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Ma X, Fang WH, Long R, Prezhdo OV. Compression of Organic Molecules Coupled with Hydrogen Bonding Extends the Charge Carrier Lifetime in BA 2SnI 4. J Am Chem Soc 2024; 146:16314-16323. [PMID: 38812460 DOI: 10.1021/jacs.4c05191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Two-dimensional (2D) metal halide perovskites, such as BA2SnI4 (BA═CH3(CH2)3NH3), exhibit an enhanced charge carrier lifetime in experiments under strain. Experiments suggest that significant compression of the BA molecule, rather than of the inorganic lattice, contributes to this enhancement. To elucidate the underlying physical mechanism, we apply a moderate compressive strain to the entire system and subsequently introduce significant compression to the BA molecules. We then perform ab initio nonadiabatic molecular dynamics simulations of nonradiative electron-hole recombination. We observe that the overall lattice compression reduces atomic motions and decreases nonadiabatic coupling, thereby delaying electron-hole recombination. Additionally, compression of the BA molecules enhances hydrogen bonding between the BA molecules and iodine atoms, which lengthens the Sn-I bonds, distorts the [SnI6]4- octahedra, and suppresses atomic motions further, thus reducing nonadiabatic coupling. Also, the elongated Sn-I bonds and weakened antibonding interactions increase the band gap. Altogether, the compression delays the nonradiative electron-hole recombination by more than a factor of 3. Our simulations provide new and valuable physical insights into how compressive strain, accommodated primarily by the organic ligands, positively influences the optoelectronic properties of 2D layered halide perovskites, offering a promising pathway for further performance improvements.
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Affiliation(s)
- Xinbo Ma
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Oleg V Prezhdo
- University of Southern California, Los Angeles, California 90007, United States
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2
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Ma X, Long R. The sp 3 Defect Decreases Charge Carrier Lifetime in (8,3) Single-Walled Carbon Nanotubes. J Phys Chem Lett 2023; 14:10242-10248. [PMID: 37937588 DOI: 10.1021/acs.jpclett.3c02923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
A recent experimental approach introduces sp3 defects into single-walled carbon nanotubes (SWNTs) through controlled functionalization with guanine, resulting in a decrease in charge carrier lifetime. However, the physical mechanism behind this phenomenon remains unclear. We employ nonadiabatic molecular dynamics to systematically model the nonradiative recombination process of electron-hole pairs in SWNTs with sp3 defects generated by a guanine molecule. We demonstrate that the introduction of sp3 defects creates an overlapping channel between the highest occupied (HOMO) and lowest unoccupied molecular orbital (LUMO), significantly enhancing the nonadiabatic (NA) coupling and leading to a 4.7-fold acceleration in charge carrier recombination compared to defect-free SWNTs. The charge carrier recombination slows significantly at a lower temperature (50 K) due to the weakening of the NA coupling. Our results rationalize the accelerated recombination of charge carriers in SWNTs with sp3 defects in experiments and contribute to a deeper understanding of the carrier dynamics in SWNTs.
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Affiliation(s)
- Xinbo Ma
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
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3
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Ultra-narrow room-temperature emission from single CsPbBr 3 perovskite quantum dots. Nat Commun 2022; 13:2587. [PMID: 35546149 PMCID: PMC9095639 DOI: 10.1038/s41467-022-30016-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Semiconductor quantum dots have long been considered artificial atoms, but despite the overarching analogies in the strong energy-level quantization and the single-photon emission capability, their emission spectrum is far broader than typical atomic emission lines. Here, by using ab-initio molecular dynamics for simulating exciton-surface-phonon interactions in structurally dynamic CsPbBr3 quantum dots, followed by single quantum dot optical spectroscopy, we demonstrate that emission line-broadening in these quantum dots is primarily governed by the coupling of excitons to low-energy surface phonons. Mild adjustments of the surface chemical composition allow for attaining much smaller emission linewidths of 35−65 meV (vs. initial values of 70–120 meV), which are on par with the best values known for structurally rigid, colloidal II-VI quantum dots (20−60 meV). Ultra-narrow emission at room-temperature is desired for conventional light-emitting devices and paramount for emerging quantum light sources. Narrow emission is desired for light-emitting devices. Here, Kovalenko et al. demonstrate that the emission line-broadening in perovskite quantum dots is dominated by the coupling between excitons and surface phonon modes which can be controlled by minimal surface modifications.
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Ha Y, Park JG, Hong KH, Kim H. Enhanced Light Emission through Symmetry Engineering of Halide Perovskites. J Am Chem Soc 2021; 144:297-305. [PMID: 34958207 DOI: 10.1021/jacs.1c09891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Metal-halide perovskites (MHPs) have attracted tremendous attention as active materials in optoelectronic devices. For light-emitting diode (LED) applications, nanostructuring of MHPs is considered to be inevitable, but its light-enhancement mechanism is still elusive because the particle (or grain) size is often beyond the quantum confinement regime. As motivated by the experimental finding that the nanostructuring can change the preferred crystalline symmetry from the orthorhombic phase to the high-symmetric cubic phase, we here investigated the carrier dynamics in various polymorphic phases of CsPbBr3 using ab initio quantum dynamics simulation. We found that the cubic phase shows a smaller inelastic phonon scattering than the orthorhombic phase; the suppression of the octahedral tilt minimizes the longitudinal Br fluctuation and helps disentangle the A-site cation dynamics from the nonadiabatic carrier dynamics. We thus anticipate that our present work will offer a material design principle to enhance the quantum yield of MHPs via symmetry engineering, which will help develop highly luminescent LED technology based on MHPs.
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Affiliation(s)
- Yoonhoo Ha
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jong-Goo Park
- Department of Materials Science and Engineering, Hanbat National University, Daejeon 34158, Republic of Korea
| | - Ki-Ha Hong
- Department of Materials Science and Engineering, Hanbat National University, Daejeon 34158, Republic of Korea
| | - Hyungjun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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5
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Akimov AV. Extending the Time Scales of Nonadiabatic Molecular Dynamics via Machine Learning in the Time Domain. J Phys Chem Lett 2021; 12:12119-12128. [PMID: 34913701 DOI: 10.1021/acs.jpclett.1c03823] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A novel methodology for direct modeling of long-time scale nonadiabatic dynamics in extended nanoscale and solid-state systems is developed. The presented approach enables forecasting the vibronic Hamiltonians as a direct function of time via machine-learning models trained directly in the time domain. The use of periodic and aperiodic functions that transform time into effective input modes of the artificial neural network is demonstrated to be essential for such an approach to work for both abstract and atomistic models. The best strategies and possible limitations pertaining to the new methodology are explored and discussed. An exemplary direct simulation of unprecedentedly long 20 picosecond trajectories is conducted for a divacancy-containing monolayer black phosphorus system, and the importance of conducting such extended simulations is demonstrated. New insights into the excited states photophysics in this system are presented, including the role of decoherence and model definition.
