He is currently serving as an an Associate Editor of Nano Energy (Elsevier), an Executive Advisory Board in Advanced Electronic Materials (Wiley), the Editor-in-Chief in Korean Journal of Materials Research, and the Journal of Sensor Science and Technology. His main research interest is focused on nanogenerators based on piezoelectric, triboelectric and coupling effect of piezo/triboelectric for energy harvesting. Also, he is interested in synthesis of 2D nanomaterials such as graphene, h-BN and TMD (Transition Metal Dichalcogenides) for their novel flexible device applications and tribotronics. Recently, he investigates not only the principles of triboelectric phenomenon, but also biomaterials and biomedical application such as implantable triboelectric nanogenerator. He has published over 300 papers, which have cited more than 30,000 times (h-index of 96) and delivered over 150 international/national plenary, keynote, and invited talks.