Seed-layer-assisted growth of AgBiS2 thin films by chemical bath deposition for photovoltaics

AgBiS2 (ABS) is a promising material for thin-film photovoltaics due to its suitable optoelectronic properties and the abundance of non-toxic constituent elements. However, most reported synthesis methods of nanocrystalline/quantum dot ABS solar cells are complex, limiting its practical application. In this work, we developed a simple and efficient seed-layer-assisted chemical bath deposition (SL-CBD) approach for fabricating nanocrystalline ABS thin films. ABS was deposited on both bare FTO and Sb2S3 seed-layer (SL)-coated FTO substrates using an Ag–Bi–S precursor solution at 60 ∘C. Compared to films grown directly on bare FTO, the SL-grown ABS films exhibited greater thickness, improved crystallinity, and enhanced grain growth. Post-deposition annealing at 300 ∘C further improved crystallinity in the SL-grown films relative to those on bare FTO. Elemental analysis also confirmed improved stoichiometry for the SL-grown films. Furthermore, SL-grown ABS films were annealed at 250–400 ∘C, revealing enhanced crystallinity and grain size with increasing annealing temperature, although Ag2S secondary phases emerged at 350–400 ∘C. These results demonstrate the critical role of seed-layer growth and optimized annealing in tailoring the structural quality of ABS thin films for photovoltaic integration.