we find that the supramolecular cage around each QD strongly modifies the photophysics of the QD by universally increasing the rates of QD relaxation processes via ultrafast electron and vibrational energy transfer. Taken together, these efforts expand the scope of substrates in host-guest systems and provide a new approach to tune the optical properties of QDs.
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Affiliation(s)
- Shuai Lu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China.,Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Darien J Morrow
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Zhikai Li
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Chenxing Guo
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Xiujun Yu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Heng Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Jonathan D Schultz
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - James P O'Connor
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - Na Jin
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Fang Fang
- Instrumental Analysis Center, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Wu Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Ran Cui
- Key Laboratory of Analytical Chemistry for Biology and Medicine, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Ou Chen
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Chenliang Su
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - Xuedan Ma
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Center for Molecular Quantum Transduction, Northwestern-Argonne Institute of Science and Engineering, 2205 Tech Drive, Evanston, Illinois 60208, United States.,Consortium for Advanced Science and Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Xiaopeng Li
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China.,Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University, Shenzhen, Guangdong 518055, China
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8
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Shulenberger KE, Jilek MR, Sherman SJ, Hohman BT, Dukovic G. Electronic Structure and Excited State Dynamics of Cadmium Chalcogenide Nanorods. Chem Rev 2023; 123:3852-3903. [PMID: 36881852 DOI: 10.1021/acs.chemrev.2c00676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The cylindrical quasi-one-dimensional shape of colloidal semiconductor nanorods (NRs) gives them unique electronic structure and optical properties. In addition to the band gap tunability common to nanocrystals, NRs have polarized light absorption and emission and high molar absorptivities. NR-shaped heterostructures feature control of electron and hole locations as well as light emission energy and efficiency. We comprehensively review the electronic structure and optical properties of Cd-chalcogenide NRs and NR heterostructures (e.g., CdSe/CdS dot-in-rods, CdSe/ZnS rod-in-rods), which have been widely investigated over the last two decades due in part to promising optoelectronic applications. We start by describing methods for synthesizing these colloidal NRs. We then detail the electronic structure of single-component and heterostructure NRs and follow with a discussion of light absorption and emission in these materials. Next, we describe the excited state dynamics of these NRs, including carrier cooling, carrier and exciton migration, radiative and nonradiative recombination, multiexciton generation and dynamics, and processes that involve trapped carriers. Finally, we describe charge transfer from photoexcited NRs and connect the dynamics of these processes with light-driven chemistry. We end with an outlook that highlights some of the outstanding questions about the excited state properties of Cd-chalcogenide NRs.
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Affiliation(s)
| | - Madison R Jilek
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Skylar J Sherman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Benjamin T Hohman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Gordana Dukovic
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States.,Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
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9
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Muñoz RN, Frazer L, Yuan G, Mulvaney P, Pollock FA, Modi K. Memory in quantum dot blinking. Phys Rev E 2022; 106:014127. [PMID: 35974537 DOI: 10.1103/physreve.106.014127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
The photoluminescence intermittency (blinking) of quantum dots is interesting because it is an easily measured quantum process whose transition statistics cannot be explained by Fermi's golden rule. Commonly, the transition statistics are power-law distributed, implying that quantum dots possess at least trivial memories. By investigating the temporal correlations in the blinking data, we demonstrate with high statistical confidence that there is nontrivial memory between the on and off brightness duration data of blinking quantum dots. We define nontrivial memory to be statistical complexity greater than one. We show that this memory cannot be discovered using the transition distribution. We show by simulation that this memory does not arise from standard data manipulations. Finally, we conclude that at least three physical mechanisms can explain the measured nontrivial memory: (1) storage of state information in the chemical structure of a quantum dot; (2) the existence of more than two intensity levels in a quantum dot; and (3) the overlap in the intensity distributions of the quantum dot states, which arises from fundamental photon statistics.
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Affiliation(s)
- Roberto N Muñoz
- ARC Centre of Excellence in Exciton Science and School of Physics & Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Laszlo Frazer
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, Clayton, VIC 3800, Australia
| | - Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, Clayton, VIC 3800, Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Felix A Pollock
- School of Physics & Astronomy, Monash University, Clayton, Victoria 3800, Australia
| | - Kavan Modi
- ARC Centre of Excellence in Exciton Science and School of Physics & Astronomy, Monash University, Clayton, Victoria 3800, Australia
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10
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Ghosh S, Hollingsworth JA, Gallea JI, Majumder S, Enderlein J, Chizhik AI. Excited state lifetime modulation in semiconductor nanocrystals for super-resolution imaging. NANOTECHNOLOGY 2022; 33:365201. [PMID: 35617874 DOI: 10.1088/1361-6528/ac73a2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
We report on proof of principle measurements of a concept for a super-resolution imaging method that is based on excitation field density-dependent lifetime modulation of semiconductor nanocrystals. The prerequisite of the technique is access to semiconductor nanocrystals with emission lifetimes that depend on the excitation intensity. Experimentally, the method requires a confocal microscope with fluorescence-lifetime measurement capability that makes it easily accessible to a broad optical imaging community. We demonstrate with single particle imaging that the method allows one to achieve a spatial resolution of the order of several tens of nanometers at moderate fluorescence excitation intensity.
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Affiliation(s)
- Subhabrata Ghosh
- Third Institute of Physics-Biophysics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany
| | - Jennifer A Hollingsworth
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Jose Ignacio Gallea
- Third Institute of Physics-Biophysics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany
| | - Somak Majumder
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Jörg Enderlein
- Third Institute of Physics-Biophysics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), Georg August University, D-37077 Göttingen, Germany
| | - Alexey I Chizhik
- Third Institute of Physics-Biophysics, University of Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany
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11
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Zhu C, Marczak M, Feld L, Boehme SC, Bernasconi C, Moskalenko A, Cherniukh I, Dirin D, Bodnarchuk MI, Kovalenko MV, Rainò G. Room-Temperature, Highly Pure Single-Photon Sources from All-Inorganic Lead Halide Perovskite Quantum Dots. NANO LETTERS 2022; 22:3751-3760. [PMID: 35467890 PMCID: PMC9101069 DOI: 10.1021/acs.nanolett.2c00756] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/28/2022] [Indexed: 05/08/2023]
Abstract
Attaining pure single-photon emission is key for many quantum technologies, from optical quantum computing to quantum key distribution and quantum imaging. The past 20 years have seen the development of several solid-state quantum emitters, but most of them require highly sophisticated techniques (e.g., ultrahigh vacuum growth methods and cryostats for low-temperature operation). The system complexity may be significantly reduced by employing quantum emitters capable of working at room temperature. Here, we present a systematic study across ∼170 photostable single CsPbX3 (X: Br and I) colloidal quantum dots (QDs) of different sizes and compositions, unveiling that increasing quantum confinement is an effective strategy for maximizing single-photon purity due to the suppressed biexciton quantum yield. Leveraging the latter, we achieve 98% single-photon purity (g(2)(0) as low as 2%) from a cavity-free, nonresonantly excited single 6.6 nm CsPbI3 QDs, showcasing the great potential of CsPbX3 QDs as room-temperature highly pure single-photon sources for quantum technologies.
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Affiliation(s)
- Chenglian Zhu
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Malwina Marczak
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Leon Feld
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Simon C. Boehme
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Caterina Bernasconi
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Anastasiia Moskalenko
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Ihor Cherniukh
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Dmitry Dirin
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Maryna I. Bodnarchuk
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Maksym V. Kovalenko
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Gabriele Rainò
- Institute
of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
- Laboratory
for Thin Films and Photovoltaics, Empa −
Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland
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12
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Xie M, Tao CL, Zhang Z, Liu H, Wan S, Nie Y, Yang W, Wang X, Wu XJ, Tian Y. Nonblinking Colloidal Quantum Dots via Efficient Multiexciton Emission. J Phys Chem Lett 2022; 13:2371-2378. [PMID: 35254074 DOI: 10.1021/acs.jpclett.2c00378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonblinking colloidal quantum dots (QDs) are significant to their applications as single-photon sources or light-emitting materials. Herein, a simple heat-up method was developed to synthesize high-qualityWZ-CdSe/CdS core-shell colloidal QDs, which achieved a near-unity photoluminescence quantum yield (PLQY). It was found that the blinking behavior of such QDs was completely suppressed at high excitation intensities, and ultra-stable PL emission was observed. For this reason, a systematic investigation was conducted, revealing that the complete blinking suppression was attributed mainly to the efficient multiexciton emission at high excitation intensities. Such high-quality QDs with nonblinking behaviors and nearly ideal PL properties at high excitation intensities have massive potential applications in various robust conditions, including QD display screens, single-particle tracks, and single-photon sources.
