Lead-free perovskite KCsSnI1.7Cl1.3 material exhibiting superior photocatalytic antimicrobial activity

Abstract

Abstract The development of environmentally friendly and highly efficient materials is critical for next-generation antibacterial and optoelectronic applications. In this study, we present the successful synthesis of a novel lead-free perovskite, KCsSnI1.7Cl1.3, via a rapid and scalable chemical bath deposition method at 150 °C for just 5 min. The resulting film features well-defined orthorhombic, pyramid-like crystals with uniform grain sizes (800–1000 nm) and a compact, pinhole-free morphology. Remarkably, the material exhibits strong optical absorption up to 800 nm, positioning it as a promising candidate for hot electron generation and light-driven applications. KCsSnI1.7Cl1.3 also demonstrated outstanding antibacterial performance, showing broad-spectrum activity against multiple bacterial strains. The highest inhibition was recorded against Staphylococcus aureus, with inhibition zones increasing from 17 mm in the dark to 35 mm under UV illumination—highlighting its efficient photocatalytic response. The antibacterial effect followed the order: S. aureus > B. subtilis > E. coli > Salmonella sp., and was significantly enhanced with increasing concentrations (100–400 ppm). No inhibition was observed in control wells, confirming the selective activity of the material. With its lead-free composition, strong light-harvesting ability, and exceptional antibacterial properties, KCsSnI1.7Cl1.3 emerges as a highly promising material for future applications in antibacterial coatings, water purification systems, and advanced optoelectronic devices. Its green synthesis, scalability, and multifunctionality offer a sustainable pathway toward real-world deployment in environmental and biomedical fields.