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Ossia Y, Levi A, Chefetz N, Peleg A, Remennik S, Vakahi A, Banin U. Seeing is believing: Correlating optoelectronic functionality with atomic scale imaging of single semiconductor nanocrystals. J Chem Phys 2024; 160:134201. [PMID: 38573848 DOI: 10.1063/5.0198140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 02/29/2024] [Indexed: 04/06/2024] Open
Abstract
A unique on-chip method for the direct correlation of optical properties, with atomic-scale chemical-structural characteristics for a single quantum dot (QD), is developed and utilized in various examples. This is based on performing single QD optical characterization on a modified glass substrate, followed by the extraction of the relevant region of interest by focused-ion-beam-scanning electron microscope processing into a lamella for high resolution scanning transmission electron microscopy (STEM) characterization with atomic scale resolution. The direct correlation of the optical response under an electric field with STEM analysis of the same particle allows addressing several single particle phenomena: first, the direct correlation of single QD photoluminescence (PL) polarization and its response to the external field with the QD crystal lattice alignment, so far inferred indirectly; second, the identification of unique yet rare few-QD assemblies, correlated directly with their special spectroscopic optical characteristics, serving as a guide for future designed assemblies; and third, the study on the effect of metal island growth on the PL behavior of hybrid semiconductor-metal nanoparticles, with relevance for their possible functionality in photocatalysis. This work, therefore, establishes the use of the direct on-chip optical-structural correlation method for numerous scenarios and timely questions in the field of QD research.
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Affiliation(s)
- Yonatan Ossia
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Adar Levi
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nadav Chefetz
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Amir Peleg
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Sergei Remennik
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Atzmon Vakahi
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Uri Banin
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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2
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Yuan G, Higginbotham HF, Han J, Yadav A, Kirkwood N, Mulvaney P, Bell TDM, Cole JH, Funston AM. Tuning the Photoluminescence Anisotropy of Semiconductor Nanocrystals. ACS NANO 2023; 17:19109-19120. [PMID: 37748102 DOI: 10.1021/acsnano.3c05214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Semiconductor nanocrystals are promising optoelectronic materials. Understanding their anisotropic photoluminescence is fundamental for developing quantum-dot-based devices such as light-emitting diodes, solar cells, and polarized single-photon sources. In this study, we experimentally and theoretically investigate the photoluminescence anisotropy of CdSe semiconductor nanocrystals with various shapes, including plates, rods, and spheres, with either wurtzite or zincblende structures. We use defocused wide-field microscopy to visualize the emission dipole orientation and find that spheres, rods, and plates exhibit the optical properties of 2D, 1D, and 2D emission dipoles, respectively. We rationalize the seemingly counterintuitive observation that despite having similar aspect ratios (width/length), rods and long nanoplatelets exhibit different defocused emission patterns by considering valence band structures calculated using multiband effective mass theory and the dielectric effect. The principles are extended to provide general relationships that can be used to tune the emission dipole orientation for different materials, crystalline structures, and shapes.
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Affiliation(s)
- Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science, Monash University, Clayton, Victoria 3800, Australia
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | | | - Jiho Han
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anchal Yadav
- ARC Centre of Excellence in Exciton Science, Monash University, Clayton, Victoria 3800, Australia
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Toby D M Bell
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Jared H Cole
- ARC Centre of Excellence in Exciton Science and Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, 3001, Australia
| | - Alison M Funston
- ARC Centre of Excellence in Exciton Science, Monash University, Clayton, Victoria 3800, Australia
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
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3
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Chen C, Luo X, Kaplan AE, Bawendi MG, Macfarlane RJ, Bathe M. Ultrafast dense DNA functionalization of quantum dots and rods for scalable 2D array fabrication with nanoscale precision. SCIENCE ADVANCES 2023; 9:eadh8508. [PMID: 37566651 PMCID: PMC10421044 DOI: 10.1126/sciadv.adh8508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/14/2023] [Indexed: 08/13/2023]
Abstract
Scalable fabrication of two-dimensional (2D) arrays of quantum dots (QDs) and quantum rods (QRs) with nanoscale precision is required for numerous device applications. However, self-assembly-based fabrication of such arrays using DNA origami typically suffers from low yield due to inefficient QD and QR DNA functionalization. In addition, it is challenging to organize solution-assembled DNA origami arrays on 2D device substrates while maintaining their structural fidelity. Here, we reduced manufacturing time from a few days to a few minutes by preparing high-density DNA-conjugated QDs/QRs from organic solution using a dehydration and rehydration process. We used a surface-assisted large-scale assembly (SALSA) method to construct 2D origami lattices directly on solid substrates to template QD and QR 2D arrays with orientational control, with overall loading yields exceeding 90%. Our fabrication approach enables the scalable, high fidelity manufacturing of 2D addressable QDs and QRs with nanoscale orientational and spacing control for functional 2D photonic devices.
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Affiliation(s)
- Chi Chen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xin Luo
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alexander E. K. Kaplan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Moungi G. Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert J. Macfarlane
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mark Bathe
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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4
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Rodríguez Ortiz F, Zhao B, Wen JR, Yim JE, Bauer G, Champ A, Sheldon MT. The Anisotropic Complex Dielectric Function of CsPbBr 3 Perovskite Nanorods Obtained via an Iterative Matrix Inversion Method. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:14812-14821. [PMID: 38356733 PMCID: PMC10863055 DOI: 10.1021/acs.jpcc.3c03423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/29/2023] [Indexed: 02/16/2024]
Abstract
Colloidal lead halide perovskite nanorods have recently emerged as promising optoelectronic materials. However, more information about how shape anisotropy impacts their complex dielectric function is required to aid the development of applications that take advantage of the strongly polarized absorption and emission. Here, we have determined the anisotropy of the complex dielectric function of CsPbBr3 nanorods by analyzing the ensemble absorption spectra in conjunction with the ensemble spectral fluorescence anisotropy. This strategy allows us to distinguish the absorption of light parallel and perpendicular to the main axis so that the real and imaginary components of the dielectric function along each direction can be determined by the use of an iterative matrix inversion (IMI) methodology. We find that quantum confinement gives rise to unique axis-dependent electronic features in the dielectric function that increase the overall fluorescence anisotropy in addition to the optical anisotropy that results from particle shape, even in the absence of quantum confinement. Further, the procedure outlined here provides a strategy for obtaining anisotropic complex dielectric functions of colloidal materials of varying composition and aspect ratios using ensemble solution-phase spectroscopy.
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Affiliation(s)
| | - Boqin Zhao
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Je-Ruei Wen
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Ju Eun Yim
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Giselle Bauer
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Anna Champ
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Matthew T. Sheldon
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Department
of Materials Science and Engineering, Texas
A&M University, College Station, Texas 77843, United States
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5
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Amgar D, Lubin G, Yang G, Rabouw FT, Oron D. Resolving the Emission Transition Dipole Moments of Single Doubly Excited Seeded Nanorods via Heralded Defocused Imaging. NANO LETTERS 2023. [PMID: 37290051 DOI: 10.1021/acs.nanolett.3c00155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Semiconductor nanocrystal emission polarization is a crucial probe of nanocrystal physics and an essential factor for nanocrystal-based technologies. While the transition dipole moment for the lowest excited state to ground state transition is well characterized, the dipole moment of higher multiexcitonic transitions is inaccessible via most spectroscopy techniques. Here, we realize direct characterization of the doubly excited-state relaxation transition dipole by heralded defocused imaging. Defocused imaging maps the dipole emission pattern onto a fast single-photon avalanche diode detector array, allowing the postselection of photon pairs emitted from the biexciton-exciton emission cascade and resolving the differences in transition dipole moments. Type-I1/2 seeded nanorods exhibit higher anisotropy of the biexciton-to-exciton transition compared to the exciton-to-ground state transition. In contrast, type-II seeded nanorods display a reduction of biexciton emission anisotropy. These findings are rationalized in terms of an interplay between the transient dynamics of the refractive index and the excitonic fine structure.