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Affiliation(s)
- Mingcai Xie
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chen-Lei Tao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhen Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
| | - Hanyu Liu
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Sushu Wan
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yan Nie
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Weiqing Yang
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
| | - Xue-Jun Wu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yuxi Tian
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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13
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Effects of local matrix environment on the spectroscopic properties of ensemble to single-particle level carbon dots. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2021.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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14
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Hu Z, Shu Y, Qin H, Hu X, Peng X. Water Effects on Colloidal Semiconductor Nanocrystals: Correlation of Photophysics and Photochemistry. J Am Chem Soc 2021; 143:18721-18732. [PMID: 34705444 DOI: 10.1021/jacs.1c09363] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
With high-quality CdSe/CdS core/shell nanocrystals as the main model system and under a controlled atmosphere, responses of photoexcited semiconductor nanocrystals to two active species (water and/or oxygen) in an ambient environment are studied systematically. Under photoexcitation, although high-quality semiconductor nanocrystals in either thin solid films or various solutions have a near-unity photoluminescence quantum yield, there is still a small probability (∼10-5 per photon absorbed) to be photoreduced by the water molecules efficiently accumulated in the highly hydrophilic nanocrystal-ligands interface. The resulting negatively charged nanocrystals are the starting point of most photophysical variations, and the hydroxyl radical─key photo-oxidation product of water─plays the main role for initiating various photochemical processes. Depending on the supplementation of water to the interface, accessibility to oxygen, photoirradiation power, type of matrices, type of measurement schemes, and solubility of nanocrystals in the solution, various photophysical/photochemical phenomena─either reported or not reported in the literature─are reproducibly observed. Results confirm that photophysical properties and photochemical reactions can be well-correlated, offering a unified and unique basis for fundamental studies and the design of processing techniques in industry.
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Affiliation(s)
- Zhuang Hu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Yufei Shu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Haiyan Qin
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xiaofei Hu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xiaogang Peng
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou 310027, China
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15
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Baronnier J, Mahler B, Boisron O, Dujardin C, Kulzer F, Houel J. Optical properties of fully inorganic core/gradient-shell CdSe/CdZnS nanocrystals at the ensemble and single-nanocrystal levels. Phys Chem Chem Phys 2021; 23:22750-22759. [PMID: 34608907 DOI: 10.1039/d1cp02927d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis and optical characterization of fully inorganic gradient-shell CdSe/CdZnS nanocrystals (NCs) with high luminescence quantum yield (QY, 50%), which were obtained by replacing native oleic-acid (OA) ligands with halide ions (Cl-and Br-). Absorption, photoluminescence excitation (PLE) and photoluminescence (PL) spectra in solution were unaffected by the ligand-exchange procedure. The halide-capped NCs were stable in solution for several weeks without modification of their PL spectra; once deposited as unprotected thin films and exposed to air, however, they did show signs of aging which we attribute to increasing heterogeneity of (effective) NC size. Time-resolved PL measurements point to the existence of four distinct emissive states, which we attribute to neutral, singly-charged and multi-excitonic entities. We found that the relative contribution of these four components to the overall PL decay is modified by the OA-to-halide ligand exchange, while the excited-state lifetimes themselves, surprisingly, remain largely unaffected. The high PL quantum yield of the halide-capped NCs allowed observation of single particle blinking and photon-antibunching; one surprising result was that aging processes that occurs during the first few days after deposition on glass seemed to offer a certain increased protection against photobleaching. These results suggest that halide-capped CdSe/CdZnS NCs are promising candidates for incorporation into opto-electronic devices, based on, for example, hybrid perovskite matrices, which require eliminating the steric hindrance and electronic barrier of bulky organic ligands to ensure efficient coupling.
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Affiliation(s)
- Justine Baronnier
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
| | - Benoit Mahler
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
| | - Olivier Boisron
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
| | - Christophe Dujardin
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
| | - Florian Kulzer
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
| | - Julien Houel
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR5306, Institut Lumière Matière, 69622 Villeurbanne, France.
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16
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Zhou Y, Califano M. Decoupling Radiative and Auger Processes in Semiconductor Nanocrystals by Shape Engineering. J Phys Chem Lett 2021; 12:9155-9161. [PMID: 34524827 DOI: 10.1021/acs.jpclett.1c02300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
One of the most challenging aspects of semiconductor nanotechnology is the presence of extremely efficient nonradiative decay pathways (known as Auger processes) that hinder any attempt at creating population inversion and obtaining gain in nanocrystals. What is even more frustrating is that, in most cases, the strategies adopted to slow down Auger in these nanostructures also lead to a comparable increase in the radiative recombination times, so that there is no overall improvement from the point of view of their applicability as emissive media. Here we present a comprehensive theoretical characterization of CdTe tetrapods and show that in these versatile nanostructures it is possible to achieve a complete decoupling between radiative and Auger processes, where the latter can be strongly suppressed compared to spherical structures, by careful shape engineering, without affecting the efficiency of radiative recombination.
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Affiliation(s)
- Yang Zhou
- Pollard Institute, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Marco Califano
- Pollard Institute, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
- Bragg Centre for Materials Research University of Leeds, Leeds LS2 9JT, United Kingdom
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17
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Lubin G, Tenne R, Ulku AC, Antolovic IM, Burri S, Karg S, Yallapragada VJ, Bruschini C, Charbon E, Oron D. Heralded Spectroscopy Reveals Exciton-Exciton Correlations in Single Colloidal Quantum Dots. NANO LETTERS 2021; 21:6756-6763. [PMID: 34398604 PMCID: PMC8397400 DOI: 10.1021/acs.nanolett.1c01291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Multiply excited states in semiconductor quantum dots feature intriguing physics and play a crucial role in nanocrystal-based technologies. While photoluminescence provides a natural probe to investigate these states, room-temperature single-particle spectroscopy of their emission has proved elusive due to the temporal and spectral overlap with emission from the singly excited and charged states. Here, we introduce biexciton heralded spectroscopy enabled by a single-photon avalanche diode array based spectrometer. This allows us to directly observe biexciton-exciton emission cascades and measure the biexciton binding energy of single quantum dots at room temperature, even though it is well below the scale of thermal broadening and spectral diffusion. Furthermore, we uncover correlations hitherto masked in ensembles of the biexciton binding energy with both charge-carrier confinement and fluctuations of the local electrostatic potential. Heralded spectroscopy has the potential of greatly extending our understanding of charge-carrier dynamics in multielectron systems and of parallelization of quantum optics protocols.
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Affiliation(s)
- Gur Lubin
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Ron Tenne
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
- Department
of Physics and Center for Applied Photonics, University of Konstanz, Konstanz D-78457, Germany
| | - Arin Can Ulku
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Ivan Michel Antolovic
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Samuel Burri
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Sean Karg
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
| | | | - Claudio Bruschini
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Edoardo Charbon
- School
of Engineering, École Polytechnique
Fédérale de Lausanne (EPFL), Neuchâtel 2002, Switzerland
| | - Dan Oron
- Deptartment
of Physics of Complex Systems, Weizmann
Institute of Science, Rehovot 7610001, Israel
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18
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Hou X, Qin H, Peng X. Enhancing Dielectric Screening for Auger Suppression in CdSe/CdS Quantum Dots by Epitaxial Growth of ZnS Shell. NANO LETTERS 2021; 21:3871-3878. [PMID: 33938759 DOI: 10.1021/acs.nanolett.1c00396] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Auger recombination is the main nonradiative process in multicarrier states of high-quality quantum dots (QDs). For the most-studied CdSe/CdS core/shell QDs, we effectively reduce the biexciton Auger rate by enhancing dielectric screening of band-edge carriers via epitaxial growth of additional ZnS shells. Super volume scaling of negative-trion Auger lifetime for CdSe/CdS core/shell QDs is achieved with the outermost ZnS shells. The volume of CdSe/CdS/ZnS QDs can be less than half that of CdSe/CdS QDs with the same negative-trion Auger lifetime. Auger suppression by the ZnS shells is more pronounced for QDs with wave functions of band-edge carriers spreading close to the inorganic-organic interface, such as CdSe/CdS QDs with small cores. A maximum drop of biexciton Auger rate of ∼50% and a maximum enhancement of biexciton emission quantum yield of 75% are achieved. Auger engineering by dielectric screening opens up new opportunities to improve the emission properties of multicarrier states in QDs.