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Affiliation(s)
- Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
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6
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Akimov AV. Excited state dynamics in monolayer black phosphorus revisited: Accounting for many-body effects. J Chem Phys 2021; 155:134106. [PMID: 34624981 DOI: 10.1063/5.0065606] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dynamics of electron-hole recombination in pristine and defect-containing monolayer black phosphorus (ML-BP) has been studied computationally by several groups relying on the one-particle description of electronic excited states. Our recent developments enabled a more sophisticated and accurate treatment of excited states dynamics in systems with pronounced excitonic effects, including 2D materials such as ML-BP. In this work, I present a comprehensive characterization of optoelectronic properties and nonadiabatic dynamics of the ground state recovery in pristine and divacancy-containing ML-BP, relying on the linear-response time-dependent density functional theory description of excited states combined with several trajectory surface hopping methodologies and decoherence correction schemes. This work presents a revision and new implementation of the decoherence-induced surface hopping methodology. Several popular algorithms for nonadiabatic dynamics algorithms are assessed. The kinetics of nonradiative relaxation of lower-lying excited states in ML-BP systems is revised considering the new methodological developments. A general mechanism that explains the sensitivity of the nonradiative dynamics to the presence of divacancy defect in ML-BP is proposed. According to this mechanism, the excited states' relaxation may be inhibited by the presence of energetically close higher-energy states if electronic decoherence is present in the system.
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Affiliation(s)
- Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
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7
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Marri I, Ossicini S. Multiple exciton generation in isolated and interacting silicon nanocrystals. NANOSCALE 2021; 13:12119-12142. [PMID: 34250528 DOI: 10.1039/d1nr01747k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An important challenge in the field of renewable energy is the development of novel nanostructured solar cell devices which implement low-dimensional materials to overcome the limits of traditional photovoltaic systems. For optimal energy conversion in photovoltaic devices, one important requirement is that the full energy of the solar spectrum is effectively used. In this context, the possibility of exploiting features and functionalities induced by the reduced dimensionality of the nanocrystalline phase, in particular by the quantum confinement of the electronic density, can lead to a better use of the carrier excess energy and thus to an increment of the thermodynamic conversion efficiency of the system. Carrier multiplication, i.e. the generation of multiple electron-hole pairs after absorption of one single high-energy photon (with energy at least twice the energy gap of the system), can be exploited to maximize cell performance, promoting a net reduction of loss mechanisms. Over the past fifteen years, carrier multiplication has been recorded in a large variety of semiconductor nanocrystals and other nanostructures. Owing to the role of silicon in solar cell applications, the mission of this review is to summarize the progress in this fascinating research field considering carrier multiplication in Si-based low-dimensional systems, in particular Si nanocrystals, both from the experimental and theoretical point of view, with special attention given to the results obtained by ab initio calculations.
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Affiliation(s)
- Ivan Marri
- Department of Sciences and Methods for Engineering, University of Modena e Reggio Emilia, 42122 Reggio Emilia, Italy.
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8
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He J, Casanova D, Fang WH, Long R, Prezhdo OV. MAI Termination Favors Efficient Hole Extraction and Slow Charge Recombination at the MAPbI 3/CuSCN Heterojunction. J Phys Chem Lett 2020; 11:4481-4489. [PMID: 32423207 DOI: 10.1021/acs.jpclett.0c01467] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoinduced charge separation is the key step determining the efficiency of photon-to-electron conversion in solar cells, while charge carrier lifetimes govern the overall solar cell performance. Experiments report that copper(I) thiocyanate (CuSCN) is a very promising hole extraction layer for perovskite solar cells. Using nonadiabatic molecular dynamics combined with ab initio time-domain density functional theory, we show that termination of CH3NH3PbI3 (MAPbI3) at MAPbI3/CuSCN heterojunctions has a strong influence on both charge separation and recombination. Both processes are favored by MAI termination, compared to PbI2 termination. Because the MAPbI3 valence band originates from iodine orbitals while the conduction band arises from Pb orbitals, MAI termination places holes close to CuSCN, favoring extraction, and creates an MAI barrier for recombination of electrons in MAPbI3 and holes in CuSCN. The opposite is true for PbI2 termination. The origin of these effects is attributed solely to the properties of the MAPbI3 surfaces, and therefore, the conclusions should apply to other hole-transporting materials and can be generalized to other perovskites. Importantly, the simulations show that the injected hole remains hot for several hundreds of femtoseconds, allowing it to escape the interfacial region and prevent formation of bound excitons. This study suggests that metal halide perovskites should be treated with an organic precursor, such as MAI, prior to the formation of their interfaces with hole-transporting materials. The reported results advance the fundamental understanding of the highly unusual properties of metal halide perovskites and provide specific guidelines for optimizing the performance of perovskite solar cells and other devices.
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Affiliation(s)
- Jinlu He
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - David Casanova
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Euskadi, Spain
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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9
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Smith B, Akimov AV. Hot Electron Cooling in Silicon Nanoclusters via Landau-Zener Nonadiabatic Molecular Dynamics: Size Dependence and Role of Surface Termination. J Phys Chem Lett 2020; 11:1456-1465. [PMID: 31958367 DOI: 10.1021/acs.jpclett.9b03687] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We develop a new express methodology for modeling excited-state dynamics occurring in dense manifolds of electronic states in atomistic systems. The approach leverages a modified Landau-Zener formula, the neglect of a back-reaction approximation, and the highly efficient density functional tight-binding method. We study the hot electron dynamics in a series of H- and F-terminated silicon nanocrystals (NCs) containing up to several hundred atoms. We explain the slower electron cooling dynamics in F-terminated NCs by the larger energy gaps between the adjacent electronic states in these systems as well as their slower fluctuations. We conclude that both the mass and chemical identity of the surface termination groups equally influence the electron dynamics, on average. However, the mass effect becomes dominant for higher-energy excitations. We find that the electron decay dynamics in F-terminated NCs has a greater sensitivity to the mass of the surface ligands than do the H-terminated NCs and explain this observation by the details of the electron-phonon coupling in the systems. We find that in the H-terminated NCs, electronic transitions in the cooling process occur predominantly between the surface states, whereas in F-terminated Si NCs, both surface and NC core states are coupled to the nuclear vibrations. We find that electron energy relaxation is accelerated in larger NCs and attribute this effect to the higher densities of states and smaller energy gaps in these systems.
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Affiliation(s)
- Brendan Smith
- Department of Chemistry , University at Buffalo, The State University of New York , Buffalo , New York 14260 , United States
| | - Alexey V Akimov
- Department of Chemistry , University at Buffalo, The State University of New York , Buffalo , New York 14260 , United States
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10
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Zhang Z, Long R. Doping-Induced Rapid Decoherence Suppresses Charge Recombination in Mono/Divalent Cation Mixed Perovskites from Nonadiabatic Molecular Dynamics Simulation. J Phys Chem Lett 2019; 10:3433-3439. [PMID: 31181933 DOI: 10.1021/acs.jpclett.9b01330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Experiment shows that solar cells based on FA0.75Cs0.25Pb0.5Sn0.5I3 carry a lower charge recombination rate and higher power conversion efficiency than those of FAPbI3 despite the fact that the former has a smaller band gap. However, the underlying mechanism remains unclear. Using nonadiabatic (NA) molecular dynamics, we demonstrate that low-frequency vibrations drive electron-hole recombination in pristine FAPbI3 occurring in about 1 ns, showing excellent agreement with experiment. Cs/Sn substitution to FA/Pb not only narrows its band gap by 0.3 eV but also delocalizes the electron wave function significantly, leading to enhancement of NA coupling. Importantly, doping accelerates quantum decoherence caused by increased atomic fluctuations. As a result, rapid decoherence prevails a small band gap and strong NA coupling, slowing charge recombination and extending the charge carriers' lifetime to several nanoseconds. Our study reveals the importance of quantum coherence on quantum dynamics in perovskite materials and suggests a rational strategy to design high-performance perovskite solar cells.
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Affiliation(s)
- Zhaosheng Zhang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing 100875 , People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing 100875 , People's Republic of China
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11
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Levine BG, Esch MP, Fales BS, Hardwick DT, Peng WT, Shu Y. Conical Intersections at the Nanoscale: Molecular Ideas for Materials. Annu Rev Phys Chem 2019; 70:21-43. [DOI: 10.1146/annurev-physchem-042018-052425] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ability to predict and describe nonradiative processes in molecules via the identification and characterization of conical intersections is one of the greatest recent successes of theoretical chemistry. Only recently, however, has this concept been extended to materials science, where nonradiative recombination limits the efficiencies of materials for various optoelectronic applications. In this review, we present recent advances in the theoretical study of conical intersections in semiconductor nanomaterials. After briefly introducing conical intersections, we argue that specific defects in materials can induce conical intersections between the ground and first excited electronic states, thus introducing pathways for nonradiative recombination. We present recent developments in theoretical methods, computational tools, and chemical intuition for the prediction of such defect-induced conical intersections. Through examples in various nanomaterials, we illustrate the significance of conical intersections for nanoscience. We also discuss challenges facing research in this area and opportunities for progress.
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Affiliation(s)
- Benjamin G. Levine
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Michael P. Esch
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - B. Scott Fales
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Dylan T. Hardwick
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Wei-Tao Peng
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Yinan Shu
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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12
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Dong J, Wu C. Crossover from hopping to band-like transport in crystalline organic semiconductors: The effect of shallow traps. J Chem Phys 2019; 150:044903. [PMID: 30709264 DOI: 10.1063/1.5066563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We show a crossover from coherent to incoherent behavior of charge transport in crystalline organic semiconductors by considering the effect of shallow traps within the dynamical disorder model. The mixed quantum-classical system is treated by the Ehrenfest dynamics method complementing with instantaneous decoherence corrections and energy relaxation, which has been shown to properly make the system close to equilibrium. The shallow traps, which are incorporated by a static diagonal disorder, are shown to play a central role in the crossover. Temperature dependence of charge-carrier mobility is shown to be changed from being negative to positive with the strength of shallow traps increasing, which implies that there is a crossover from hopping to band-like transport. A higher electric field helps to recover the charge-carrier band-like transport behavior from the traps-caused hopping transport. In this way, a unified physical picture of the charge transport in crystalline organic semiconductors is proposed.
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Affiliation(s)
- Jingjuan Dong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Changqin Wu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
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13
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Gordi M, Moravvej-Farshi MK, Ramezani H. Effects of Electric Fields on Multiple Exciton Generation. Chemphyschem 2018; 19:2782-2787. [PMID: 29993169 DOI: 10.1002/cphc.201800400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Indexed: 11/06/2022]
Abstract
Unique properties of lead chalcogenides have enabled multiple exciton generation (MEG) in their nanocrystals that can be beneficial in enhancing the efficiency of third-generation solar cells. Although the intrinsic electric field plays an imperative role in a solar cell, its effect on the multiple exciton generation (MEG) has been overlooked, so far. Using EOM-CCSD as a many-body approach, we show that any electric field can affect the absorptivity spectra of the lead chalcogenide nanocrystals (Pb4 Te4 , Pb4 Se4 , and Pb4 S4 ). The same electric field, however, has insignificant effects on the MEG quantum probabilities and the thresholds in these nanocrystals. Furthermore, simulations show that Pb4 Te4 , among the aforementioned nanocrystals, has the lowest MEG threshold and the strongest absorptivity peak that is located in the multi-excitation window, irrespective of the field strength, making it the most suitable candidate for MEG applications. Simulations also demonstrate that an electric field affects the MEG characteristics in the Pb4 Te4 nanocrystal, in general, less than it perturbs MEG characteristics in Pb4 Se4 and Pb4 S4 nanocrystals. Our results can have a great impact in designing optoelectronic devices whose performance can be significantly influenced by MEG.
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Affiliation(s)
- Mahdi Gordi
- University of Tarbiat Modares, Faculty of Electrical and Computer Engineering, Nano Plasmo-photonic Research Group, P. O. Box 14115-194, Tehran, 1411713116, Iran
| | - Mohammad Kazem Moravvej-Farshi
- University of Tarbiat Modares, Faculty of Electrical and Computer Engineering, Nano Plasmo-photonic Research Group, P. O. Box 14115-194, Tehran, 1411713116, Iran
| | - Hamidreza Ramezani
- University of Texas Rio Grande Valley, Department of Physics and Astronomy, Brownsville, TX 78520, USA
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14
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Zhang J, Hong H, Zhang J, Fu H, You P, Lischner J, Liu K, Kaxiras E, Meng S. New Pathway for Hot Electron Relaxation in Two-Dimensional Heterostructures. NANO LETTERS 2018; 18:6057-6063. [PMID: 30103610 DOI: 10.1021/acs.nanolett.8b03005] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) heterostructures composed of transition-metal dichalcogenide atomic layers are the new frontier for novel optoelectronic and photovoltaic device applications. Some key properties that make these materials appealing, yet are not well understood, are ultrafast hole/electron dynamics, interlayer energy transfer and the formation of interlayer hot excitons. Here, we study photoexcited electron/hole dynamics in a representative heterostructure, the MoS2/WSe2 interface, which exhibits type II band alignment. Employing time-dependent density functional theory in the time domain, we observe ultrafast charge dynamics with lifetimes of tens to hundreds of femtoseconds. Most importantly, we report the discovery of an interfacial pathway in 2D heterostructures for the relaxation of photoexcited hot electrons through interlayer hopping, which is significantly faster than intralayer relaxation. This finding is of particular importance for understanding many experimentally observed photoinduced processes, including charge and energy transfer at an ultrafast time scale (<1 ps).
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Affiliation(s)
- Jin Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- Departments of Materials and Physics and the Thomas Young Centre for Theory and Simulation of Materials , Imperial College London , London SW7 2AZ , United Kingdom
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Hao Hong
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , P. R. China
| | - Jia Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Huixia Fu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Peiwei You
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Johannes Lischner
- Departments of Materials and Physics and the Thomas Young Centre for Theory and Simulation of Materials , Imperial College London , London SW7 2AZ , United Kingdom
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing 100190 , P. R. China
| | - Efthimios Kaxiras
- Department of Physics and School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
- Collaborative Innovation Center of Quantum Matter , Beijing 100190 , P. R. China
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15
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Kennehan ER, Doucette GS, Marshall AR, Grieco C, Munson KT, Beard MC, Asbury JB. Electron-Phonon Coupling and Resonant Relaxation from 1D and 1P States in PbS Quantum Dots. ACS NANO 2018; 12:6263-6272. [PMID: 29792675 DOI: 10.1021/acsnano.8b03216] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Observations of the hot-phonon bottleneck, which is predicted to slow the rate of hot carrier cooling in quantum confined nanocrystals, have been limited to date for reasons that are not fully understood. We used time-resolved infrared spectroscopy to directly measure higher energy intraband transitions in PbS colloidal quantum dots. Direct measurements of these intraband transitions permitted detailed analysis of the electronic overlap of the quantum confined states that may influence their relaxation processes. In smaller PbS nanocrystals, where the hot-phonon bottleneck is expected to be most pronounced, we found that relaxation of parity selection rules combined with stronger electron-phonon coupling led to greater spectral overlap of transitions among the quantum confined states. This created pathways for fast energy transfer and relaxation that may bypass the predicted hot-phonon bottleneck. In contrast, larger, but still quantum confined nanocrystals did not exhibit such relaxation of the parity selection rules and possessed narrower intraband states. These observations were consistent with slower relaxation dynamics that have been measured in larger quantum confined systems. These findings indicated that, at small radii, electron-phonon interactions overcome the advantageous increase in energetic separation of the electronic states for PbS quantum dots. Selection of appropriately sized quantum dots, which minimize spectral broadening due to electron-phonon interactions while maximizing electronic state separation, is necessary to observe the hot-phonon bottleneck. Such optimization may provide a framework for achieving efficient hot carrier collection and multiple exciton generation.
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Affiliation(s)
| | | | - Ashley R Marshall
- Chemical and Materials Science , National Renewable Energy Laboratory (NREL) , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
| | | | | | - Matthew C Beard
- Chemical and Materials Science , National Renewable Energy Laboratory (NREL) , Golden , Colorado 80401 , United States
- Department of Chemistry and Biochemistry , University of Colorado , Boulder , Colorado 80309 , United States
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16
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Zhang Z, Fang WH, Tokina MV, Long R, Prezhdo OV. Rapid Decoherence Suppresses Charge Recombination in Multi-Layer 2D Halide Perovskites: Time-Domain Ab Initio Analysis. NANO LETTERS 2018. [PMID: 29533630 DOI: 10.1021/acs.nanolett.8b00035] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Two-dimensional (2D) Ruddlesden-Popper halide perovskites are appealing candidates for optoelectronics and photovoltaics. Nonradiative electron-hole recombination constitutes a major pathway for charge and energy losses in these materials. Surprisingly, experimental recombination is slower in multilayers than a monolayer, even though multilayer systems have smaller energy gaps and higher frequency phonons that should accelerate the recombination. Focusing on (BA)2(MA) n-1Pb nI3 n+1 with n = 1 and 3, BA = CH3(CH2)3NH3, and MA = CH3NH3, we show that it is the enhancement of elastic electron-phonon scattering that suppresses charge recombination for n = 3, by causing rapid loss of electronic coherence. The scattering is enhanced in the multilayer 2D perovskites because, in contrast to the monolayer, they contain MA cations embedded into the inorganic Pb-I lattice. Although MAs do not contribute directly to electron and hole wave functions, they perturb the Pb-I lattice and create strong electric fields that interact with the charges. The rapid loss of coherence explains long excited state lifetimes that extend into nanoseconds. Both electron-hole recombination and coherence times show excellent agreement with the corresponding lifetime and line width measurements. The simulations rationalize the observed dependence of excited state lifetime in 2D layered halide perovskites on layer thickness and advance our understanding of the atomistic mechanisms underlying charge-phonon dynamics in nanoscale materials.
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Affiliation(s)
- Zhaosheng Zhang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China
| | - Marina V Tokina
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing , 100875 , P. R. China
| | - Oleg V Prezhdo
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
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17
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Liu XY, Xie XY, Fang WH, Cui G. Photoinduced relaxation dynamics of nitrogen-capped silicon nanoclusters: a TD-DFT study. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1433335] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Xiang-Yang Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Xiao-Ying Xie
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
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18
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Nijamudheen A, Akimov AV. Criticality of Symmetry in Rational Design of Chalcogenide Perovskites. J Phys Chem Lett 2018; 9:248-257. [PMID: 29275636 DOI: 10.1021/acs.jpclett.7b02589] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chalcogenide perovskites constitute an emerging class of promising photovoltaic materials that are stable and less toxic than popular lead-halide perovskites. Transition-metal and chalcogenide doping are the possible strategies for improving the photovoltaic properties of these materials via the band gap engineering. At the same time, doping can facilitate nonradiative charge-carrier recombination in these materials, adversely affecting their photovoltaic properties. We report a systematic study of electronic structure and nonadiabatic dynamics in transition-metal- and chalcogenide-doped barium-zirconium-sulfide-based perovskites. The potential of these doping strategies to modulate the performance of photovoltaic materials is explored. Through the detailed analysis of the factors affecting the dynamics, we illustrate how symmetry (both structural and orbital) and decoherence can be critical to furnishing the most favorable properties. The noted factors of symmetry and decoherence may provide new rational design principles for efficient photovoltaics.
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Affiliation(s)
- A Nijamudheen
- Department of Chemistry, University at Buffalo, The State University of New York , Buffalo, New York 14260-3000, United States
| | - Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York , Buffalo, New York 14260-3000, United States
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19
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Vanacore GM, Hu J, Liang W, Bietti S, Sanguinetti S, Carbone F, Zewail AH. Ultrafast atomic-scale visualization of acoustic phonons generated by optically excited quantum dots. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044034. [PMID: 28852685 PMCID: PMC5552391 DOI: 10.1063/1.4998009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 07/28/2017] [Indexed: 05/31/2023]
Abstract
Understanding the dynamics of atomic vibrations confined in quasi-zero dimensional systems is crucial from both a fundamental point-of-view and a technological perspective. Using ultrafast electron diffraction, we monitored the lattice dynamics of GaAs quantum dots-grown by Droplet Epitaxy on AlGaAs-with sub-picosecond and sub-picometer resolutions. An ultrafast laser pulse nearly resonantly excites a confined exciton, which efficiently couples to high-energy acoustic phonons through the deformation potential mechanism. The transient behavior of the measured diffraction pattern reveals the nonequilibrium phonon dynamics both within the dots and in the region surrounding them. The experimental results are interpreted within the theoretical framework of a non-Markovian decoherence, according to which the optical excitation creates a localized polaron within the dot and a travelling phonon wavepacket that leaves the dot at the speed of sound. These findings indicate that integration of a phononic emitter in opto-electronic devices based on quantum dots for controlled communication processes can be fundamentally feasible.
