[1] ASTAR, Inst Mat Res & Engn, Singapore 117602, Singapore
[2] Nanyang Technol Univ, Sch Mat Sci & Engn, Singapore 639798, Singapore
[3] Natl Univ Singapore, Dept Mat Sci & Engn, Singapore 117576, Singapore
[4] Nanjing Tech Univ Nanjing Tech, Key Lab Flexible Elect KLOFE, Nanjing 211816, Jiangsu, Peoples R China
[5] Nanjing Tech Univ Nanjing Tech, Inst Adv Mat IAM, Jiangsu Natl Synergist Innovat Ctr Adv Mat SICAM, Nanjing 211816, Jiangsu, Peoples R China