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 CsCu2I3 and Cs3Cu2I5 nanocrystals within polystyrene (PS) polymers, CsCu2I3@PS (Y-fiber) and Cs3Cu2I5@PS (B-fiber) were prepared by one-step electrospinning of the precursor solutions containing the precursors (CsI and CuI) and PS. The embedded nanocrystals had highly uniform sizes, spatial distribution, well-developed crystal structure, and pure phases. The Y-fibers and B-fibers showed bright yellow and blue color emission under ultraviolet (UV) light, respectively, and a white emission fiber layer was fabricated via dual-nozzle co-electrospinning using yellow-emissive CsCu2I3, and blue-emissive Cs3Cu2I5 precursor solutions. The as-prepared B-fibers exhibited improved water stability without changing crystal structure and PL emission in deionized water for 20 days. To enhance environmental stability and mechanical properties, the transparent polydimethylsiloxane (PDMS) films containing IPNCs@PS fibers presented strong PL emission without a shift in PL emission wavelength under 100% tensile strain, indicating highly flexible and humidity-durable characteristics.