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Affiliation(s)
- Xiaoqi Hou
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
- Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province, Hangzhou Innovation Institute, Beihang University, Hangzhou, 310051, P.R. China
| | - Haiyan Qin
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Xiaogang Peng
- Key Laboratory of Excited-State Materials of Zhejiang Province, and Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
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19
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Liu Q, Wackenhut F, Wang L, Hauler O, Roldao JC, Adam PM, Brecht M, Gierschner J, Meixner AJ. Direct Observation of Structural Heterogeneity and Tautomerization of Single Hypericin Molecules. J Phys Chem Lett 2021; 12:1025-1031. [PMID: 33470816 DOI: 10.1021/acs.jpclett.0c03459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tautomerization is a fundamental chemical reaction which involves the relocation of a proton in the reactants. Studying the optical properties of tautomeric species is challenging because of ensemble averaging. Many molecules, such as porphines, porphycenes, or phenanthroperylene quinones, exhibit a reorientation of the transition dipole moment (TDM) during tautomerization, which can be directly observed in single-molecule experiments. Here, we study single hypericin molecules, which is a prominent phenanthroperylene quinone showing antiviral, antidepressive, and photodynamical properties. Observing abrupt flipping of the image pattern combined with time-dependent density functional theory calculations allows drawing conclusions about the coexistence of four tautomers and their conversion path. This approach allows the unambiguous assignment of a TDM orientation to a specific tautomer and enables the determination of the chemical structure in situ. Our approach can be applied to other molecules showing TDM reorientation during tautomerization, helping to gain a deeper understanding of this important process.
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Affiliation(s)
- Quan Liu
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Laboratoire Lumière, Nanomatériaux & Nanotechnologies - L2n and CNRS ERL 7004, Universitéde Technologie de Troyes, 10000 Troyes, France
| | - Frank Wackenhut
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Liangxuan Wang
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Otto Hauler
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Reutlingen Research Institute, Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstraße 150, 72762 Reutlingen, Germany
| | - Juan Carlos Roldao
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Pierre-Michel Adam
- Laboratoire Lumière, Nanomatériaux & Nanotechnologies - L2n and CNRS ERL 7004, Universitéde Technologie de Troyes, 10000 Troyes, France
| | - Marc Brecht
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Reutlingen Research Institute, Process Analysis and Technology (PA&T), Reutlingen University, Alteburgstraße 150, 72762 Reutlingen, Germany
| | - Johannes Gierschner
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, C/Faraday 9, 28049 Madrid, Spain
| | - Alfred J Meixner
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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20
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Affiliation(s)
- Christopher Melnychuk
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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21
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Hu Z, Liu S, Qin H, Zhou J, Peng X. Oxygen Stabilizes Photoluminescence of CdSe/CdS Core/Shell Quantum Dots via Deionization. J Am Chem Soc 2020; 142:4254-4264. [DOI: 10.1021/jacs.9b11978] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Zhuang Hu
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Shaojie Liu
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Jianhai Zhou
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, Hangzhou 310027, People’s Republic of China
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22
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Salakhutdinov V, Sondermann M, Carbone L, Giacobino E, Bramati A, Leuchs G. Single Photons Emitted by Nanocrystals Optically Trapped in a Deep Parabolic Mirror. PHYSICAL REVIEW LETTERS 2020; 124:013607. [PMID: 31976723 DOI: 10.1103/physrevlett.124.013607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Indexed: 06/10/2023]
Abstract
We investigate the emission of single photons from CdSe/CdS dots-in-rod which are optically trapped in the focus of a deep parabolic mirror. Thanks to this mirror, we are able to image almost the full 4π emission pattern of nanometer-sized elementary dipoles and verify the alignment of the rods within the optical trap. From the motional dynamics of the emitters in the trap, we infer that the single-photon emission occurs from clusters comprising several emitters. We demonstrate the optical trapping of rod-shaped quantum emitters in a configuration suitable for efficiently coupling an ensemble of linear dipoles with the electromagnetic field in free space.
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Affiliation(s)
- Vsevolod Salakhutdinov
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Physics, Staudtstrasse 7/B2, 91058 Erlangen, Germany
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
| | - Markus Sondermann
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Physics, Staudtstrasse 7/B2, 91058 Erlangen, Germany
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
| | - Luigi Carbone
- CNR NANOTEC-Institute of Nanotechnology, c/o Campus Ecotekne, University of Salento, via Monteroni, Lecce 73100, Italy
| | - Elisabeth Giacobino
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL, Research University, Collège de France, 4 place Jussieu, case 74, F-75005 Paris, France
| | - Alberto Bramati
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL, Research University, Collège de France, 4 place Jussieu, case 74, F-75005 Paris, France
| | - Gerd Leuchs
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Physics, Staudtstrasse 7/B2, 91058 Erlangen, Germany
- Max Planck Institute for the Science of Light, Staudtstrasse 2, 91058 Erlangen, Germany
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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23
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Ahmed T, Seth S, Samanta A. Mechanistic Investigation of the Defect Activity Contributing to the Photoluminescence Blinking of CsPbBr 3 Perovskite Nanocrystals. ACS NANO 2019; 13:13537-13544. [PMID: 31714741 DOI: 10.1021/acsnano.9b07471] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Exploration of the full potential of the perovskite nanocrystals (NCs) for different applications requires a thorough understanding of the pathways of recombination of the photogenerated charge carriers and associated dynamics. In this work, we have tracked the recombination routes of the charge carriers by probing photoluminescence (PL) intermittency of the immobilized and freely diffusing single CsPbBr3 NCs employing a time-tagged-time-resolved method. The immobilized single CsPbBr3 NCs show a complex PL time-trace, a careful analysis of which reveals that nonradiative band-edge recombination through trap states, trion recombination, and trapping of the hot carriers contribute to the blinking behavior of any given NC. A drastically suppressed PL blinking observed for the NCs treated with a tetrafluoroborate salt indicates elimination of most of the undesired recombination processes. A fluorescence correlation spectroscopy (FCS) study on the freely diffusing single NCs shows that enhanced PL and suppressed blinking of the treated particles are the outcome of an increase in per-particle brightness, not due to any increase in the number of particles undergoing "off"-"on" transition in the observation volume. The mechanistic details obtained from this study on the origin of blinking in CsPbBr3 NCs provide deep insight into the radiative and nonradiative charge carrier recombination pathways in these important materials, and this knowledge is expected to be useful for better design and development of bright photoluminescent samples of this class for optoelectronic applications.
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Affiliation(s)
- Tasnim Ahmed
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
| | - Sudipta Seth
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
| | - Anunay Samanta
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
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24
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Affiliation(s)
- Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University Uji, Kyoto 611-0011, Japan
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25
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Tang X, Yang J, Li S, Liu Z, Hu Z, Hao J, Du J, Leng Y, Qin H, Lin X, Lin Y, Tian Y, Zhou M, Xiong Q. Single Halide Perovskite/Semiconductor Core/Shell Quantum Dots with Ultrastability and Nonblinking Properties. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900412. [PMID: 31559125 PMCID: PMC6755528 DOI: 10.1002/advs.201900412] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/27/2019] [Indexed: 05/05/2023]
Abstract
The further practical applications of halide perovskite quantum dots (QDs) are blocked by problems of instability and nonradiative Auger recombination manifested as photoluminescence blinking. Here, single core/shell structured perovskite semiconductor QDs are successfully fabricated by capping CsPbBr3 QD core with CdS shell. It is demonstrated that CsPbBr3/CdS core/shell QDs exhibit ultrahigh chemical stability and nonblinking photoluminescence with high quantum yield due to the reduced electronic traps within the core/shell structure. Efficiency of amplified spontaneous emission exhibits obvious enhancement compared to that of pure CsPbBr3 QDs, originating from the mitigated competition between stimulated emission and suppressed nonradiative biexciton Auger recombination. Furthermore, low-threshold whispering-gallery-mode lasing with a high-quality factor is achieved by incorporating CsPbBr3/CdS QDs into microtubule resonators. Density functional theory (DFT)-based first-principles calculations are also performed to reveal the atomic interface structure, which supports the existence of CsPbBr3/CdS structure. An interesting feature of spatially separated charge density at CsPbBr3/CdS interface is found, which may greatly contribute to the suppressed Auger recombination. The results provide a practical approach to improve the stability and suppress the blinking of halide perovskite QDs, which may pave the way for future applications for various optoelectronic devices.
