1
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Tolmachev DO, Fernée MJ, Shornikova EV, Siverin NV, Yakovlev DR, Van Avermaet H, Hens Z, Bayer M. Positive Trions in InP/ZnSe/ZnS Colloidal Nanocrystals. ACS Nano 2024; 18:9378-9388. [PMID: 38498768 DOI: 10.1021/acsnano.3c09971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
InP-based colloidal nanocrystals are being developed as an alternative to cadmium-based materials. However, their optical properties have not been widely studied. In this paper, the fundamental magneto-optical properties of InP/ZnSe/ZnS nanocrystals are investigated at cryogenic temperatures. Ensemble measurements using two-photon excitation spectroscopy revealed the band-edge hole state to have 1Sh symmetry, resolving some controversy on this issue. Single nanocrystal microphotoluminescence measurements provided increased spectral resolution that facilitated direct detection of the lowest energy confined acoustic phonon mode at 0.9 meV, which is several times smaller than the previously reported values for similar nanocrystals. Zeeman splitting of narrow spectral lines in a magnetic field indicated a bright trion emission. A simple trion model was used to identify a positive trion charge. Furthermore, the Zeeman split spectra allowed the direct measurement of both the electron and hole g-factors, which match existing theoretical predictions.
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Affiliation(s)
- Danil O Tolmachev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Mark J Fernée
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Nikita V Siverin
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Hannes Van Avermaet
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany
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2
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Zhang Z, Liang W, Xue J, Li X, Wu K, Lu H. Induced Circularly Polarized Luminescence and Exciton Fine Structure Splitting in Magnetic-Doped Chiral Perovskites. ACS Nano 2024. [PMID: 38324334 DOI: 10.1021/acsnano.3c12851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Magnetic impurity doping in semiconductors has emerged as an important strategy to endow exotic photophysical and magnetic properties. While most reported hosts are centrosymmetric semiconductors, doping magnetic ions into a noncentrosymmetric chiral semiconductor can offer additional control of photonic and spin polarization. In this work, we synthesized a Mn2+-doped chiral two-dimensional (2D) perovskite, Mn2+:(R-MPA)2PbBr4 (R-MPA+ = R-methyl phenethylammonium). We found that the optical activity of chiral 2D perovskites is enhanced with an increased concentration of Mn2+ ions. Additionally, efficient energy transfer from the chiral host to the Mn2+ dopants is observed. This energy transfer process gives rise to circularly polarized luminescence from the excited state of Mn2+ (4T1 → 6A1), exhibiting a photoluminescence quantum yield up to 24% and a dissymmetry factor of 11%. The exciton fine structures of undoped and Mn2+-doped (R-MPA)2PbBr4 are further studied through magnetic circular dichroism (MCD) spectroscopy. Our analysis shows that chiral organic cations lead to an exciton fine structure splitting energy as large as 5.0 meV, and the splitting is further increased upon Mn2+ doping. Our results reveal the strong impacts of molecular chirality and magnetic dopants on the exciton structures of halide perovskites.
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Affiliation(s)
- Zixuan Zhang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR) 999077, China
| | - Wenfei Liang
- State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Jie Xue
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR) 999077, China
| | - Xin Li
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR) 999077, China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Haipeng Lu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR) 999077, China
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3
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Conradt F, Bezold V, Wiechert V, Huber S, Mecking S, Leitenstorfer A, Tenne R. Electric-Field Fluctuations as the Cause of Spectral Instabilities in Colloidal Quantum Dots. Nano Lett 2023; 23:9753-9759. [PMID: 37871158 PMCID: PMC10636921 DOI: 10.1021/acs.nanolett.3c02318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/25/2023]
Abstract
Spectral diffusion (SD) represents a substantial obstacle toward implementation of solid-state quantum emitters as a source of indistinguishable photons. By performing high-resolution emission spectroscopy for individual colloidal quantum dots at cryogenic temperatures, we prove the causal link between the quantum-confined Stark effect and SD. Statistically analyzing the wavelength of emitted photons, we show that increasing the sensitivity of the transition energy to an applied electric field results in amplified spectral fluctuations. This relation is quantitatively fit to a straightforward model, indicating the presence of a stochastic electric field on a microscopic scale, whose standard deviation is 9 kV/cm, on average. The current method will enable the study of SD in multiple types of quantum emitters such as solid-state defects or organic lead halide perovskite quantum dots, for which spectral instability is a critical barrier for applications in quantum sensing.
