Enhancing Sb2(S,Se)3 Solar Cell Performance Via Air Annealing for Interfacial Defect Passivation and Absorber Property Optimization

Abstract

For superstrate configured Sb2(Se, S)3 solar cells, the absorber layer quality and heterojunction interface characteristics are the crucial factors. Luckily, the absorber layer quality including its bandgap can easily be tunned by altering the S/Se ratio, but excessively reducing the bandgap may limit its open circuit voltage, and its suitablity as a top cell multijunction devices. In this study, we present an efficient post-air-annealing treatment of heterjunction to optimize charachteristics of the Sb2(Se, S)3 absorber including bandgap, and passivate the interfacial defects at the heterjunction interface. The post-air annealing of the precursor film at 180℃ limit the emergence of (hk0) orientations, prolong depletion width of photovoltaic device, promote the preferred (hk1) orientation, and reduce the interface defect of heterjunction. Compared to the device annealed solely in N₂, the air-annealed device demonstrated reduced interfacial carrier recombination. Through air annealing at 180°C, the champion device arealised a istriking power conversion efficiency (PCE) of 8.1%, enhancing open circuit voltage from 570 to 597 mV, short circuit current denisty from 20.70 to 21.05 mA/cm², and fill factor from 60 to 64%, significantly outperforming the control device (7.15% PCE). This highlights the effectiveness of the air annealing process in suppressing interfacial recombination and enhancing photovoltaic performance, establishing it as a promising process for designing high-efficiency photovoltaic devices.

Keywords: Sb2(S, Se)3, Air annealing, Interface defects, Power conversion efficiency