Remarkably Enhanced Charge Density of Inorganic Material Via Regulating Contact Barrier Difference and Charge Trapping for Triboelectric Nanogenerator

Currently, the research on improving charge density of charge-excitation triboelectric nanogenerators (CE-TENG) mainly focuses on surface modification and thinning of organic polymer materials. However, to increase durability and output, the exploration of high permittivity and high-thickness inorganic materials is important for extensive applications. Meanwhile, the physical mechanism of air ionization caused by air breakdown during secondary self-charge excitation (SSCE) needs to be explored. Herein, this study proposes a new strategy for CE-TENG based on inorganic materials by de-trapping reverse charge and increasing the contact barrier difference to obtain high charge density and achieve secondary self-charge excitation. SSCE of three types of films with different leakage currents are evaluated according to their trapping and de-trapping reverse charges. It is found that the trap distribution of dielectric films with larger leakage currents are mostly shallow-level traps, whose de-trapping ability becomes stronger after reverse charge injection. By regulating the contact barrier difference with thin organic polymer on thick inorganic high permittivity material, this study has achieved a high charge density of 1310 & mu;C m(-2) with a fast start-up time of SSCE, which is a new record for the charge density of inorganic materials. This study promotes TENG of inorganic materials toward high-energy output applications.