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Affiliation(s)
- Frieder Conradt
- Department
of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - Vincent Bezold
- Department
of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - Volker Wiechert
- Department
of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - Steffen Huber
- Chair
of Chemical Materials Science, Department of Chemistry, University of Konstanz, D-78457 Konstanz, Germany
| | - Stefan Mecking
- Chair
of Chemical Materials Science, Department of Chemistry, University of Konstanz, D-78457 Konstanz, Germany
| | - Alfred Leitenstorfer
- Department
of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - Ron Tenne
- Department
of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
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4
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Shinde A, Rajput PK, Makhija U, Tanwar R, Mandal P, Nag A. Emissive Dark Excitons in Monoclinic Two-Dimensional Hybrid Lead Iodide Perovskites. Nano Lett 2023; 23:6985-6993. [PMID: 37487113 DOI: 10.1021/acs.nanolett.3c01627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Typically, bright excitons (XB) emit light in two-dimensional (2D) layered hybrid perovskites. There are also dark excitons (XD), for which radiative recombination is spin-forbidden. Application of a magnetic field can somewhat relax the spin-rule, yielding XD emission. Can we obtain XD light emission in the absence of a magnetic field? Indeed, we observe unusually intense XD emission at ∼7 K for (Rac-MBA)2PbI4, (Rac-4-Br-MBA)2PbI4, and (R-4-Br-MBA)2PbI4 (Rac-MBA: racemic methylbenzylammonium), which crystallize in a lower symmetry monoclinic phase. For comparison, orthorhombic (R-MBA)2PbI4 does not exhibit XD emission. XD has a lower energy than XB, with energy difference ΔE. In monoclinic samples, ΔE ∼ 20 meV is large enough to suppress the thermal excitation of XD to XB, at temperatures <30 K. Consequently, XD recombines by emitting light with a long lifetime (∼205 ns). At higher temperatures, the emission switches to the spin-allowed XB (lifetime < 1 ns).
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Affiliation(s)
- Aparna Shinde
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Parikshit Kumar Rajput
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Urmila Makhija
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Riteeka Tanwar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Pankaj Mandal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Angshuman Nag
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
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5
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Guilloux V, Ghribi A, Majrab S, Margaillan F, Bernard M, Bernardot F, Legrand L, Lhuillier E, Boujdaria K, Chamarro M, Testelin C, Barisien T. Exciton Fine Structure of CsPbCl 3 Nanocrystals: An Interplay of Electron-Hole Exchange Interaction, Crystal Structure, Shape Anisotropy, and Dielectric Mismatch. ACS Nano 2023. [PMID: 37366625 DOI: 10.1021/acsnano.3c00772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
In the semiconducting perovskite materials family, the cesium-lead-chloride compound (CsPbCl3) supports robust excitons characterized by a blue-shifted transition and the largest binding energy, thus presenting a high potential to achieve demanding solid-state room-temperature photonic or quantum devices. Here we study the fundamental emission properties of cubic-shaped colloidal CsPbCl3 nanocrystals (NCs), examining in particular individual NC responses using micro-photoluminescence in order to unveil the exciton fine structure (EFS) features. Within this work, NCs with average dimensions ⟨Lα⟩ ≈ 8 nm (α = x, y, z) are studied with a level of dispersity in their dimensions that allows disentangling the effects of size and shape anisotropy in the analysis. We find that most of the NCs exhibit an optical response under the form of a doublet with crossed polarized peaks and an average inter-bright-state splitting, ΔBB ≈ 1.53 meV, but triplets are also observed though being a minority. The origin of the EFS patterns is discussed in the frame of the electron-hole exchange model by taking into account the dielectric mismatch at the NC interface. The different features (large dispersity in the ΔBB values and occasional occurrence of triplets) are reconciled by incorporating a moderate degree of shape anisotropy, observed in the structural characterization, by preserving the relatively high degree of the NC lattice symmetry. The energy distance between the optically inactive state and the bright manifold, ΔBD, is also extracted from time-resolved photoluminescence measurements (ΔBD ≈ 10.7 meV), in good agreement with our theoretical predictions.
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Affiliation(s)
- Victor Guilloux
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Amal Ghribi
- LR01ES15 Laboratoire de Physique des Matériaux: Structure et Propriétés, Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Silbé Majrab
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Florent Margaillan
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Mathieu Bernard
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Frédérick Bernardot
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Laurent Legrand
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Emmanuel Lhuillier
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Kaïs Boujdaria
- LR01ES15 Laboratoire de Physique des Matériaux: Structure et Propriétés, Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Maria Chamarro
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Christophe Testelin
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - Thierry Barisien
- Institut des NanoSciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
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6
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Prin E, Xia C, Won YH, Jang E, Goupalov SV, Tamarat P, Lounis B. Revealing the Band-Edge Exciton Fine Structure of Single InP Nanocrystals. Nano Lett 2023. [PMID: 37350682 DOI: 10.1021/acs.nanolett.3c01419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
We investigate the fundamental optical properties of single zinc-blende InP/ZnSe/ZnS nanocrystals (NCs) using frequency- and time-resolved magneto-photoluminescence spectroscopy. At liquid helium temperature, highly resolved spectral fingerprints are obtained and identified as the recombination lines of the three lowest states of the band-edge exciton fine structure. The evolutions of the photoluminescence spectra and decays under magnetic fields show evidence for a ground dark exciton level 0L with zero angular momentum projection along the NC main elongation axis. It lies 300 to 600 μeV below the ±1L bright exciton doublet, which is finely split by the NC shape anisotropy. These spectroscopic findings are well reproduced with a model of exciton fine structure accounting for shape anisotropy of the InP core. Our spectral fingerprints are extremely sensitive to the NC morphologies and unveil highly uniform shapes with prolate deviations of less than 3% from perfect sphericity.
