Enhanced triboelectric performance of graphene oxide-conducting polymer hybrid modified polydimethylsiloxane composites

Abstract

Energy harvesting nanogenerators have received significant attention as they utilize unused mechanical energy from the ambient environment. Nanogenerators based on the triboelectric effect display superior output performance to other types of nanogenerators. In this study, a triboelectric nanogenerator (TENG) based on polydimethylsiloxane (PDMS) is developed by incorporating binary hybrids of graphene oxide (GO) and conducting polymers (CPs) such as polyaniline (PANI) or polypyrrole (PPy) into the bulk of PDMS by an ultrasonication assisted dispersion technique at room temperature. Of various PDMS composites, higher TENG performances were observed for 1 : 4 GO : PANI (23.88 V and 0.515 mA m⁻²) and 1 : 4 GO : PPy (27 V and 0.501 mA m⁻²) filler added systems. The primary reason for the enhancement in the TENG performance of the PDMS composite is the improvement in the dielectric properties. The GO and CP ratios in the binary hybrids change the dielectric properties of the PDMS composite by various phenomena such as dielectric polarization including electronic, vibrational, orientation, ionic, and interfacial polarization. Secondly, the electron donating–accepting process between PDMS and the GO/CP filler enhances the surface charge density of the PDMS composite and overall TENG performance. The presence of electron trapping GO in the filler can also improve the charge density of the composite material. Therefore, the superior performances of GO/CP-PDMS composites to neat PDMS can be attributed to the intensified negative charges on PDMS from the functional groups of GO, PANI, or PPy chains and the enhanced dielectric properties. Also, it was observed that the PANI nanofiber intercalated GO morphology of the GO/PANI hybrid in the PDMS composite resulted in better current generation when compared to the PPy nanosphere intercalated GO incorporated PDMS system. The energy harvesting studies using the PDMS composites were demonstrated using various body movements such as single finger tapping and foot stamping. A current of 40 nA and a voltage of 208 V were generated by finger tapping, whereas a short circuit current of 2 μA and a voltage of 27 V were generated by foot stamping or walking. These studies hint at the utility of the proposed material for mechanical energy harvesting using simple body movements.