[Ang, Yee Sin; Tho, Che Chen] Singapore Univ Technol & Design SUTD, Sci Math & Technol SMT, Singapore 487372, Singapore.
[Guo, San-Dong] Xian Univ Posts & Telecommun, Sch Elect Engn, Xian 710121, Peoples R China.
[Liang, Shi-Jun] Nanjing Univ, Collaborat Innovat Ctr Adv Microstruct, Sch Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Peoples R China.
[Ong, Wee Liat] Zhejiang Univ, ZJU UIUC Inst, Coll Energy Engn, Haining 314400, Zhejiang, Peoples R China.
[Ong, Wee Liat] Zhejiang Univ, State Key Lab Clean Energy Utilizat, Hangzhou 310027, Zhejiang, Peoples R China.
