Performance improvement of organic thin film transistors by using active layer with sandwich structureYao Ni, Jianlin Zhou, Peng Kuang, Hui Lin, Ping Gan, Shengdong Hu and Zhi LinEur. Phys. J. Appl. Phys., 79 3 (2017) 30102DOI: https://doi.org/10.1051/epjap/2017170172