Direct-laser-patterned friction layer for the output enhancement of a triboelectric nanogenerator

Among the many types of wasted energy around us, mechanical energy has been considered to have a considerable amount of potential to be scavenged due to its abundance and ubiquity in our lives. To convert ambient mechanical energy into electrical energy efficiently, the triboelectric nanogenerator (TENG) has been intensively studied. Polydimethylsiloxane (PDMS), due to its superior mechanical and electrical properties, has commonly been selected as a friction layer in TENGs. Herein, it is newly discovered that the output power of a fabricated TENG is highly correlated with the Young's modulus of PDMS. An enhancement of the output power is achieved by the optimization of the PDMS mixture ratio. In addition, to improve the output power of the TENG further, a well-ordered microstructure was directly created on the surface of the PDMS by means of ultrafast laser irradiation. Direct patterning to create the surface morphology on the PDMS surface with the aid of laser irradiation is more efficient than conventional surface modification techniques such as replication and a few microfabrication steps. Compared to a control TENG using bare PDMS, an increase in the output power of more than twofold is achieved by an experimental TENG using patterned PDMS with a laser power of 29 mW. The TENG utilizing the patterned PDMS achieves a maximum output power density level of 107.3 mu W/cm(2).