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Affiliation(s)
- Daniel Amgar
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gur Lubin
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gaoling Yang
- School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Freddy T Rabouw
- Debye Institute of Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Dan Oron
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
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6
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Lan X, Shi X, Zhang L, Guo Q, Zou Z, Zhu G, Li X, Du W, Wang T. Highly polarized light emission from hybrid of quantum dots and plasmons in the intermediate coupling regime. OPTICS LETTERS 2023; 48:3095-3098. [PMID: 37262289 DOI: 10.1364/ol.489777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/16/2023] [Indexed: 06/03/2023]
Abstract
Colloidal semiconductor quantum dots (QDs), with a size tunable bandgap and remarkably high quantum efficiency, have been recognized as ideal light sources in quantum information and light emitting devices. For light sources, besides the emission intensity and spectral profile, the degree of polarization (DoP) is an essential parameter. Here, by embedding a monolayer of QDs inside the nanogap between a bottom Au mirror and a top Ag nanowire, we have demonstrated highly polarized light emission from the QDs with an average DoP of 0.89. In addition to the anisotropic photoluminescence (PL) intensity, the PL spectra are distinct at different polarizations, with an asymmetric spectral shape or even two-peak features. Such an anisotropic emission behavior arises from the coupling between the QDs and the largely confined and polarization-dependent gap-plasmons in the Au/QD/Ag nanocavities in the intermediate coupling regime. Our results demonstrate the possibility of achieving highly polarized light sources by coupling spherical QDs to single anisotropic plasmonic nanocavities, to provide new opportunities in the future design of polarized QD-based display devices.
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7
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Diroll BT, Banerjee P, Shevchenko EV. Optical anisotropy of CsPbBr 3 perovskite nanoplatelets. NANO CONVERGENCE 2023; 10:18. [PMID: 37186268 PMCID: PMC10130288 DOI: 10.1186/s40580-023-00367-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/09/2023] [Indexed: 05/17/2023]
Abstract
The two-dimensional CsPbBr3 nanoplatelets have a quantum well electronic structure with a band gap tunable with sample thicknesses in discreet steps based upon the number of monolayers. The polarized optical properties of CsPbBr3 nanoplatelets are studied using fluorescence anisotropy and polarized transient absorption spectroscopies. Polarized spectroscopy shows that they have absorption and emission transitions which are strongly plane-polarized. In particular, photoluminescence excitation and transient absorption measurements reveal a band-edge polarization approaching 0.1, the limit of isotropic two-dimensional ensembles. The degree of anisotropy is found to depend on the thickness of the nanoplatelets: multiple measurements show a progressive decrease in optical anisotropy from 2 to 5 monolayer thick nanoplatelets. In turn, larger cuboidal CsPbBr3 nanocrystals, are found to have consistently positive anisotropy which may be attributed to symmetry breaking from ideal perovskite cubes. Optical measurements of anisotropy are described with respect to the theoretical framework developed to describe exciton fine structure in these materials. The observed planar absorption and emission are close to predicted values at thinner nanoplatelet sizes and follow the predicted trend in anisotropy with thickness, but with larger anisotropy than theoretical predictions. Dominant planar emission, albeit confined to the thinnest nanoplatelets, is a valuable attribute for enhanced efficiency of light-emitting devices.
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Affiliation(s)
- Benjamin T Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60438, USA.
| | - Progna Banerjee
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60438, USA
| | - Elena V Shevchenko
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60438, USA
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8
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Liu L, Bai B, Yang X, Du Z, Jia G. Anisotropic Heavy-Metal-Free Semiconductor Nanocrystals: Synthesis, Properties, and Applications. Chem Rev 2023; 123:3625-3692. [PMID: 36946890 DOI: 10.1021/acs.chemrev.2c00688] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
Heavy-metal (Cd, Hg, and Pb)-containing semiconductor nanocrystals (NCs) have been explored widely due to their unique optical and electrical properties. However, the toxicity risks of heavy metals can be a drawback of heavy-metal-containing NCs in some applications. Anisotropic heavy-metal-free semiconductor NCs are desirable replacements and can be realized following the establishment of anisotropic growth mechanisms. These anisotropic heavy-metal-free semiconductor NCs can possess lower toxicity risks, while still exhibiting unique optical and electrical properties originating from both the morphological and compositional anisotropy. As a result, they are promising light-emitting materials in use various applications. In this review, we provide an overview on the syntheses, properties, and applications of anisotropic heavy-metal-free semiconductor NCs. In the first section, we discuss hazards of heavy metals and introduce the typical heavy-metal-containing and heavy-metal-free NCs. In the next section, we discuss anisotropic growth mechanisms, including solution-liquid-solid (SLS), oriented attachment, ripening, templated-assisted growth, and others. We discuss mechanisms leading both to morphological anisotropy and to compositional anisotropy. Examples of morphological anisotropy include growth of nanorods (NRs)/nanowires (NWs), nanotubes, nanoplatelets (NPLs)/nanosheets, nanocubes, and branched structures. Examples of compositional anisotropy, including heterostructures and core/shell structures, are summarized. Third, we provide insights into the properties of anisotropic heavy-metal-free NCs including optical polarization, fast electron transfer, localized surface plasmon resonances (LSPR), and so on, which originate from the NCs' anisotropic morphologies and compositions. Finally, we summarize some applications of anisotropic heavy-metal-free NCs including catalysis, solar cells, photodetectors, lighting-emitting diodes (LEDs), and biological applications. Despite the huge progress on the syntheses and applications of anisotropic heavy-metal-free NCs, some issues still exist in the novel anisotropic heavy-metal-free NCs and the corresponding energy conversion applications. Therefore, we also discuss the challenges of this field and provide possible solutions to tackle these challenges in the future.
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Affiliation(s)
- Long Liu
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Bing Bai
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Xuyong Yang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai 200072, P. R. China
| | - Zuliang Du
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China
| | - Guohua Jia
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
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9
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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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10
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Bai B, Zhang C, Dou Y, Kong L, Wang L, Wang S, Li J, Zhou Y, Liu L, Liu B, Zhang X, Hadar I, Bekenstein Y, Wang A, Yin Z, Turyanska L, Feldmann J, Yang X, Jia G. Atomically flat semiconductor nanoplatelets for light-emitting applications. Chem Soc Rev 2023; 52:318-360. [PMID: 36533300 DOI: 10.1039/d2cs00130f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The last decade has witnessed extensive breakthroughs and significant progress in atomically flat two-dimensional (2D) semiconductor nanoplatelets (NPLs) in terms of synthesis, growth mechanisms, optical and electronic properties and practical applications. Such NPLs have electronic structures similar to those of quantum wells in which excitons are predominantly confined along the vertical direction, while electrons are free to move in the lateral directions, resulting in unique optical properties, such as extremely narrow emission line width, short photoluminescence (PL) lifetime, high gain coefficient, and giant oscillator strength transition (GOST). These unique optical properties make NPLs favorable for high color purity light-emitting applications, in particular in light-emitting diodes (LEDs), backlights for liquid crystal displays (LCDs) and lasers. This review article first introduces the intrinsic characteristics of 2D semiconductor NPLs with atomic flatness. Subsequently, the approaches and mechanisms for the controlled synthesis of atomically flat NPLs are summarized followed by an insight on recent progress in the mediation of core/shell, core/crown and core/crown@shell structures by selective epitaxial growth of passivation layers on different planes of NPLs. Moreover, an overview of the unique optical properties and the associated light-emitting applications is elaborated. Despite great progress in this research field, there are some issues relating to heavy metal elements such as Cd2+ in NPLs, and the ambiguous gain mechanisms of NPLs and others are the main obstacles that prevent NPLs from widespread applications. Therefore, a perspective is included at the end of this review article, in which the current challenges in this stimulating research field are discussed and possible solutions to tackle these challenges are proposed.
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Affiliation(s)
- Bing Bai
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henaon University, Kaifeng 475004, China
| | - Chengxi Zhang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Yongjiang Dou
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Lingmei Kong
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Lin Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Sheng Wang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Jun Li
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henaon University, Kaifeng 475004, China
| | - Yi Zhou
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henaon University, Kaifeng 475004, China
| | - Long Liu
- Key Lab for Special Functional Materials, Ministry of Education, National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henaon University, Kaifeng 475004, China
| | - Baiquan Liu
- School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xiaoyu Zhang
- Key Laboratory of Automobile Materials, Ministry of Education, College of Materials Science and Engineering, Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Electron Microscopy Center, Jilin University, Changchun 130012, China
| | - Ido Hadar
- Institute of Chemistry, and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yehonadav Bekenstein
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Aixiang Wang
- School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, P. R. China
| | - Zongyou Yin
- Research School of Chemistry, The Australian National University, ACT 2601, Australia
| | - Lyudmila Turyanska
- Faculty of Engineering, The University of Nottingham, Additive Manufacturing Building, Jubilee Campus, University Park, Nottingham NG7 2RD, UK
| | - Jochen Feldmann
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, Munich 80539, Germany
| | - Xuyong Yang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai 200072, China.
| | - Guohua Jia
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia.
