1. Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, School of Physics and Optoelectronics, Xiangtan University, Xiangtan, Hunan 411105, People’s Republic of China
2. Hunan First Normal University, No. 1015 Fenglin Road (the third), Yuelu District, Changsha, Hunan 410205, People’s Republic of China