1. Key Laboratory of Advanced Display and System Applications of Ministry of Education Shanghai University 149 Yanchang Road Shanghai 200072 China
2. Department of Electrical and Computer Engineering University of Toronto 35 St. George Street Toronto Ontario M5S 1A4 Canada
3. Institute of Solar Energy Materials and Devices College of Materials Science and Engineering Sichuan University No. 24 South Section 1, Yihuan Road Chengdu 610065 China