Enhanced efficiency of polymer solar cells by improving molecular aggregation and broadening the absorption spectra
Journal article, 2019
Alkylthio-substituted thiophene-based benzo[1,2-b:4,5-b’]dithiophene (BDT) was used to construct PBDTS-DTBT, a medium band gap donor-acceptor (D-A) polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c] [1,2,5]thiadiazole (DTBT). The incorporation of sulfur atoms into the side chains not only lowered the highest occupied molecular orbital (HOMO) energy level but also improved molecular aggregation and thus afforded lower band gap (1.68 eV) with full width at half maximum (FWHM) of 170 nm in comparison to that of the analogous polymer (PBDT-DTBT) without sulfur atoms in side chains. Therefore, the bulk heterojunction polymer solar cells based on PBDTS-DTBT with 2% diiodooctane (DIO) as processing additive showed a high power conversion efficiency (PCE) of 9.73% with high open-circuit voltage (V OC , 0.93 V), large short-circuit current density (J SC , 14.23 mA/cm 2 ) and high fill factor (FF, 0.735).
Alkylthio-substituents
Polymer solar cells
Molecular aggregation
Absorption spectra
High fill factor
Author
W. Chen
Qingdao University
Donghua University
W. F. Shen
Qingdao University
Huan Wang
Qingdao University
Fushuai Liu
Chinese Academy of Sciences
Linrui Duan
Chinese Academy of Sciences
Xiaofeng Xu
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
D. Q. Zhu
Chinese Academy of Sciences
Meng Qiu
Chinese Academy of Sciences
Ergang Wang
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
R. Yang
Chinese Academy of Sciences
Dyes and Pigments
0143-7208 (ISSN) 18733743 (eISSN)
Vol. 166 42-48Subject Categories
Physical Chemistry
Theoretical Chemistry
Condensed Matter Physics
DOI
10.1016/j.dyepig.2019.03.014