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Agrawal S, Wang B, Wu Y, Casanova D, Prezhdo OV. Photocatalytic activity of dual defect modified graphitic carbon nitride is robust to tautomerism: machine learning assisted ab initio quantum dynamics. NANOSCALE 2024. [PMID: 38623607 DOI: 10.1039/d4nr00606b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Two-dimensional graphitic carbon nitride (GCN) is a popular metal-free polymer for sustainable energy applications due to its unique structure and semiconductor properties. Dopants and defects are used to tune GCN, and dual defect modified GCN exhibits superior properties and enhanced photocatalytic efficiency in comparison to pristine or single defect GCN. We employ a multistep approach combining time-dependent density functional theory and nonadiabatic molecular dynamics (NAMD) with machine learning (ML) to investigate coupled structural and electronic dynamics in GCN over a nanosecond timescale, comparable to and exceeding the lifetimes of photo-generated charge carriers and photocatalytic events. Although frequent hydrogen hopping transitions occur among four tautomeric structures, the electron-hole separation and recombination processes are only weakly sensitive to the tautomerism. The charge separated state survives for about 10 ps, sufficiently long to enable photocatalysis. The employed ML-NAMD methodology provides insights into rare events that can influence excited state dynamics in the condensed phase and nanoscale materials and extends NAMD simulations from pico- to nanoseconds. The ab initio quantum dynamics simulation provides a detailed atomistic mechanism of photoinduced evolution of charge carriers in GCN and rationalizes how GCN remains photo-catalytically active despite its multiple isomeric and tautomeric forms.
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Affiliation(s)
- Sraddha Agrawal
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
| | - Bipeng Wang
- Department of Chemical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Yifan Wu
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
| | - David Casanova
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
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2
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Agrawal S, Casanova D, Trivedi DJ, Prezhdo OV. Enhanced Charge Separation in Single Atom Cobalt Based Graphitic Carbon Nitride: Time Domain Ab Initio Analysis. J Phys Chem Lett 2024; 15:2202-2208. [PMID: 38373150 PMCID: PMC10910588 DOI: 10.1021/acs.jpclett.3c03621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
In recent years, single atom catalysts have been at the forefront of energy conversion research, particularly in the field of catalysis. Carbon nitrides offer great potential as hosts for stabilizing metal atoms due to their unique electronic structure. We use ab initio nonadiabatic molecular dynamics to study photoexcitation dynamics in single atom cobalt based graphitic carbon nitride. The results elucidate the positive effect of the doped cobalt atom on the electronic structure of GCN. Cobalt doping produces filled midgap states that serve as oxidation centers, advantageous for various redox reactions. The presence of midgap states enables the harvesting of longer wavelength photons, thereby extending the absorption range of solar light. Although doping accelerates charge relaxation overall, charge recombination is significantly slower than charge separation, creating beneficial conditions for catalysis applications. The simulations reveal the detailed microscopic mechanism underlying the improved performance of the doped system due to atomic defects and demonstrate an effective charge separation strategy to construct highly efficient and stable photocatalytic two-dimensional materials.
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Affiliation(s)
- Sraddha Agrawal
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - David Casanova
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- IKERBASQUE,
Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Dhara J. Trivedi
- Department
of Physics, Clarkson University, Potsdam, New York 13699, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
- Department
of Physics and Astronomy, University of
Southern California, Los Angeles, California 90007, United States
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3
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Gumber S, Prezhdo OV. Zeno and Anti-Zeno Effects in Nonadiabatic Molecular Dynamics. J Phys Chem Lett 2023; 14:7274-7282. [PMID: 37556319 PMCID: PMC10440816 DOI: 10.1021/acs.jpclett.3c01831] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023]
Abstract
Decoherence plays an important role in nonadiabatic (NA) molecular dynamics (MD) simulations because it provides a physical mechanism for trajectory hopping and can alter transition rates by orders of magnitude. Generally, decoherence effects slow quantum transitions, as exemplified by the quantum Zeno effect: in the limit of infinitely fast decoherence, the transitions stop. If the measurements are not sufficiently frequent, an opposite quantum anti-Zeno effect occurs, in which the transitions are accelerated with faster decoherence. Using two common NA-MD approaches, fewest switches surface hopping and decoherence-induced surface hopping, combined with analytic examination, we demonstrate that including decoherence into NA-MD slows down NA transitions; however, many realistic systems operate in the anti-Zeno regime. Therefore, it is important that NA-MD methods describe both Zeno and anti-Zeno effects. Numerical simulations of charge trapping and relaxation in graphitic carbon nitride suggest that time-dependent NA Hamiltonians encountered in realistic systems produce robust results with respect to errors in the decoherence time, a favorable feature for NA-MD simulations.
