Role of a buried indium zinc oxide layer in the performance enhancement of triboelectric nanogenerators

Abstract

Generally, triboelectric generators (TENGs) demonsrate a considerably lower output current than output voltage; this has largely limited their performance enhancement. Thus, enormous research efforts have been made to address this problem. In this work, we present a simple method to enhance the triboelectric output current by burying an indium zinc oxide (IZO) layer under the triboelectric polymer friction layer. The IZO layer provides large interface density of states, which function as a charge reservoir. During frictional contact-separation motion of the TENG, electrons can be stored in or pumped out of these states. By optimizing the properties of the IZO layer, the output performance of the TENG is greatly improved, generating an output power density of ~ 25 mW/cm2. Specifically, an output voltage and current density of ~ 140 V and ~ 180 μA/cm2 were obtained, which are 4-fold and 9-fold higher, respectively, than a TENG without an IZO layer. The method introduced here suffers less from friction layer wear-out and can effectively enhance the performance of TENGs.