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Climente JI, Movilla JL, Planelles J. Electronic Structure of Biexcitons in Metal Halide Perovskite Nanoplatelets. J Phys Chem Lett 2024; 15:7379-7386. [PMID: 38995267 DOI: 10.1021/acs.jpclett.4c01719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
A theoretical description of biexcitons in metal halide perovskite nanoplatelets is presented. The description is based on a variational effective mass model, including polaronic effects by means of a Haken potential. The strong quantum and dielectric confinements are shown to squeeze the biexciton under the polaronic radius, which greatly enhances Coulomb attractions and (to a lesser extent) repulsions. This explains the need for effective dielectric constants approaching the high-frequency limit in previous simulations, and the binding energies exceeding 40 meV observed in single-monolayer nanoplatelets. Biexcitons are formed by a pair of weakly interacting excitons, with a roughly rectangular geometry. This translates into a constant ratio between biexciton and exciton binding energies (2D Haynes rule) well below the ideal value of ΔBX/ΔX = 0.228 proposed for squared biexcitons. The ratio is independent of the number of monolayers in the platelet, but it does depend on the lateral and dielectric confinement.
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Affiliation(s)
- Juan I Climente
- Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló de la Plana, Spain
| | - José L Movilla
- Dept. d'Educació i Didàctiques Específiques, Universitat Jaume I, 12080, Castelló, Spain
| | - Josep Planelles
- Departament de Química Física i Analítica, Universitat Jaume I, E-12080, Castelló de la Plana, Spain
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2
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Lou X, Li Y, Lei H, Zhang Y, Zhou H, Shi E, Zhu H. Robust and Efficient Out-of-Plane Exciton Transport in Two-Dimensional Perovskites via Ultrafast Förster Energy Transfer. ACS NANO 2024. [PMID: 39041395 DOI: 10.1021/acsnano.4c06336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Two-dimensional (2D) perovskites, comprising inorganic semiconductor layers separated by organic spacers, hold promise for light harvesting and optoelectronic applications. Exciton transport in these materials is pivotal for device performance, often necessitating deliberate alignment of the inorganic layers with respect to the contacting layers to facilitate exciton transport. While much attention has focused on in-plane exciton transport, little has been paid to out-of-plane interlayer transport, which presumably is sluggish and unfavorable. Herein, by time-resolved photoluminescence, we unveil surprisingly efficient out-of-plane exciton transport in 2D perovskites, with diffusion coefficients (up to ∼0.1 cm2 s-1) and lengths (∼100 nm) merely a few times smaller or comparable to their in-plane counterparts. We unambiguously confirm that the out-of-plane exciton diffusion coefficient corresponds to a subpicosecond interlayer exciton transfer, governed by the Förster resonance energy transfer (FRET) mechanism. Intriguingly, in contrast to temperature-sensitive intralayer band-like transport, the interlayer exciton transport exhibits negligible temperature dependence, implying a lowest-lying bright exciton state in 2D perovskites, irrespective of spacer molecules. The robust and ultrafast interlayer exciton transport alleviates the constraints on crystal orientation that are crucial for the design of 2D perovskite-based light harvesting and optoelectronic devices.
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Affiliation(s)
- Xue Lou
- State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
| | - Yahui Li
- Research Center for Industries of the Future and School of Engineering, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Haixin Lei
- State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
| | - Yao Zhang
- State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
| | - Hongzhi Zhou
- State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
| | - Enzheng Shi
- Research Center for Industries of the Future and School of Engineering, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Haiming Zhu
- State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, China
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3
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Tang B, Wei Q, Wang S, Liu H, Mou N, Liu Q, Wu Y, Portniagin AS, Kershaw SV, Gao X, Li M, Rogach AL. Ultraviolet Circularly Polarized Luminescence in Chiral Perovskite Nanoplatelet-Molecular Hybrids: Direct Binding Versus Efficient Triplet Energy Transfer. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2311639. [PMID: 38204283 DOI: 10.1002/smll.202311639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Indexed: 01/12/2024]
Abstract
The development of ultraviolet circularly polarized light (UVCPL) sources has the potential to benefit plenty of practical applications but remains a challenge due to limitations in available material systems and a limited understanding of the excited state chirality transfer. Herein, by constructing hybrid structures of the chiral perovskite CsPbBr3 nanoplatelets and organic molecules, excited state chirality transfer is achieved, either via direct binding or triplet energy transfer, leading to efficient UVCPL emission. The underlying photophysical mechanisms of these two scenarios are clarified by comprehensive optical studies. Intriguingly, UVCPL realized via the triple energy transfer, followed by the triplet-triplet annihilation upconversion processes, demonstrates a 50-fold enhanced dissymmetry factor glum. Furthermore, stereoselective photopolymerization of diacetylene monomer is demonstrated by using such efficient UVCPL. This study provides both novel insights and a practical approach for realizing UVCPL, which can also be extended to other material systems and spectral regions, such as visible and near-infrared.