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Affiliation(s)
- Shriya Gumber
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department
of Physics and Astronomy, University of
Southern California, Los Angeles, California 90089, United States
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4
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Bian F, Wu X, Yang Z, Shao S, Meng X, Qin G. Quantitative Evaluation of the Carrier Separation Performance of Heterojunction Photocatalysts: The Case of g-C 3N 4/SrTiO 3. J Phys Chem Lett 2023; 14:2927-2932. [PMID: 36930040 DOI: 10.1021/acs.jpclett.3c00427] [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
Heterojunction photocatalysts are of great interest in the energy and environmental fields, because of their potential to significantly increase the efficiency of harvesting solar energy. Advances in design have been hampered by the continued use of only qualitative analyses. Quantitative evaluation of the carrier separation performance is urgently needed for the design and application of heterojunction photocatalysts. Taking the g-C3N4/SrTiO3 heterojunction as an example, we address the conventional energy band and electronic structure issues by first-principles analysis. After interface coupling, the band edge alignment reverses from that of the respective isolated states of the heterojunction components, suggesting new ways of thinking about the catalytic mechanism of the heterojunction. More significantly, we show the carrier separation performance of heterojunction photocatalysts can be quantitatively predicted by the nonadiabatic molecular dynamics method, enabling more precisely directed research and promoting the quantified design and application of heterojunction photocatalysis, making a contribution of great scientific significance.
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Affiliation(s)
- Fang Bian
- Key Laboratory for Anisotropy and Texture of Materials (MoE), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Xinge Wu
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Zhaoying Yang
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Shuai Shao
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Xiangying Meng
- College of Sciences, Northeastern University, Shenyang 110819, China
- Institute of Materials Intelligence Technology, Liaoning Academy of Materials, Shenyang 110167, China
| | - Gaowu Qin
- Key Laboratory for Anisotropy and Texture of Materials (MoE), School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
- Institute of Materials Intelligence Technology, Liaoning Academy of Materials, Shenyang 110167, China
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5
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Orcutt EK, Varapragasam SJ, Peterson ZC, Andriolo JM, Skinner JL, Grumstrup EM. Ultrafast Charge Injection in Silver-Modified Graphitic Carbon Nitride. ACS APPLIED MATERIALS & INTERFACES 2023; 15:15478-15485. [PMID: 36926802 PMCID: PMC10064998 DOI: 10.1021/acsami.2c22870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Graphitic carbon nitride (gCN) is a promising organic platform for driving light-activated charge-transfer reactions in a number of valuable photocatalytic cycles. A primary limitation of gCN as a photocatalyst is its short excited-state lifetime, which is mediated by a high density of trap and defect sites that result in rapid excited-state decay and low photocatalytic efficiency. To enhance the catalytic activity, gCN is often functionalized with a metal co-catalyst; however, the mechanism by which metal co-catalysts enhance the reactivity has not been clearly established. In this work, the excited-state dynamics of gCN and silver-modified gCN are compared using ultrafast transient absorption and time-resolved photoluminescence spectroscopies. In silver-modified gCN, an ultrafast spectral shift in the silver plasmon resonance provides direct spectral evidence of electron transfer from gCN to the silver nanoparticles. The electron-transfer rate is competitive with other non-radiative relaxation pathways, with electron-transfer yields approaching 50%, thus providing an effective strategy for mitigating losses associated with defects and trap sites.