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Affiliation(s)
- Elise Prin
- Université de Bordeaux, LP2N, Talence F-33405, France
- Institut d'Optique and CNRS, LP2N, Talence F-33405, France
| | - Chenghui Xia
- Université de Bordeaux, LP2N, Talence F-33405, France
- Institut d'Optique and CNRS, LP2N, Talence F-33405, France
| | - Yu-Ho Won
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, South Korea
| | - Eunjoo Jang
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, South Korea
| | - Serguei V Goupalov
- Ioffe Institute, St. Petersburg 194021, Russia
- Department of Physics, Jackson State University, Jackson, Mississippi 39217, United States
| | - Philippe Tamarat
- Université de Bordeaux, LP2N, Talence F-33405, France
- Institut d'Optique and CNRS, LP2N, Talence F-33405, France
| | - Brahim Lounis
- Université de Bordeaux, LP2N, Talence F-33405, France
- Institut d'Optique and CNRS, LP2N, Talence F-33405, France
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7
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Li WH, Lin JD, Lo PY, Peng GH, Hei CY, Chen SY, Cheng SJ. The Key Role of Non-Local Screening in the Environment-Insensitive Exciton Fine Structures of Transition-Metal Dichalcogenide Monolayers. Nanomaterials (Basel) 2023; 13:nano13111739. [PMID: 37299642 DOI: 10.3390/nano13111739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/21/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023]
Abstract
In this work, we present a comprehensive theoretical and computational investigation of exciton fine structures of WSe2-monolayers, one of the best-known two-dimensional (2D) transition-metal dichalcogenides (TMDs), in various dielectric-layered environments by solving the first-principles-based Bethe-Salpeter equation. While the physical and electronic properties of atomically thin nanomaterials are normally sensitive to the variation of the surrounding environment, our studies reveal that the influence of the dielectric environment on the exciton fine structures of TMD-MLs is surprisingly limited. We point out that the non-locality of Coulomb screening plays a key role in suppressing the dielectric environment factor and drastically shrinking the fine structure splittings between bright exciton (BX) states and various dark-exciton (DX) states of TMD-MLs. The intriguing non-locality of screening in 2D materials can be manifested by the measurable non-linear correlation between the BX-DX splittings and exciton-binding energies by varying the surrounding dielectric environments. The revealed environment-insensitive exciton fine structures of TMD-ML suggest the robustness of prospective dark-exciton-based optoelectronics against the inevitable variation of the inhomogeneous dielectric environment.
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Affiliation(s)
- Wei-Hua Li
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Jhen-Dong Lin
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Ping-Yuan Lo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Guan-Hao Peng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Ching-Yu Hei
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Shao-Yu Chen
- Center of Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan
- Center of Atomic Initiative for New Material, National Taiwan University, Taipei 106, Taiwan
| | - Shun-Jen Cheng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
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8
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Golovatenko AA, Kalitukha IV, Dimitriev GS, Sapega VF, Rakhlin MV, Galimov AI, Shubina TV, Shornikova EV, Qiang G, Yakovlev DR, Bayer M, Biermann A, Hoffmann A, Aubert T, Hens Z, Rodina AV. A Comparative Study of the Band-Edge Exciton Fine Structure in Zinc Blende and Wurtzite CdSe Nanocrystals. Nanomaterials (Basel) 2022; 12:4269. [PMID: 36500892 PMCID: PMC9736692 DOI: 10.3390/nano12234269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
In this paper, we studied the role of the crystal structure in spheroidal CdSe nanocrystals on the band-edge exciton fine structure. Ensembles of zinc blende and wurtzite CdSe nanocrystals are investigated experimentally by two optical techniques: fluorescence line narrowing (FLN) and time-resolved photoluminescence. We argue that the zero-phonon line evaluated by the FLN technique gives the ensemble-averaged energy splitting between the lowest bright and dark exciton states, while the activation energy from the temperature-dependent photoluminescence decay is smaller and corresponds to the energy of an acoustic phonon. The energy splittings between the bright and dark exciton states determined using the FLN technique are found to be the same for zinc blende and wurtzite CdSe nanocrystals. Within the effective mass approximation, we develop a theoretical model considering the following factors: (i) influence of the nanocrystal shape on the bright-dark exciton splitting and the oscillator strength of the bright exciton, and (ii) shape dispersion in the ensemble of the nanocrystals. We show that these two factors result in similar calculated zero-phonon lines in zinc blende and wurtzite CdSe nanocrystals. The account of the nanocrystals shape dispersion allows us to evaluate the linewidth of the zero-phonon line.