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Affiliation(s)
- Bing Tang
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Qi Wei
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, 999077, P. R. China
| | - Shixun Wang
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Haochen Liu
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Nanli Mou
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Qi Liu
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Ye Wu
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Arsenii S Portniagin
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Stephen V Kershaw
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
| | - Xiaoqing Gao
- Wenzhou Key Laboratory of Biophysics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, 325000, P. R. China
| | - Mingjie Li
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, 999077, P. R. China
| | - Andrey L Rogach
- Department of Materials Science and Engineering, and Centre for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, 999077, P. R. China
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4
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Krajewska CJ, Kick M, Kaplan AEK, Berkinsky DB, Zhu H, Sverko T, Van Voorhis T, Bawendi MG. A-Site Cation Influence on the Structural and Optical Evolution of Ultrathin Lead Halide Perovskite Nanoplatelets. ACS NANO 2024; 18:8248-8258. [PMID: 38428021 DOI: 10.1021/acsnano.3c12286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Imposing quantum confinement has the potential to significantly modulate both the structural and optical parameters of interest in many material systems. In this work, we investigate strongly confined ultrathin perovskite nanoplatelets APbBr3. We compare the all-inorganic and hybrid compositions with the A-sites cesium and formamidinium, respectively. Compared to each other and their bulk counterparts, the materials show significant differences in variable-temperature structural and optical evolution. We quantify and correlate structural asymmetry with the excitonic transition energy, spectral purity, and emission rate. Negative thermal expansion, structural and photoluminescence asymmetry, photoluminescence full width at half-maximum, and splitting between bright and dark excitonic levels are found to be reduced in the hybrid composition. This work provides composition- and structure-based mechanisms for engineering of the excitons in these materials.
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Affiliation(s)
- Chantalle J Krajewska
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Matthias Kick
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander E K Kaplan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - David B Berkinsky
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Hua Zhu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Tara Sverko
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Moungi G Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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5
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Posmyk K, Zawadzka N, Łucja Kipczak, Dyksik M, Surrente A, Maude DK, Kazimierczuk T, Babiński A, Molas MR, Bumrungsan W, Chooseng C, Paritmongkol W, Tisdale WA, Baranowski M, Plochocka P. Bright Excitonic Fine Structure in Metal-Halide Perovskites: From Two-Dimensional to Bulk. J Am Chem Soc 2024; 146:4687-4694. [PMID: 38324275 PMCID: PMC10885139 DOI: 10.1021/jacs.3c11957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
The optical response of two-dimensional (2D) perovskites, often referred to as natural quantum wells, is primarily governed by excitons, whose properties can be readily tuned by adjusting the perovskite layer thickness. We have investigated the exciton fine structure splitting in the archetypal 2D perovskite (PEA)2(MA)n-1PbnI3n+1 with varying numbers of inorganic octahedral layers n = 1, 2, 3, and 4. We demonstrate that the in-plane excitonic states exhibit splitting and orthogonally oriented dipoles for all confinement regimes. The evolution of the exciton states in an external magnetic field provides further insights into the g-factors and diamagnetic coefficients. With increasing n, we observe a gradual evolution of the excitonic parameters characteristic of a 2D to three-dimensional transition. Our results provide valuable information concerning the evolution of the optoelectronic properties of 2D perovskites with the changing confinement strength.