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11
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Panfil Y, Cui J, Koley S, Banin U. Complete Mapping of Interacting Charging States in Single Coupled Colloidal Quantum Dot Molecules. ACS NANO 2022; 16:5566-5576. [PMID: 35289161 PMCID: PMC9047002 DOI: 10.1021/acsnano.1c10329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Colloidal quantum dots (CQDs), major building blocks in modern optoelectronic devices, have so far been synthesized with only one emission center where the exciton resides. Recent development of coupled colloidal quantum dots molecules (CQDM), where two core-shell CQDs are fused to form two emission centers in close proximity, allows exploration of how charge carriers in one CQD affect the charge carriers in the other CQD. Cryogenic single particle spectroscopy reveals that while CQD monomers manifest a simple emission spectrum comprising a main emission peak with well-defined phonon sidebands, CQDMs exhibit a complex spectrum with multiple peaks that are not all spaced according to the known phonon frequencies. Based on complementary emission polarization and time-resolved analysis, this is assigned to fluorescence of the two coupled emission centers. Moreover, the complex peak structure shows correlated spectral diffusion indicative of the coupling between the two emission centers. Utilizing Schrödinger-Poisson self-consistent calculations, we directly map the spectral behavior, alternating between neutral and charged states of the CQDM. Spectral shifts related to electrostatic interaction between a charged emission center and the second emission center are thus fully mapped. Furthermore, effects of moving surface charges are identified, whereby the emission center proximal to the charge shows larger shifts. Instances where the two emission centers are negatively charged simultaneously are also identified. Such detailed mapping of charging states is enabled by the coupling within the CQDM and its anisotropic structure. This understanding of the coupling interactions is progress toward quantum technology and sensing applications based on CQDMs.
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12
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Ratnaweera RJ, Rodríguez Ortiz FA, Gripp NJ, Sheldon MT. Quantifying Order during Field-Driven Alignment of Colloidal Semiconductor Nanorods. ACS NANO 2022; 16:3834-3842. [PMID: 35188744 DOI: 10.1021/acsnano.1c08488] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Aligning large populations of colloidal nanorods (NRs) into ordered assemblies provides a strategy for engineering macroscopic functional materials with strong optical anisotropy. The bulk optical properties of such systems depend not only on the individual NR building blocks but also on their meso- and macroscale ordering, in addition to more complex interparticle coupling effects. Here, we investigate the dynamic alignment of colloidal CdSe/CdS NRs in the presence of AC electric fields by measuring concurrent changes in optical transmission. Our work identifies two distinct scales of interaction that give rise to the field-driven optical response: (1) the spontaneous mesoscale self-assembly of colloidal NRs into structures with increased optical anisotropy and (2) the macroscopic ordering of NR assemblies along the direction of the applied AC field. By modeling the alignment of NR ensembles using directional statistics, we experimentally quantify the maximum degree of order in terms of the average deviation angle relative to the field axis. Results show a consistent improvement in alignment as a function of NR concentration─with a minimum average deviation of 36.2°─indicating that mesoscale assembly helps facilitate field-driven alignment of colloidal NRs.
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Affiliation(s)
- Rivi J Ratnaweera
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | | | - Nicholas J Gripp
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Matthew T Sheldon
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
- Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77843-3255, United States
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13
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Stone D, Koley S, Remennik S, Asor L, Panfil YE, Naor T, Banin U. Luminescent Anisotropic Wurtzite InP Nanocrystals. NANO LETTERS 2021; 21:10032-10039. [PMID: 34807613 DOI: 10.1021/acs.nanolett.1c03719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Indium phosphide (InP) nanocrystals are emerging as an alternative to heavy metal containing nanocrystals for optoelectronic applications but lag behind in terms of synthetic control. Herein, luminescent wurtzite InP nanocrystals with narrow size distribution were synthesized via a cation exchange reaction from hexagonal Cu3P nanocrystals. A comprehensive surface treatment with NOBF4 was performed, which removes excess copper while generating stoichiometric In/P nanocrystals with fluoride surface passivation. The attained InP nanocrystals manifest a highly resolved absorption spectrum with a narrow emission line of 80 meV, and photoluminescence quantum yield of up to 40%. Optical anisotropy measurements on ensemble and single particle bases show the occurrence of polarized transitions directly mirroring the anisotropic wurtzite lattice, as also manifested from modeling of the quantum confined electronic levels. This shows a green synthesis path for achieving wurtzite InP nanocrystals with desired optoelectronic properties including color purity and light polarization with potential for diverse optoelectronic applications.
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Affiliation(s)
- David Stone
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Somnath Koley
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Sergei Remennik
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Lior Asor
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yossef E Panfil
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Tom Naor
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Uri Banin
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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14
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Prodanov MF, Gupta SK, Kang C, Diakov MY, Vashchenko VV, Srivastava AK. Thermally Stable Quantum Rods, Covering Full Visible Range for Display and Lighting Application. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2004487. [PMID: 33345459 DOI: 10.1002/smll.202004487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/09/2020] [Indexed: 06/12/2023]
Abstract
Recently, quantum rods (QRs) have been studied heavily for display and lighting applications. QRs offer serious advantages over the quantum dots such as higher light out-coupling coefficient, and polarized emission. The QR enhancement films double liquid crystal display efficiency. However, it is still a challenge to synthesize good quality green (λem ≈ 520 nm) and blue (λem ≈ 465 nm) emitting QRs, due to very large bathochromic shift during the shell growth. Furthermore, until now, the presence of cadmium in high-quality QRs is inevitable, but due to its toxicity, RoHS has restricted the amount of cadmium in consumer products. In this article, low Cd core-shell QRs, with a narrow-band luminescence spectrum tuned in the whole visible range, are prepared by replacing Cd with Zn in a one-pot post-synthetic development. These QRs possess the good thermal stability of photoluminescence properties, and therefore, show high performance for the on-chip LED configuration. The designed white LEDs (WLEDs) are characterized by a high brightness of 120000 nits, and color gamut covering 122% NTSC (90% of BT2020), in the 1931CIE color space. Additionally, these LEDs show a high luminous efficiency of 115 lm W-1 . Thus, these quantum rod LED are perfectly viable for display backlighting and lighting applications.
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Affiliation(s)
- Maksym F Prodanov
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Swadesh K Gupta
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Chengbin Kang
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Maksym Y Diakov
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Valerii V Vashchenko
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Abhishek K Srivastava
- State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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15
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Usman M. Tunable bandgap and isotropic light absorption from bismuth-containing GaAs core-shell and multi-shell nanowires. NANOSCALE 2020; 12:20973-20983. [PMID: 33053001 DOI: 10.1039/d0nr04728g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Semiconductor core-shell nanowires based on the GaAs substrate are the building blocks of many photonic, photovoltaic and electronic devices, thanks to their associated direct bandgap and highly tunable optoelectronic properties. The selection of a suitable material system is crucial for custom designed nanowires tailored for optimised device performance. Bismuth-containing GaAs materials are an imminent class of semiconductors which not only enable an exquisite control over the alloy strain and electronic structure but also offer the possibility to suppress internal loss mechanisms in photonic devices. Whilst the experimental efforts to incorporate GaBixAs1-x alloys in the nanowire active region are still at an early stage, the theoretical understanding of the optoelectronic properties of such nanowires is only rudimentary. This work elucidates and quantifies the role of nanowire physical attributes such as its geometry parameters and bismuth incorporation in designing light absorption wavelength and polarisation response. Based on the multi-million atom tight-binding simulations of the GaBixAs1-x/GaAs core-shell and GaAs/GaBixAs1-x/GaAs multi-shell nanowires, our results predict a large tuning of the absorption wavelength, ranging from 0.9 μm to 1.6 μm, which can be controlled by engineering either Bi composition or nanowire diameter. The analysis of their strain profiles indicates a tensile character leading to significant light-hole mixing in the valence band states. This offers a possibility to achieve polarisation-insensitive light interaction, which is desirable for several photonic devices involving amplification and modulation of light. Furthermore, at low Bi compositions, the carrier confinement is quasi type-II, which further broadens the suitability of these nanowires for a myriad of applications requiring large carrier separations. The presented results provide a systematic and comprehensive understanding of the GaBixAs1-x nanowire properties and highlight new possibilities for future technologies in photonics, quantum optics and solar energy harvesting.
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Affiliation(s)
- Muhammad Usman
- School of Computing and Information Systems, Melbourne School of Engineering, The University of Melbourne, Parkville, 3010, Victoria, Australia. and School of Physics, The University of Melbourne, Parkville, 3010, Victoria, Australia
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16
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Investigation of Magnetic Circular Dichroism Spectra of Semiconductor Quantum Rods and Quantum Dot-in-Rods. NANOMATERIALS 2020; 10:nano10061059. [PMID: 32486321 PMCID: PMC7352828 DOI: 10.3390/nano10061059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 12/22/2022]
Abstract
Anisotropic quantum nanostructures have attracted a lot of attention due to their unique properties and a range of potential applications. Magnetic circular dichroism (MCD) spectra of semiconductor CdSe/ZnS Quantum Rods and CdSe/CdS Dot-in-Rods have been studied. Positions of four electronic transitions were determined by data fitting. MCD spectra were analyzed in the A and B terms, which characterize the splitting and mixing of states. Effective values of A and B terms were determined for each transition. A relatively high value of the B term is noted, which is most likely associated with the anisotropy of quantum rods.
