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Theoretical studies of photovoltaic properties of five new silol dithiophene based D 2 ‐A‐D 1 ‐A‐D 2 donors
Author(s) -
Xiang Yunjie,
Peng Suoping,
Zheng Shaohui
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.26047
Subject(s) - thiazole , homo/lumo , moiety , acceptor , density functional theory , molecule , energy conversion efficiency , organic solar cell , materials science , molecular orbital , crystallography , solar cell , computational chemistry , chemistry , stereochemistry , physics , organic chemistry , optoelectronics , composite material , condensed matter physics , polymer
Organic solar cell of silol dithiophene based D 2 ‐A‐D 1 ‐A‐D 2 /PC 71 BM (D: donor part; A: acceptor part; 1 and 2 denote different units) possesses promising power conversion efficiency. Researchers have studied D 2 ‐A‐D 1 ‐A‐D 2 molecules carefully, including the effects of the different number of terminal thiophenes, the different central moiety (D 1 ), and the length of the alkyl chain. However, there are few investigations, especially theoretical studies, on the influences of different A (acceptor) units on the properties of D 2 ‐A‐D 1 ‐A‐D 2 molecule. In the present work, we have designed and modeled five new D 2 ‐A‐D 1 ‐A‐D 2 (D 2 = bithiophene and D 1 = silol dithiophene) donors by changing A units (A = diketopyrrolopyrrole, naphtho[1,2‐ c :5,6‐ c ′]bis[1,2,5]thiadiazole, 5‐fluoro‐2,1,3‐benzoselenadiazole, benzobisthiadiazole, and thiazolo[5,4‐ d ]thiazole). We have applied density functional theory (DFT) and time‐dependent DFT to predict their ground‐state electronic structures and the UV–vis spectra, and the open circuit voltages (Vocs) of organic solar cells of D 2 ‐A‐D 1 ‐A‐D 2 /PC 71 BM. Based on the calculated results, we find that bithiophene thiazolo[5,4‐ d ]thiazole siloldithiophene (BTTS) (D 2 = bithiophene, A = thiazolo[5,4‐ d ]thiazole, D 1 = silol dithiophene) possesses the highest lowest unoccupied molecular orbital (−2.60 eV) and the lowest highest occupied molecular orbital (−5.33 eV) energies, and the strongest absorption in the visible region. Besides, the solar cell of BTTS/PC 71 BM has the highest Voc of 1.02 V. These results indicate that it may be a promising donor. In contrast, bithiophene benzobisthiadiazole siloldithiophene (BBBS) (A = benzobisthiadiazole) has low absorption strength in the visible region, which indicates that it may not be a suitable donor material.