1. Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
2. Department of Chemistry, Portland State University, Portland, Oregon 97207, United States
3. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P.R. China