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A novel electrochemically and thermally stable polythiophene for photovoltaic application
Author(s) -
Hanif Muddasir,
Zuo Lijian,
Yan Quanxiang,
Hu Xiaolian,
Shi Minmin,
Chen Hongzheng
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.37852
Subject(s) - polythiophene , materials science , terthiophene , exciton , polymer solar cell , band gap , polymer , homo/lumo , thermal stability , cyclic voltammetry , conjugated system , conductive polymer , photoluminescence , electrochemistry , energy conversion efficiency , polymer chemistry , photochemistry , optoelectronics , chemical engineering , chemistry , electrode , organic chemistry , composite material , molecule , physics , quantum mechanics , engineering
Abstract Conjugated polymers having good electrochemical and thermal stability are highly desired in optoelectronics. We report a new polythiophene consisting of alternating 4,4′‐didodecyl‐2,2′‐bithiophene and terthiophene units (HPL1) synthesized via Stille coupling reaction. The optical band gap of HPL1 (1.92 eV) is similar to that of regioregular poly(3‐hexylthiophene) (rr‐P3HT, 1.89 eV). In comparison to rr‐P3HT, the HPL1 when subjected to the cyclic voltammetry as thin film shows much superior electrochemical stability and a lower highest occupied molecular orbital energy level (−4.87 eV for rr‐P3HT and −4.95 eV for HPL1). The transient photoluminescence study of HPL1 and rr‐P3HT shows that both materials have two exciton decay processes, and the excitons of rr‐P3HT are quenched more quickly. The onset decomposition, T d for rr‐P3HT (465°C) is 4°C lower than HPL1 (469°C). Preliminary photovoltaic study disclosed that the polymer solar cell based on HPL1:[6,6]‐phenyl‐C 61 ‐butyric acid methyl ester blend showed a power conversion efficiency of 0.63%, with a V oc of 0.6 V, and a short circuit current ( J sc ) of 2.79 mA cm −2 under AM 1.5 illumination (100 mW cm −2 ). The whole study provided an important example to design new electrochemically and thermally stable polymers with longer exciton life time for application in bulk heterojunction polymer solar cells. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013