1. College of Materials Science and Engineering, Shenzhen University, Shenzhen, Guangdong 518060, P. R. China
2. Key Laboratory of Special Functional Materials, Shenzhen, Guangdong 518060, P. R. China
3. Guangdong
Engineering Research Center of Optoelectronic Functional Materials
and Devices, Institute of Optoelectronic Materials and Technology,South China Normal University, Guangzhou, Guangdong 510631, P. R. China