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Affiliation(s)
| | - Ina V. Kalitukha
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | | | - Victor F. Sapega
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Maxim V. Rakhlin
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Aidar I. Galimov
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Tatiana V. Shubina
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Elena V. Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Gang Qiang
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Dmitri R. Yakovlev
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Amelie Biermann
- Institut für Festkörperphysik, Technische Universitat Berlin, 10623 Berlin, Germany
| | - Axel Hoffmann
- Institut für Festkörperphysik, Technische Universitat Berlin, 10623 Berlin, Germany
| | - Tangi Aubert
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Zeger Hens
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Anna V. Rodina
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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9
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Anand A, Zaffalon ML, Cova F, Pinchetti V, Khan AH, Carulli F, Brescia R, Meinardi F, Moreels I, Brovelli S. Optical and Scintillation Properties of Record-Efficiency CdTe Nanoplatelets toward Radiation Detection Applications. Nano Lett 2022; 22:8900-8907. [PMID: 36331389 PMCID: PMC9706671 DOI: 10.1021/acs.nanolett.2c02975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Colloidal CdTe nanoplatelets featuring a large absorption coefficient and ultrafast tunable luminescence coupled with heavy-metal-based composition present themselves as highly desirable candidates for radiation detection technologies. Historically, however, these nanoplatelets have suffered from poor emission efficiency, hindering progress in exploring their technological potential. Here, we report the synthesis of CdTe nanoplatelets possessing a record emission efficiency of 9%. This enables us to investigate their fundamental photophysics using ultrafast transient absorption, temperature-controlled photoluminescence, and radioluminescence measurements, elucidating the origins of exciton- and defect-related phenomena under both optical and ionizing excitation. For the first time in CdTe nanoplatelets, we report the cumulative effects of a giant oscillator strength transition and exciton fine structure. Simultaneously, thermally stimulated luminescence measurements reveal the presence of both shallow and deep trap states and allow us to disclose the trapping and detrapping dynamics and their influence on the scintillation properties.
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Affiliation(s)
- Abhinav Anand
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | - Matteo L. Zaffalon
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | - Francesca Cova
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | - Valerio Pinchetti
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | | | - Francesco Carulli
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | - Rosaria Brescia
- Electron
Microscopy Facility, Istituto Italiano di
Tecnologia, Via Morego 30, 16163Genova, Italy
| | - Francesco Meinardi
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
| | - Iwan Moreels
- Department
of Chemistry, Ghent University, 9000Ghent, Belgium
- Electron
Microscopy Facility, Istituto Italiano di
Tecnologia, Via Morego 30, 16163Genova, Italy
| | - Sergio Brovelli
- Dipartimento
di Scienza dei Materiali, Università
degli Studi di Milano-Bicocca, via R. Cozzi 55, 20125Milano, Italy
- Electron
Microscopy Facility, Istituto Italiano di
Tecnologia, Via Morego 30, 16163Genova, Italy
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10
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Marcato T, Krumeich F, Shih CJ. Confinement-Tunable Transition Dipole Moment Orientation in Perovskite Nanoplatelet Solids and Binary Blends. ACS Nano 2022; 16:18459-18471. [PMID: 36350363 DOI: 10.1021/acsnano.2c06600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Tuning the transition dipole moment (TDM) orientation in low-dimensional semiconductors is of fundamental and practical interest, as it enables high-efficiency nanophotonics and light-emitting diodes. However, despite recent progress in nanomaterials physics and chemistry, material systems that allow continuous tuning of the TDM orientation remain rare. Here, combining k-space photoluminescence spectroscopy and multiscale modeling, we demonstrate that the TDM orientation in lead halide perovskite (LHP) nanoplatelet (NPL) solids is largely confinement-tunable through the NPL geometry that regulates the anisotropy of Bloch states, dielectric confinement, and exciton fine structure. We further quantified the role of uniaxial ordering during NPL assembly in modifying the macroscopic emission directionality of thin films, which is especially important in actual optoelectronic devices. Our theoretical framework successfully corroborates the previous prediction of exciton bright level order reversal with experimental evidence of a counterintuitive reduction of in-plane dipole ratio in ultrathin (one- and two-monolayer-thick) NPLs, even at room temperature. More interestingly, the NPLs retain their TDM orientation in binary blends irrespective of interparticle energy transfer, owing to the phase segregation and NPL-NPL decoupling, enabling the design of films whose fluorescence exhibits an intrinsic angle-dependent color gradient.
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Affiliation(s)
- Tommaso Marcato
- Institute for Chemical and Bioengineering, ETH Zürich, 8093Zürich, Switzerland
| | - Frank Krumeich
- Laboratory of Inorganic Chemistry, ETH Zürich, 8093Zürich, Switzerland
| | - Chih-Jen Shih
- Institute for Chemical and Bioengineering, ETH Zürich, 8093Zürich, Switzerland
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11
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Shinokita K, Watanabe K, Taniguchi T, Matsuda K. Valley Relaxation of the Moiré Excitons in a WSe 2/MoSe 2 Heterobilayer. ACS Nano 2022; 16:16862-16868. [PMID: 36169188 DOI: 10.1021/acsnano.2c06813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The moiré superlattice consisting of lattice- or angular-mismatched van der Waals heterostructures drastically changes the physical properties of constituent atomically thin materials by confinement of the exciton by the moiré potential, which is promising for next-generation quantum optics. The moiré superlattice also affects the valley degrees of freedom of the monolayer transition-metal dichalcogenides (TMDs) and the valley-dependent optical selection rule, which results in the characteristic circular polarized light emission of the moiré exciton. However, the valley relaxation process of excitons in the moiré superlattice remains to be understood. Here, we studied valley relaxation of moiré excitons in a twisted WSe2/MoSe2 heterobilayer by circularly polarized photoluminescence and photoluminescence excitation (PLE) spectroscopy. The experimentally observed circularly polarized emission strongly depends on the excitation power density, which contrasts with the case of two-dimensional monolayer TMDs. The excitation power-dependent circularly polarized emission suggests the characteristic valley relaxation of the moiré exciton with a small density of states in zero-dimensional systems. In addition, the resonant PLE measurement reveals the intravalley relaxation process from the triplet to singlet state of the moiré exciton via Γ5 phonon emission. Our findings clarified the valley relaxation of the moiré excitons, which would lead to the application of the circularly polarized quantum light emitter in twisted semiconducting heterobilayers.
