1. Australian Centre for Advanced Photovoltaics School of Photovoltaic and Renewable Energy Engineering University of New South Wales Sydney NSW 2052 Australia
2. Institute of New Energy Technology College of Information Science and Technology Jinan University Guangzhou 510632 China
3. Research Center for Photovoltaic Technologies National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibaraki 305-8568 Japan
4. Department of Applied Physics Faculty of Pure and Applied Sciences University of Tsukuba Tsukuba 305-8573 Japan
5. Wuhan National Laboratory for Optoelectronics (WNLO) Huazhong University of Science and Technology (HUST) Wuhan 430074 China