1. School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
2. Institute of Flexible Electronics (IFE, Future Technologies), Xiang’an Campus, Xiamen University, Xiang’an South Road, Xiamen, Fujian 361102, China
3. Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology (SCUT), Guangzhou, Guangdong 510641, China
4. School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore