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Novel Low Bandgap EDOT‐Naphthalene Bisimides Conjugated Polymers: Synthesis, Redox, and Optical Properties
Author(s) -
Wei Yufeng,
Zhang Qing,
Jiang Yadong,
Yu Junsheng
Publication year - 2009
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200900020
Subject(s) - conjugated system , band gap , materials science , stille reaction , homo/lumo , substituent , ionization energy , photochemistry , electron affinity (data page) , cyclic voltammetry , naphthalene , electrochemistry , polymer , absorption spectroscopy , polymer chemistry , optoelectronics , chemistry , organic chemistry , ionization , electrode , optics , molecule , ion , physics , composite material
Low band‐gap conjugated polymers based on naphthalene bisimide (NBI) and 3,4‐ethylenedioxythiophene (EDOT) were synthesized by Stille cross‐coupling reaction. The alternating conjugated poly(EDOT‐NBI) ( P1 ) and random poly(EDOT‐NBI) ( P2 ) are both solution‐processable due to the existence of bulky 2,6‐diisopropylphenyl substituent. Their optical and electrochemical properties were characterized. P1 and P2 films show optical band gaps of 1.75 and 1.38 eV estimated from UV‐Vis absorption spectra. Cyclic voltammograms of both polymers display reversible reduction peaks with onset reduction potentials at −0.55 V for P1 and −0.61 V for P2 , which correspond to the electron affinity (EA) values (LUMO energy level) of 3.85 and 3.79 eV, respectively. The ionization potential (IP, HOMO level) values of 5.60 eV for P1 and 5.17 eV for P2 were also calculated by combining solid‐state optical and electrochemical data. A double heterojunction device was fabricated. It exhibits an open circuit voltage of 0.30 V and average power conversion efficiency of 0.15%.