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Affiliation(s)
- Keisuke Shinokita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kazunari Matsuda
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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12
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Jin T, He S, Zhu Y, Egap E, Lian T. Bright State Sensitized Triplet Energy Transfer from Quantum Dot to Molecular Acceptor Revealed by Temperature Dependent Energy Transfer Dynamics. Nano Lett 2022; 22:3897-3903. [PMID: 35561343 DOI: 10.1021/acs.nanolett.2c00017] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Quantum dot (QD) sensitized molecular triplet excited state generation has been a promising alternative for traditional triplet state harvesting schemes. However, the correlation between QD bright/dark states and QD sensitized triplet energy transfer (TET) has been unclear. Herein, we studied the bright/dark states contribution to TET with CdSe/CdS core/shell QD-oligothiophene as the model system. Equilibrium between QD bright and dark states was tuned by changing temperature, and TET dynamics were monitored with transient absorption spectroscopy. Analysis of acceptor triplet excited state growth kinetics yields rates of TET from bright and dark states as 0.492 ± 0.011 ns-1 and 0.0271 ± 0.0014 ns-1 at 5 K, suggesting significant contribution of bright states to TET. The result was rationalized by bright state wave function components with the same electron/hole spin projections leading to nonzero TET probability. The study provides new insights into QD sensitized TET mechanisms and inspiration for future TET efficiency optimization through QD exciton engineering.
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Affiliation(s)
- Tao Jin
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Sheng He
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Yifan Zhu
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Eilaf Egap
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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13
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Abstract
The band-gap energy of most bulk semiconductors tends to increase as the temperature decreases. However, non-monotonic temperature dependence of the emission energy has been observed in semiconductor quantum dots (QDs) at cryogenic temperatures. Here, using stable and highly efficient CdSe/CdS/ZnS QDs as the model system, we quantitatively reveal the origins of the anomalous emission red-shift (∼8 meV) below 40 K by correlating ensemble and single QD spectroscopy measurements. About one-quarter of the anomalous red-shift (∼2.2 meV) is caused by the temperature-dependent population of the band-edge exciton fine levels. The enhancement of electron-optical phonon coupling caused by the increasing population of dark excitons with temperature decreases contributes an ∼3.4 meV red-shift. The remaining ∼2.4 meV red-shift is attributed to temperature-dependent electron-acoustic phonon coupling.
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Affiliation(s)
- Shaojie Liu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yufei Shu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Meiyi Zhu
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Haiyan Qin
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Xiaogang Peng
- Key Laboratory of Excited-State Materials of Zhejiang Province and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
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14
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Gramlich M, Swift MW, Lampe C, Lyons JL, Döblinger M, Efros AL, Sercel PC, Urban AS. Dark and Bright Excitons in Halide Perovskite Nanoplatelets. Adv Sci (Weinh) 2022; 9:e2103013. [PMID: 34939751 PMCID: PMC8844578 DOI: 10.1002/advs.202103013] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/13/2021] [Indexed: 05/22/2023]
Abstract
Semiconductor nanoplatelets (NPLs), with their large exciton binding energy, narrow photoluminescence (PL), and absence of dielectric screening for photons emitted normal to the NPL surface, could be expected to become the fastest luminophores amongst all colloidal nanostructures. However, super-fast emission is suppressed by a dark (optically passive) exciton ground state, substantially split from a higher-lying bright (optically active) state. Here, the exciton fine structure in 2-8 monolayer (ML) thick Csn - 1 Pbn Br3n + 1 NPLs is revealed by merging temperature-resolved PL spectra and time-resolved PL decay with an effective mass model taking quantum confinement and dielectric confinement anisotropy into account. This approach exposes a thickness-dependent bright-dark exciton splitting reaching 32.3 meV for the 2 ML NPLs. The model also reveals a 5-16 meV splitting of the bright exciton states with transition dipoles polarized parallel and perpendicular to the NPL surfaces, the order of which is reversed for the thinnest NPLs, as confirmed by TR-PL measurements. Accordingly, the individual bright states must be taken into account, while the dark exciton state strongly affects the optical properties of the thinnest NPLs even at room temperature. Significantly, the derived model can be generalized for any isotropically or anisotropically confined nanostructure.
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Affiliation(s)
- Moritz Gramlich
- Nanospectroscopy GroupNano‐Institute MunichDepartment of PhysicsLudwig‐Maximilians‐Universität München (LMU)Munich80539Germany
| | - Michael W. Swift
- Center for Computational Materials ScienceU.S. Naval Research LaboratoryWashington D.C.20375USA
| | - Carola Lampe
- Nanospectroscopy GroupNano‐Institute MunichDepartment of PhysicsLudwig‐Maximilians‐Universität München (LMU)Munich80539Germany
| | - John L. Lyons
- Center for Computational Materials ScienceU.S. Naval Research LaboratoryWashington D.C.20375USA
| | - Markus Döblinger
- Department of ChemistryLudwig‐Maximilians‐Universität München (LMU) & Center for NanoScience (CeNS)Munich81377Germany
| | - Alexander L. Efros
- Center for Computational Materials ScienceU.S. Naval Research LaboratoryWashington D.C.20375USA
| | - Peter C. Sercel
- Center for Hybrid Organic Inorganic Semiconductors for EnergyGoldenCO80401USA
| | - Alexander S. Urban
- Nanospectroscopy GroupNano‐Institute MunichDepartment of PhysicsLudwig‐Maximilians‐Universität München (LMU)Munich80539Germany
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15
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Ghribi A, Ben Aich R, Boujdaria K, Barisien T, Legrand L, Chamarro M, Testelin C. Dielectric Confinement and Exciton Fine Structure in Lead Halide Perovskite Nanoplatelets. Nanomaterials (Basel) 2021; 11:3054. [PMID: 34835818 DOI: 10.3390/nano11113054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 12/28/2022]
Abstract
Owing to their flexible chemical synthesis and the ability to shape nanostructures, lead halide perovskites have emerged as high potential materials for optoelectronic devices. Here, we investigate the excitonic band edge states and their energies levels in colloidal inorganic lead halide nanoplatelets, particularly the influence of dielectric effects, in a thin quasi-2D system. We use a model including band offset and dielectric confinements in the presence of Coulomb interaction. Short- and long-range contributions, modified by dielectric effects, are also derived, leading to a full modelization of the exciton fine structure, in cubic, tetragonal and orthorhombic phases. The fine splitting structure, including dark and bright excitonic states, is discussed and compared to recent experimental results, showing the importance of both confinement and dielectric contributions.
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16
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Fedin I, Goryca M, Liu D, Tretiak S, Klimov VI, Crooker SA. Enhanced Emission from Bright Excitons in Asymmetrically Strained Colloidal CdSe/Cd xZn 1-xSe Quantum Dots. ACS Nano 2021; 15:14444-14452. [PMID: 34473467 DOI: 10.1021/acsnano.1c03864] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Colloidal CdSe quantum dots (QDs) designed with a high degree of asymmetric internal strain have recently been shown to host a number of desirable optical properties including subthermal room-temperature line widths, suppressed spectral diffusion, and high photoluminescence (PL) quantum yields. It remains an open question, however, whether they are well-suited for applications requiring emission of identical single photons. Here we measure the low-temperature PL dynamics and the polarization-resolved fluorescence line narrowing spectra from ensembles of these strained QDs. Our spectroscopy reveals the radiative recombination rates of bright and dark excitons, the relaxation rate between the two, and the energy spectra of the quantized acoustic phonons in the QDs that can contribute to relaxation processes. In comparison to conventional colloidal CdSe/ZnS core/shell QDs, we find that in asymmetrically strained CdSe QDs over six times more light is emitted directly by the bright exciton. These results are therefore encouraging for the prospects of chemically synthesized colloidal QDs as emitters of single indistinguishable photons.
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Affiliation(s)
- Igor Fedin
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Mateusz Goryca
- National High Magnetic Field Lab, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Dan Liu
- Theory Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Theory Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Scott A Crooker
- National High Magnetic Field Lab, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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17
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Liu S, Granados Del Águila A, Liu X, Zhu Y, Han Y, Chaturvedi A, Gong P, Yu H, Zhang H, Yao W, Xiong Q. Room-Temperature Valley Polarization in Atomically Thin Semiconductors via Chalcogenide Alloying. ACS Nano 2020; 14:9873-9883. [PMID: 32806059 DOI: 10.1021/acsnano.0c02703] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Room-temperature manipulation and processing of information encoded in the electronic valley pseudospin and spin degrees of freedoms lie at the heart of the next technological quantum revolution. In atomically thin layers of transition-metal dichalcogenides (TMDs) with hexagonal lattices, valley-polarized excitations and valley quantum coherence can be generated by simply shining with adequately polarized light. In turn, the polarization states of light can induce topological Hall currents in the absence of an external magnetic field, which underlies the fundamental principle of opto-valleytronics devices. However, demonstration of optical generation of valley polarization at room temperature has remained challenging and not well understood. Here, we demonstrate control of strong valley polarization (valley quantum coherence) at room temperature of up to ∼50% (∼20%) by strategically designing Coulomb forces and spin-orbit interactions in atomically thin TMDs via chalcogenide alloying. We show that tailor making the carrier density and the relative order between optically active (bright) and forbidden (dark) states by key variations on the chalcogenide atom ratio allows full control of valley pseudospin dynamics. Our findings set a comprehensive approach for intrinsic and efficient manipulation of valley pseudospin and spin degree of freedom toward realistic opto-valleytronics devices.
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Affiliation(s)
- Sheng Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Andrés Granados Del Águila
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Xue Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yihan Zhu
- Advance Membrane and Porous Materials Center, Division of Physical and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
- Center for Electron Microscopy and State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yu Han
- Advance Membrane and Porous Materials Center, Division of Physical and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Apoorva Chaturvedi
- School of Material Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Pu Gong
- Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China
| | - Hongyi Yu
- Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing and School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai 519082, China
| | - Hua Zhang
- Department of Chemistry and Hong Kong Branch of National Precious Metals Material Engineering Research Centre (NPMM), City University of Hong Kong, Hong Kong, China
| | - Wang Yao
- Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China
| | - Qihua Xiong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
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18
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Huo C, Fong CF, Amara MR, Huang Y, Chen B, Zhang H, Guo L, Li H, Huang W, Diederichs C, Xiong Q. Optical Spectroscopy of Single Colloidal CsPbBr 3 Perovskite Nanoplatelets. Nano Lett 2020; 20:3673-3680. [PMID: 32212737 DOI: 10.1021/acs.nanolett.0c00611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Optically bright lead halide perovskite nanocrystals of different morphologies ranging from nanocubes to flat nanoplatelets to elongated nanowires have been reported. The morphology of the nanocrystals is expected to affect various properties such as the band edge energy and the electron-hole exchange interaction. However, aside from nanocubes, the investigation of optical properties in the lead halide perovskite nanocrystals of different morphologies at the single emitter level has been lacking. We have performed optical spectroscopy in single CsPbBr3 nanoplatelets and observed single photon emission without blinking. Furthermore, the photoluminescence emission exhibits excitonic fine structure peaks similar to what has been previously observed in nanocubes. Our work stimulates further investigations into the excitonic and quantum optics properties when the lateral size and morphology can be further controlled in lead halide perovskite nanocrystals.
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Affiliation(s)
- Caixia Huo
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
- State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an 710072, China
| | - Chee Fai Fong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Mohamed-Raouf Amara
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France
| | - Yuqing Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Bo Chen
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Hua Zhang
- Department of Chemistry, City University of Hong Kong, Hong Kong China
- Hong Kong Branch of National Precious Metals Material Engineering Research Center (NPMM), City University of Hong Kong, Hong Kong, China
| | - Lingjun Guo
- State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an 710072, China
| | - Hejun Li
- State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an 710072, China
| | - Wei Huang
- Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), Xi'an 710072, China
| | - Carole Diederichs
- MajuLab, International Joint Research Unit, UMI 3654, CNRS, Université Côte d'Azur, Sorbonne Université, National University of Singapore, Nanyang Technological University, 637371 Singapore
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France
| | - Qihua Xiong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
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19
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Pandya R, Steinmetz V, Puttisong Y, Dufour M, Chen WM, Chen RYS, Barisien T, Sharma A, Lakhwani G, Mitioglu A, Christianen PCM, Legrand L, Bernardot F, Testelin C, Chin AW, Ithurria S, Chamarro M, Rao A. Fine Structure and Spin Dynamics of Linearly Polarized Indirect Excitons in Two-Dimensional CdSe/CdTe Colloidal Heterostructures. ACS Nano 2019; 13:10140-10153. [PMID: 31490653 DOI: 10.1021/acsnano.9b03252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Heterostructured two-dimensional colloidal nanoplatelets are a class of material that has attracted great interest for optoelectronic applications due to their high photoluminescence yield, atomically tunable thickness, and ultralow lasing thresholds. Of particular interest are laterally heterostructured core-crown nanoplatelets with a type-II band alignment, where the in-plane spatial separation of carriers leads to indirect (or charge transfer) excitons with long lifetimes and bright, highly Stokes shifted emission. Despite this, little is known about the nature of the lowest energy exciton states responsible for emission in these materials. Here, using polarization-controlled, steady-state, and time-resolved photoluminescence measurements, at temperatures down to 1.6 K and magnetic fields up to 30 T, we study the exciton fine structure and spin dynamics of archetypal type-II CdSe/CdTe core-crown nanoplatelets. Complemented by theoretical modeling and zero-field quantum beat measurements, we find the bright-exciton fine structure consists of two linearly polarized states with a fine structure splitting ∼50 μeV and an indirect exciton Landé g-factor of 0.7. In addition, we show the exciton spin lifetime to be in the microsecond range with an unusual B-3 magnetic field dependence. The discovery of linearly polarized exciton states and emission highlights the potential for use of such materials in display and imaging applications without polarization filters. Furthermore, the small exciton fine structure splitting and a long spin lifetime are fundamental advantages when envisaging CdSe/CdTe nanoplatelets as elementary bricks for the next generation of quantum devices, particularly given their ease of fabrication.
