1. Institute of New Energy Technology, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 510632, China
2. Key Laboratory of New Semiconductors and Devices of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China
3. Guangdong Mellow Energy Co., Ltd., Guangzhou 510630, China
4. School of Semiconductor and Chemical Engineering, Solar Energy Research Center, Jeonbuk National University, 567 Baekjedaero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 54896, Republic of Korea