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17
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Lee H, Yoon DE, Koh S, Kang MS, Lim J, Lee DC. Ligands as a universal molecular toolkit in synthesis and assembly of semiconductor nanocrystals. Chem Sci 2020; 11:2318-2329. [PMID: 32206291 PMCID: PMC7069383 DOI: 10.1039/c9sc05200c] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 02/10/2020] [Indexed: 01/05/2023] Open
Abstract
The multiple ligands with different functionalities enable atomic-precision control of NCs morphology and subtle inter-NC interactions, which paves the way for novel optoelectronic applications.
Successful exploitation of semiconductor nanocrystals (NCs) in commercial products is due to the remarkable progress in the wet-chemical synthesis and controlled assembly of NCs. Central to the cadence of this progress is the ability to understand how NC growth and assembly can be controlled kinetically and thermodynamically. The arrested precipitation strategy offers a wide opportunity for materials selection, size uniformity, and morphology control. In this colloidal approach, capping ligands play an instrumental role in determining growth parameters and inter-NC interactions. The impetus for exquisite control over the size and shape of NCs and orientation of NCs in an ensemble has called for the use of two or more types of ligands in the system. In multiple ligand approaches, ligands with different functionalities confer extended tunability, hinting at the possibility of atomic-precision growth and long-range ordering of desired superlattices. Here, we highlight the progress in understanding the roles of ligands in size and shape control and assembly of NCs. We discuss the implication of the advances in the context of optoelectronic applications.
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Affiliation(s)
- Hyeonjun Lee
- Department of Chemical and Biomolecular Engineering , KAIST Institute for the Nanocentury , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea .
| | - Da-Eun Yoon
- Department of Chemical and Biomolecular Engineering , KAIST Institute for the Nanocentury , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea .
| | - Sungjun Koh
- Department of Chemical and Biomolecular Engineering , KAIST Institute for the Nanocentury , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea .
| | - Moon Sung Kang
- Department of Chemical and Biomolecular Engineering , Sogang University , Seoul 04107 , Republic of Korea
| | - Jaehoon Lim
- Department of Energy Science , Center for Artificial Atoms , Sungkyunkwan University (SKKU) , Suwon , Gyeonggi-do 16419 , Republic of Korea .
| | - Doh C Lee
- Department of Chemical and Biomolecular Engineering , KAIST Institute for the Nanocentury , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea .
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18
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Single-particle spectroscopy for functional nanomaterials. Nature 2020; 579:41-50. [PMID: 32132689 DOI: 10.1038/s41586-020-2048-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022]
Abstract
Tremendous progress in nanotechnology has enabled advances in the use of luminescent nanomaterials in imaging, sensing and photonic devices. This translational process relies on controlling the photophysical properties of the building block, that is, single luminescent nanoparticles. In this Review, we highlight the importance of single-particle spectroscopy in revealing the diverse optical properties and functionalities of nanomaterials, and compare it with ensemble fluorescence spectroscopy. The information provided by this technique has guided materials science in tailoring the synthesis of nanomaterials to achieve optical uniformity and to develop novel applications. We discuss the opportunities and challenges that arise from pushing the resolution limit, integrating measurement and manipulation modalities, and establishing the relationship between the structure and functionality of single nanoparticles.
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19
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Efficient and Stable CdSe/CdS/ZnS Quantum Rods-in-Matrix Assembly for White LED Application. NANOMATERIALS 2020; 10:nano10020317. [PMID: 32059468 PMCID: PMC7075110 DOI: 10.3390/nano10020317] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/11/2022]
Abstract
CdSe/CdS core-shell quantum rods (QRs) are a promising prospect in optoelectronic applications but usually have a relatively low quantum efficiency and stability. Here, we report on an efficient and stable CdSe/CdS/ZnS QRs-in-matrix assembly (QRAs) by growing and embedding CdSe/CdS QRs in ZnS matrices. Structural characterizations show that the CdSe/CdS QRs are encapsulated and interconnected by ZnS in the QRAs structure. The stable ZnS encapsulation renders the CdSe/CdS QRs high quantum efficiency (QE) up to 85%. The QRAs also present high photo- and thermal-stability and can preserve 93% of the initial QE at 100 °C. The QRAs powder presents a light degradation of only 2% under continuous excitation for 100 h, displaying profound potential in optoelectronic applications. White light-emitting diodes (WLEDs) are fabricated by packaging the QRAs powder as phosphor on top of blue GaN chip. The WLED shows high optical performance and light quality.
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20
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Yang G, Zhong H. Multi‐Dimensional Quantum Nanostructures with Polarization Properties for Display Applications. Isr J Chem 2019. [DOI: 10.1002/ijch.201900001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Gaoling Yang
- Department of Physics of Complex SystemsWeizmann Institute of Science Rehovot 76100 Israel
| | - Haizheng Zhong
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic SystemsSchool of Materials Science & EngineeringBeijing Institute of Technology Beijing China
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21
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Chakrabarty A, Raffy G, Maity M, Gartzia-Rivero L, Marre S, Aymonier C, Maitra U, Del Guerzo A. Nanofiber-Directed Anisotropic Self-Assembly of CdSe-CdS Quantum Rods for Linearly Polarized Light Emission Evidenced by Quantum Rod Orientation Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1802311. [PMID: 30112796 DOI: 10.1002/smll.201802311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Hybrid soft materials composed of CdSe-CdS nanorods or "quantum rods" (QRs) and the fluorescent 2,3-didecyloxyanthracene (DDOA) low molecular weight organogelator are obtained through self-assembly. Spectroscopy, microscopy, and rheology studies show that the QRs and DDOA coassemble, thereby stabilizing the organogels. Depending on the QR load and excitation wavelength, single nanofibers (NFs) of the hybrid gel display either sharp polarized red luminescence (under green excitation), or dual perpendicularly polarized blue and red emissions (under UV excitation). Transmission electron microscopy, microspectroscopy, and quantum rod orientation microscopy (QROM) reveal that QRs align along the organogel NFs with order parameters reaching 76% and 87%. This paves the way for obtaining surfaces of QR/NF assemblies yielding sharp red linearly polarized emission. In addition, this work demonstrates that QRs can be used more generally to probe nanostructured soft materials, even nonemissive ones. QROM allows to establish maps of the orientation of single QRs dispersed onto or within a gel network by measuring the polarization of the emission of the individual QRs. As occurs within this work in which QRs and NFs interact, the orientation of each QR reveals information on the underlying nanostructure (such as surface striation, bundle formation, and helicity).
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Affiliation(s)
- Arkajyoti Chakrabarty
- Institut des Sciences Moléculaires, UMR 5255, Université de Bordeaux, CNRS, 351 Cours de la Libération, 33400, Talence, France
- ICMCB, Bordeaux INP, UMR 5026, Université de Bordeaux, CNRS, 87 av. du Dr. Schweitzer, 33600, Pessac, France
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Guillaume Raffy
- Institut des Sciences Moléculaires, UMR 5255, Université de Bordeaux, CNRS, 351 Cours de la Libération, 33400, Talence, France
| | - Mitasree Maity
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Leire Gartzia-Rivero
- Institut des Sciences Moléculaires, UMR 5255, Université de Bordeaux, CNRS, 351 Cours de la Libération, 33400, Talence, France
- Department of Physical Chemistry, University of the Basque Country (UPV/EHU), Apartado 644, 48080, Bilbao, Spain
| | - Samuel Marre
- ICMCB, Bordeaux INP, UMR 5026, Université de Bordeaux, CNRS, 87 av. du Dr. Schweitzer, 33600, Pessac, France
| | - Cyril Aymonier
- ICMCB, Bordeaux INP, UMR 5026, Université de Bordeaux, CNRS, 87 av. du Dr. Schweitzer, 33600, Pessac, France
| | - Uday Maitra
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - André Del Guerzo
- Institut des Sciences Moléculaires, UMR 5255, Université de Bordeaux, CNRS, 351 Cours de la Libération, 33400, Talence, France
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22
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He J, Towers A, Wang Y, Yuan P, Jiang Z, Chen J, Gesquiere AJ, Wu ST, Dong Y. In situ synthesis and macroscale alignment of CsPbBr 3 perovskite nanorods in a polymer matrix. NANOSCALE 2018; 10:15436-15441. [PMID: 30094423 DOI: 10.1039/c8nr04895a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report an in situ catalyst-free strategy to synthesize inorganic CsPbBr3 perovskite nanorods in a polymer matrix (NRs-PM) with good dimensional control, outstanding optical properties and ultrahigh environmental stability. Polarization photoluminescence (PL) imaging with high spatial resolution was carried out for the first time on single nanorod (NR) and shows a relatively high local polarization ratio (∼0.4) consistent with theoretical predictions based on a dielectric contrast model. We further demonstrate that macroscale alignment of the CsPbBr3 nanorods can be achieved through mechanically stretching the NRs-PM films at elevated temperature, without deteriorating the optical quality of the NRs. A polarization ratio of 0.23 is observed for these aligned NRs-PM films, suggesting their potential as polarized down-converters to increase the light efficiency in liquid crystal display (LCD) backlights.