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Affiliation(s)
- Emma K. Orcutt
- Department
of Chemistry and Biochemistry, Montana State
University, Bozeman, Montana 59717, United
States
| | - Shelton J. Varapragasam
- Department
of Chemistry and Biochemistry, Montana State
University, Bozeman, Montana 59717, United
States
| | - Zöe C. Peterson
- Department
of Chemistry and Biochemistry, Montana State
University, Bozeman, Montana 59717, United
States
| | - Jessica M. Andriolo
- Montana
Tech Nanotechnology Laboratory, Montana
Technological University, Butte, Montana 59701, United States
| | - Jack L. Skinner
- Montana
Tech Nanotechnology Laboratory, Montana
Technological University, Butte, Montana 59701, United States
| | - Erik M. Grumstrup
- Department
of Chemistry and Biochemistry, Montana State
University, Bozeman, Montana 59717, United
States
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Wen L, Li M, Shi J, Yu T, Liu Y, Liu M, Zhou Z, Guo L. Rational design of covalent heptazine framework photocatalysts with high oxidation ability through reaction-dependent strategy. J Colloid Interface Sci 2023; 630:394-402. [DOI: 10.1016/j.jcis.2022.10.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 10/12/2022] [Accepted: 10/22/2022] [Indexed: 11/21/2022]
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Lu TF, Agrawal S, Tokina M, Chu W, Hirt D, Hopkins PE, Prezhdo OV. Control of Charge Carrier Relaxation at the Au/WSe 2 Interface by Ti and TiO 2 Adhesion Layers: Ab Initio Quantum Dynamics. ACS APPLIED MATERIALS & INTERFACES 2022; 14:57197-57205. [PMID: 36516838 DOI: 10.1021/acsami.2c18793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Phonon-mediated charge relaxation plays a vital role in controlling thermal transport across an interface for efficient functioning of two-dimensional (2D) nanostructured devices. Using a combination of nonadiabatic molecular dynamics with real-time time-dependent density functional theory, we demonstrate a strong influence of adhesion layers at the Au/WSe2 interface on nonequilibrium charge relaxation, rationalizing recent ultrafast time-resolved experiments. Ti oxide layers (TiOx) create a barrier to the interaction between Au and WSe2 and extend hot carrier lifetimes, creating benefits for photovoltaic and photocatalytic applications. In contrast, a metallic Ti layer accelerates the energy flow, as needed for efficient heat dissipation in electronic devices. The interaction of metallic Ti with WSe2 causes W-Se bond scissoring and pins the Fermi level. The Ti adhesion layer enhances the electron-phonon coupling due to an increased density of states and the light mass of the Ti atom. The conclusions are robust to presence of typical point defects. The atomic-scale ab initio analysis of carrier relaxation at the interfaces advances our knowledge in fabricating nanodevices with optimized electronic and thermal properties.
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Affiliation(s)
- Teng-Fei Lu
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, Liaoning Province, China
| | - Sraddha Agrawal
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Marina Tokina
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Weibin Chu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, Fudan University, Shanghai 200433, People's Republic of China
| | - Daniel Hirt
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Patrick E Hopkins
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
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8
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Zhao X, Vasenko AS, Prezhdo OV, Long R. Anion Doping Delays Nonradiative Electron-Hole Recombination in Cs-Based All-Inorganic Perovskites: Time Domain ab Initio Analysis. J Phys Chem Lett 2022; 13:11375-11382. [PMID: 36454707 DOI: 10.1021/acs.jpclett.2c03072] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Using time-domain density functional theory combined with nonadiabatic (NA) molecular dynamics, we demonstrate that composition engineering of the X-site anions has a strong influence on the nonradiative electron-hole recombination and thermodynamic stability of cesium-based all-inorganic perovskites. Partial substitution of iodine(I) with bromine (Br) and acetate (Ac) anions reduces the NA electron-vibrational coupling by minimizing the overlap between the electron and hole wave functions and suppressing atomic fluctuations. The doping also widens the energy gap to further reduce the NA coupling and to enhance the open-circuit voltage of perovskite solar cells. These factors increase the charge carrier lifetime by an order of magnitude and improve structural stability in the series CsPbI1.88BrAc0.12 > CsPbI2Br > CsPbI3. The fundamental atomistic insights into the influence of anion doping on the photophysical properties of the all-inorganic lead halide perovskites guide the design of efficient optoelectronic materials.
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Affiliation(s)
- Xi Zhao
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, People's Republic of China
| | - Andrey S Vasenko
- HSE University, 101000Moscow, Russia
- I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991Moscow, Russia
| | - Oleg V Prezhdo
- Departments of Chemistry, and Physics and Astronomy, University of Southern California, Los Angeles, California90089, United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, People's Republic of China
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Actis A, Melchionna M, Filippini G, Fornasiero P, Prato M, Salvadori E, Chiesa M. Morphology and Light-Dependent Spatial Distribution of Spin Defects in Carbon Nitride. Angew Chem Int Ed Engl 2022; 61:e202210640. [PMID: 36074040 PMCID: PMC9828381 DOI: 10.1002/anie.202210640] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Indexed: 01/12/2023]
Abstract
Carbon nitride (CN) is a heterogeneous photocatalyst that combines good structural properties and a broad scope. The photocatalytic efficiency of CN is associated with the presence of defective and radical species. An accurate description of defective states-both at a local and extended level-is key to develop a thorough mechanistic understanding of the photophysics of CN. In turn, this will maximise the generation and usage of photogenerated charge carriers and minimise wasteful charge recombination. Here the influence of morphology and light-excitation on the number and chemical nature of radical defects is assessed. By exploiting the magnetic dipole-dipole coupling, the spatial distribution of native radicals in CN is derived with high precision. From the analysis an average distance in the range 1.99-2.34 nm is determined, which corresponds to pairs of radicals located approximately four tri-s-triazine units apart.
