1. School of Electronic and Information Engineering Lanzhou Jiaotong University Lanzhou 730070 China
2. School of Materials Science and Engineering Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology Lanzhou Jiaotong University Lanzhou 730070 China
3. Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China