On the modeling and simulation of reaction-transfer dynamics in semiconductor-electrolyte solar cells
This work provides a more accurate modeling framework for designing semiconductor-liquid junction solar cells, but the contribution is incremental as it extends existing drift-diffusion-Poisson models to coupled semiconductor-electrolyte systems.
The authors propose a macroscopic mathematical model for charge transfer dynamics in semiconductor-electrolyte solar cells and show numerically that replacing the electrolyte with a Schottky contact is only accurate at extremely high reductant-oxidant densities, otherwise it yields significant inaccuracies.
The mathematical modeling and numerical simulation of semiconductor-electrolyte systems play important roles in the design of high-performance semiconductor-liquid junction solar cells. In this work, we propose a macroscopic mathematical model, a system of nonlinear partial differential equations, for the complete description of charge transfer dynamics in such systems. The model consists of a reaction-drift-diffusion-Poisson system that models the transport of electrons and holes in the semiconductor region and an equivalent system that describes the transport of reductants and oxidants, as well as other charged species, in the electrolyte region. The coupling between the semiconductor and the electrolyte is modeled through a set of interfacial reaction and current balance conditions. We present some numerical simulations to illustrate the quantitative behavior of the semiconductor-electrolyte system in both dark and illuminated environments. We show numerically that one can replace the electrolyte region in the system with a Schottky contact only when the bulk reductant-oxidant pair density is extremely high. Otherwise, such replacement gives significantly inaccurate description of the real dynamics of the semiconductor-electrolyte system.