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Affiliation(s)
- Katarzyna Posmyk
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
- Laboratoire National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228, Université Grenoble Alpes, Université Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble, Toulouse 31400, France
| | - Natalia Zawadzka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Łucja Kipczak
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Mateusz Dyksik
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
| | - Alessandro Surrente
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
| | - Duncan K Maude
- Laboratoire National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228, Université Grenoble Alpes, Université Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble, Toulouse 31400, France
| | - Tomasz Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Adam Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw 02-093, Poland
| | - Wakul Bumrungsan
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Chanisara Chooseng
- Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Watcharaphol Paritmongkol
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, 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
| | - Michał Baranowski
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
| | - Paulina Plochocka
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
- Laboratoire National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228, Université Grenoble Alpes, Université Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble, Toulouse 31400, France
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6
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Ren L, Robert C, Glazov M, Semina M, Amand T, Lombez L, Lagarde D, Taniguchi T, Watanabe K, Marie X. Control of the Bright-Dark Exciton Splitting Using the Lamb Shift in a Two-Dimensional Semiconductor. PHYSICAL REVIEW LETTERS 2023; 131:116901. [PMID: 37774277 DOI: 10.1103/physrevlett.131.116901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 07/19/2023] [Indexed: 10/01/2023]
Abstract
We investigate the exciton fine structure in atomically thin WSe_{2}-based van der Waals heterostructures where the density of optical modes at the location of the semiconductor monolayer can be tuned. The energy splitting Δ between the bright and dark exciton is measured by photoluminescence spectroscopy. We demonstrate that Δ can be tuned by a few meV as a result of a significant Lamb shift of the optically active exciton that arises from emission and absorption of virtual photons triggered by the vacuum fluctuations of the electromagnetic field. We also measure strong variations of the bright exciton radiative linewidth as a result of the Purcell effect. All these experimental results illustrate the strong sensitivity of the excitons to local vacuum field fluctuations. We find a very good agreement with a model that demonstrates the equivalence, for our system, of a classical electrodynamical transfer matrix formalism and quantum-electrodynamical approach. The bright-dark splitting control we demonstrate here in the weak light-matter coupling regime should apply to any semiconductor structures.
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Affiliation(s)
- L Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - C Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - M Glazov
- Ioffe Institute, 26 Polytechnicheskaya, 194021 Saint Petersburg, Russia
| | - M Semina
- Ioffe Institute, 26 Polytechnicheskaya, 194021 Saint Petersburg, Russia
| | - T Amand
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - L Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - D Lagarde
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-00044, Japan
| | - X Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
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7
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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 LETTERS 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] [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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8
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Harkort C, Kudlacik D, Kopteva NE, Yakovlev DR, Karzel M, Kirstein E, Hordiichuk O, Kovalenko MV, Bayer M. Spin-Flip Raman Scattering on Electrons and Holes in Two-Dimensional (PEA) 2 PbI 4 Perovskites. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300988. [PMID: 37066731 DOI: 10.1002/smll.202300988] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/14/2023] [Indexed: 06/19/2023]
Abstract
The class of Ruddlesden-Popper type (PEA)2 PbI4 perovskites comprises 2D structures whose optical properties are determined by excitons with a large binding energy of about 260 meV. It complements the family of other 2D semiconductor materials by having the band structure typical for lead halide perovskites, that can be considered as inverted compared to conventional III-V and II-VI semiconductors. Accordingly, novel spin phenomena can be expected for them. Spin-flip Raman scattering is used here to measure the Zeeman splitting of electrons and holes in a magnetic field up to 10 T. From the recorded data, the electron and hole Landé factors (g-factors) are evaluated, their signs are determined, and their anisotropies are measured. The electron g-factor value changes from +2.11 out-of-plane to +2.50 in-plane, while the hole g-factor ranges between -0.13 and -0.51. The spin flips of the resident carriers are arranged via their interaction with photogenerated excitons. Also the double spin-flip process, where a resident electron and a resident hole interact with the same exciton, is observed showing a cumulative Raman shift. Dynamic nuclear spin polarization induced by spin-polarized holes is detected in corresponding changes of the hole Zeeman splitting. An Overhauser field of the polarized nuclei acting on the holes as large as 0.6 T can be achieved.