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Affiliation(s)
| | | | | | - Sergio Bietti
- L-NESS and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 53, I-20125 Milano, Italy
| | - Stefano Sanguinetti
- L-NESS and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 53, I-20125 Milano, Italy
| | - Fabrizio Carbone
- Institute of Physics, Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ahmed H Zewail
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, USA
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20
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Zhou Z, Liu J, Long R, Li L, Guo L, Prezhdo OV. Control of Charge Carriers Trapping and Relaxation in Hematite by Oxygen Vacancy Charge: Ab Initio Non-adiabatic Molecular Dynamics. J Am Chem Soc 2017; 139:6707-6717. [DOI: 10.1021/jacs.7b02121] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Zhaohui Zhou
- International
Research Center for Renewable Energy, State Key Laboratory of Multiphase
Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Jin Liu
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875, P. R. China
| | - Linqiu Li
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - Liejin Guo
- International
Research Center for Renewable Energy, State Key Laboratory of Multiphase
Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
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21
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Pal S, Nijjar P, Frauenheim T, Prezhdo OV. Atomistic Analysis of Room Temperature Quantum Coherence in Two-Dimensional CdSe Nanostructures. NANO LETTERS 2017; 17:2389-2396. [PMID: 28234486 DOI: 10.1021/acs.nanolett.6b05368] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Recent experiments on CdSe nanoplatelets synthesized with precisely controlled thickness that eliminates ensemble disorder have allowed accurate measurement of quantum coherence at room temperature. Matching exactly the CdSe cores of the experimentally studied particles and considering several defects, we establish the atomistic origins of the loss of coherence between heavy and light hole excitations in two-dimensional CdSe and CdSe/CdZnS core/shell structures. The coherence times obtained using molecular dynamics based on tight-binding density functional theory are in excellent agreement with the measured values. We show that a long coherence time is a consequence of both small fluctuations in the energy gap between the excited state pair, which is much less than thermal energy, and a slow decay of correlation between the energies of the two states. Anionic defects at the core/shell interface have little effect on the coherence lifetime, while cationic defects strongly perturb the electronic structure, destroying the experimentally observed coherence. By coupling to the same phonon modes, the heavy and light holes synchronize their energy fluctuations, facilitating long-lived coherence. We further demonstrate that the electronic excitations are localized close to the surface of these narrow nanoscale systems, and therefore, they couple most strongly to surface acoustic phonons. The established features of electron-phonon coupling and the influence of defects, surfaces, and core/shell interfaces provide important insights into quantum coherence in nanoscale materials in general.
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Affiliation(s)
- Sougata Pal
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Parmeet Nijjar
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, Universität Bremen , Otto-Hahn-Alle 1, 28359 Bremen, Germany
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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22
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Long R, Prezhdo OV, Fang W. Nonadiabatic charge dynamics in novel solar cell materials. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2017. [DOI: 10.1002/wcms.1305] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education Beijing Normal University Beijing P.R. China
| | - Oleg V. Prezhdo
- Department of Chemistry University of Southern California Los Angeles CA USA
| | - Weihai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education Beijing Normal University Beijing P.R. China
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23
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Aguirre ME, Municoy S, Grela MA, Colussi AJ. Low intensity, continuous wave photodoping of ZnO quantum dots – photon energy and particle size effects. Phys Chem Chem Phys 2017; 19:4494-4499. [DOI: 10.1039/c6cp06829d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ethylene glycol capped quantum dots (1.7 < r (nm) < 2.7) are photocharged with electron densities that depend sigmoidally on the excess energy, E*, reaching at E* = 0.5 eV.
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Affiliation(s)
- Matías E. Aguirre
- Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR)-Departamento de Química
- Facultad de Ciencias Exactas y Naturales
- Universidad Nacional de Mar del Plata-CONICET
- (7600) Mar del Plata
- Argentina
| | - S. Municoy
- Departamento de Micro y Nanotecnología
- GAIANN – Centro Atómico Constituyentes
- Comisión Nacional de Energía Atómica
- San Martín
- Argentina
| | - M. A. Grela
- Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR)-Departamento de Química
- Facultad de Ciencias Exactas y Naturales
- Universidad Nacional de Mar del Plata-CONICET
- (7600) Mar del Plata
- Argentina
| | - A. J. Colussi
- Linde Center for Global Environmental Science
- California Institute of Technology
- Pasadena
- USA
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24
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Lin Y, Akimov AV. Dependence of Nonadiabatic Couplings with Kohn–Sham Orbitals on the Choice of Density Functional: Pure vs Hybrid. J Phys Chem A 2016; 120:9028-9041. [DOI: 10.1021/acs.jpca.6b09660] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yuhan Lin
- Department
of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Alexey V. Akimov
- Department
of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
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25
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Oh E, Huston AL, Shabaev A, Efros A, Currie M, Susumu K, Bussmann K, Goswami R, Fatemi FK, Medintz IL. Energy Transfer Sensitization of Luminescent Gold Nanoclusters: More than Just the Classical Förster Mechanism. Sci Rep 2016; 6:35538. [PMID: 27774984 PMCID: PMC5075882 DOI: 10.1038/srep35538] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/28/2016] [Indexed: 12/19/2022] Open
Abstract
Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with three structurally/functionally-distinct donor classes including organic dyes, metal chelates and semiconductor quantum dots (QDs). Donor quenching was observed for every donor-acceptor pair although AuNC sensitization was only observed from metal-chelates and QDs. FRET theory dramatically underestimated the observed energy transfer while NSET-based damping models provided better fits but could not reproduce the experimental data. We consider additional factors including AuNC magnetic dipoles, density of excited-states, dephasing time, and enhanced intersystem crossing that can also influence ET. Cumulatively, data suggests that AuNC sensitization is not by classical FRET or NSET and we provide a simplified distance-independent ET model to fit such experimental data.
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Affiliation(s)
- Eunkeu Oh
- Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA
- Sotera Defense Solutions, Inc. Columbia, MD 21046, USA
| | - Alan L. Huston
- Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Andrew Shabaev
- Center for Computational Material Science Code 6390, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Alexander Efros
- Center for Computational Material Science Code 6390, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Marc Currie
- Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Kimihiro Susumu
- Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA
- Sotera Defense Solutions, Inc. Columbia, MD 21046, USA
| | - Konrad Bussmann
- Materials and Sensors Branch Code 6361, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Ramasis Goswami
- Multifunctional Materials Code 6351, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Fredrik K. Fatemi
- Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Igor L. Medintz
- Center for Bio/Molecular Science and Engineering Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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26
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Dong J, Si W, Wu CQ. Drift of charge carriers in crystalline organic semiconductors. J Chem Phys 2016; 144:144905. [PMID: 27083750 DOI: 10.1063/1.4945778] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the direct-current response of crystalline organic semiconductors in the presence of finite external electric fields by the quantum-classical Ehrenfest dynamics complemented with instantaneous decoherence corrections (IDC). The IDC is carried out in the real-space representation with the energy-dependent reweighing factors to account for both intermolecular decoherence and energy relaxation by which conduction occurs. In this way, both the diffusion and drift motion of charge carriers are described in a unified framework. Based on an off-diagonal electron-phonon coupling model for pentacene, we find that the drift velocity initially increases with the electric field and then decreases at higher fields due to the Wannier-Stark localization, and a negative electric-field dependence of mobility is observed. The Einstein relation, which is a manifestation of the fluctuation-dissipation theorem, is found to be restored in electric fields up to ∼10(5) V/cm for a wide temperature region studied. Furthermore, we show that the incorporated decoherence and energy relaxation could explain the large discrepancy between the mobilities calculated by the Ehrenfest dynamics and the full quantum methods, which proves the effectiveness of our approach to take back these missing processes.
