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A theoretical analysis on the electron and energy transfer between host and guest materials in phosphor–doped OLED. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Manjanath A, Yang CH, Kue K, Wang CI, Claudio GC, Hsu CP. Enhancing Singlet Fission Coupling with Nonbonding Orbitals. J Chem Theory Comput 2022; 18:1017-1029. [PMID: 34982933 DOI: 10.1021/acs.jctc.1c00868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet fission (SF) is a process where a singlet exciton is split into a pair of triplet excitons. The increase in the excitonic generation can be exploited to enhance the efficiency of solar cells. Molecules with conjugated π bonds are commonly developed for optoelectronic applications including SF, due to their low energy gaps. The electronic coupling for SF in such well-stacked π-conjugated molecule pairs can be rather limited due to the orthogonal π and π* orbital overlaps that are involved in the coupling elements, leading to a large cancellation in the coupling. In the present work, we show that such limits can be removed by involving triplet states of different origins, such as those with nonbonding n orbitals. We demonstrate such an effect for formaldehyde and methylenimine dimers, with a low-lying n-π* triplet state (T1) in addition to the π-π* triplet (T2). We show that the coupling can be enhanced by 40 times or more for the formaldehyde dimer, and 15 times or more for the methylenimine dimer, with the T1-T2 state as the end product of SF. With 1759 randomly oriented pairs of formaldehyde derived from a molecular dynamics simulation, the coupling from a singlet exciton to this T1-T2 state is, on an average, almost two times larger than that for a regular T1-T1 state. We investigated a few families that have been shown to be prospective candidates for SF, using our proposed strategy. However, our unfavorable results indicate that there are clear difficulties in fulfilling the ES1 ≳ ET1 + ET2 energy criterion. Nevertheless, our results provide a new molecular design concept for better SF (and triplet-triplet annihilation, TTA) materials that allows future development.
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Affiliation(s)
- Aaditya Manjanath
- Institute of Chemistry, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei, 115, Taiwan
| | - Chou-Hsun Yang
- Institute of Chemistry, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei, 115, Taiwan
| | - Karl Kue
- Institute of Chemistry, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei, 115, Taiwan.,Institute of Chemistry, University of the Philippines Diliman, Quezon City, 1101, Philippines
| | - Chun-I Wang
- Institute of Chemistry, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei, 115, Taiwan
| | - Gil C Claudio
- Institute of Chemistry, University of the Philippines Diliman, Quezon City, 1101, Philippines
| | - Chao-Ping Hsu
- Institute of Chemistry, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei, 115, Taiwan.,National Center for Theoretical Sciences, 1, Section 4, Roosevelt Road, Taipei, 106, Taiwan
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Fujita T, Noguchi Y. Fragment-Based Excited-State Calculations Using the GW Approximation and the Bethe-Salpeter Equation. J Phys Chem A 2021; 125:10580-10592. [PMID: 34871000 DOI: 10.1021/acs.jpca.1c07337] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we present a fragment-based approach for calculating the charged and neutral excited states in molecular systems, based on the many-body Green's function method within the GW approximation and the Bethe-Salpeter equation (BSE). The implementation relies on the many-body expansion of the total irreducible polarizability on the basis of fragment molecular orbitals. The GW quasi-particle energies in complex molecular environments are obtained by the GW calculation for the target fragment plus induced polarization contributions of the surrounding fragments at the static Coulomb-hole plus screened exchange level. In addition, we develop a large-scale GW/BSE method for calculating the delocalized excited states of molecular aggregates, based on the fragment molecular orbital method and the exciton model. The accuracy of fragment-based GW and GW/BSE methods was evaluated on molecular clusters and molecular crystals. We found that the accuracy of the total irreducible polarizability can be improved systematically by including two-body correction terms, and the fragment-based calculations can reasonably reproduce the results of the corresponding unfragmented calculations with a relative error of less than 100 meV. The proposed approach enables efficient excited-state calculations for large molecular systems with reasonable accuracy.