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Affiliation(s)
- Carolin Harkort
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Dennis Kudlacik
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Natalia E Kopteva
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Marek Karzel
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Erik Kirstein
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
| | - Oleh Hordiichuk
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093, Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600, Dübendorf, Switzerland
| | - Maksym V Kovalenko
- Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093, Zürich, Switzerland
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, CH-8600, Dübendorf, Switzerland
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund, D-44227, Dortmund, Germany
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9
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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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10
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Lampe C, Kouroudis I, Harth M, Martin S, Gagliardi A, Urban AS. Rapid Data-Efficient Optimization of Perovskite Nanocrystal Syntheses through Machine Learning Algorithm Fusion. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208772. [PMID: 36681859 DOI: 10.1002/adma.202208772] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/18/2023] [Indexed: 06/17/2023]
Abstract
With the demand for renewable energy and efficient devices rapidly increasing, a need arises to find and optimize novel (nano)materials. With sheer limitless possibilities for material combinations and synthetic procedures, obtaining novel, highly functional materials has been a tedious trial and error process. Recently, machine learning has emerged as a powerful tool to help optimize syntheses; however, most approaches require a substantial amount of input data, limiting their pertinence. Here, three well-known machine-learning models are merged with Bayesian optimization into one to optimize the synthesis of CsPbBr3 nanoplatelets with limited data demand. The algorithm can accurately predict the photoluminescence emission maxima of nanoplatelet dispersions using only the three precursor ratios as input parameters. This allows us to fabricate previously unobtainable seven and eight monolayer-thick nanoplatelets. Moreover, the algorithm dramatically improves the homogeneity of 2-6-monolayer-thick nanoplatelet dispersions, as evidenced by narrower and more symmetric photoluminescence spectra. Decisively, only 200 total syntheses are required to achieve this vast improvement, highlighting how rapidly material properties can be optimized. The algorithm is highly versatile and can incorporate additional synthetic parameters. Accordingly, it is readily applicable to other less-explored nanocrystal syntheses and can help rapidly identify and improve exciting compositions' quality.
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Affiliation(s)
- Carola Lampe
- Nanospectroscopy Group and Center for NanoScience, Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Ioannis Kouroudis
- Department of Electrical and Computer Engineering, Technical University of Munich, Hans-Piloty-Straße 1, 85748, Garching bei München, Germany
| | - Milan Harth
- Department of Electrical and Computer Engineering, Technical University of Munich, Hans-Piloty-Straße 1, 85748, Garching bei München, Germany
| | - Stefan Martin
- Nanospectroscopy Group and Center for NanoScience, Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Alessio Gagliardi
- Department of Electrical and Computer Engineering, Technical University of Munich, Hans-Piloty-Straße 1, 85748, Garching bei München, Germany
| | - Alexander S Urban
- Nanospectroscopy Group and Center for NanoScience, Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
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11
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Krajewska CJ, Kaplan AEK, Kick M, Berkinsky DB, Zhu H, Sverko T, Van Voorhis T, Bawendi MG. Controlled Assembly and Anomalous Thermal Expansion of Ultrathin Cesium Lead Bromide Nanoplatelets. NANO LETTERS 2023; 23:2148-2157. [PMID: 36884029 DOI: 10.1021/acs.nanolett.2c04526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Quantum confined lead halide perovskite nanoplatelets are anisotropic materials displaying strongly bound excitons with spectrally pure photoluminescence. We report the controlled assembly of CsPbBr3 nanoplatelets through varying the evaporation rate of the dispersion solvent. We confirm the assembly of superlattices in the face-down and edge-up configurations by electron microscopy, as well as X-ray scattering and diffraction. Polarization-resolved spectroscopy shows that superlattices in the edge-up configuration display significantly polarized emission compared to face-down counterparts. Variable-temperature X-ray diffraction of both face-down and edge-up superlattices uncovers a uniaxial negative thermal expansion in ultrathin nanoplatelets, which reconciles the anomalous temperature dependence of the emission energy. Additional structural aspects are investigated by multilayer diffraction fitting, revealing a significant decrease in superlattice order with decreasing temperature, with a concomitant expansion of the organic sublattice and increase of lead halide octahedral tilt.