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Affiliation(s)
- Xiaosheng Tang
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Jie Yang
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Shiqi Li
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Zhengzheng Liu
- State Key Laboratory of High Field Laser PhysicsShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai201800China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049China
| | - Zhiping Hu
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Jiongyue Hao
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Juan Du
- State Key Laboratory of High Field Laser PhysicsShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai201800China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049China
| | - Yuxin Leng
- State Key Laboratory of High Field Laser PhysicsShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai201800China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049China
| | - Haiyan Qin
- Center for Chemistry of Nover and High‐Performance Materialsand Department of ChemistryZhejiang UniversityHangzhou310027P. R. China
| | - Xing Lin
- Center for Chemistry of Nover and High‐Performance Materialsand Department of ChemistryZhejiang UniversityHangzhou310027P. R. China
| | - Yue Lin
- Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefei230026China
| | - Yuxi Tian
- School of Chemistry and Chemical EngineeringKey Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory of Vehicle Emissions ControlNanjing UniversityNanjing210023China
| | - Miao Zhou
- Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education)College of Optoelectronic EngineeringChongqing UniversityChongqing400044China
| | - Qihua Xiong
- Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
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26
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Nakahara S, Ohara K, Tahara H, Yumoto G, Kawawaki T, Saruyama M, Sato R, Teranishi T, Kanemitsu Y. Ionization and Neutralization Dynamics of CsPbBr 3 Perovskite Nanocrystals Revealed by Double-Pump Transient Absorption Spectroscopy. J Phys Chem Lett 2019; 10:4731-4736. [PMID: 31362511 DOI: 10.1021/acs.jpclett.9b01554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ionization of nanocrystals (NCs) causes both photoluminescence intermittency and a reduction in luminescence quantum efficiency and thus plays a critical role in the optoelectronic performance of NC-based devices. Here, we study the ionization and neutralization processes of CsPbBr3 perovskite NCs under strong photoexcitation by means of double-pump transient absorption spectroscopy. A strong initial pulse is used to generate ionized NCs, and their optical responses are investigated by varying the excitation intensity and delay time of the second pump pulse. We find that charging can occur either via nonradiative Auger recombination of biexcitons or via any possible recombination of trions. The presence of the extra charge inside of an ionized perovskite NC significantly reduces its absorption cross section. The experiments reveal that ionized NCs exhibit two types of neutralization processes with time constants on the order of nanoseconds and microseconds. These results are useful for the optimal design of NC-based photonic devices.
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Affiliation(s)
- Satoshi Nakahara
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Keiichi Ohara
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Hirokazu Tahara
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Go Yumoto
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Tokuhisa Kawawaki
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Masaki Saruyama
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Ryota Sato
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Toshiharu Teranishi
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
| | - Yoshihiko Kanemitsu
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 611-0011 , Japan
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27
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Au TH, Buil S, Quélin X, Hermier JP, Lai ND. Photostability and long-term preservation of a colloidal semiconductor-based single photon emitter in polymeric photonic structures. NANOSCALE ADVANCES 2019; 1:3225-3231. [PMID: 36133591 PMCID: PMC9417270 DOI: 10.1039/c9na00411d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 05/27/2023]
Abstract
Colloidal semiconductor quantum dots (QDs) are promising candidates for various applications in electronics and quantum optics. However, they are sensitive and vulnerable to the chemical environment due to their highly dynamic surface with a large portion of exposed atoms. Hence, oxidation and detrimental defects on the nanocrystal (NC) interface dramatically deteriorate their optical as well as electrical properties. In this study, a simple strategy is proposed not only to obtain good preservation of colloidal semiconductor QDs by using a protective polymer matrix but also to provide excellent accessibility to micro-fabrication by optical lithography. A high-quality QD-polymer nanocomposite with mono-dispersion of the NCs is synthesized by incorporating the colloidal CdSe/CdS NCs into an SU-8 photoresist. Our approach shows that the oxidation of the core/shell QDs embedded in the SU-8 resist is completely avoidable. The deterministic insertion of multiple QDs or a single QD into photonic structures is demonstrated. Single photon generation is obtained and well-preserved in the nanocomposite and the polymeric structures.
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Affiliation(s)
- Thi Huong Au
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, Centrale Supélec, CNRS, Université Paris-Saclay 61 Avenue du Président Wilson 94235 Cachan Cedex France
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Stéphanie Buil
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Xavier Quélin
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Jean-Pierre Hermier
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Ngoc Diep Lai
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, Centrale Supélec, CNRS, Université Paris-Saclay 61 Avenue du Président Wilson 94235 Cachan Cedex France
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28
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Rabouw F, Antolinez FV, Brechbühler R, Norris DJ. Microsecond Blinking Events in the Fluorescence of Colloidal Quantum Dots Revealed by Correlation Analysis on Preselected Photons. J Phys Chem Lett 2019; 10:3732-3738. [PMID: 31204809 PMCID: PMC6614792 DOI: 10.1021/acs.jpclett.9b01348] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 06/15/2019] [Indexed: 05/24/2023]
Abstract
Nearly all colloidal quantum dots, when measured at the single-emitter level, exhibit fluorescence "blinking". However, despite over 20 years of research on this phenomenon, its microscopic origins are still debated. One reason is a gap in available experimental information, specifically for dynamics at short (submillisecond) time scales. Here, we use photon-correlation analysis to investigate microsecond blinking events in individual quantum dots. While the strongly distributed kinetics of blinking normally makes such events difficult to study, we show that they can be analyzed by excluding photons emitted during long bright or dark periods. Moreover, we find that submillisecond blinking events are more common than one might expect from extrapolating the power-law blinking statistics observed on longer (millisecond) time scales. This result provides important experimental data for developing a microscopic understanding of blinking. More generally, our method offers a simple strategy for analyzing microsecond switching dynamics in the fluorescence of quantum emitters.
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29
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Emergence of multiple fluorophores in individual cesium lead bromide nanocrystals. Nat Commun 2019; 10:2930. [PMID: 31266944 PMCID: PMC6606627 DOI: 10.1038/s41467-019-10870-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 06/06/2019] [Indexed: 12/03/2022] Open
Abstract
Cesium-based perovskite nanocrystals (PNCs) possess alluring optical and electronic properties via compositional and structural versatility, tunable bandgap, high photoluminescence quantum yield and facile chemical synthesis. Despite the recent progress, origins of the photoluminescence emission in various types of PNCs remains unclear. Here, we study the photon emission from individual three-dimensional and zero-dimensional cesium lead bromide PNCs. Using photon antibunching and lifetime measurements, we demonstrate that emission statistics of both type of PNCs are akin to individual molecular fluorophores, rather than traditional semiconductor quantum dots. Aided by density functional modelling, we provide compelling evidence that green emission in zero-dimensional PNCs stems from exciton recombination at bromide vacancy centres within lead-halide octahedra, unrelated to external confinement. These findings provide key information about the nature of defect formation and the origin of emission in cesium lead halide perovskite materials, which foster their utilization in the emerging optoelectronic applications. Inorganic perovskite nanocrystals attract lots of research attention but the origin of their photoluminescence remains debatable. Here Zhang et al. show that behavior of both CsPbBr3 and Cs4PbBr6 nanocrystals is like individual molecular fluorophores and independent of the structural dimensionalities.