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Affiliation(s)
- Juan He
- College of Optics and Photonics, University of Central Florida, Orlando, Florida, USA.
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23
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Panfil YE, Oded M, Banin U. Colloidal Quantum Nanostructures: Emerging Materials for Display Applications. Angew Chem Int Ed Engl 2018; 57:4274-4295. [PMID: 28975692 PMCID: PMC6001641 DOI: 10.1002/anie.201708510] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Indexed: 11/11/2022]
Abstract
Colloidal semiconductor nanocrystals (SCNCs) or, more broadly, colloidal quantum nanostructures constitute outstanding model systems for investigating size and dimensionality effects. Their nanoscale dimensions lead to quantum confinement effects that enable tuning of their optical and electronic properties. Thus, emission color control with narrow photoluminescence spectra, wide absorbance spectra, and outstanding photostability, combined with their chemical processability through control of their surface chemistry leads to the emergence of SCNCs as outstanding materials for present and next-generation displays. In this Review, we present the fundamental chemical and physical properties of SCNCs, followed by a description of the advantages of different colloidal quantum nanostructures for display applications. The open challenges with respect to their optical activity are addressed. Both photoluminescent and electroluminescent display scenarios utilizing SCNCs are described.
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Affiliation(s)
- Yossef E. Panfil
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Meirav Oded
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Uri Banin
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
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24
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Panfil YE, Oded M, Banin U. Kolloidale Quantennanostrukturen: neue Materialien für Displayanwendungen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201708510] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yossef E. Panfil
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
| | - Meirav Oded
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
| | - Uri Banin
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
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25
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Li ZJ, Hofman E, Blaker A, Davis AH, Dzikovski B, Ma DK, Zheng W. Interface Engineering of Mn-Doped ZnSe-Based Core/Shell Nanowires for Tunable Host-Dopant Coupling. ACS NANO 2017; 11:12591-12600. [PMID: 29172442 DOI: 10.1021/acsnano.7b06773] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Transition metal ion doped one-dimensional (1-D) nanocrystals (NCs) have advantages of larger absorption cross sections and polarized absorption and emissions in comparison to 0-D NCs. However, direct synthesis of doped 1-D nanorods (NRs) or nanowires (NWs) has proven challenging. In this study, we report the synthesis of 1-D Mn-doped ZnSe NWs using a colloidal hot-injection method and shell passivation for core/shell NWs with tunable optical properties. Experimental results show optical properties of the NWs are controlled by the composition and thickness of the shell lattice. It was found that both the host-Mn energy transfer and Mn-Mn coupling are strongly dependent on the type of alloy at the interface of doped core/shell NWs. For Mn-doped type I ZnSe/ZnS core/shell NWs, the ZnS shell passivation can enhance florescence quantum yield with little effect on the location of the incorporated Mn dopant due to the identical cationic Zn2+ site available for Mn dopants throughout the core/shell NWs. However, for Mn-doped quasi type II ZnSe/CdS NWs and ZnSe/CdS/ZnS core/shell NWs, the cation alloying (Zn1-xCdxS(e)) can lead to metal dopant migration from the core to the alloyed interface and tunable host-dopant energy transfer efficiencies and Mn-Mn coupling. As a result, a tunable dual-band emission can be achieved for the doped NWs with the cation-alloyed interface. The interfacial alloying mediated energy transfer and Mn-Mn coupling provides a method to control the optical properties of the doped 1-D core/shell NWs.
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Affiliation(s)
- Zhi-Jun Li
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Elan Hofman
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Amanda Blaker
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Andrew Hunter Davis
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Boris Dzikovski
- National Biomedical Center for Advanced Electron Spin Resonance Technology , Ithaca, New York 14853, United States
| | - De-Kun Ma
- Zhejiang Key Laboratory of Carbon Materials, Wenzhou University , Wenzhou, Zhejiang 325027, People's Republic of China
| | - Weiwei Zheng
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
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26
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Kim D, Lee YK, Lee D, Kim WD, Bae WK, Lee DC. Colloidal Dual-Diameter and Core-Position-Controlled Core/Shell Cadmium Chalcogenide Nanorods. ACS NANO 2017; 11:12461-12472. [PMID: 29131591 DOI: 10.1021/acsnano.7b06542] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
To capitalize on shape- and structure-dependent properties of semiconductor nanorods (NRs), high-precision control and exquisite design of their growth are desired. Cadmium chalcogenide (CdE; E = S or Se) NRs are the most studied class of such, whose growth exhibits axial anisotropy, i.e., different growth rates along the opposite directions of {0001} planes. However, the mechanism behind asymmetric axial growth of NRs remains unclear because of the difficulty in instant analysis of growth surfaces. Here, we design colloidal dual-diameter semiconductor NRs (DDNRs) under the quantum confinement regime, which have two sections along the long axis with different diameters. The segmentation of the DDNRs allows rigorous assessment of the kinetics of NR growth at a molecular level. The reactivity of a terminal facet passivated by an organic ligand is governed by monomer diffusivity through the surface ligand monolayer. Therefore, the growth rate in two polar directions can be finely tuned by controlling the strength of ligand-ligand attraction at end surfaces. Building on these findings, we report the synthesis of single-diameter CdSe/CdS core/shell NRs with CdSe cores of controllable position, which reveals a strong structure-optical polarization relationship. The understanding of the NR growth mechanism with controllable anisotropy will serve as a cornerstone for the exquisite design of more complex anisotropic nanostructures.
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Affiliation(s)
- Dahin Kim
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Korea
| | - Young Kuk Lee
- Advanced Materials Division, Korea Research Institute of Chemical Technology (KRICT) , Daejeon 34114, Korea
| | - Dongkyu Lee
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Korea
| | - Whi Dong Kim
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Korea
| | - Wan Ki Bae
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology (KIST) , Seoul 02792, Korea
| | - Doh C Lee
- Department of Chemical and Biomolecular Engineering, KAIST Institute for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Korea
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27
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Ji B, Panfil YE, Banin U. Heavy-Metal-Free Fluorescent ZnTe/ZnSe Nanodumbbells. ACS NANO 2017; 11:7312-7320. [PMID: 28654241 DOI: 10.1021/acsnano.7b03407] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
For visible range emitting particles, which are relevant for display and additional applications, Cd-chalcogenide nanocrystals have reached the highest degree of control and performance. Considering potential toxicity and regulatory limitations, there is a challenge to successfully develop Cd-free emitting nanocrystals and, in particular, heterostructures with desirable properties. Herein, we report a colloidal synthesis of fluorescent heavy-metal-free Zn-chalcogenide semiconductor nanodumbbells (NDBs), in which ZnSe tips were selectively grown on the apexes of ZnTe rods, as evidenced by a variety of methods. The fluorescence of the NDBs can be tuned between ∼500 and 585 nm by changing the ZnSe tip size. The emission quantum yield can be greatly increased through chloride surface treatment and reaches more than 30%. Simulations within an effective-mass-based model show that the hole wave function is spread over the ZnTe nanorods, while the electron wave function is localized on the ZnSe tips. Quantitative agreement for the red-shifted emission wavelength is obtained between the simulations and the experiments. Additionally, the changes in radiative lifetimes correlate well with the calculated decrease in electron-hole overlap upon growth of larger ZnSe tips. The heavy-metal-free ZnTe/ZnSe NDBs may be relevant for optoelectronic applications such as displays or light-emitting diodes.
