1. Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Photonic Technique for Information School of Electronics Science and Engineering Faculty of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710049 P. R. China
2. Xi'an Key Laboratory of Liquid Crystal and Organic Photovoltaic Materials State Key Laboratory of Fluorine and Nitrogen Chemicals Xi'an Modern Chemistry Research Institute Xi'an 710065 P. R. China
3. College of New Materials and New Energies Shenzhen Technology University Shenzhen 518118 P. R. China
4. School of Materials Science and Engineering Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology Lanzhou Jiaotong University Lanzhou 730070 P. R. China