Simultaneously Solving the Photovoltage and Photocurrent at Semiconductor–Liquid Interfaces

Abstract

In this work, we present a general theoretical and numerical approach for simultaneously solving the photovoltage and photocurrent at semiconductor–liquid interfaces. Our methodology extends drift-diffusion methods developed for metal–semiconductor Schottky contacts in the device physics community into the domain of semiconductor–liquid “pseudo-Schottky” contacts. This model is applied to the study of photoelectrochemical anodes, utilized in the oxidative splitting of water. To capture both the photovoltage and photocurrent at semiconductor–liquid interfaces, we show that it is necessary to solve both the electron and hole current continuity equations simultaneously. The electron continuity equation is needed to primarily capture the photovoltage formation at photoanodes, whereas the hole continuity equation must be solved to obtain the photocurrent. Both continuity equations are solved through coupled recombination and generation terms. Moreover, to capture charge transfer at the semiconductor–liquid int...