Numerical device modeling for direct Z-scheme junctions using a solar cell simulator

Abstract

Carbon capture and utilization (CCU) is a promising solution for reducing reliance on fossil fuels and incentivizing the capture of CO2. A key requirement for CCU is the development of effective photo/electrocatalysts with high CO2 reduction activity that can produce high-value products. Direct Z-scheme heterojunctions named after their charge transfer mechanism, use sunlight to conduct various photocatalytic reactions, similar to photosynthesis in plants. Solar cell simulation techniques can be used to obtain material properties and insights into the electronic characteristics of these materials. By solving semiconductor differential equations that model the behavior of semiconductors under different light intensities and applied biases, the solar cell simulator program (SCAPS) can evaluate the energy band edges, carrier concentrations, and output characteristics of the device. In this study, a method is proposed for modeling direct Z-scheme junctions in SCAPS by simulating the Shockley Read Hall (SRH) recombination using defect densities at the interface of the recombination junction (RJ). An example using a TiO2/CdIn2S4 Z-scheme junction is presented and the impact of defects on the performance of the junction is discussed. It is presented that the high recombination rates at the interface via these defects improve the device performance.