Experimental disclosing the composition- and structure-dependent deep-level defect in photovoltaic antimony trisulfide materials

Abstract Antimony trisulfide (Sb2S3) represents a kind of emerging light-harvesting material with excellent stability and abundant elemental storage. Due to the low-symmetry, theoretical investigation has pointed out that there exists complicated defect properties. However, there is no experimental verification on the defect property. Here, we conduct optical deep-level transient spectroscopy to investigate defect properties in Sb2S3 and show that there are maximum three kinds of deep level defects observed, depending on the composition of Sb2S3. We also find that the Sb-interstitial (Sbi) defect does not show critical influence on the carrier lifetime, indicating the high tolerance of the one-dimensional crystal structure where the space of (Sb4S6)n ribbons is able to accommodate impurities to certain extent. This work provides basic understanding on the defect properties of quasi-one-dimensional materials and a guidance for the efficiency improvement of Sb2S3 solar cells.