SLJCompact: A semiconductor-liquid junction solver for rapid band diagram insights into photoelectrochemical devices
SLJCompact is a Matlab based program that computes the band diagram and current-voltage characteristics of semiconductor photoanodes. To enable rapid insights, corresponding to various semiconductor-liquid junction (SLJ) properties and observable current-voltage characteristics, an abridged set of semi-analytical conservation equations are employed in the semiconductor region coupled with Gouy-Chapman screening within the liquid region. Electrostatic interactions between these regions across the junction are solved self-consistently through a variation on the Scharfetter-Gummel method. In this manner, the model is able to provide key band diagram insights regarding the correlated operation of photoanodes, both under illumination and in the dark, with respect to: current-voltage trends, quasi-Fermi level splitting, hole transfer rates, electron transfer rates, depletion region screening, hole inversion screening, and carrier recombination lifetimes. Motivated by Kroemer's lemma, SLJCompact is intended to further the adoption of band diagram methods within the photoelectrochemical device literature, by providing a computationally inexpensive approach residing between computationally intensive full continuity equation solvers and more approximate analytical expressions.