The role of sulfurization temperature on the morphological, structural and optical properties of electroplated Cu₂MnSnS₄ absorbers for photovoltaics

In the present work, the effect mechanisms of the sulfurization temperature on the Cu₂MnSnS₄ (CMTS) absorbers and the photovoltaic characteristics of devices were studied systematically. The results indicate that an increase in sulfurization temperature form 500 °C to 560 °C significantly improves the crystallinity and morphology, lowers the band gap of the CMTS absorbers, and eventually enhances the photovoltaic performance. However, a further increase in the temperature to 590 °C degrades the crystallinity and morphology. By tuning sulfurization temperature, the short current density (J_sc) and power conversion efficiency (PCE) increase over fourfold. When the temperature optimized to 560 °C, the CMTS solar cell shows the highest PCE of 0.91% with J_sc = 7.71 mA·cm⁻², V_oc = 320 mV and FF = 37%.