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30
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Simi NJ, Vinayakan R, Ison VV. Photoinduced electron transfer in novel CdSe-Cu 2Se type II core-shell quantum dots. RSC Adv 2019; 9:15092-15098. [PMID: 35516312 PMCID: PMC9064209 DOI: 10.1039/c9ra02027f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 05/08/2019] [Indexed: 01/11/2023] Open
Abstract
Herein we report the synthesis, characterisation and electron transfer studies of CdSe–Cu2Se QDs, a novel type II core–shell system. The synthesis was achieved by a high temperature organometallic method with oleylamine as ligand. Structural and optical properties of the nanostructures were investigated using X-ray diffraction, high resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy, inductive coupled plasma optical emission spectroscopy, cyclic voltammetry, X-ray photoelectron spectroscopy and absorption spectroscopy. The electron transfer dynamics were investigated by observing the variations in steady state and time resolved emission spectra in the presence of an electron acceptor-methyl viologen. Localization of electrons in the shells was evident from the studies performed indicating efficient charge separation. Herein we report the synthesis, characterisation and electron transfer studies of CdSe–Cu2Se QDs, a novel type II core–shell system.![]()
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Affiliation(s)
- N J Simi
- Centre for Nano Bio Polymer Science and Technology, Department of Physics, St. Thomas College Palai, Arunapuram Kottayam-686574 Kerala India +919446126926
| | - R Vinayakan
- NSS Hindu College Changanacherry Kottayam-686102 Kerala India
| | - V V Ison
- Centre for Nano Bio Polymer Science and Technology, Department of Physics, St. Thomas College Palai, Arunapuram Kottayam-686574 Kerala India +919446126926
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31
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Hou X, Kang J, Qin H, Chen X, Ma J, Zhou J, Chen L, Wang L, Wang LW, Peng X. Engineering Auger recombination in colloidal quantum dots via dielectric screening. Nat Commun 2019; 10:1750. [PMID: 30988287 PMCID: PMC6465357 DOI: 10.1038/s41467-019-09737-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/22/2019] [Indexed: 11/09/2022] Open
Abstract
Auger recombination is the main non-radiative decay pathway for multi-carrier states of colloidal quantum dots, which affects performance of most of their optical and optoelectronic applications. Outstanding single-exciton properties of CdSe/CdS core/shell quantum dots enable us to simultaneously study the two basic types of Auger recombination channels-negative trion and positive trion channels. Though Auger rates of positive trion are regarded to be much faster than that of negative trion for II-VI quantum dots in literature, our experiments find the two rates can be inverted for certain core/shell geometries. This is confirmed by theoretical calculations as a result of geometry-dependent dielectric screening. By varying the core/shell geometry, both types of Auger rates can be independently tuned for ~ 1 order of magnitude. Experimental and theoretical findings shed new light on designing quantum dots with necessary Auger recombination characteristics for high-power light-emitting-diodes, lasers, single-molecular tracking, super-resolution microscope, and advanced quantum light sources.
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Affiliation(s)
- Xiaoqi Hou
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China
| | - Jun Kang
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China.
| | - Xuewen Chen
- School of Physics, Huazhong University of Science and Technology, 430074, Wuhan, People's Republic of China
| | - Junliang Ma
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China
| | - Jianhai Zhou
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China
| | - Liping Chen
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China
| | - Linjun Wang
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China
| | - Lin-Wang Wang
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, and Department of Chemistry, Zhejiang University, 310027, Hangzhou, People's Republic of China.
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32
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Park YS, Lim J, Klimov VI. Asymmetrically strained quantum dots with non-fluctuating single-dot emission spectra and subthermal room-temperature linewidths. NATURE MATERIALS 2019; 18:249-255. [PMID: 30617342 DOI: 10.1038/s41563-018-0254-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/16/2018] [Indexed: 05/21/2023]
Abstract
The application of colloidal semiconductor quantum dots as single-dot light sources still requires several challenges to be overcome. Recently, there has been considerable progress in suppressing intensity fluctuations (blinking) by encapsulating an emitting core in a thick protective shell. However, these nanostructures still show considerable fluctuations in both emission energy and linewidth. Here we demonstrate type-I core/shell heterostructures that overcome these deficiencies. They are made by combining wurtzite semiconductors with a large, directionally anisotropic lattice mismatch, which results in strong asymmetric compression of the emitting core. This modifies the structure of band-edge excitonic states and leads to accelerated radiative decay, reduced exciton-phonon interactions, and suppressed coupling to the fluctuating electrostatic environment. As a result, individual asymmetrically strained dots exhibit highly stable emission energy (<1 meV standard deviation) and a subthermal room-temperature linewidth (~20 meV), concurrent with nearly nonblinking behaviour, high emission quantum yields, and a widely tunable emission colour.
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Affiliation(s)
- Young-Shin Park
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Centre for High Technology Materials, University of New Mexico, Albuquerque, NM, USA
| | - Jaehoon Lim
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Chemical Engineering & Department of Energy System Research, Ajou University, Suwon, Republic of Korea
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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33
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Lee W, Oh J, Kwon W, Lee SH, Kim D, Kim S. Synthesis of Ag/Mn Co-Doped CdS/ZnS (Core/Shell) Nanocrystals with Controlled Dopant Concentration and Spatial Distribution and the Dynamics of Excitons and Energy Transfer between Co-Dopants. NANO LETTERS 2019; 19:308-317. [PMID: 30584809 DOI: 10.1021/acs.nanolett.8b03923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report lightly Ag/Mn co-doped CdS/ZnS (core/shell) nanocrystals (NCs) as a model system for studying interactions between co-dopants and between NCs and dopants. The co-doped NCs were prepared with a varying average number of Ag dopant atoms per CdS core of the NC from zero to eight; at the same time, the depth profile of the Mn dopants in the ZnS shells was controlled to be either close to or far from the Ag dopants. The incorporation of an average of one to two Ag dopant atoms per NC increased the band-edge photoluminescence (PL); however, it was quenched at higher doping concentration. This alternation is attributed to change of the Ag ion occupancy from PL-enhancing interstitial sites to PL-quenching substitutional sites. Mn PL increased as the number of Ag atoms per NC increased up to approximately seven and then decreased. For NCs doped only with Ag ions, the Ag dopants in substitutional sites acted as PL-quenching hole traps. In Ag/Mn co-doped NCs, the Ag dopants acted as Dexter-type relay sites that enhanced the energy transfer from NC to Mn ions; this effect increased as the distance between Ag and Mn dopants decreased. This model study demonstrates that the simultaneous control of dopant concentrations and spatial distributions in co-doped semiconductor NCs enables sophisticated control of their optical properties.
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Affiliation(s)
| | - Juwon Oh
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-gu, Seoul 03722 , South Korea
| | - Woosung Kwon
- Department of Chemical and Biological Engineering , Sookmyung Women's University , 100 Cheongpa-ro 47-gil , Seoul 04310 , South Korea
| | - Sang Hyeon Lee
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-gu, Seoul 03722 , South Korea
| | - Dongho Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry , Yonsei University , 50 Yonsei-ro , Seodaemun-gu, Seoul 03722 , South Korea
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34
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Reid KR, McBride JR, La Croix AD, Freymeyer NJ, Click SM, Macdonald JE, Rosenthal SJ. Role of Surface Morphology on Exciton Recombination in Single Quantum Dot-in-Rods Revealed by Optical and Atomic Structure Correlation. ACS NANO 2018; 12:11434-11445. [PMID: 30403844 DOI: 10.1021/acsnano.8b06472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The physical structure of colloidal quantum dot (QD) nanostructures strongly influences their optical and electronic behavior. A fundamental understanding of this interplay between structure and function is crucial to fully tailor the performance of QDs and their assemblies. Here, by directly correlating the atomic and chemical structure of single CdSe-CdS quantum dot-in-rods with time-resolved fluorescence measurements on the same structures, we identify morphological irregularities at their surfaces that moderate photoluminescence efficiencies. We find that two nonradiative exciton recombination mechanisms are triggered by these imperfections: charging and trap-assisted nonradiative processes. Furthermore, we show that the proximity of the surface defects to the CdSe core of the core-shell structures influences whether the charging or trap-assisted nonradiative channel dominates exciton recombination. Our results extend to other QD nanostructures and emphasize surface roughness as a crucial parameter when designing colloidal QDs with specific excitonic fates.
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35
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Guo X, Kuang Y, Wang S, Li Z, Shen H, Guo L. Shell-dependent blinking behavior and fluorescence dynamics of single ZnSe/CdS core/shell quantum dots. NANOSCALE 2018; 10:18696-18705. [PMID: 30270388 DOI: 10.1039/c8nr06749j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An understanding of blinking behavior and photodynamics is crucial for improving the optical properties of quantum dots (QDs). Here we report the emission blinking behavior and dynamical mechanisms of single ZnSe/CdS core/shell QDs with the shell thickness varying from 1 to 6 monolayers. We find that the emission blinking behavior can be efficiently suppressed in the single-exciton regime and that the photoluminescence (PL) quantum yields (QY) and the corresponding fraction-bright of ZnSe/CdS QDs can be optimized by regulating the shell thickness. Specifically, the PL QY reaches a maximum of 93% when the shell thickness is 4 monolayers. The intensity-resolved and time-resolved fluorescence dynamics of single QDs indicate that three exciton decay pathways via trion emission, band-edge emission and shallow surface trap-state emission contribute to the blinking behavior of ZnSe/CdS QDs. The competitive contribution ratios of these three decay components are responsible for the significant difference in emission properties of ZnSe/CdS QDs with different shell thicknesses. Our findings in this work demonstrate that an effective way to improve the quantum yields and fraction-bright of core/shell QDs is to enhance the band-edge emission while suppressing the trion emission and surface trap-state emission.
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Affiliation(s)
- Xing Guo
- Institute of Micro/Nano Photonic Materials and Application, School of Physics and Electronics, Henan University, Kaifeng, 475004, People's Republic of China.
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36
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Manceau M, Vezzoli S, Glorieux Q, Giacobino E, Carbone L, De Vittorio M, Hermier JP, Bramati A. CdSe/CdS Dot-in-Rods Nanocrystals Fast Blinking Dynamics. Chemphyschem 2018; 19:3288-3295. [PMID: 30281885 DOI: 10.1002/cphc.201800694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Indexed: 11/07/2022]
Abstract
Analyzing the autocorrelation function of the fluorescence intensity, we demonstrate that these nanoemitters are characterized by a short value of the mean duration of bright periods (ten to a few hundreds of microseconds). The comparison of the results obtained for samples with different geometries shows that not only the shell thickness is crucial but also the shape of the dot-in-rods. Increasing the shell aspect ratio results in shorter bright periods suggesting that surface traps impact the stability of the fluorescence intensity.
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Affiliation(s)
- M Manceau
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
- Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430, Villetaneuse, France
| | - S Vezzoli
- The Blackett Laboratory, Department of Physics, Imperial College London, London, SW72AZ, United Kingdom
| | - Q Glorieux
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
| | - E Giacobino
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research, University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
| | - L Carbone
- CNR NANOTEC-Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via Monteroni -, 73100, Lecce, Italy
| | - M De Vittorio
- Istituto Italiano di Tecnologia (IIT) Center for Bio-Molecular Nanotechnologies Via Barsanti sn, 73010 Arnesano (Lecce), Italy, CNR NANOTEC-Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via Monteroni -, 73100, Lecce, Italy
| | - J-P Hermier
- Groupe d'Etude de la Matière Condensée (GEMaC), Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles Cedex, France
| | - A Bramati
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
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37
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Chen B, Liu J, Yang T, Chen L, Hou J, Feng C, Huang CZ. Development of a portable device for Ag + sensing using CdTe QDs as fluorescence probe via an electron transfer process. Talanta 2018; 191:357-363. [PMID: 30262071 DOI: 10.1016/j.talanta.2018.08.088] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/25/2018] [Accepted: 08/31/2018] [Indexed: 02/03/2023]
Abstract
Ag+ as one of the most commonly seen toxic heavy metal ions is involved in numerous vital biological processes, which would cause fatal damages and environmental contamination when Ag+ is excessive. In the present work, CdTe quantum dots (QDs) with green, orange, and red emission capped by mercaptoacetic acid (TGA) were synthesized at one time by controlling the synthesis time and utilized for Ag+ detection. Both fluorescence spectral red-shift and intensity decrease could be used for Ag+ discrimination. Fluorescence lifetime, Zeta potential, and XRD, etc. were carried out to analyze the detection mechanism. Results displayed that surface passivation and electron transfer due to binding effects of Ag+ to Te atom on traps of QDs could be relied on to explain the sensing mechanism. Additionally, in accordance with PCA analysis, Ag+ could be also be successfully differentiated from Hg2+ and the other metal ions. Importantly, a home-made portable device based on a 32 bit embed Micro Control Unit (MCU) system was first proposed for Ag+ detection. The power supply system adopt the mini-sized lithium cell instead of the power supply system, which ensure its practical applicability. The relative position of light source and detector is set at 90° to minimize the interference. According to the detection results, the linear detection range using the device was from 5 nM to 200 nM (with a larger coefficient of determination, R2), and the detection limit was calculated to be about 5 nM, which indicated that this proposed method and device could fulfil the practical application requirements.
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Affiliation(s)
- Bin Chen
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, Chongqing Key Laboratory of Non-linear Circuit and Intelligent Information Processing, College of Electronic and Information Engineering, Southwest University, Chongqing 400715, China; Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Junjie Liu
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Tong Yang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Lin Chen
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Jia Hou
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Changhao Feng
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, Chongqing Key Laboratory of Non-linear Circuit and Intelligent Information Processing, College of Electronic and Information Engineering, Southwest University, Chongqing 400715, China; Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China
| | - Cheng Zhi Huang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, China.
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38
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Bar-Elli O, Steinitz D, Yang G, Tenne R, Ludwig A, Kuo Y, Triller A, Weiss S, Oron D. Rapid Voltage Sensing with Single Nanorods via the Quantum Confined Stark Effect. ACS PHOTONICS 2018; 5:2860-2867. [PMID: 30042952 PMCID: PMC6053642 DOI: 10.1021/acsphotonics.8b00206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Indexed: 05/05/2023]
Abstract
Properly designed colloidal semiconductor quantum dots (QDs) have already been shown to exhibit high sensitivity to external electric fields via the quantum confined Stark effect (QCSE). Yet, detection of the characteristic spectral shifts associated with the effect of the QCSE has traditionally been painstakingly slow, dramatically limiting the sensitivity of these QD sensors to fast transients. We experimentally demonstrate a new detection scheme designed to achieve shot-noise-limited sensitivity to emission wavelength shifts in QDs, showing feasibility for their use as local electric field sensors on the millisecond time scale. This regime of operation is already potentially suitable for detection of single action potentials in neurons at a high spatial resolution.
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Affiliation(s)
- Omri Bar-Elli
- Department of Physics
of Complex Systems, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Dan Steinitz
- Department of Physics
of Complex Systems, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Gaoling Yang
- Department of Physics
of Complex Systems, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Ron Tenne
- Department of Physics
of Complex Systems, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Anastasia Ludwig
- L’Ecole
Normale Superieure, Institute of Biologie
(IBENS), Paris Sciences et Lettres (PSL), CNRS UMR 8197, Inserm 1024, 46 Rue d’Ulm, Paris 75005, France
| | - Yung Kuo
- Department of Chemistry and Biochemistry, Department of Physiology,
and California NanoSystems Institute, University
of California Los Angeles, Los
Angeles, California 90095, United States
| | - Antoine Triller
- L’Ecole
Normale Superieure, Institute of Biologie
(IBENS), Paris Sciences et Lettres (PSL), CNRS UMR 8197, Inserm 1024, 46 Rue d’Ulm, Paris 75005, France
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, Department of Physiology,
and California NanoSystems Institute, University
of California Los Angeles, Los
Angeles, California 90095, United States
- Department of Physics, Institute for Nanotechnology
and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Dan Oron
- Department of Physics
of Complex Systems, Weizmann Institute of
Science, Rehovot 76100, Israel
- E-mail:
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39
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Jazi R, Ung TPL, Maso P, Colas Des Francs G, Nasilowski M, Dubertret B, Hermier JP, Quélin X, Buil S. Measuring the orientation of a single CdSe/CdS nanocrystal at the end of a near-field tip for the realization of a versatile active SNOM probe. Phys Chem Chem Phys 2018; 20:16444-16448. [PMID: 29876544 DOI: 10.1039/c8cp02147c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The orientation of a CdSe/CdS nanocrystal attached at the end of a scanning near field optical microscope (SNOM) tip is analyzed by its coupling with a flat gold layer. The Purcell factors for a set of distances to the gold surface are measured after a NC is caught by a SNOM tip. These measurements are compared with the modeling of the emission of a 2D dipole on a gold layer taking into account the layer of polymer serving as a glue for the NC. The 2D dipole is perpendicular to the c-axis of the NC, which is the growth axis. The behavior of the Purcell factor as a function of the distance to the gold layer depends on the angle made by this axis and the surface. The adjustment of the experimental results and the modelization gives the orientation of the NC at the end of the SNOM tip. Different orientations of the c-axis are determined.
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Affiliation(s)
- R Jazi
- Groupe d'Étude de la Matière Condensée (GEMaC), Université de Versailles-Saint-Quentin-en-Yvelines, CNRS UMR8635, Université Paris-Saclay, 45, Avenue des États-Unis, Versailles F-78035, France.