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Affiliation(s)
- Botao Ji
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Yossef E Panfil
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Uri Banin
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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28
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Gao Y, Weidman MC, Tisdale WA. CdSe Nanoplatelet Films with Controlled Orientation of their Transition Dipole Moment. NANO LETTERS 2017; 17:3837-3843. [PMID: 28534407 DOI: 10.1021/acs.nanolett.7b01237] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Using liquid-liquid interfacial assembly, we control the deposition of CdSe nanoplatelets into face-down or edge-up configurations. Controlled assembly, combined with back focal plane imaging, enabled unambiguous determination of the transition dipole orientation. The transition dipole moment of the emissive band-edge exciton in CdSe nanoplatelets was found to be isotropically oriented within the plane of the nanoplatelet with no measurable out-of-plane component and no preference for the long- or short-axis of the nanoplatelet. Importantly, CdSe nanoplatelet films in the face-down configuration exhibited unity dipole orientation within the plane of the film, which could improve the external efficiency of nanoplatelet LEDs, lasers, photodetectors, and photovoltaic cells beyond that which is possible with isotropic emitters. We also show that the two self-assembled configurations have different Förster energy transfer rates, as a result of different dipole orientation and internanoplatelet distance.
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Affiliation(s)
- Yunan Gao
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Mark C Weidman
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - William A Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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29
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Hadar I, Philbin JP, Panfil YE, Neyshtadt S, Lieberman I, Eshet H, Lazar S, Rabani E, Banin U. Semiconductor Seeded Nanorods with Graded Composition Exhibiting High Quantum-Yield, High Polarization, and Minimal Blinking. NANO LETTERS 2017; 17:2524-2531. [PMID: 28221804 DOI: 10.1021/acs.nanolett.7b00254] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Seeded semiconductor nanorods represent a unique family of quantum confined materials that manifest characteristics of mixed dimensionality. They show polarized emission with high quantum yield and fluorescence switching under an electric field, features that are desirable for use in display technologies and other optical applications. So far, their robust synthesis has been limited mainly to CdSe/CdS heterostructures, thereby constraining the spectral tunability to the red region of the visible spectrum. Herein we present a novel synthesis of CdSe/Cd1-xZnxS seeded nanorods with a radially graded composition that show bright and highly polarized green emission with minimal intermittency, as confirmed by ensemble and single nanorods optical measurements. Atomistic pseudopotential simulations elucidate the importance of the Zn atoms within the nanorod structure, in particular the effect of the graded composition. Thus, the controlled addition of Zn influences and improves the nanorods' optoelectronic performance by providing an additional handle to manipulate the degree confinement beyond the common size control approach. These nanorods may be utilized in applications that require the generation of a full, rich spectrum such as energy-efficient displays and lighting.
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Affiliation(s)
- Ido Hadar
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - John P Philbin
- Department of Chemistry, University of California and Lawrence Berkeley National Laboratory , Berkeley, California 94720-1460, United States
| | - Yossef E Panfil
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Shany Neyshtadt
- Qlight Nanotech Ltd. (Merck KGaA), Edmond J. Safra Campus, Danciger Building A, POB: 39082, 9139002 Jerusalem, Israel
| | - Itai Lieberman
- Merck KGaA , Performance Materials, Advanced Technologies, OLED & Quantum Materials, Frankfurter Straße 250, 64293 Darmstadt, Germany
| | - Hagai Eshet
- The Sackler Institute for Computational Molecular and Materials Science, Tel Aviv University , Tel Aviv, Israel 69978
- School of Chemistry, Tel Aviv University , Tel Aviv, Israel 69978
| | - Sorin Lazar
- FEI Company, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Eran Rabani
- Department of Chemistry, University of California and Lawrence Berkeley National Laboratory , Berkeley, California 94720-1460, United States
- The Sackler Institute for Computational Molecular and Materials Science, Tel Aviv University , Tel Aviv, Israel 69978
| | - Uri Banin
- The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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30
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Liu P, Singh S, Guo Y, Wang JJ, Xu H, Silien C, Liu N, Ryan KM. Assembling Ordered Nanorod Superstructures and Their Application as Microcavity Lasers. Sci Rep 2017; 7:43884. [PMID: 28272427 PMCID: PMC5341026 DOI: 10.1038/srep43884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/30/2017] [Indexed: 01/15/2023] Open
Abstract
Herein we report the formation of multi-layered arrays of vertically aligned and close packed semiconductor nanorods in perfect registry at a substrate using electric field assisted assembly. The collective properties of these CdSexS1-x nanorod emitters are harnessed by demonstrating a relatively low amplified spontaneous emission (ASE) threshold and a high net optical gain at medium pump intensity. The importance of order in the system is highlighted where a lower ASE threshold is observed compared to disordered samples.
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Affiliation(s)
- Pai Liu
- Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Shalini Singh
- Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Yina Guo
- Bernal Institute University of Limerick, Limerick, Ireland
| | - Jian-Jun Wang
- Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Hongxing Xu
- The School of Physics and Technology, The Institute for Advanced Studies and The Center for Nanoscience and Nanotechnology, Wuhan University, Wuhan, 430072, China
| | - Christophe Silien
- Department of Physics and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Ning Liu
- Department of Physics and Bernal Institute, University of Limerick, Limerick, Ireland
| | - Kevin M Ryan
- Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick, Ireland
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31
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Shroder DY, Lippert LG, Goldman YE. Single molecule optical measurements of orientation and rotations of biological macromolecules. Methods Appl Fluoresc 2016; 4:042004. [PMID: 28192292 PMCID: PMC5308470 DOI: 10.1088/2050-6120/4/4/042004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Subdomains of macromolecules often undergo large orientation changes during their catalytic cycles that are essential for their activity. Tracking these rearrangements in real time opens a powerful window into the link between protein structure and functional output. Site-specific labeling of individual molecules with polarized optical probes and measurement of their spatial orientation can give insight into the crucial conformational changes, dynamics, and fluctuations of macromolecules. Here we describe the range of single molecule optical technologies that can extract orientation information from these probes, review the relevant types of probes and labeling techniques, and highlight the advantages and disadvantages of these technologies for addressing specific inquiries.
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32
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Mukhina MV, Baimuratov AS, Rukhlenko ID, Maslov VG, Purcell Milton F, Gun'ko YK, Baranov AV, Fedorov AV. Circular Dichroism of Electric-Field-Oriented CdSe/CdS Quantum Dots-in-Rods. ACS NANO 2016; 10:8904-8909. [PMID: 27556811 DOI: 10.1021/acsnano.6b04875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Here we report anisotropy of intrinsic chiroptical response in CdSe/CdS quantum dot-in-rod systems. These nanostructures being oriented in an external electric field demonstrate dependence of circular dichroism signal on the orientation of the nanocrystals. The type of circular polarization in these nanostructures correlates with preferential direction of linear polarization, and the degree of circular polarization is the maximal for the first circular dichroism band corresponding to the absorption band edge. We also support our experimental data with a theoretical model. Using this model, we show a direct connection between theoretically derived morphological parameters of twisting in nanocrystals lattices and calculated from experimental data parameters of circular dichroism anisotropy.
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Affiliation(s)
- Maria V Mukhina
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
| | - Anvar S Baimuratov
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
| | - Ivan D Rukhlenko
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
- Monash University, Clayton Campus , Victoria 3800, Australia
| | - Vladimir G Maslov
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
| | - Finn Purcell Milton
- School of Chemistry and CRANN Institute, Trinity College, Dublin , Dublin 2, Ireland
| | - Yurii K Gun'ko
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
- School of Chemistry and CRANN Institute, Trinity College, Dublin , Dublin 2, Ireland
| | - Alexander V Baranov
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
| | - Anatoly V Fedorov
- Department of Optical Physics and Modern Natural Science, ITMO University , Saint Petersburg 197101, Russia
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33
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Cunningham PD, Souza JB, Fedin I, She C, Lee B, Talapin DV. Assessment of Anisotropic Semiconductor Nanorod and Nanoplatelet Heterostructures with Polarized Emission for Liquid Crystal Display Technology. ACS NANO 2016; 10:5769-81. [PMID: 27203222 DOI: 10.1021/acsnano.5b07949] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Semiconductor nanorods can emit linear-polarized light at efficiencies over 80%. Polarization of light in these systems, confirmed through single-rod spectroscopy, can be explained on the basis of the anisotropy of the transition dipole moment and dielectric confinement effects. Here we report emission polarization in macroscopic semiconductor-polymer composite films containing CdSe/CdS nanorods and colloidal CdSe nanoplatelets. Anisotropic nanocrystals dispersed in polymer films of poly butyl-co-isobutyl methacrylate (PBiBMA) can be stretched mechanically in order to obtain unidirectionally aligned arrays. A high degree of alignment, corresponding to an orientation factor of 0.87, was achieved and large areas demonstrated polarized emission, with the contrast ratio I∥/I⊥ = 5.6, making these films viable candidates for use in liquid crystal display (LCD) devices. To some surprise, we observed significant optical anisotropy and emission polarization for 2D CdSe nanoplatelets with the electronic structure of quantum wells. The aligned nanorod arrays serve as optical funnels, absorbing unpolarized light and re-emitting light from deep-green to red with quantum efficiencies over 90% and high degree of linear polarization. Our results conclusively demonstrate the benefits of anisotropic nanostructures for LCD backlighting. The polymer films with aligned CdSe/CdS dot-in-rod and rod-in-rod nanostructures show more than 2-fold enhancement of brightness compared to the emitter layers with randomly oriented nanostructures. This effect can be explained as the combination of linearly polarized luminescence and directional emission from individual nanostructures.
