1. Photovoltaic Materials GroupCenter for Green Research on Energy and Environmental MaterialsNational Institute for Materials Science Tsukuba Ibaraki 305‐0047 Japan
2. International Center for Materials NanoarchitectonicsNational Institute for Materials Science Tsukuba Ibaraki 305‐0044 Japan
3. International Center for Young ScientistsNational Institute for Materials Science Tsukuba Ibaraki 305‐0044 Japan
4. State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 China