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New Conjugated Molecules with Two and Three Dithienyldiketopyrrolopyrrole (DPP) Moieties Substituted at meta Positions of Benzene toward p‐ and n‐Type Organic Photovoltaic Materials
Author(s) -
Yu Chenmin,
He Chang,
Yang Yang,
Cai Zhengxu,
Luo Hewei,
Li Wenqiang,
Peng Qian,
Zhang Guanxin,
Liu Zitong,
Zhang Deqing
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201400089
Subject(s) - conjugated system , benzene , molecule , photovoltaic system , chemistry , type (biology) , materials science , stereochemistry , combinatorial chemistry , organic chemistry , polymer , engineering , ecology , electrical engineering , biology
Two conjugated molecules, TADPP3 and TADPP2‐TT , are reported, in which three and two dithienyldiketopyrrolopyrrole (DPP) moieties, respectively, are substituted at the meta positions of benzene. Based on cyclic voltammetry and absorption data, TADPP3 and TADPP2‐TT possess similar HOMO and LUMO energies of about −5.2 and −3.4 eV, respectively. Thin films of TADPP3 and TADPP2‐TT exhibit p‐type semiconducting behavior with hole mobilities of 2.36×10 −3 and 3.76×10 −4 cm 2 V −1 s −1 after thermal annealing. Molecules TADPP3 and TADPP2‐TT were utilized as p‐type photovoltaic materials to fabricate organic solar cells after blending with phenyl C 71 butyric acid methyl ester ( PC 71 BM ) and phenyl C 61 butyric acid methyl ester ( PC 61 BM ). The relatively low J SC and fill factor values can be attributed to poor film morphologies based on AFM and XRD studies. A solar cell with a thin film of TADPP3 with PC 71 BM in a weight ratio of 1:2 exhibits a high open‐circuit voltage ( V OC ) of 0.99 V and a power conversion efficiency (PCE) of 2.47 %. Interestingly, TADPP3 can also be employed as an n‐type photovoltaic material. The blended thin film of TADPP3 with P3HT in a weight ratio of 1:2 gave a high V OC of 1.11 V and a PCE of 1.08 % after thermal annealing.