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Extended Conjugated Donor–Acceptor Molecules with E ‐(1,2‐Difluorovinyl) and Diketopyrrolopyrrole (DPP) Moieties toward High‐Performance Ambipolar Organic Semiconductors
Author(s) -
Cai Zhengxu,
Luo Hewei,
Chen Xin,
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.201301312
Subject(s) - ambipolar diffusion , homo/lumo , materials science , annealing (glass) , organic semiconductor , electron mobility , conjugated system , thin film , inert gas , acceptor , organic field effect transistor , thin film transistor , molecule , polymer , photochemistry , field effect transistor , electron , chemistry , optoelectronics , organic chemistry , transistor , nanotechnology , condensed matter physics , voltage , layer (electronics) , composite material , physics , quantum mechanics
Two diketopyrrolopyrrole (DPP)‐based donor–acceptor (D–A) conjugated molecules, DPP‐F and DPP‐2F, which contain E ‐(1,2‐difluorovinyl) moieties, are reported. The LUMO energies of DPP‐F and DPP‐2F were estimated to be −3.49 and −3.70 eV, respectively, based on their redox potentials and absorption spectral data; these values were clearly lowered because of the incorporation of electron‐withdrawing E ‐(1,2‐difluorovinyl) moieties. Organic field‐effect transistors (OFETs) with thin films of DPP‐F and DPP‐2F were successfully fabricated with conventional techniques. Based on the respective transfer and output characteristics measured in an inert atmosphere, thin films of DPP‐2F display ambipolar semiconducting behavior with hole and electron mobilities reaching 0.42 and 0.80 cm 2 V −1 s −1 , respectively. The as‐prepared OFET of DPP‐2F already shows high hole and electron mobilities that are not influenced remarkably by thermal annealing. For thin films of DPP‐F, only p‐type semiconducting behavior was observed in both an inert atmosphere and air, and the hole mobility increased to 0.1 cm 2 V −1 s −1 after thermal annealing. XRD and AFM studies were performed with thin films of DPP‐F and DPP‐2F after annealing at different temperatures.