Numerical Investigation of Interface Passivation Strategies for Sb2Se3/CdS Solar Cells

<p>Sb₂Se₃&nbsp;is an emerging earth-abundant material praised for its promising optoelectronic properties, although the presence of interfacial defects at the vicinity of the p&ndash;n junction limit its performance as photovoltaic absorber. Using a device modeling approach and a realistic set of material parameters, it unravels pathways mitigating the impact of interfacial defects with a baseline Sb₂Se₃/CdS. Two straightforward strategies are devised and tested against the baseline. First, a thin front surface sulfurization of the Sb₂Se₃&nbsp;absorber allowing a local lowering of the valence band and creating a &ldquo;front surface field,&rdquo; resulting in an increased carrier selectivity and limiting the density of holes available for interface recombination, leading to a significant efficiency improvement for optimized conditions. Second, the use of an ultrathin insulating Al₂O₃&nbsp;layer between the absorber and the buffer layer is considered, helping in preventing detrimental chemical interdiffusion at the junction. This strategy provides a direct interface passivation, though the interlayer thickness needs a fine tuning to balance the benefits of reduced interface recombination and a detrimental Al₂O₃&nbsp;low-conductivity layer. In each case, an analysis covering a broad range of parameters is presented, and conclusions are made in the frame of past numerical and experimental results.</p>