1. Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering; Nanyang Technological University; Nanyang Avenue Singapore 639798 Singapore
2. Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology; Bilkent University; Bilkent, Ankara 06800 Turkey
3. School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Avenue Singapore 639798 Singapore
4. State Key Lab of Luminescence Materials and Devices, Institute of Optical Communication Materials; South China University of Technology; Guangdong 510641 China
5. Institute of Materials Research and Engineering; A* STAR (Agency for Science, Technology and Research); 3 Research Link Singapore 117602 Singapore
6. South University of Science and Technology; 1088 Xue-Yuan Road Shenzhen Guangdong 518055 China