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Affiliation(s)
- Jingjuan Dong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Wei Si
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Chang-Qin Wu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
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27
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Pal S, Trivedi DJ, Akimov AV, Aradi B, Frauenheim T, Prezhdo OV. Nonadiabatic Molecular Dynamics for Thousand Atom Systems: A Tight-Binding Approach toward PYXAID. J Chem Theory Comput 2016; 12:1436-48. [DOI: 10.1021/acs.jctc.5b01231] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sougata Pal
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Dhara J. Trivedi
- Department
of Physics and Astronomy, University of Rochester, Rochester, New York 14627, United States
| | - Alexey V. Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Bálint Aradi
- Bremen
Center for Computational Materials Science, Universität Bremen, Otto-Hahn-Alle 1, 28359 Bremen, Germany
| | - Thomas Frauenheim
- Bremen
Center for Computational Materials Science, Universität Bremen, Otto-Hahn-Alle 1, 28359 Bremen, Germany
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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28
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Madjet MEA, Akimov AV, El-Mellouhi F, Berdiyorov GR, Ashhab S, Tabet N, Kais S. Enhancing the carrier thermalization time in organometallic perovskites by halide mixing. Phys Chem Chem Phys 2016; 18:5219-31. [DOI: 10.1039/c5cp06603d] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-adiabatic molecular dynamics simulations of non-radiative relaxation dynamics of charge carriers in hybrid perovskites show that the carrier relaxation time can be considerably increased by halide mixing.
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Affiliation(s)
- Mohamed El-Amine Madjet
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
| | - Alexey V. Akimov
- Department of Chemistry
- University at Buffalo
- Buffalo
- State University of New York
- NY 14260-3000
| | - Fadwa El-Mellouhi
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
| | - Golibjon R. Berdiyorov
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
| | - Sahel Ashhab
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
| | - Nouar Tabet
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
| | - Sabre Kais
- Qatar Environment and Energy Research Institute
- Hamad Bin Khalifa University
- Qatar Foundation
- Doha
- Qatar
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29
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Long R, Prezhdo OV. Dopants Control Electron-Hole Recombination at Perovskite-TiO₂ Interfaces: Ab Initio Time-Domain Study. ACS NANO 2015; 9:11143-11155. [PMID: 26456384 DOI: 10.1021/acsnano.5b05843] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
TiO2 sensitized with organohalide perovskites gives rise to solar-to-electricity conversion efficiencies reaching close to 20%. Nonradiative electron-hole recombination across the perovskite/TiO2 interface constitutes a major pathway of energy losses, limiting quantum yield of the photoinduced charge. In order to establish the fundamental mechanisms of the energy losses and to propose practical means for controlling the interfacial electron-hole recombination, we applied ab initio nonadiabatic (NA) molecular dynamics to pristine and doped CH3NH3PbI3(100)/TiO2 anatase(001) interfaces. We show that doping by substitution of iodide with chlorine or bromine reduces charge recombination, while replacing lead with tin enhances the recombination. Generally, lighter and faster atoms increase the NA coupling. Since the dopants are lighter than the atoms they replace, one expects a priori that all three dopants should accelerate the recombination. We rationalize the unexpected behavior of chlorine and bromine by three effects. First, the Pb-Cl and Pb-Br bonds are shorter than the Pb-I bond. As a result, Cl and Br atoms are farther away from the TiO2 surface, decreasing the donor-acceptor coupling. In contrast, some iodines form chemical bonds with Ti atoms, increasing the coupling. Second, chlorine and bromine reduce the NA electron-vibrational coupling, because they contribute little to the electron and hole wave functions. Tin increases the coupling, since it is lighter than lead and contributes to the hole wave function. Third, higher frequency modes introduced by chlorine and bromine shorten quantum coherence, thereby decreasing the transition rate. The recombination occurs due to coupling of the electronic subsystem to low-frequency perovskite and TiO2 modes. The simulation shows excellent agreement with the available experimental data and advances our understanding of electronic and vibrational dynamics in perovskite solar cells. The study provides design principles for optimizing solar cell performance and increasing photon-to-electron conversion efficiency through creative choice of dopants.
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Affiliation(s)
- Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University , Beijing, 100875, People's Republic of China
- School of Physics, Complex & Adaptive Systems Lab, University College Dublin , Dublin, Ireland
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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30
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Dong S, Trivedi D, Chakrabortty S, Kobayashi T, Chan Y, Prezhdo OV, Loh ZH. Observation of an Excitonic Quantum Coherence in CdSe Nanocrystals. NANO LETTERS 2015; 15:6875-82. [PMID: 26359970 DOI: 10.1021/acs.nanolett.5b02786] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Recent observations of excitonic coherences within photosynthetic complexes suggest that quantum coherences could enhance biological light harvesting efficiencies. Here, we employ optical pump-probe spectroscopy with few-femtosecond pulses to observe an excitonic quantum coherence in CdSe nanocrystals, a prototypical artificial light harvesting system. This coherence, which encodes the high-speed migration of charge over nanometer length scales, is also found to markedly alter the displacement amplitudes of phonons, signaling dynamics in the non-Born-Oppenheimer regime.
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Affiliation(s)
- Shuo Dong
- Division of Chemistry and Biological Chemistry, and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
| | - Dhara Trivedi
- Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States
| | - Sabyasachi Chakrabortty
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543, Singapore
| | - Takayoshi Kobayashi
- Advanced Ultrafast Laser Research Center, The University of Electro-Communications , 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
- JST, CREST, K'Gobancho , 7 Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan
- Department of Electrophysics, National Chiao-Tung University , Hsinchu 300, Taiwan
- Institute of Laser Engineering, Osaka University , 2-6 Yamada-oka, Suita, Osaka 565-0971, Japan
| | - Yinthai Chan
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543, Singapore
- Institute of Materials Research & Engineering, A*STAR , 3 Research Link, Singapore 117602, Singapore
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
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31
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Liu J, Kilina SV, Tretiak S, Prezhdo OV. Ligands Slow Down Pure-Dephasing in Semiconductor Quantum Dots. ACS NANO 2015; 9:9106-9116. [PMID: 26284384 DOI: 10.1021/acsnano.5b03255] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It is well-known experimentally and theoretically that surface ligands provide additional pathways for energy relaxation in colloidal semiconductor quantum dots (QDs). They increase the rate of inelastic charge-phonon scattering and provide trap sites for the charges. We show that, surprisingly, ligands have the opposite effect on elastic electron-phonon scattering. Our simulations demonstrate that elastic scattering slows down in CdSe QDs passivated with ligands compared to that in bare QDs. As a result, the pure-dephasing time is increased, and the homogeneous luminescence line width is decreased in the presence of ligands. The lifetime of quantum superpositions of single and multiple excitons increases as well, providing favorable conditions for multiple excitons generation (MEG). Ligands reduce the pure-dephasing rates by decreasing phonon-induced fluctuations of the electronic energy levels. Surface atoms are most mobile in QDs, and therefore, they contribute greatly to the electronic energy fluctuations. The mobility is reduced by interaction with ligands. A simple analytical model suggests that the differences between the bare and passivated QDs persist for up to 5 nm diameters. Both low-frequency acoustic and high-frequency optical phonons participate in the dephasing processes in bare QDs, while low-frequency acoustic modes dominate in passivated QDs. The theoretical predictions regarding the pure-dephasing time, luminescence line width, and MEG can be verified experimentally by studying QDs with different surface passivation.
