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Agrawal S, Wang B, Wu Y, Casanova D, Prezhdo OV. Photocatalytic activity of dual defect modified graphitic carbon nitride is robust to tautomerism: machine learning assisted ab initio quantum dynamics. NANOSCALE 2024. [PMID: 38623607 DOI: 10.1039/d4nr00606b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Two-dimensional graphitic carbon nitride (GCN) is a popular metal-free polymer for sustainable energy applications due to its unique structure and semiconductor properties. Dopants and defects are used to tune GCN, and dual defect modified GCN exhibits superior properties and enhanced photocatalytic efficiency in comparison to pristine or single defect GCN. We employ a multistep approach combining time-dependent density functional theory and nonadiabatic molecular dynamics (NAMD) with machine learning (ML) to investigate coupled structural and electronic dynamics in GCN over a nanosecond timescale, comparable to and exceeding the lifetimes of photo-generated charge carriers and photocatalytic events. Although frequent hydrogen hopping transitions occur among four tautomeric structures, the electron-hole separation and recombination processes are only weakly sensitive to the tautomerism. The charge separated state survives for about 10 ps, sufficiently long to enable photocatalysis. The employed ML-NAMD methodology provides insights into rare events that can influence excited state dynamics in the condensed phase and nanoscale materials and extends NAMD simulations from pico- to nanoseconds. The ab initio quantum dynamics simulation provides a detailed atomistic mechanism of photoinduced evolution of charge carriers in GCN and rationalizes how GCN remains photo-catalytically active despite its multiple isomeric and tautomeric forms.
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Affiliation(s)
- Sraddha Agrawal
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
| | - Bipeng Wang
- Department of Chemical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Yifan Wu
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
| | - David Casanova
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Oleg V Prezhdo
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA.
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
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de Bragança RH, de Moraes LMT, Romaguera ARDC, Aguiar JA, Croitoru MD. Impact of Correlated Disorder on Surface Superconductivity: Revealing the Robustness of the Surface Ordering Effect. J Phys Chem Lett 2024; 15:2573-2579. [PMID: 38417042 DOI: 10.1021/acs.jpclett.3c03448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
Surface superconductivity, wherein electron pairing occurs at material surfaces or interfaces, has attracted a remarkable amount of attention since its discovery. Recent theoretical predictions have unveiled increased critical temperatures, especially at the surfaces of certain compounds and/or structures. The notion of "surface ordering" has been advanced to elucidate this phenomenon. Employing the framework of self-consistent Bogoliubov-de Gennes equations and a model incorporating correlated disorder, our study demonstrates the persistence of the surface ordering effect in the presence of weak to moderate bulk disorder. Intriguingly, our findings indicate that under moderate disorder conditions the surface critical temperature can be further increased, depending on the intensity and correlation of the disorder.
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Affiliation(s)
- R H de Bragança
- Departamento de Física, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-560, Brazil
| | - L M T de Moraes
- Departamento de Física, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-560, Brazil
| | - A R de C Romaguera
- Departamento de Física, Universidade Federal Rural de Pernambuco, Recife, Pernambuco 52171-900, Brazil
| | - J Albino Aguiar
- Departamento de Física, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-560, Brazil
| | - M D Croitoru
- Departamento de Física, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-560, Brazil
- HSE University, 101000 Moscow, Russian Federation
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Agrawal S, Casanova D, Trivedi DJ, Prezhdo OV. Enhanced Charge Separation in Single Atom Cobalt Based Graphitic Carbon Nitride: Time Domain Ab Initio Analysis. J Phys Chem Lett 2024; 15:2202-2208. [PMID: 38373150 PMCID: PMC10910588 DOI: 10.1021/acs.jpclett.3c03621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
In recent years, single atom catalysts have been at the forefront of energy conversion research, particularly in the field of catalysis. Carbon nitrides offer great potential as hosts for stabilizing metal atoms due to their unique electronic structure. We use ab initio nonadiabatic molecular dynamics to study photoexcitation dynamics in single atom cobalt based graphitic carbon nitride. The results elucidate the positive effect of the doped cobalt atom on the electronic structure of GCN. Cobalt doping produces filled midgap states that serve as oxidation centers, advantageous for various redox reactions. The presence of midgap states enables the harvesting of longer wavelength photons, thereby extending the absorption range of solar light. Although doping accelerates charge relaxation overall, charge recombination is significantly slower than charge separation, creating beneficial conditions for catalysis applications. The simulations reveal the detailed microscopic mechanism underlying the improved performance of the doped system due to atomic defects and demonstrate an effective charge separation strategy to construct highly efficient and stable photocatalytic two-dimensional materials.
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Affiliation(s)
- Sraddha Agrawal
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
| | - David Casanova
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- IKERBASQUE,
Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Dhara J. Trivedi
- Department
of Physics, Clarkson University, Potsdam, New York 13699, United States
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90007, United States
- Department
of Physics and Astronomy, University of
Southern California, Los Angeles, California 90007, United States
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Ghosh A, Kumar S, Sarkar P. Point defect-mediated hot carrier relaxation dynamics of lead-free FASnI 3 perovskites. NANOSCALE 2024; 16:4737-4744. [PMID: 38299671 DOI: 10.1039/d3nr04039a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
In search of a promising optoelectronic performance, we herein investigated the hot carrier relaxation dynamics of a lead-free cubic phased bulk formamidinium tin triiodide (FASnI3) perovskite. To gain detailed theoretical insights, we should estimate the carrier relaxation dynamics of this pristine perovskite. To control the dynamics, point defects like central tin (Sn), iodine(I) anions, and formamidinium (FA) cations were introduced. With the iodine vacancy in the FASnI3 perovskite, the system seems to be unstable at room temperature, whereas the other three types of FASnI3 perovskites (pristine, Sn vacancy, and FA vacancy) are significantly stable at 300 K having semiconducting nature and excellent optical absorption in the UV-visible range. The computed electron-hole recombination time for the pristine system is 3.9 nanoseconds, which is in good agreement with the experimental investigation. The exciton relaxation processes in Sn and FA vacancy perovskites require 2.8 and 4.8 nanoseconds, respectively. These variations in the hot carrier relaxation dynamics processes are caused by the generation of significant changes in non-adiabatic coupling between energy levels, electron-phonon coupling, and quantum decoherence in different point defect analogous systems. The results presented here offer deeper insight into the temperature-dependent carrier relaxation dynamics of FASnI3 perovskites and thus open up opportunities for future exploration of their optoelectronic properties.
