Methylthio side-chain modified quinoidal benzo-[1,2-b:4,5-b']dithiophene derivatives for high-performance ambipolar organic field-effect transistors  

作　　者：Li Chen Xiaoqi Luo Nuoya Li Shaoqian Peng Qing Jiang Di Wu Jianlong Xia 

机构地区：[1]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Center of Smart Materials and Devices,Wuhan University of Technology,Wuhan 430070,China [2]School of Chemistry,Chemical Engineering and Life Science,Wuhan University of Technology,Wuhan 430070,China [3]Department of Chemistry,National University of Singapore,Singapore 117543,Singapore

出　　处：《Science China Chemistry》2024年第10期3357-3365,共9页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21801201,51773160,21975194,22175134);the Research Fund for Distinguished Young Scholars of Hubei Province(2019CFA042)。

摘　　要：Quinoidal small molecule semiconductors hold huge potential in ambipolar organic field-effect transistors(OFETs)and organic spintronic devices.Here,two quinoidal molecules with methylthio side chains were synthesized to develop molecular semiconductors with high ambipolar mobility,designated QBDTS and QTBDTS.The theoretical calculation results reveal that QBDTS has a closed-shell structure while QTBDTS showed an open-shell structure with a biradical character(y0)of 0.46 and its magnetic properties were further investigated using electron paramagnetic resonance(EPR)and superconducting quantum interference device(SQUID)methods.The methyl side chains showed a large impact on the molecular orbital levels.The HOMO/LUMO levels of QBDTS and QTBDTS were measured to be-5.66/-4.56 and-5.27/-4.48 eV,respectively,which are favorable for ambipolar charge transport in OFETs.Importantly,the spin-coated QBDTS displayed hole and electron mobilities of 0.01 and 0.5 cm^(2)V^(-1)s^(-1)while QTBDTS showed a record high hole mobility of 1.8 cm^(2)V^(-1)s^(-1)and electron mobility of 0.3 cm^(2)V^(-1)s^(-1).Moreover,comparative studies of the thin film morphologies also manifested the beneficial influence of methyl side chains on film crystallinity and molecule orientation.These results strongly proved that methyl side chain engineering can be a simple but efficient strategy for modulating electronic properties and molecular stacking behaviors.This work also represents a big advancement for quinoidal molecular semiconductors in ambipolar OFET applications.

关 键 词：side-chain modification quinoidal molecules AMBIPOLAR DIRADICALS organic field-effect transistors 

分 类 号：TB34[一般工业技术—材料科学与工程] TN386[电子电信—物理电子学]