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Affiliation(s)
- Jin Liu
- Department of Chemical Engineering, University of Rochester , Rochester, New York 14627, United States
| | - Svetlana V Kilina
- Department of Chemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - Sergei Tretiak
- Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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32
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Akimov AV, Asahi R, Jinnouchi R, Prezhdo OV. What Makes the Photocatalytic CO2 Reduction on N-Doped Ta2O5 Efficient: Insights from Nonadiabatic Molecular Dynamics. J Am Chem Soc 2015; 137:11517-25. [DOI: 10.1021/jacs.5b07454] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexey V. Akimov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Ryoji Asahi
- Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute-shi, Aichi 480-1192, Japan
| | - Ryosuke Jinnouchi
- Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute-shi, Aichi 480-1192, Japan
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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33
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Si W, Wu CQ. Decoherence and energy relaxation in the quantum-classical dynamics for charge transport in organic semiconducting crystals: An instantaneous decoherence correction approach. J Chem Phys 2015; 143:024103. [DOI: 10.1063/1.4926534] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Wei Si
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Chang-Qin Wu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
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34
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Wang L, Prezhdo OV, Beljonne D. Mixed quantum-classical dynamics for charge transport in organics. Phys Chem Chem Phys 2015; 17:12395-406. [PMID: 25772795 DOI: 10.1039/c5cp00485c] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Charge transport plays a crucial role in the working principle of most opto-electronic and energy devices. This is especially true for organic materials where the first theoretical models date back to the 1950s and have continuously evolved ever since. Most of these descriptions rely on perturbation theory to treat small interactions in the Hamiltonian. In particular, applying a perturbative treatment to the electron-phonon and electron-electron coupling results in the band and hopping models, respectively, the signature of which is conveyed by a characteristic temperature dependence of mobility. This perspective describes recent progress of studying charge transport in organics using mixed quantum-classical dynamics techniques, including mean field and surface hopping theories. The studies go beyond the perturbation treatments and represent the processes explicitly in the time-domain, as they occur in real life. The challenges, advantages, and disadvantages of both approaches are systematically discussed. Special focus is dedicated to the temperature dependence of mobility, the role of local and nonlocal electron-phonon couplings, as well as the interplay between electronic and electron-phonon interactions.
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Affiliation(s)
- Linjun Wang
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA.
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35
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da Silva R, Hoff DA, Rego LGC. Coupled quantum-classical method for long range charge transfer: relevance of the nuclear motion to the quantum electron dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:134206. [PMID: 25767107 DOI: 10.1088/0953-8984/27/13/134206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Charge and excitonic-energy transfer phenomena are fundamental for energy conversion in solar cells as well as artificial photosynthesis. Currently, much interest is being paid to light-harvesting and energy transduction processes in supramolecular structures, where nuclear dynamics has a major influence on electronic quantum dynamics. For this reason, the simulation of long range electron transfer in supramolecular structures, under environmental conditions described within an atomistic framework, has been a difficult problem to study. This work describes a coupled quantum mechanics/molecular mechanics method that aims at describing long range charge transfer processes in supramolecular systems, taking into account the atomistic details of large molecular structures, the underlying nuclear motion, and environmental effects. The method is applied to investigate the relevance of electron-nuclei interaction on the mechanisms for photo-induced electron-hole pair separation in dye-sensitized interfaces as well as electronic dynamics in molecular structures.
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Affiliation(s)
- Robson da Silva
- Department of Chemistry, Universidade Federal de Santa Catarina, SC 88040-900, Brazil
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36
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Sherman MC, Corcelli SA. Thermal equilibrium properties of surface hopping with an implicit Langevin bath. J Chem Phys 2015; 142:024110. [DOI: 10.1063/1.4905253] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- M. C. Sherman
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - S. A. Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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37
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Kambhampati P. On the kinetics and thermodynamics of excitons at the surface of semiconductor nanocrystals: Are there surface excitons? Chem Phys 2015. [DOI: 10.1016/j.chemphys.2014.11.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Nie Z, Long R, Sun L, Huang CC, Zhang J, Xiong Q, Hewak DW, Shen Z, Prezhdo OV, Loh ZH. Ultrafast carrier thermalization and cooling dynamics in few-layer MoS2. ACS NANO 2014; 8:10931-40. [PMID: 25268655 DOI: 10.1021/nn504760x] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Femtosecond optical pump-probe spectroscopy with 10 fs visible pulses is employed to elucidate the ultrafast carrier dynamics of few-layer MoS2. A nonthermal carrier distribution is observed immediately following the photoexcitation of the A and B excitonic transitions by the ultrashort, broadband laser pulse. Carrier thermalization occurs within 20 fs and proceeds via both carrier-carrier and carrier-phonon scattering, as evidenced by the observed dependence of the thermalization time on the carrier density and the sample temperature. The n(-0.37 ± 0.03) scaling of the thermalization time with carrier density suggests that equilibration of the nonthermal carrier distribution occurs via non-Markovian quantum kinetics. Subsequent cooling of the hot Fermi-Dirac carrier distribution occurs on the ∼ 0.6 ps time scale via carrier-phonon scattering. Temperature- and fluence-dependence studies reveal the involvement of hot phonons in the carrier cooling process. Nonadiabatic ab initio molecular dynamics simulations, which predict carrier-carrier and carrier-phonon scattering time scales of 40 fs and 0.5 ps, respectively, lend support to the assignment of the observed carrier dynamics.
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Affiliation(s)
- Zhaogang Nie
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
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39
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Neukirch AJ, Neumark DM, Kling MF, Prezhdo OV. Resolving multi-exciton generation by attosecond spectroscopy. OPTICS EXPRESS 2014; 22:26285-26293. [PMID: 25401661 DOI: 10.1364/oe.22.026285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose an experimentally viable attosecond transient absorption spectroscopy scheme to resolve controversies regarding multiexciton (ME) generation in nanoscale systems. Absence of oscillations indicates that light excites single excitons, and MEs are created by incoherent impact ionization. An oscillation indicates the coherent mechanism, involving excitation of superpositions of single and MEs. The oscillation decay, ranging from 5 fs at ambient temperature to 20 fs at 100 K, gives the elastic exciton-phonon scattering time. The signal is best observed with multiple-cycle pump pulses.