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Affiliation(s)
- Chantalle J Krajewska
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alexander E K Kaplan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Matthias Kick
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - David B Berkinsky
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Hua Zhu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Tara Sverko
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Moungi G Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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12
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He S, Jin T, Ni A, Lian T. Electron Trapping Prolongs the Lifetime of Charge-Separated States in 2D Perovskite Nanoplatelet-Hole Acceptor Complexes. J Phys Chem Lett 2023; 14:2241-2250. [PMID: 36820889 PMCID: PMC10009813 DOI: 10.1021/acs.jpclett.2c03815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) lead halide perovskite nanoplatelets (NPLs) are promising materials for blue light emission because of the strong quantum confinement in the 2D morphology. However, the identity of carrier traps and the trap influence on charge transfer in these NPLs remain unclear. Herein, transient absorption studies revealed two types of electron traps in 3 monolayer lead bromide perovskite NPLs with trapping lifetime of 9.0 ± 0.6 and 516 ± 59 ps, respectively, while no hole traps were observed. Systematic charge transfer experiments show that electron traps have negligible influence on ultrafast electron transfer or hole transfer but extend the half-lifetime of the charge-separated state from 2.1 ± 0.1 to 68 ± 3 ns after hole transfer, which is explained by the reduced electron-hole overlap. This work contributes to the understanding of the fundamental carrier dynamics in 2D perovskite NPLs and offers guidelines for boosting their performance in optoelectronics and photocatalysis.
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13
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Wang Y, Liu J, Wang A, Gao S, Li Z, Li J, Yan S, Cheng S, Song Z, Zhang Y, Dong J, Cao J, Wang F, Huang W, Qin T. Heterostructural Nanosheets Consisting of Polycyclic Aromatic Hydrocarbon Shields and Layered Perovskite Cores for Optical Image Encryption. J Phys Chem Lett 2023; 14:2047-2055. [PMID: 36795606 DOI: 10.1021/acs.jpclett.3c00316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Optical image encryption technology, in which the emission on/off can be controlled by using specially appointed wavelengths, is useful in information storage and protection. Herein, we report a family of sandwiched heterostructural nanosheets, consisting of three-layered (n = 3) perovskite (PSK) frameworks in center with two different polycyclic aromatic hydrocarbons [triphenylene (Tp) and pyrene (Py)] in periphery. Both heterostructural nanosheets (Tp-PSK and Py-PSK) exhibit blue emissions under UVA-I irradiation; however, different photoluminescent properties are observed under UVA-II. A bright emission of Tp-PSK is attributed to the fluorescence resonance energy transfer (FRET) from Tp-shield to PSK-core, whereas the observed photoquenching phenomenon in Py-PSK is due to the competitive absorption between Py-shield and PSK-core. We exploited the unique photophysical features (on/off emission) of the two nanosheets in a narrow UV window (320-340 nm) for optical image encrypting.
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Affiliation(s)
- Yanchen Wang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Jiaxin Liu
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Aifei Wang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Song Gao
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Zihao Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Junjie Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Suhao Yan
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Suwen Cheng
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Zhicheng Song
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Yupeng Zhang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Jingjin Dong
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Jiupeng Cao
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Fangfang Wang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Wei Huang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
| | - Tianshi Qin
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (Nanjing Tech), Nanjing, Jiangsu 211816, China
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14
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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] [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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15
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Wang S, Dyksik M, Lampe C, Gramlich M, Maude DK, Baranowski M, Urban AS, Plochocka P, Surrente A. Thickness-Dependent Dark-Bright Exciton Splitting and Phonon Bottleneck in CsPbBr 3-Based Nanoplatelets Revealed via Magneto-Optical Spectroscopy. NANO LETTERS 2022; 22:7011-7019. [PMID: 36036573 PMCID: PMC9479212 DOI: 10.1021/acs.nanolett.2c01826] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The optimized exploitation of perovskite nanocrystals and nanoplatelets as highly efficient light sources requires a detailed understanding of the energy spacing within the exciton manifold. Dark exciton states are particularly relevant because they represent a channel that reduces radiative efficiency. Here, we apply large in-plane magnetic fields to brighten optically inactive states of CsPbBr3-based nanoplatelets for the first time. This approach allows us to access the dark states and directly determine the dark-bright splitting, which reaches 22 meV for the thinnest nanoplatelets. The splitting is significantly less for thicker nanoplatelets due to reduced exciton confinement. Additionally, the form of the magneto-PL spectrum suggests that dark and bright state populations are nonthermalized, which is indicative of a phonon bottleneck in the exciton relaxation process.
