1. Institute of Photoelectronic Thin Film Devices and Technology Renewable Energy Conversion and Storage Center Solar Energy Conversion Center Nankai University Tianjin 300350 P. R. China
2. Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin Tianjin 300350 P. R. China
3. Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education Tianjin 300350 P.R. China
4. School of Physical Science and Technology Inner Mongolia University Key Laboratory of Semiconductor Hohhot 010021 P. R. China
5. Photovoltaic Technology at Universities of Inner Mongolia Autonomous Region Hohhot 010021 P. R. China
6. Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 P. R. China