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40
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Long R, English NJ, Prezhdo OV. Minimizing Electron-Hole Recombination on TiO2 Sensitized with PbSe Quantum Dots: Time-Domain Ab Initio Analysis. J Phys Chem Lett 2014; 5:2941-6. [PMID: 26278240 DOI: 10.1021/jz5013627] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
TiO2 sensitized with quantum dots (QDs) gives efficient photovoltaic and photocatalytic systems due to high stability and large absorption cross sections of QDs and rapid photoinduced charge separation at the interface. The yields of the light-induced processes are limited by electron-hole recombination that also occurs at the interface. We combine ab initio nonadiabatic molecular dynamics with analytic theory to investigate the experimentally studied charge recombination at the PbSe QD-TiO2 interface. The time-domain atomistic simulation directly mimics the laser experiment and generates important details of the recombination mechanism. The process occurs due to coupling of the electronic subsystem to polar optical modes of the TiO2 surface. The inelastic electron-phonon scattering happens on a picosecond time scale, while the elastic scattering takes 40 fs. Counter to expectations, the donor-acceptor bonding strengthens at an elevated temperature. An analytic theory extends the simulation results to larger QDs and longer QD-TiO2 bridges. It shows that the electron-hole recombination rate decreases significantly for longer bridges and larger dots and that the main effect arises due to reduced donor-acceptor coupling rather than changes in the donor-acceptor energy gap. The study indicates that by varying QD size or ligands one can reduce charge losses while still maintaining efficient charge separation, providing design principles for optimizing solar cell design and increasing photon-to-electron conversion efficiencies.
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Affiliation(s)
- Run Long
- ‡Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089, United States
| | | | - Oleg V Prezhdo
- ‡Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089, United States
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41
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Akimov AV, Long R, Prezhdo OV. Coherence penalty functional: A simple method for adding decoherence in Ehrenfest dynamics. J Chem Phys 2014; 140:194107. [DOI: 10.1063/1.4875702] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Long R, Prezhdo OV. Instantaneous Generation of Charge-Separated State on TiO2 Surface Sensitized with Plasmonic Nanoparticles. J Am Chem Soc 2014; 136:4343-54. [DOI: 10.1021/ja5001592] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Run Long
- School of Physics and Complex & Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Oleg V Prezhdo
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
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43
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44
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Wang L, Prezhdo OV. A Simple Solution to the Trivial Crossing Problem in Surface Hopping. J Phys Chem Lett 2014; 5:713-719. [PMID: 26270842 DOI: 10.1021/jz500025c] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Surface hopping studies on supramolecular and nanoscale systems suffer severely from the trivial crossing problem, arising due to high density of adiabatic potential energy surfaces. We present a straightforward solution to the problem by introducing a self-consistency test to the well-known fewest switches surface hopping (FSSH) procedure. If the test is failed, the hopping probabilities are corrected with a simple procedure. The novel self-consistent fewest switches surface hopping (SC-FSSH) approach is applied to the Holstein Hamiltonian to study the time-dependence of the electron population. Already in the five-state system, SC-FSSH allows us to reduce the simulation time 10(4)-fold to achieve the FSSH accuracy. The reliable performance and simple formulation of SC-FSSH greatly expands the applicability range of the surface hopping method.
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Affiliation(s)
- Linjun Wang
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Oleg V Prezhdo
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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45
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Akimov AV, Prezhdo OV. Advanced Capabilities of the PYXAID Program: Integration Schemes, Decoherence Effects, Multiexcitonic States, and Field-Matter Interaction. J Chem Theory Comput 2014; 10:789-804. [DOI: 10.1021/ct400934c] [Citation(s) in RCA: 342] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Alexey V. Akimov
- Department
of Chemistry, University of Rochester, Rochester, New York 14627
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York, 11973
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Rochester, Rochester, New York 14627
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46
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Trimithioti M, Akimov AV, Prezhdo OV, Hayes SC. Analysis of depolarization ratios of ClNO 2 dissolved in methanol. J Chem Phys 2014; 140:014301. [DOI: 10.1063/1.4854055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Hyeon-Deuk K, Kobayashi Y, Tamai N. Evidence of Phonon-Assisted Auger Recombination and Multiple Exciton Generation in Semiconductor Quantum Dots Revealed by Temperature-Dependent Phonon Dynamics. J Phys Chem Lett 2014; 5:99-105. [PMID: 26276187 DOI: 10.1021/jz402305r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Auger processes, multiple exciton generation, and Auger recombination, provide and disturb a potential route to increase solar cell efficiencies by creating multiple charge carriers, respectively. Physical mechanisms of the Auger processes can be deduced from the temperature dependence. Our real-time ab initio simulation found logarithmic temperature dependence of the Auger rates in semiconductor quantum dots (QDs), which agrees well with the recent experimental observations. This anomalous temperature dependence is not only determined by static electronic structures of the QDs depending on temperature, but also attributed to dynamical electron-phonon couplings, directly demonstrating that the Auger processes are actually induced by the electron-phonon couplings and can be controlled by phonon modes. Our findings suggest that high-frequency and broad phonon modes of a QD including the surface ligands dictate efficient Auger dynamics in a QD.
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Affiliation(s)
- Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto, 606-8502, Japan
- Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
- Department of Chemistry, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa, 252-5258, Japan
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
| | - Yoichi Kobayashi
- Department of Chemistry, Kyoto University, Kyoto, 606-8502, Japan
- Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
- Department of Chemistry, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa, 252-5258, Japan
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
| | - Naoto Tamai
- Department of Chemistry, Kyoto University, Kyoto, 606-8502, Japan
- Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
- Department of Chemistry, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa, 252-5258, Japan
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
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48
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Akimov AV, Prezhdo OV. The PYXAID Program for Non-Adiabatic Molecular Dynamics in Condensed Matter Systems. J Chem Theory Comput 2013; 9:4959-72. [DOI: 10.1021/ct400641n] [Citation(s) in RCA: 425] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Alexey V. Akimov
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
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49
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Liu J, Neukirch AJ, Prezhdo OV. Phonon-induced pure-dephasing of luminescence, multiple exciton generation, and fission in silicon clusters. J Chem Phys 2013; 139:164303. [DOI: 10.1063/1.4825401] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Lenngren N, Garting T, Zheng K, Abdellah M, Lascoux N, Ma F, Yartsev A, Žídek K, Pullerits T. Multiexciton Absorption Cross Sections of CdSe Quantum Dots Determined by Ultrafast Spectroscopy. J Phys Chem Lett 2013; 4:3330-3336. [PMID: 26705821 DOI: 10.1021/jz401522h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Multiexciton absorption cross sections are important for analysis of a number of experiments, including multiple exciton generation and stimulated emisson. We present a rigorous method to determine these cross sections using transient absorption (TA) measurements. We apply the method to CdSe quantum dots (QDs) and core-shell (CdSe)ZnS QDs. The method involves measuring TA dynamics for various excitation intensities over a broad time range and analyzing the experiments in terms of a kinetic multiexciton model taking into account all contributions to the signal. In this way, we were able to quantify exciton and multiexciton absorption cross sections at different spectral positions. The absorption cross sections decrease with increasing number of excitations, qualitatively in agreement with the state-filling effective mass model but showing a slower decrease. The cross sections for single-exciton to biexciton absorption range between 57 and 99% of the ground to single-exciton cross section.
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Affiliation(s)
- Nils Lenngren
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Tommy Garting
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Kaibo Zheng
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Mohamed Abdellah
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
- Department of Chemistry, Qena Faculty of Science, South Valley University , Qena 83523, Egypt
| | - Noëlle Lascoux
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Fei Ma
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Arkady Yartsev
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Karel Žídek
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
| | - Tõnu Pullerits
- Department of Chemical Physics, Lund University , Box 124, 221 00 Lund, Sweden
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