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Affiliation(s)
- Takatoshi Fujita
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Tokai, Ibaraki 319-1106, Japan
| | - Yoshifumi Noguchi
- Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan
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Błasiak B, Bartkowiak W, Góra RW. An effective potential for Frenkel excitons. Phys Chem Chem Phys 2021; 23:1923-1935. [PMID: 33459313 DOI: 10.1039/d0cp04636a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Excitation energy transfer (EET) is a ubiquitous process in life and materials sciences. Here, a new and computationally efficient method of evaluating the electronic EET couplings between interacting chromophores is introduced that is valid in a wide range of intermolecular distances. The proposed approach is based on the effective elimination of electron repulsion integrals from the excitonic Hamiltonian matrix elements via the density-fitting approach and distributed multipole approximation. The excitonic Hamiltonian represented in a basis including charge transfer (CT) states is re-cast in terms of the effective one-electron potential functions (EOPs) and adapted into the effective fragment parameter (EFP) framework. Calculations for model systems indicate that the speedup of at least three orders of magnitude, as compared to the state-of-the-art methods, can be achieved while maintaining the accuracy of the EET couplings even at short intermolecular distances.
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Affiliation(s)
- Bartosz Błasiak
- Department of Physical and Quantum Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
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Bao P, Hettich CP, Shi Q, Gao J. Block-Localized Excitation for Excimer Complex and Diabatic Coupling. J Chem Theory Comput 2020; 17:240-254. [PMID: 33370101 DOI: 10.1021/acs.jctc.0c01015] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We describe a block-localized excitation (BLE) method to carry out constrained optimization of block-localized orbitals for constructing valence bond-like, diabatic excited configurations using multistate density functional theory (MSDFT). The method is an extension of the previous block-localized wave function method through a fragment-based ΔSCF approach to optimize excited determinants within a molecular complex. In BLE, both the number of electrons and the electronic spin of different fragments in a whole system can be constrained, whereas electrostatic, exchange, and polarization interactions among different blocks can be fully taken into account of. To avoid optimization collapse to unwanted states, a ΔSCF projection scheme and a maximum overlap of wave function approach have been presented. The method is illustrated by the excimer complex of two naphthalene molecules. With a minimum of eight spin-adapted configurational state functions, it was found that the inversion of La- and Lb- states near the optimal structure of the excimer complex is correctly produced, which is in quantitative agreement with DMRG-CASPT2 calculations and experiments. Trends in the computed transfer integrals associated with excited-state energy transfer both in the singlet and triplet states are discussed. The results suggest that MSDFT may be used as an efficient approach to treat intermolecular interactions in excited states with a minimal active space (MAS) for interpretation of the results and for dynamic simulations, although the selection of a small active space is often system dependent.
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Affiliation(s)
- Peng Bao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Christian P Hettich
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Qiang Shi
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jiali Gao
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China.,Beijing University Shenzhen Graduate School, Shenzhen 518055, China
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Yonehara T, Nakajima T. Electron dynamics method using a locally projected group diabatic Fock matrix for molecules and aggregates. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yonehara T, Nakajima T. A quantum dynamics method for excited electrons in molecular aggregate system using a group diabatic Fock matrix. J Chem Phys 2017; 147:074110. [PMID: 28830170 DOI: 10.1063/1.4998746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We introduce a practical calculation scheme for the description of excited electron dynamics in molecular aggregate systems within a local group diabatic Fock representation. This scheme makes it easy to analyze the interacting time-dependent excitation of local sites in complex systems. In addition, light-electron couplings are considered. The present scheme is intended for investigations on the migration dynamics of excited electrons in light-induced energy transfer systems. The scheme was applied to two systems: a naphthalene-tetracyanoethylene dimer and a 20-mer circle of ethylene molecules. Through local group analyses of the dynamical electrons, we obtained an intuitive understanding of the electron transfers between the monomers.
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Affiliation(s)
- Takehiro Yonehara
- RIKEN Advanced Institute for Computational Science, Kobe 650-0047, Japan
| | - Takahito Nakajima
- RIKEN Advanced Institute for Computational Science, Kobe 650-0047, Japan
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Suzuki Y, Ebina K, Tanaka S. Four-electron model for singlet and triplet excitation energy transfers with inclusion of coherence memory, inelastic tunneling and nuclear quantum effects. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Hong SK, Yoon JS, Nam SW. Excitons and polaritons in quasi-molecular eigenbasis of the excitation hopping system interacting with a photon field. J Chem Phys 2013; 138:214315. [DOI: 10.1063/1.4808110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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