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40
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Orfield NJ, Majumder S, McBride JR, Yik-Ching Koh F, Singh A, Bouquin SJ, Casson JL, Johnson AD, Sun L, Li X, Shih CK, Rosenthal SJ, Hollingsworth JA, Htoon H. Photophysics of Thermally-Assisted Photobleaching in "Giant" Quantum Dots Revealed in Single Nanocrystals. ACS NANO 2018; 12:4206-4217. [PMID: 29709173 DOI: 10.1021/acsnano.7b07450] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum dots (QDs) are steadily being implemented as down-conversion phosphors in market-ready display products to enhance color rendering, brightness, and energy efficiency. However, for adequate longevity, QDs must be encased in a protective barrier that separates them from ambient oxygen and humidity, and device architectures are designed to avoid significant heating of the QDs as well as direct contact between the QDs and the excitation source. In order to increase the utility of QDs in display technologies and to extend their usefulness to more demanding applications as, for example, alternative phosphors for solid-state lighting (SSL), QDs must retain their photoluminescence emission properties over extended periods of time under conditions of high temperature and high light flux. Doing so would simplify the fabrication costs for QD display technologies and enable QDs to be used as down-conversion materials in light-emitting diodes for SSL, where direct-on-chip configurations expose the emitters to temperatures approaching 100 °C and to photon fluxes from 0.1 W/mm2 to potentially 10 W/mm2. Here, we investigate the photobleaching processes of single QDs exposed to controlled temperature and photon flux. In particular, we investigate two types of room-temperature-stable core/thick-shell QDs, known as "giant" QDs for which shell growth is conducted using either a standard layer-by-layer technique or by a continuous injection method. We determine the mechanistic pathways responsible for thermally-assisted photodegradation, distinguishing effects of hot-carrier trapping and QD charging. The findings presented here will assist in the further development of advanced QD heterostructures for maximum device lifetime stability.
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Affiliation(s)
- Noah J Orfield
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Somak Majumder
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - James R McBride
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Faith Yik-Ching Koh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Ajay Singh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Sarah J Bouquin
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Joanna L Casson
- Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Alex D Johnson
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Liuyang Sun
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Xiaoqin Li
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Chih-Kang Shih
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sandra J Rosenthal
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Jennifer A Hollingsworth
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Han Htoon
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
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41
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Wang T, Zhu B, Wang S, Yuan Q, Zhang H, Kang Z, Wang R, Zhang H, Ji W. Influence of Shell Thickness on the Performance of NiO-Based All-Inorganic Quantum Dot Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14894-14900. [PMID: 29637767 DOI: 10.1021/acsami.8b01814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effect of shell thickness on the performance of all-inorganic quantum dot light-emitting diodes (QLEDs) is explored by employing a series of green quantum dots (QDs) (Zn xCd1- xSe/ZnS core/shell QDs with different ZnS shell thicknesses) as the emitters. ZnO nanoparticles and sol-gel NiO are employed as the electron and hole transport materials, respectively. Time-resolved and steady-state photoluminescence results indicate that positive charging processes might occur for the QDs deposited on NiO, which results in emission quenching of QDs and poor device performance. The thick shell outside the core in QDs not only largely suppresses the QD emission quenching but also effectively preserves the excitons in QDs from dissociation of electron-hole pairs when they are subjected to an electric field. The peak efficiency of 4.2 cd/A and maximum luminance of 4205 cd/m2 are achieved for the device based on QDs with the thickest shells (∼4.2 nm). We anticipate that these results will spur progress toward the design and realization of efficient all-inorganic QLEDs as a platform for the QD-based full-colored displays.
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Affiliation(s)
- Ting Wang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Bingyan Zhu
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Shuangpeng Wang
- Institute of Applied Physics and Materials Engineering , University of Macau , Avenida da Universidade , Taipa 999078 , Macau SAR , China
| | - Qilin Yuan
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Han Zhang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Zhihui Kang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Rong Wang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Hanzhuang Zhang
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
| | - Wenyu Ji
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics , Jilin University , 2699 Qianjin Street , Changchun 130012 , China
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42
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Yuan G, Gómez DE, Kirkwood N, Boldt K, Mulvaney P. Two Mechanisms Determine Quantum Dot Blinking. ACS NANO 2018; 12:3397-3405. [PMID: 29579376 DOI: 10.1021/acsnano.7b09052] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many potential applications of quantum dots (QDs) can only be realized once the luminescence from single nanocrystals (NCs) is understood. These applications include the development of quantum logic devices, single-photon sources, long-life LEDs, and single-molecule biolabels. At the single-nanocrystal level, random fluctuations in the QD photoluminescence occur, a phenomenon termed blinking. There are two competing models to explain this blinking: Auger recombination and surface trap induced recombination. Here we use lifetime scaling on core-shell chalcogenide NCs to demonstrate that both types of blinking occur in the same QDs. We prove that Auger-blinking can yield single-exponential on/off times in contrast to earlier work. The surface passivation strategy determines which blinking mechanism dominates. This study summarizes earlier studies on blinking mechanisms and provides some clues that stable single QDs can be engineered for optoelectronic applications.
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Affiliation(s)
- Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | | | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Klaus Boldt
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
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43
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Ghimire S, Biju V. Relations of exciton dynamics in quantum dots to photoluminescence, lasing, and energy harvesting. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2018. [DOI: 10.1016/j.jphotochemrev.2018.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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44
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Yuan G, Gómez D, Kirkwood N, Mulvaney P. Tuning Single Quantum Dot Emission with a Micromirror. NANO LETTERS 2018; 18:1010-1017. [PMID: 29302972 DOI: 10.1021/acs.nanolett.7b04482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The photoluminescence of single quantum dots fluctuates between bright (on) and dark (off) states, also termed fluorescence intermittency or blinking. This blinking limits the performance of quantum dot-based devices such as light-emitting diodes and solar cells. However, the origins of the blinking remain unresolved. Here, we use a movable gold micromirror to determine both the quantum yield of the bright state and the orientation of the excited state dipole of single quantum dots. We observe that the quantum yield of the bright state is close to unity for these single QDs. Furthermore, we also study the effect of a micromirror on blinking, and then evaluate excitation efficiency, biexciton quantum yield, and detection efficiency. The mirror does not modify the off-time statistics, but it does change the density of optical states available to the quantum dot and hence the on times. The duration of the on times can be lengthened due to an increase in the radiative recombination rate.
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Affiliation(s)
- Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Daniel Gómez
- School of Chemical Sciences, RMIT University , Melbourne, Victoria 3001, Australia
| | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia
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45
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Shornikova EV, Biadala L, Yakovlev DR, Feng D, Sapega VF, Flipo N, Golovatenko AA, Semina MA, Rodina AV, Mitioglu AA, Ballottin MV, Christianen PCM, Kusrayev YG, Nasilowski M, Dubertret B, Bayer M. Electron and Hole g-Factors and Spin Dynamics of Negatively Charged Excitons in CdSe/CdS Colloidal Nanoplatelets with Thick Shells. NANO LETTERS 2018; 18:373-380. [PMID: 29160075 DOI: 10.1021/acs.nanolett.7b04203] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We address spin properties and spin dynamics of carriers and charged excitons in CdSe/CdS colloidal nanoplatelets with thick shells. Magneto-optical studies are performed by time-resolved and polarization-resolved photoluminescence, spin-flip Raman scattering and picosecond pump-probe Faraday rotation in magnetic fields up to 30 T. We show that at low temperatures the nanoplatelets are negatively charged so that their photoluminescence is dominated by radiative recombination of negatively charged excitons (trions). Electron g-factor of 1.68 is measured, and heavy-hole g-factor varying with increasing magnetic field from -0.4 to -0.7 is evaluated. Hole g-factors for two-dimensional structures are calculated for various hole confining potentials for cubic- and wurtzite lattice in CdSe core. These calculations are extended for various quantum dots and nanoplatelets based on II-VI semiconductors. We developed a magneto-optical technique for the quantitative evaluation of the nanoplatelets orientation in ensemble.
