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Fusing Benzo[c][1,2,5]oxadiazole Unit with Thiophene for Constructing Wide‐bandgap High‐performance IDT‐based Polymer Solar Cell Donor Material
Author(s) -
Song Xin,
Fan Meijie,
Zhang Kaili,
Ding Dakang,
Chen Weiye,
Li Yonghai,
Yu Liangmin,
Sun Mingliang,
Yang Renqiang
Publication year - 2018
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201700782
Subject(s) - moiety , materials science , oxadiazole , acceptor , conjugated system , band gap , thiophene , quantum efficiency , solar cell , polymer , optoelectronics , homo/lumo , photochemistry , chemistry , stereochemistry , molecule , organic chemistry , physics , composite material , condensed matter physics
Abstract Benzo[c][1,2,5]oxadiazole (BO) moiety is a strong electron‐withdrawing unit compared to benzo[c][1,2,5]thiadiazole (BT). It is usually introduced as an acceptor to construct narrow band‐gap donor‐acceptor (D‐A) materials. Herein, the π‐extended conjugated moiety dithieno[3′,2′:3,4″;2,3″:5,6]benzo[1,2‐c][1,2,5]oxadiazole (BOT) was adopted as the acceptor moiety to design D‐A polymers. Considering the more extended π‐conjugated molecular system of BOT compared to the BO unit, a narrower optical band‐gap is expected for BOT‐based IDT polymer (PIDT‐BOT). Unexpectedly, the UV‐vis absorption spectra of PIDT‐BOT films display a great hypochromatic shift of about 60 nm compared to a BO‐based analog (PIDT‐BO). The optical band‐gaps of the materials are broadened from 1.63 eV (PIDT‐BO) to 2.00 eV (PIDT‐BOT) accordingly. Although the range of external quantum efficiency (EQE) of PIDT‐BOT‐based polymer solar cell (PSC) devices is not as wide as for PIDT‐BO‐based devices, the EQE response intensities of the PIDT‐BOT based device are evidently high. As a result, PSC devices based on PIDT‐BOT reveal the best power conversion efficiency at 6.08%.