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Affiliation(s)
- Shuli Wang
- Laboratoire
National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228,
Université Grenoble Alpes, Université
Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble
and 31400 Toulouse, France
| | - Mateusz Dyksik
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Carola Lampe
- Nanospectroscopy
Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department
of Physics, Ludwig-Maximilians-Universität
München (LMU), Munich 80539 Germany
| | - Moritz Gramlich
- Nanospectroscopy
Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department
of Physics, Ludwig-Maximilians-Universität
München (LMU), Munich 80539 Germany
| | - Duncan K. Maude
- Laboratoire
National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228,
Université Grenoble Alpes, Université
Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble
and 31400 Toulouse, France
| | - Michał Baranowski
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Alexander S. Urban
- Nanospectroscopy
Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department
of Physics, Ludwig-Maximilians-Universität
München (LMU), Munich 80539 Germany
| | - Paulina Plochocka
- Laboratoire
National des Champs Magnétiques Intenses, EMFL, CNRS UPR 3228,
Université Grenoble Alpes, Université
Toulouse, Université Toulouse 3, INSA-T, 38042 Grenoble
and 31400 Toulouse, France
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Alessandro Surrente
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
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16
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Wang CW, Liu X, Qiao T, Khurana M, Akimov AV, Son DH. Photoemission of the Upconverted Hot Electrons in Mn-Doped CsPbBr 3 Nanocrystals. NANO LETTERS 2022; 22:6753-6759. [PMID: 35939549 DOI: 10.1021/acs.nanolett.2c02342] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Hot electrons play a crucial role in enhancing the efficiency of photon-to-current conversion or photocatalytic reactions. In semiconductor nanocrystals, energetic hot electrons capable of photoemission can be generated via the upconversion process involving the dopant-originated intermediate state, currently known only in Mn-doped cadmium chalcogenide quantum dots. Here, we report that Mn-doped CsPbBr3 nanocrystals are an excellent platform for generating hot electrons via upconversion that can benefit from various desirable exciton properties and the structural diversity of metal halide perovskites (MHPs). Two-dimensional Mn-doped CsPbBr3 nanoplatelets are particularly advantageous for hot electron upconversion due to the strong exciton-dopant interaction mediating the upconversion process. Furthermore, nanoplatelets reveal evidence for the hot electron upconversion via long-lived dark excitons in addition to bright excitons that may enhance the upconversion efficiency. This study establishes the feasibility of hot electron upconversion in MHP hosts and demonstrates the potential merits of two-dimensional MHP nanocrystals in the upconversion process.
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Affiliation(s)
- Chih-Wei Wang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Xiaohan Liu
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - Tian Qiao
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Mohit Khurana
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - Alexey V Akimov
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - Dong Hee Son
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Center for Nanomedicine, Institute for Basic Science and Graduate Program of Nano Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
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17
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Greiner MG, Singldinger A, Henke NA, Lampe C, Leo U, Gramlich M, Urban AS. Energy Transfer in Stability-Optimized Perovskite Nanocrystals. NANO LETTERS 2022; 22:6709-6715. [PMID: 35939043 DOI: 10.1021/acs.nanolett.2c02108] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Outstanding optoelectronic properties and a facile synthesis render halide perovskite nanocrystals (NCs) a promising material for nanostructure-based devices. However, the commercialization is hindered mainly by the lack of NC stability under ambient conditions and inefficient charge carrier injection. Here, we investigate solutions to both problems, employing methylammonium lead bromide (MAPbBr3) NCs encapsulated in diblock copolymer core-shell micelles of tunable size. We confirm that the shell does not prohibit energy transfer, as FRET efficiencies between these NCs and 2D CsPbBr3 nanoplatelets (NPLs) reach 73.6%. This value strongly correlates to the micelle size, with thicker shells displaying significantly reduced FRET efficiencies. Those high efficiencies come with a price, as the thinnest shells protect the encapsulated NCs less from environmentally induced degradation. Finding the sweet spot between efficiency and protection could lead to the realization of tailored energy funnels with enhanced carrier densities for high-power perovskite NC-based optoelectronic applications.
