Naujokaitis A., Talaikis M., Pakstas V., Jocytė G., Le T., Siebentritt S., Valle N., Kondrotas R.
Solar Rrl, vol. 10, n° 1, art. no. e202500848, 2026
Antimony selenide (Sb<sub>2</sub>Se<sub>3</sub>) thin films have attracted significant interest for developing low-cost, hazardous-element-free photovoltaic technology. While the initial progress in Sb<sub>2</sub>Se<sub>3</sub> solar cells was rapid, the growth of power conversion efficiency slowed down. High open-circuit voltage (V<sub>OC</sub>) deficit is recognized as the critical performance-reducing factor, barely reaching 50% of the radiative limit even in the record-efficiency solar cells. In this article, using heat treatment under sulfur atmosphere and Cl-doping, we investigate passivation strategies by measuring photoluminescence (PL) emission. We show that the PL response was strongly enhanced after the S-treatment and correlated with the level of incorporated S. From absolute PL measurements, a quasi-Fermi-level splitting of 562 meV was achieved in Cl-doped Sb<sub>2</sub>Se<sub>3</sub> thin films and annealed under optimal conditions. This article provides a technological route for reducing nonradiative recombination in Sb<sub>2</sub>Se<sub>3</sub> which is a highly encouraging process for mitigating V<sub>OC</sub> deficit in Sb<sub>2</sub>Se<sub>3</sub> solar cells.
