Cu-Doped Sb₂Se₃ Thin-Film Solar Cells Based on Hybrid Pulsed Electron Deposition/Radio Frequency Magnetron Sputtering Growth Techniques

In recent years, research attention has increasingly focused on thin-film photovoltaics utilizing Sb2Se3 as an ideal absorber layer. This compound is favored due to its abundance, non-toxic nature, long-term stability, and the potential to employ various cost-effective and scalable vapor deposition (PVD) routes. On the other hand, improving passivation, surface treatment and p-type carrier concentration is essential for developing high-performance and commercially viable Sb2Se3 solar cells. In this study, Cu-doped Sb2Se3 solar devices were fabricated using two distinct PVD techniques, pulsed electron deposition (PED) and radio frequency magnetron sputtering (RFMS). Furthermore, 5%Cu:Sb2Se3 films grown via PED exhibited high open-circuit voltages (VOC) of around 400 mV but very low short-circuit current densities (JSC). Conversely, RFMS-grown Sb2Se3 films resulted in low VOC values of around 300 mV and higher JSC. To enhance the photocurrent, we employed strategies involving a thin NaF layer to introduce controlled local doping at the back interface and a bilayer p-doped region grown sequentially using PED and RFMS. The optimized Sb2Se3 bilayer solar cell achieved a maximum efficiency of 5.25%.