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Affiliation(s)
- Atish Ghosh
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India.
| | - Subhash Kumar
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India.
| | - Pranab Sarkar
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India.
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Valero R, Morales-García Á, Illas F. Estimating Nonradiative Excited-State Lifetimes in Photoactive Semiconducting Nanostructures. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:2713-2721. [PMID: 38379918 PMCID: PMC10875665 DOI: 10.1021/acs.jpcc.3c08053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 02/22/2024]
Abstract
The time evolution of the exciton generated by light adsorption in a photocatalyst is an important feature that can be approached from full nonadiabatic molecular dynamics simulations. Here, a crucial parameter is the nonradiative recombination rate between the hole and the electron that form the exciton. In the present work, we explore the performance of a Fermi's golden rule-based approach on predicting the recombination rate in a set of photoactive titania nanostructures, relying solely on the coupling of the ground and first excited state. In this scheme the analysis of the first excited state is carried out by invoking Kasha's rule thus avoiding computationally expensive nonadiabatic molecular dynamics simulations and resulting in an affordable estimate of the recombination rate. Our results show that, compared to previous ones from nonadiabatic molecular dynamics simulations, semiquantitative recombination rates can be predicted for the smaller titania nanostructures, and qualitative values are obtained from the larger ones. The present scheme is expected to be useful in the field of computational heterogeneous photocatalysis whenever a complex and computationally expensive full nonadiabatic molecular dynamics cannot be carried out.
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Affiliation(s)
- Rosendo Valero
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona. c/Martí i Franquès 1-11, 08028 Barcelona, Spain
- Headquarters
Research Institute, Zhejiang Huayou Cobalt, 018 Wuzhen East Rd, 314599 Jiaxing, Zhejiang, China
| | - Ángel Morales-García
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona. c/Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Francesc Illas
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona. c/Martí i Franquès 1-11, 08028 Barcelona, Spain
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Akimov AV. Energy-Conserving and Thermally Corrected Neglect of Back-Reaction Approximation Method for Nonadiabatic Molecular Dynamics. J Phys Chem Lett 2023; 14:11673-11683. [PMID: 38109379 DOI: 10.1021/acs.jpclett.3c03029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
In this work, the energy-conserving and thermally corrected neglect of the back-reaction approximation approach for nonadiabatic molecular dynamics in extended atomistic systems is developed. The new approach introduces three key corrections to the original method: (1) it enforces the total energy conservation, (2) it introduces an explicit coupling of the system to its environment, and (3) it introduces a renormalization of nonadiabatic couplings to account for a difference between the instantaneous nuclear kinetic energy and the kinetic energy of guiding trajectories. In the new approach, an auxiliary kinetic energy variable is introduced as an independent dynamical variable. The new approach produces nonzero equilibrium populations, whereas the original neglect of the back-reaction approximation method does not. It yields population relaxation time scales that are favorably comparable to the reference values, and it introduces an explicit and controllable way of dissipating energy into a bath without an assumption of the bath being at equilibrium.
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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 United States
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Wang B, Wu Y, Liu D, Vasenko AS, Casanova D, Prezhdo OV. Efficient Modeling of Quantum Dynamics of Charge Carriers in Materials Using Short Nonequilibrium Molecular Dynamics. J Phys Chem Lett 2023; 14:8289-8295. [PMID: 37681642 PMCID: PMC10518862 DOI: 10.1021/acs.jpclett.3c02187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
Nonadiabatic molecular dynamics provides essential insights into excited-state processes, but it is computationally intense and simplifications are needed. The classical path approximation provides critical savings. Still, long heating and equilibration steps are required. We demonstrate that practical results can be obtained with short, partially equilibrated ab initio trajectories. Once the system's structure is adequate and essential fluctuations are sampled, the nonadiabatic Hamiltonian can be constructed. Local structures require only 1-2 ps trajectories, as demonstrated with point defects in metal halide perovskites. Short trajectories represent anharmonic motions common in defective structures, an essential improvement over the harmonic approximation around the optimized geometry. Glassy systems, such as grain boundaries, require different simulation protocols, e.g., involving machine learning force fields. 10-fold shorter trajectories generate 10-20% time scale errors, which are acceptable, given experimental uncertainties and other approximations. The practical NAMD protocol enables fast screening of excited-state dynamics for rapid exploration of new materials.
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Affiliation(s)
- Bipeng Wang
- Department
of Chemical Engineering, University of Southern
California, Los Angeles, California 90089, United States
| | - Yifan Wu
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | | | - Andrey S. Vasenko
- HSE
University, 101000 Moscow, Russia
- Donostia
International Physics Center (DIPC), 20018 San Sebastián-Donostia, Euskadi, Spain
| | - David Casanova
- Donostia
International Physics Center (DIPC), 20018 San Sebastián-Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Oleg V. Prezhdo
- Department
of Chemical Engineering, University of Southern
California, Los Angeles, California 90089, United States
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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