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Affiliation(s)
- Patrick D Cunningham
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
| | - João B Souza
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
- Instituto de Química de São Carlos, Universidade de São Paulo-USP, Colloidal Materials Group , CP 780, 13566-590 São Carlos, São Paulo, Brazil
| | - Igor Fedin
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
| | - Chunxing She
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
| | - Byeongdu Lee
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Dmitri V Talapin
- Department of Chemistry and James Franck Institute, University of Chicago , Chicago, Illinois 60637, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
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34
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He W, Ye X, Yao X, Wu X, Lin Q, Huang G, Hua Y, Hui Y. Characterization of the binding of shikonin to human immunoglobulin using scanning electron microscope, molecular modeling and multi-spectroscopic methods. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 150:514-522. [PMID: 26073597 DOI: 10.1016/j.saa.2015.04.085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/01/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
Shikonin, one of the active components isolated from the root of Arnebia euchroma (Royle) Johnst, have anti-tumor, anti-bacterial and anti-inflammatory activities and has been used clinically in phlebitis and vascular purpura. In the present work, the interaction of human immunoglobulin (HIg) with shikonin has been investigated by using scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, fluorescence polarization, synchronous and 3D fluorescence spectroscopy in combination with molecular modeling techniques under physiological conditions with drug concentrations of 3.33-36.67 μM. The results of SEM exhibited visually the special effect on aggregation behavior of the complex formed between HIg and shikonin. The fluorescence polarization values indicated that shikonin molecules were found in a motionally unrestricted environment introduced by HIg. Molecular docking showed the shikonin moiety bound to the hydrophobic cavity of HIg, and there are four hydrogen-bonding interactions between shikonin and the residues of protein. The synchronous and 3D fluorescence spectra confirmed that shikonin could quench the intrinsic fluorescence of HIg and has an effect on the microenvironment around HIg in aqueous solution. The changes in the secondary structure of HIg were estimated by qualitative and quantitative FT-IR spectroscopic analysis. The binding constants and thermodynamic parameters for shikonin-HIg systems were obtained under different temperatures (300 K, 310 K and 320 K). The above results revealed the binding mechanism of shikonin and HIg at the ultrastructure and molecular level.
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Affiliation(s)
- Wenying He
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China.
| | - Xinyu Ye
- College of Chemical and Chemical Engineering, Central South University, Changsha 410083, PR China
| | - Xiaojun Yao
- College of Chemical and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
| | - Xiuli Wu
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
| | - Qiang Lin
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
| | - Guolei Huang
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
| | - Yingjie Hua
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
| | - Yang Hui
- College of Chemical and Chemical Engineering, Hainan Normal University, Haikou 571158, PR China
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35
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Wu K, Chen J, McBride JR, Lian T. CHARGE TRANSFER. Efficient hot-electron transfer by a plasmon-induced interfacial charge-transfer transition. Science 2015; 349:632-5. [PMID: 26250682 DOI: 10.1126/science.aac5443] [Citation(s) in RCA: 487] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plasmon-induced hot-electron transfer from metal nanostructures is a potential new paradigm for solar energy conversion; however, the reported efficiencies of devices based on this concept are often low because of the loss of hot electrons via ultrafast electron-electron scattering. We propose a pathway, called the plasmon-induced interfacial charge-transfer transition (PICTT), that enables the decay of a plasmon by directly exciting an electron from the metal to a strongly coupled acceptor. We demonstrated this concept in cadmium selenide nanorods with gold tips, in which the gold plasmon was strongly damped by cadmium selenide through interfacial electron transfer. The quantum efficiency of the PICTT process was high (>24%), independent of excitation photon energy over a ~1-electron volt range, and dependent on the excitation polarization.
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Affiliation(s)
- K Wu
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA
| | - J Chen
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA
| | - J R McBride
- Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - T Lian
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA.
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36
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Vezzoli S, Manceau M, Leménager G, Glorieux Q, Giacobino E, Carbone L, De Vittorio M, Bramati A. Exciton Fine Structure of CdSe/CdS Nanocrystals Determined by Polarization Microscopy at Room Temperature. ACS NANO 2015; 9:7992-8003. [PMID: 26212764 DOI: 10.1021/acsnano.5b01354] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a method that allows determining the band-edge exciton fine structure of CdSe/CdS dot-in-rods samples based on single particle polarization measurements at room temperature. We model the measured emission polarization of such single particles considering the fine structure properties, the dielectric effect induced by the anisotropic shell, and the measurement configuration. We use this method to characterize the band-edge exciton fine structure splitting of various samples of dot-in-rods. We show that, when the diameter of the CdSe core increases, a transition from a spherical like band-edge exciton symmetry to a rod-like band edge exciton symmetry occurs. This explains the often reported large emission polarization of such particles compared to spherical CdSe/CdS emitters.
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Affiliation(s)
- Stefano Vezzoli
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France , 4, Place Jussieu Case 74, F-75005 Paris, France
- Center for Disruptive Photonic Technology (CDPT), School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
| | - Mathieu Manceau
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France , 4, Place Jussieu Case 74, F-75005 Paris, France
| | - Godefroy Leménager
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France , 4, Place Jussieu Case 74, F-75005 Paris, France
- Laboratoire de Physique de la Matière Condensée, CNRS - Ecole Polytechnique , UMR 7643, 91128 Palaiseau, France
| | - Quentin Glorieux
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France , 4, Place Jussieu Case 74, F-75005 Paris, France
| | - Elisabeth Giacobino
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France , 4, Place Jussieu Case 74, F-75005 Paris, France
| | - Luigi Carbone
- CNR NANOTEC-Istituto di Nanotecnologia U.O. Lecce , c/o Polo di Nanotecnologia-Campus Ecotekne, via Monteroni, 73100 Lecce, Italy
| | - Massimo De Vittorio
- Istituto Italiano di Tecnologia (IIT) , Center for Bio-Molecular Nanotechnologies Via Barsanti sn, 73010 Arnesano (Lecce), Italy
| | - Alberto Bramati
- Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, 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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Wu K, Hill LJ, Chen J, McBride JR, Pavlopolous NG, Richey NE, Pyun J, Lian T. Universal Length Dependence of Rod-to-Seed Exciton Localization Efficiency in Type I and Quasi-Type II CdSe@CdS Nanorods. ACS NANO 2015; 9:4591-9. [PMID: 25803834 DOI: 10.1021/acsnano.5b01245] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A critical step involved in many applications of one-dimensional seeded CdSe@CdS nanorods, such as luminescent solar concentrators, optical gains, and photocatalysis, is the localization of excitons from the light-harvesting CdS nanorod antenna into the light-emitting CdSe quantum dot seed. We report that the rod-to-seed exciton localization efficiency decreases with the rod length but is independent of band alignment between the CdSe seed and CdS rod. This universal dependence can be well modeled by the competition between exciton one-dimensional diffusion to the CdSe seed and trapping on the CdS rod. This finding provides a rational approach for optimizing these materials for their various device applications.
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Affiliation(s)
- Kaifeng Wu
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - Lawrence J Hill
- ‡Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States
| | - Jinquan Chen
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
| | - James R McBride
- §Department of Chemistry, The Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Nicholas G Pavlopolous
- ‡Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States
| | - Nathaniel E Richey
- ‡Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States
| | - Jeffrey Pyun
- ‡Department of Chemistry and Biochemistry, University of Arizona, 1306 East University Boulevard, Tucson, Arizona 85721, United States
| | - Tianquan Lian
- †Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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38
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Cipolloni M, Kaleta J, Mašát M, Dron PI, Shen Y, Zhao K, Rogers CT, Shoemaker RK, Michl J. Time-Resolved Fluorescence Anisotropy of Bicyclo[1.1.1]pentane/Tolane-Based Molecular Rods Included in Tris( o-phenylenedioxy)cyclotriphosphazene (TPP). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2015; 119:8805-8820. [PMID: 25937858 PMCID: PMC4415047 DOI: 10.1021/acs.jpcc.5b01960] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 03/16/2015] [Indexed: 05/27/2023]
Abstract
We examine the fluorescence anisotropy of rod-shaped guests held inside the channels of tris(o-phenylenedioxy)cyclotriphosphazene (TPP) host nanocrystals, characterized by powder X-ray diffraction and solid state NMR spectroscopy. We address two issues: (i) are light polarization measurements on an aqueous colloidal solution of TPP nanocrystals meaningful, or is depolarization by scattering excessive? (ii) Can measurements of the rotational mobility of the included guests be performed at low enough loading levels to suppress depolarization by intercrystallite energy transfer? We find that meaningful measurements are possible and demonstrate that the long axis of molecular rods included in TPP channels performs negligible vibrational motion.