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Affiliation(s)
- Raj Pandya
- Cavendish Laboratory , University of Cambridge , J.J. Thomson Avenue , CB3 0HE Cambridge , United Kingdom
| | - Violette Steinmetz
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Yuttapoom Puttisong
- Functional Electronic Materials, Department of Physics, Chemistry and Biology , Linköping University , 58183 Linköping , Sweden
| | - Marion Dufour
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris , PSL Research University, CNRS , 10 rue Vauquelin , 75005 Paris , France
| | - Weimin M Chen
- Functional Electronic Materials, Department of Physics, Chemistry and Biology , Linköping University , 58183 Linköping , Sweden
| | - Richard Y S Chen
- Cavendish Laboratory , University of Cambridge , J.J. Thomson Avenue , CB3 0HE Cambridge , United Kingdom
| | - Thierry Barisien
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Ashish Sharma
- ARC Centre of Excellence in Exciton Science, School of Chemistry , The University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Girish Lakhwani
- ARC Centre of Excellence in Exciton Science, School of Chemistry , The University of Sydney , Sydney , New South Wales 2006 , Australia
| | - Anatolie Mitioglu
- High Field Magnet Laboratory (HFML - EMFL) , Radboud University , 6525 ED Nijmegen , The Netherlands
| | - Peter C M Christianen
- High Field Magnet Laboratory (HFML - EMFL) , Radboud University , 6525 ED Nijmegen , The Netherlands
| | - Laurent Legrand
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Frédérick Bernardot
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Christophe Testelin
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Alex W Chin
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris , PSL Research University, CNRS , 10 rue Vauquelin , 75005 Paris , France
| | - Maria Chamarro
- Sorbonne Université CNRS-UMR 7588, Institut des NanoSciences de Paris , INSP, 4 place Jussieu , F-75005 Paris , France
| | - Akshay Rao
- Cavendish Laboratory , University of Cambridge , J.J. Thomson Avenue , CB3 0HE Cambridge , United Kingdom
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20
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Brodu A, Ballottin MV, Buhot J, van Harten EJ, Dupont D, La Porta A, Prins PT, Tessier MD, Versteegh MAM, Zwiller V, Bals S, Hens Z, Rabouw FT, Christianen PCM, de Mello Donega C, Vanmaekelbergh D. Exciton Fine Structure and Lattice Dynamics in InP/ZnSe Core/Shell Quantum Dots. ACS Photonics 2018; 5:3353-3362. [PMID: 30175158 PMCID: PMC6115013 DOI: 10.1021/acsphotonics.8b00615] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Indexed: 05/05/2023]
Abstract
Nanocrystalline InP quantum dots (QDs) hold promise for heavy-metal-free optoelectronic applications due to their bright and size-tunable emission in the visible range. Photochemical stability and high photoluminescence (PL) quantum yield are obtained by a diversity of epitaxial shells around the InP core. To understand and optimize the emission line shapes, the exciton fine structure of InP core/shell QD systems needs be investigated. Here, we study the exciton fine structure of InP/ZnSe core/shell QDs with core diameters ranging from 2.9 to 3.6 nm (PL peak from 2.3 to 1.95 eV at 4 K). PL decay measurements as a function of temperature in the 10 mK to 300 K range show that the lowest exciton fine structure state is a dark state, from which radiative recombination is assisted by coupling to confined acoustic phonons with energies ranging from 4 to 7 meV, depending on the core diameter. Circularly polarized fluorescence line-narrowing (FLN) spectroscopy at 4 K under high magnetic fields (up to 30 T) demonstrates that radiative recombination from the dark F = ±2 state involves acoustic and optical phonons, from both the InP core and the ZnSe shell. Our data indicate that the highest intensity FLN peak is an acoustic phonon replica rather than a zero-phonon line, implying that the energy separation observed between the F = ±1 state and the highest intensity peak in the FLN spectra (6 to 16 meV, depending on the InP core size) is larger than the splitting between the dark and bright fine structure exciton states.
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Affiliation(s)
- Annalisa Brodu
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Mariana V. Ballottin
- High Field Magnet Laboratory, HFML-EMFL, Radboud University, 6525 ED Nijmegen, The
Netherlands
| | - Jonathan Buhot
- High Field Magnet Laboratory, HFML-EMFL, Radboud University, 6525 ED Nijmegen, The
Netherlands
| | - Elleke J. van Harten
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Dorian Dupont
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Andrea La Porta
- Electron
Microscopy for Materials Research, EMAT, University of Antwerp, 2020 Antwerp, Belgium
| | - P. Tim Prins
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Mickael D. Tessier
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Marijn A. M. Versteegh
- Department
of Applied Physics, Royal Institute of Technology
(KTH), 106 91 Stockholm, Sweden
| | - Val Zwiller
- Department
of Applied Physics, Royal Institute of Technology
(KTH), 106 91 Stockholm, Sweden
| | - Sara Bals
- Electron
Microscopy for Materials Research, EMAT, University of Antwerp, 2020 Antwerp, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
| | - Freddy T. Rabouw
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Peter C. M. Christianen
- High Field Magnet Laboratory, HFML-EMFL, Radboud University, 6525 ED Nijmegen, The
Netherlands
| | - Celso de Mello Donega
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Debye Institute
for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
- E-mail:
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Sinito C, Fernée MJ, Goupalov SV, Mulvaney P, Tamarat P, Lounis B. Tailoring the exciton fine structure of cadmium selenide nanocrystals with shape anisotropy and magnetic field. ACS Nano 2014; 8:11651-11656. [PMID: 25329623 DOI: 10.1021/nn5049409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We use nominally spheroidal CdSe nanocrystals with a zinc blende crystal structure to study how shape perturbations lift the energy degeneracies of the band-edge exciton. Nanocrystals with a low degree of symmetry exhibit splitting of both upper and lower bright state degeneracies due to valence band mixing combined with the isotropic exchange interaction, allowing active control of the level splitting with a magnetic field. Asymmetry-induced splitting of the bright states is used to reveal the entire 8-state band-edge fine structure, enabling complete comparison with band-edge exciton models.
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Affiliation(s)
- Chiara Sinito
- LP2N, Université de Bordeaux , F-33405 Talence, France
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