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Affiliation(s)
- Arianna Actis
- Department of Chemistry and NIS CentreUniversity of TorinoVia Pietro Giuria 710125TorinoItaly
| | - Michele Melchionna
- Department of Chemical and Pharmaceutical, INSTM UdRUniversity of TriesteVia Licio Giorgieri 134127TriesteItaly
| | - Giacomo Filippini
- Department of Chemical and Pharmaceutical, INSTM UdRUniversity of TriesteVia Licio Giorgieri 134127TriesteItaly
| | - Paolo Fornasiero
- Department of Chemical and Pharmaceutical, INSTM UdRUniversity of TriesteVia Licio Giorgieri 134127TriesteItaly
- ICCOM-CNR URTTriesteItaly
| | - Maurizio Prato
- Department of Chemical and Pharmaceutical, INSTM UdRUniversity of TriesteVia Licio Giorgieri 134127TriesteItaly
- ICCOM-CNR URTTriesteItaly
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE)Basque Research and Technology Alliance (BRTA)Paseo Miramon 19420014Donostia San SebastiánSpain
- Basque Fdn Sci Ikerbasque48013BilbaoSpain
| | - Enrico Salvadori
- Department of Chemistry and NIS CentreUniversity of TorinoVia Pietro Giuria 710125TorinoItaly
| | - Mario Chiesa
- Department of Chemistry and NIS CentreUniversity of TorinoVia Pietro Giuria 710125TorinoItaly
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Actis A, Melchionna M, Filippini G, Fornasiero P, Prato M, Salvadori E, Chiesa M. Morphology and Light‐Dependent Spatial Distribution of Spin Defects in Carbon Nitride. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Arianna Actis
- University of Turin: Universita degli Studi di Torino Department of Chemistry ITALY
| | - Michele Melchionna
- University of Trieste: Universita degli Studi di Trieste Department of Chemical and Pharmaceutical Sciences ITALY
| | - Giacomo Filippini
- University of Trieste: Universita degli Studi di Trieste Department of Chemical and Pharmaceutical Sciences ITALY
| | - Paolo Fornasiero
- University of Trieste: Universita degli Studi di Trieste Department of Chemical and Pharmaceutical Sciences ITALY
| | - Maurizio Prato
- University of Trieste: Universita degli Studi di Trieste Department of Chemical and Pharmaceutical Sciences ITALY
| | - Enrico Salvadori
- Università degli Studi di Torino Department of Chemistry Via Pietro Giuria, 7 10125 Torino ITALY
| | - Mario Chiesa
- University of Turin: Universita degli Studi di Torino Department of Chemistry ITALY
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11
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Liu D, Perez CM, Vasenko AS, Prezhdo OV. Ag-Bi Charge Redistribution Creates Deep Traps in Defective Cs 2AgBiBr 6: Machine Learning Analysis of Density Functional Theory. J Phys Chem Lett 2022; 13:3645-3651. [PMID: 35435697 DOI: 10.1021/acs.jpclett.2c00869] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lead-free double perovskites hold promise for stable and environmentally benign solar cells; however, they exhibit low efficiencies because defects act as charge recombination centers. Identifying trap-assisted loss mechanisms and developing defect passivation strategies constitute an urgent goal. Applying unsupervised machine learning to density functional theory and nonadiabatic molecular dynamics, we demonstrate that negatively charged Br vacancies in Cs2AgBiBr6 create deep hole traps through charge redistribution between the adjacent Ag and Bi atoms. Vacancy electrons are first accepted by Bi and then shared with Ag, as the trap transforms from shallow to deep. Subsequent charge losses are promoted by Ag and Bi motions perpendicular to rather than along the Ag-Bi axis, as can be expected. In contrast, charge recombination in pristine Cs2AgBiBr6 correlates most with displacements of Cs atoms and Br-Br-Br angles. Doping with In to replace Ag at the vacancy maintains the electrons at Bi and keeps the trap shallow.
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Affiliation(s)
| | - Carlos Mora Perez
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Andrey S Vasenko
- HSE University, 101000 Moscow, Russia
- I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
- Department of Physics & Astronomy, University of Southern California, Los Angeles, California 90089, United States
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