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Affiliation(s)
- Marco Cipolloni
- Institute of Organic
Chemistry and Biochemistry, Academy of Sciences of the
Czech Republic, Flemingovo
nám. 2, 16610 Prague, Czech Republic
| | - Jiří Kaleta
- Institute of Organic
Chemistry and Biochemistry, Academy of Sciences of the
Czech Republic, Flemingovo
nám. 2, 16610 Prague, Czech Republic
| | - Milan Mašát
- Institute of Organic
Chemistry and Biochemistry, Academy of Sciences of the
Czech Republic, Flemingovo
nám. 2, 16610 Prague, Czech Republic
| | - Paul I. Dron
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Yongqiang Shen
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Ke Zhao
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Charles T. Rogers
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Richard K. Shoemaker
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Josef Michl
- Institute of Organic
Chemistry and Biochemistry, Academy of Sciences of the
Czech Republic, Flemingovo
nám. 2, 16610 Prague, Czech Republic
- Department
of Chemistry and Biochemistry and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
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Wu K, Rodríguez-Córdoba W, Lian T. Exciton Localization and Dissociation Dynamics in CdS and CdS–Pt Quantum Confined Nanorods: Effect of Nonuniform Rod Diameters. J Phys Chem B 2014; 118:14062-9. [DOI: 10.1021/jp504703t] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Kaifeng Wu
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | | | - Tianquan Lian
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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Diroll BT, Murray CB. High-temperature photoluminescence of CdSe/CdS core/shell nanoheterostructures. ACS NANO 2014; 8:6466-6474. [PMID: 24824459 DOI: 10.1021/nn5021314] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The steady-state and time-resolved photoluminescence properties of CdSe/CdS heterostructures are studied as a function of temperature from 300 to 600 K. The emission properties of samples are found to behave similarly to bulk CdSe, with the samples maintaining high color purity and a slightly contracting band gap at elevated temperature. Photoluminescence from CdSe/CdS samples is maintained with high stability over prolonged illumination and multiple heating and cooling cycles. Structures synthesized with variation in the core and the shell dimensions show that the preservation of emission intensity at high temperature depends strongly on the microscopic structure of the samples. For samples synthesized by seeded growth, the size of the CdSe core is highly correlated with the fraction of preserved sample photoluminescence intensity at high temperature. Temperature-dependent lifetime data suggest that the core structure predicts the stability of photoluminescence at elevated temperatures by controlling the radiative rate. The rate of electron capture, for which the volume fraction of the core is a structural proxy, underpins the ability for radiative processes to compete with thermally induced nonradiative decay pathways. Heterostructures synthesized below 200 °C using highly reactive organometallic precursors show markedly lower thermal stability than samples prepared by seeded growth at 360 °C, suggesting that the temperature of nanocrystal synthesis has direct consequences for the thermal stability of photoluminescence.
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Affiliation(s)
- Benjamin T Diroll
- Department of Chemistry and ‡Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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Jia G, Sitt A, Hitin GB, Hadar I, Bekenstein Y, Amit Y, Popov I, Banin U. Couples of colloidal semiconductor nanorods formed by self-limited assembly. NATURE MATERIALS 2014; 13:301-7. [PMID: 24553656 DOI: 10.1038/nmat3867] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 12/17/2013] [Indexed: 05/13/2023]
Abstract
Colloidal nanocrystal synthesis provides a powerful approach for creating unique nanostructures of relevance for applications. Here, we report that wurtzite ZnSe nanorod couples connected by twinning structures can be synthesized by means of a self-limited assembly process. Unlike for individual nanorods, the band-edge states calculated for the nanorod couples are predominantly confined to the short edges of the structure and this leads to low photoluminescence polarization anisotropy, as confirmed by single-particle fluorescence. Through a cation-exchange approach, the composition of nanorod couples can be readily expanded to additional materials, such as CdSe and PbSe. We anticipate that this family of nanorod-couple structures with distinct compositions and controlled properties will constitute an ideal system for the investigation of electronic coupling effects between individual nanorod components on the nanoscale, with relevance to applications in optics, photocatalysis and optoelectronic devices.
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42
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Cunningham PD, Boercker JE, Placencia D, Tischler JG. Anisotropic absorption in PbSe nanorods. ACS NANO 2014; 8:581-590. [PMID: 24377267 DOI: 10.1021/nn405184j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present absorption anisotropy measurements in PbSe nanostructures. This is accomplished via a new means of measuring absorption anisotropy in randomly oriented solution ensembles of nanostructures via pump-probe spectroscopy, which exploits the polarization memory effect. We observe isotropic absorption in nanocrystals and anisotropic absorption in nanorods, which increases upon elongation from aspect ratio 1 to 4 and is constant for longer nanorods. The measured volume-normalized absorption cross section is 1.8 ± 0.3 times larger for parallel pump and probe polarizations in randomly oriented nanorods as compared to nanocrystals. We show that this enhancement would be larger than an order of magnitude for aligned nanorods. Despite being in the strong quantum confinement regime, the aspect ratio dependence of the absorption anisotropy in PbSe nanorods is described classically by the effects of dielectric contrast on an anisotropic nanostructure. These results imply that the dielectric constant of the surrounding medium can be used to influence the optoelectronic properties of nanorods, including polarized absorption and emission, phonon modes, multiple exciton generation efficiency, and Auger recombination rate.
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Affiliation(s)
- Paul D Cunningham
- U.S. Naval Research Laboratory , 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
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Diroll BT, Koschitzky A, Murray CB. Tunable Optical Anisotropy of Seeded CdSe/CdS Nanorods. J Phys Chem Lett 2014; 5:85-91. [PMID: 26276185 DOI: 10.1021/jz402426f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate structurally tunable optical anisotropy of seeded-growth CdSe/CdS dot-in-rod heterostructures using polarized excitation spectroscopy. The elongated anisotropic CdS shell confers optical anisotropy to the electronic transitions of the CdSe core. Although a rod-shaped shell geometry is a necessary precondition to observing polarized optical properties, the degree of linear polarization is not a strong function of aspect ratio. Rather, tuning the local anisotropy of the emissive core materials by changing the thickness of the anisotropic shell changes the degree of optical anisotropy more dramatically. As the diameter of the core material comprises a greater share (>90%) of the dot-in-rod diameter, the anisotropy of the CdSe core states doubles compared to those for which the core represents <50% of the heterostructure diameter.
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Affiliation(s)
- Benjamin T Diroll
- †Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Adriel Koschitzky
- †Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Christopher B Murray
- †Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
- ‡Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104-6272, United States
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Wu K, Rodríguez-Córdoba WE, Liu Z, Zhu H, Lian T. Beyond band alignment: hole localization driven formation of three spatially separated long-lived exciton states in CdSe/CdS nanorods. ACS NANO 2013; 7:7173-85. [PMID: 23829512 DOI: 10.1021/nn402597p] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Colloidal one-dimensional semiconductor nanoheterostructures have emerged as an important family of functional materials for solar energy conversion, although the nature of the long-lived exciton state and their formation and dissociation dynamics remain poorly understood. In this paper we study these dynamics in CdSe/CdS dot-in-rod (DIR) NRs, a representative of 1D heterostructures, and DIR-electron-acceptor complexes by transient absorption spectroscopy. Because of a quasi-type II band alignment of CdSe and CdS, it is often assumed that there exists one long-lived exciton state with holes localized in the CdSe seed and electrons delocalized among CdSe and CdS. We show that excitation into the CdS rod forms three distinct types of long-lived excitons that are spatially localized in the CdS rod, in and near the CdSe seed and in the CdS shell surrounding the seed. The branching ratio of forming these exciton states is controlled by the competition between the band offset driven hole localization to the CdSe seed and hole trapping to the CdS surface. Because of dielectric contrast induced strong electron-hole interaction in 1D materials, the competing hole localization pathways lead to spatially separated long-lived excitons. Their distinct spatial locations affect their dissociation rates in the presence of electron acceptors, which has important implications for the application of 1D heterostructures as light-harvesting materials.
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Affiliation(s)
- Kaifeng Wu
- Department of Chemistry, Emory University, 1515 Dickey Drive, NE, Atlanta, Georgia 30322, United States
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