1 Department of Materials Science and Engineering, Center for Human-oriented Triboelectric Energy Harvesting, Yonsei University, Seoul, Republic of Korea.
2 School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
3 Department of Materials Science and Engineering, Center for Human-oriented Triboelectric Energy Harvesting, Yonsei University, Seoul, Republic of Korea. kimsw1@yonsei.ac.kr.