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Affiliation(s)
- Michèle G Greiner
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Andreas Singldinger
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Nina A Henke
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Carola Lampe
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Ulrich Leo
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Moritz Gramlich
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
| | - Alexander S Urban
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstraße 10, 80539 Munich, Germany
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18
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Elmestekawy K, Wright AD, Lohmann KB, Borchert J, Johnston MB, Herz LM. Controlling Intrinsic Quantum Confinement in Formamidinium Lead Triiodide Perovskite through Cs Substitution. ACS NANO 2022; 16:9640-9650. [PMID: 35609245 PMCID: PMC9245356 DOI: 10.1021/acsnano.2c02970] [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: 03/25/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Lead halide perovskites are leading candidates for photovoltaic and light-emitting devices, owing to their excellent and widely tunable optoelectronic properties. Nanostructure control has been central to their development, allowing for improvements in efficiency and stability, and changes in electronic dimensionality. Recently, formamidinium lead triiodide (FAPbI3) has been shown to exhibit intrinsic quantum confinement effects in nominally bulk thin films, apparent through above-bandgap absorption peaks. Here, we show that such nanoscale electronic effects can be controlled through partial replacement of the FA cation with Cs. We find that Cs-cation exchange causes a weakening of quantum confinement in the perovskite, arising from changes in the bandstructure, the length scale of confinement, or the presence of δH-phase electronic barriers. We further observe photon emission from quantum-confined regions, highlighting their potential usefulness to light-emitting devices and single-photon sources. Overall, controlling this intriguing quantum phenomenon will allow for its suppression or enhancement according to need.
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Affiliation(s)
- Karim
A. Elmestekawy
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Adam D. Wright
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Kilian B. Lohmann
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Juliane Borchert
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Michael B. Johnston
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Laura M. Herz
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
- Institute
for Advanced Study, Technical University
of Munich, Lichtenbergstrasse
2a, D-85748 Garching, Germany
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19
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Lichtenegger MF, Drewniok J, Bornschlegl A, Lampe C, Singldinger A, Henke NA, Urban AS. Electron-Hole Binding Governs Carrier Transport in Halide Perovskite Nanocrystal Thin Films. ACS NANO 2022; 16:6317-6324. [PMID: 35302740 DOI: 10.1021/acsnano.2c00369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional halide perovskite nanoplatelets (NPLs) have exceptional light-emitting properties, including wide spectral tunability, ultrafast radiative decays, high quantum yields (QY), and oriented emission. Due to the high binding energies of electron-hole pairs, excitons are generally considered the dominant species responsible for carrier transfer in NPL films. To realize efficient devices, it is imperative to understand how exciton transport progresses therein. We employ spatially and temporally resolved optical microscopy to map exciton diffusion in perovskite nanocrystal (NC) thin films between 15 °C and 55 °C. At room temperature (RT), we find the diffusion length to be inversely correlated to the thickness of the nanocrystals (NCs). With increasing temperatures, exciton diffusion declines for all NC films, but at different rates. This leads to specific temperature turnover points, at which thinner NPLs exhibit higher diffusion lengths. We attribute this anomalous diffusion behavior to the coexistence of excitons and free electron hole-pairs inside the individual NCs within our temperature range. The organic ligand shell surrounding the NCs prevents charge transfer. Accordingly, any time an electron-hole pair spends in the unbound state reduces the FRET-mediated inter-NC transfer rates and, consequently, the overall diffusion. These results clarify how exciton diffusion progresses in strongly confined halide perovskite NC films, emphasizing critical considerations for optoelectronic devices.
