1. Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
2. CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, United States
3. School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
4. Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR