1. State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Optoelectronic Materials and Devices School of Materials Science and Engineering South China University of Technology 381 Wushan Road Guangzhou 510640 P. R. China
2. School of Environment and Energy South China University of Technology Guangzhou University City Panyu District Guangzhou 510006 P. R. China
3. Innovation Center of Printed Photovoltaics South China Institute of Collaborative Innovation Dongguan 523808 P. R. China
4. Department of Materials Science and Engineering City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong
5. School of Energy and Environment City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong