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Interface configuration effects on excitation, exciton dissociation, and charge recombination in organic photovoltaic heterojunction
Author(s) -
Bai RuiRong,
Zhang CaiRong,
Wu YouZhi,
Yuan LiHua,
Zhang MeiLing,
Chen YuHong,
Liu ZiJiang,
Chen HongShan
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26103
Subject(s) - heterojunction , exciton , density functional theory , organic solar cell , excitation , excited state , acceptor , dissociation (chemistry) , chemical physics , materials science , electronic structure , hybrid functional , molecular physics , recombination , chemistry , atomic physics , optoelectronics , computational chemistry , condensed matter physics , polymer , physics , biochemistry , quantum mechanics , gene , composite material
Abstract The morphology of donor‐acceptor heterojunction interface significantly affects the electron/hole processes in organic solar cells, including charge transfer (CT), exciton dissociation (ED), and charge recombination (CR). Here, to investigate interface molecular configuration effects, the donor‐acceptor complexes with face‐on, edge‐on, and end‐on configurations were constructed as model systems for the p‐SIDT(FBTTh 2 ) 2 /C 60 heterojunction. The geometries, electronic structures, and excitation properties of monomers and the complexes with three configurations were studied based on density functional theory (DFT) and time‐dependent DFT calculations with optimally tuned range separation parameters and solid polarization effects. In terms of Marcus theory, the rate constants of ED and CR processes were analyzed. The results show that most of the excited states for p‐SIDT(FBTTh 2 ) 2 exhibit an intramolecular CT character, and the similarity of the excitation characters (CT and local excitation) and energies among three complexes with different configurations indicate that the electronic structure and excitation properties are insensitive to the interfacial molecular configurations. However, the rates of ED and CR processes heavily depend on it. These results underline the importance of controlling molecular configuration and then the morphology at the heterojunction interface in organic solar cells.