1. Institute of Optoelectronic Materials and Technology, South China Normal University; Guangzhou 510631 China
2. Research Center for Solar Energy Chemistry, Osaka University; 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan
3. Department of Chemistry, Konan University; 9-1 Okamoto, Higashinada Kobe Hyogo 658-8501 Japan