All-solid-state Photocurrent Generation System Based on p-Type Plasmon-induced Charge Separation

Abstract

Plasmon-induced charge separation (PICS), which is induced at the interface between metal nanoparticles exhibiting localized surface plasmon resonance (LSPR) and semiconductors, has attracted attention as a promising method for extracting photoenergy as electric charge. Although n-type semiconductors have been the standard, p-type semiconductors are now being explored for their potential to enhance stability and catalytic performance. In this study, RuO₂ and IrO₂ were selected as p-type semiconductors and combined with Ag nanoparticles (AgNPs) to investigate the effects of their conductivity and band gap on the charge separation efficiency. As a result of evaluating the charge separation efficiency as photocurrent using an all-solid-state cell, an incident photon-to-current efficiency (IPCE) of ∼0.15 % was achieved in the system using IrO₂, which has high conductivity and the plasmon absorption band and its own photon absorption band do not overlap. This is the highest conversion efficiency in all-solid-state cells utilizing the p-type PICS mechanism. This achievement provides an effective guideline for the design of materials for further improvement of efficiency as well as for applications such as photodetectors, photoelectric conversion devices, and photocatalysts.