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Affiliation(s)
- Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences , 630090 Novosibirsk, Russia
| | - Louis Biadala
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS , 59652 Villeneuve-d'Ascq, France
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Donghai Feng
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- State Key Laboratory of Precision Spectroscopy, East China Normal University , 200062 Shanghai, China
| | - Victor F Sapega
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Nathan Flipo
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
| | | | - Marina A Semina
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Anna V Rodina
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Anatolie A Mitioglu
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Mariana V Ballottin
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Peter C M Christianen
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Yuri G Kusrayev
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Michel Nasilowski
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI, CNRS , 75231 Paris, France
| | - Benoit Dubertret
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI, CNRS , 75231 Paris, France
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
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46
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Yarita N, Tahara H, Saruyama M, Kawawaki T, Sato R, Teranishi T, Kanemitsu Y. Impact of Postsynthetic Surface Modification on Photoluminescence Intermittency in Formamidinium Lead Bromide Perovskite Nanocrystals. J Phys Chem Lett 2017; 8:6041-6047. [PMID: 29189012 DOI: 10.1021/acs.jpclett.7b02840] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We study the origin of photoluminescence (PL) intermittency in formamidinium lead bromide (FAPbBr3, FA = HC(NH2)2) nanocrystals and the impact of postsynthetic surface treatments on the PL intermittency. Single-dot spectroscopy revealed the existence of different individual nanocrystals exhibiting either a blinking (binary on-off switching) or flickering (gradual undulation) behavior of the PL intermittency. Although the PL lifetimes of blinking nanocrystals clearly correlate with the individual absorption cross sections, those of flickering nanocrystals show no correlation with the absorption cross sections. This indicates that flickering has an extrinsic origin, which is in contrast to blinking. We demonstrate that the postsynthetic surface treatment with sodium thiocyanate improves the PL quantum yields and completely suppresses the flickering, while it has no significant effect on the blinking behavior. We conclude that the blinking is caused by Auger recombination of charged excitons, and the flickering is due to a temporal drift of the exciton recombination rate induced by surface-trapped electrons.
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Affiliation(s)
- Naoki Yarita
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Hirokazu Tahara
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Masaki Saruyama
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Tokuhisa Kawawaki
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Ryota Sato
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Toshiharu Teranishi
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
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47
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Guo T, Sampat S, Rupich SM, Hollingsworth JA, Buck M, Htoon H, Chabal YJ, Gartstein YN, Malko AV. Biexciton and trion energy transfer from CdSe/CdS giant nanocrystals to Si substrates. NANOSCALE 2017; 9:19398-19407. [PMID: 29210416 DOI: 10.1039/c7nr06272a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Observation of energy transfer (ET) from multiexcitonic (MX) complexes in nanocrystal quantum dots (NQDs) has been severely restricted due to efficient nonradiative Auger recombination leading to very low MX emission quantum yields. Here we employed "giant" CdSe/CdS NQDs with suppressed Auger recombination to study ET of biexcitons (BX) and charged excitons (trions) into Si substrate. Photoluminescence (PL) measurements of (sub)monolayers of gNQDs controllably assembled on various interacting surfaces and augmented by single gNQD's imaging reveal appearance of BX spectral signatures and progressive acceleration of PL lifetimes of all excitonic species on Si substrates. From statistical analysis of a large number of PL lifetime traces, representative exciton, trion and BX ET efficiencies are measured as ∼75%, 55% and 45% respectively. Detailed analysis of the MX's radiative rates demonstrate the crucial role of the radiative (waveguide) ET in maintaining high overall transfer efficiency despite the prevalent Auger recombination. Our observations point towards practical utilization of MX-bearing nanocrystals in future optoelectronics architectures.
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Affiliation(s)
- Tianle Guo
- Department of Physics, The University of Texas at Dallas, Richardson, TX 75080, USA.
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48
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Xu W, Hou X, Meng Y, Meng R, Wang Z, Qin H, Peng X, Chen XW. Deciphering Charging Status, Absolute Quantum Efficiency, and Absorption Cross Section of Multicarrier States in Single Colloidal Quantum Dots. NANO LETTERS 2017; 17:7487-7493. [PMID: 29160715 DOI: 10.1021/acs.nanolett.7b03399] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Upon photo- or electrical-excitation, colloidal quantum dots (QDs) are often found in multicarrier states due to multiphoton absorption, photocharging, or imbalanced carrier injection of the QDs. While many of these multicarrier states are observed in single-dot spectroscopy, their properties are not well studied due to random charging/discharging, emission intensity intermittency, and uncontrolled surface defects of single QDs. Here we report in situ deciphering of the charging status, precisely assessing the absorption cross section, and determining the absolute emission quantum yield of monoexciton and biexciton states for neutral, positively charged, and negatively charged single core/shell CdSe/CdS QDs. We uncover very different photon statistics of the three charge states in single QDs and unambiguously identify their charge signs together with the information on their photoluminescence decay dynamics. We then show their distinct photoluminescence saturation behaviors and evaluate the absolute values of absorption cross sections and quantum efficiencies of monoexcitons and biexcitons. We demonstrate that the addition of an extra hole or electron in a QD not only changes its emission properties but also varies its absorption cross section.
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Affiliation(s)
- Weiwang Xu
- School of Physics, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, People's Republic of China
| | - Xiaoqi Hou
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Yongjun Meng
- School of Physics, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, People's Republic of China
| | - Renyang Meng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Zhiyuan Wang
- School of Physics, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, People's Republic of China
| | - Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Xue-Wen Chen
- School of Physics, Huazhong University of Science and Technology , Luoyu Road 1037, Wuhan 430074, People's Republic of China
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Khan S, Li W, Karedla N, Thiart J, Gregor I, Chizhik AM, Enderlein J, Nandi CK, Chizhik AI. Charge-Driven Fluorescence Blinking in Carbon Nanodots. J Phys Chem Lett 2017; 8:5751-5757. [PMID: 29125299 DOI: 10.1021/acs.jpclett.7b02521] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study focuses on the mechanism of fluorescence blinking of single carbon nanodots, which is one of their key but less understood properties. The results of our single-particle fluorescence study show that the mechanism of carbon nanodots blinking has remarkable similarities with that of semiconductor quantum dots. In particular, the temporal behavior of carbon nanodot blinking follows a power law both at room and at cryogenic temperatures. Our experimental data suggest that static quenching via Dexter-type electron transfer between surface groups of a nanoparticle plays a major role in the transition of carbon nanodots to off or gray states, whereas the transition back to on states is governed by an electron tunneling from the particle's core. These findings advance our understanding of the complex mechanism of carbon nanodots emission, which is one of the key steps for their application in fluorescence imaging.
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Affiliation(s)
- Syamantak Khan
- School of Basic Sciences, Indian Institute of Technology Mandi , Kamand, Himachal Pradesh 175001, India
| | - Weixing Li
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
| | - Narain Karedla
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
| | - Jan Thiart
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
| | - Ingo Gregor
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
| | - Anna M Chizhik
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
| | - Jörg Enderlein
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB) , 37077 Göttingen, Germany
| | - Chayan K Nandi
- School of Basic Sciences, Indian Institute of Technology Mandi , Kamand, Himachal Pradesh 175001, India
| | - Alexey I Chizhik
- University of Göttingen , Third Institute of Physics, 37077 Göttingen, Germany
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50
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Chandrasekaran V, Tessier MD, Dupont D, Geiregat P, Hens Z, Brainis E. Nearly Blinking-Free, High-Purity Single-Photon Emission by Colloidal InP/ZnSe Quantum Dots. NANO LETTERS 2017; 17:6104-6109. [PMID: 28895398 DOI: 10.1021/acs.nanolett.7b02634] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Colloidal core/shell InP/ZnSe quantum dots (QDs), recently produced using an improved synthesis method, have a great potential in life-science applications as well as in integrated quantum photonics and quantum information processing as single-photon emitters. Single-particle spectroscopy of 10 nm QDs with 3.2 nm cores reveals strong photon antibunching attributed to fast (70 ps) Auger recombination of multiple excitons. The QDs exhibit very good photostability under strong optical excitation. We demonstrate that the antibunching is preserved when the QDs are excited above the saturation intensity of the fundamental-exciton transition. This result paves the way toward their usage as high-purity on-demand single-photon emitters at room temperature. Unconventionally, despite the strong Auger blockade mechanism, InP/ZnSe QDs also display very little luminescence intermittency ("blinking"), with a simple on/off blinking pattern. The analysis of single-particle luminescence statistics places these InP/ZnSe QDs in the class of nearly blinking-free QDs, with emission stability comparable to state-of-the-art thick-shell and alloyed-interface CdSe/CdS, but with improved single-photon purity.
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Affiliation(s)
- Vigneshwaran Chandrasekaran
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
| | - Mickaël D Tessier
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
| | - Dorian Dupont
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
| | - Pieter Geiregat
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
| | - Zeger Hens
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
| | - Edouard Brainis
- Center for Nano and Biophotonics and Physics and Chemistry of Nanostructures, Ghent University , Ghent 9000, Belgium
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