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Affiliation(s)
- Michael F Lichtenegger
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Jan Drewniok
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Andreas Bornschlegl
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Carola Lampe
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Andreas Singldinger
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Nina A Henke
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
| | - Alexander S Urban
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximiliäns-Universitat München, Königinstr. 10, 80539 Munich, Germany
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20
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Steger M, Janke SM, Sercel PC, Larson BW, Lu H, Qin X, Yu VWZ, Blum V, Blackburn JL. On the optical anisotropy in 2D metal-halide perovskites. NANOSCALE 2022; 14:752-765. [PMID: 34940772 DOI: 10.1039/d1nr06899g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Two-dimensional metal-halide perovskites (MHPs) are versatile solution-processed organic/inorganic quantum wells where the structural anisotropy creates profound anisotropy in their electronic and excitonic properties and associated optical constants. We here employ a wholistic framework, based on semiempirical modeling (k·p/effective mass theory calculations) informed by hybrid density functional theory (DFT) and multimodal spectroscopic ellipsometry on (C6H5(CH2)2NH3)2PbI4 films and crystals, that allows us to link the observed optical properties and anisotropy precisely to the underlying physical parameters that shape the electronic structure of a layered MHP. We find substantial frequency-dependent anisotropy in the optical constants and close correspondence between experiment and theory, demonstrating a high degree of in-plane alignment of the two-dimensional planes in both spin-coated thin films and cleaved single crystals made in this study. Hybrid DFT results elucidate the degree to which organic and inorganic frontier orbitals contribute to optical transitions polarized along a particular axis. The combined experimental and theoretical approach enables us to estimate the fundamental electronic bandgap of 2.65-2.68 eV in this prototypical 2D perovskite and to determine the spin-orbit coupling (ΔSO = 1.20 eV) and effective crystal field (δ = -1.36 eV) which break the degeneracy of the frontier conduction band states and determine the exciton fine structure. The methods and results described here afford a better understanding of the connection between structure and induced optical anisotropy in quantum-confined MHPs, an important structure-property relationship for optoelectronic applications and devices.
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Affiliation(s)
- Mark Steger
- National Renewable Energy Laboratory, Golden, CO 80401, USA.
| | - Svenja M Janke
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
- Institute of Advanced Study, University of Warwick, CV4 7AL Coventry, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Peter C Sercel
- Center for Hybrid Organic Inorganic Semiconductors for Energy, Golden, CO, 80401, USA
| | - Bryon W Larson
- National Renewable Energy Laboratory, Golden, CO 80401, USA.
| | - Haipeng Lu
- National Renewable Energy Laboratory, Golden, CO 80401, USA.
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Xixi Qin
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Victor Wen-Zhe Yu
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Volker Blum
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
- Department of Chemistry, Duke University, Durham, NC 27708, USA
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Gramlich M, Lampe C, Drewniok J, Urban AS. How Exciton-Phonon Coupling Impacts Photoluminescence in Halide Perovskite Nanoplatelets. J Phys Chem Lett 2021; 12:11371-11377. [PMID: 34791883 DOI: 10.1021/acs.jpclett.1c03437] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Semiconductor nanocrystals are receiving increased interest as narrow-band emitters for display applications. Here, we investigate the underlying photoluminescence (PL) linewidth broadening mechanisms in thickness-tunable 2D halide perovskite (Csn-1PbnBr3n+1) nanoplatelets (NPLs). Temperature-dependent PL spectroscopy on NPL thin films reveals a blue-shift of the PL maximum for thicker NPLs, no shift for three monolayer (ML) thick NPLs, and a red-shift for the thinnest (2 ML) NPLs with increasing temperature. Emission linewidths also strongly depend on NPL thickness, with the thinnest NPLs showing the smallest temperature-induced broadening. We determine the combined interaction of exciton-phonon coupling and thermal lattice expansion to be responsible for both effects. Additionally, the 2 ML NPLs exhibit a significantly larger Fröhlich coupling constant and optical phonon energy, possibly due to an inversion in the exciton fine structure. These results illustrate that ultrathin halide perovskite NPLs could illuminate the next generation of displays, provided a slightly greater sample homogeneity and improved stability.
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Affiliation(s)
- Moritz Gramlich
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstr. 10, 80539 Munich, Germany
| | - Carola Lampe
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstr. 10, 80539 Munich, Germany
| | - Jan Drewniok
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstr. 10, 80539 Munich, Germany
| | - Alexander S Urban
- Nanospectroscopy Group and Center for Nanoscience (CeNS), Nano-Institute Munich, Department of Physics, Ludwig-Maximilians-Universität München, Königinstr. 10, 80539 Munich, Germany
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