1. CAS Key Laboratory of Functional Materials and Devices for Special Environments Xinjiang Key Laboratory of Electronic Information Materials and Devices Xinjiang Technical Institute of Physics & Chemistry CAS 40-1 South Beijing Road Urumqi 830011 China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
3. Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208–3113 USA