Lead-Free Inorganic Nanoparticles of Perovskite Embedded within Waterproof Nanofiber Films for White Color Emission

Organic polymers can enhance the environmental stability of inorganic perovskite nanocrystals (IPNCs) by encapsulation. We fabricated lead-free IPNCs embedded in waterproof and luminous polymer fibers. The encapsulated perovskite nanocrystals within polystyrene (PS) polymers, CsCu₂I₃@PS (Y-fiber), and Cs₃Cu₂I₅@PS (B-fiber) were prepared by one-step electrospinning of the solutions containing the precursors (CsI and CuI) and PS. The embedded nanocrystals had highly uniform sizes, spatial distribution, and well-developed crystal structures. The Y- and B-fibers showed yellow and blue emission under ultraviolet (UV) light, respectively, and a white emission fiber layer was fabricated via dual-nozzle coelectrospinning using CsCu₂I₃ and Cs₃Cu₂I₅ precursor solutions. The as-prepared B-fibers exhibited improved water stability without changing the crystal structure and photoluminescence (PL) emission in deionized water for 20 days. To enhance environmental stability and mechanical properties, transparent poly­(dimethylsiloxane) (PDMS) films containing IPNCs@PS fibers presented strong PL emission without peak shift under 100% tensile strain, indicating highly flexible and humidity-durable characteristics.