Heterojunction Annealing Enabling Record Open-Circuit Voltage in Antimony Triselenide Solar Cells

Despite the fact that antimony triselenide (Sb2Se3) thin-film solar cells have undergone rapid development in recent years, the large open-circuit voltage (V-OC) deficit still remains as the biggest bottleneck, as even the world-record device suffers from a large V-OC deficit of 0.59 V. Here, an effective interface engineering approach is reported where the Sb2Se3/CdS heterojunction (HTJ) is subjected to a post-annealing treatment using a rapid thermal process. It is found that nonradiative recombination near the Sb2Se3/CdS HTJ, including interface recombination and space charge region recombination, is greatly suppressed after the HTJ annealing treatment. Ultimately, a substrate Sb2Se3/CdS thin-film solar cell with a competitive power conversion efficiency of 8.64% and a record V-OC of 0.52 V is successfully fabricated. The device exhibits a much mitigated V-OC deficit of 0.49 V, which is lower than that of any other reported efficient antimony chalcogenide solar cell.

Automated summary

This study reports an effective interface engineering approach using rapid thermal annealing to suppress nonradiative recombination near the Sb2Se3/CdS heterojunction, improving the performance of thin-film solar cells.