Laser‐Driven Halide Exchange and High‐Resolution Multicolor Patterning of Perovskite Films

ABSTRACT Translating the excellent properties of metal halide perovskites (MHPs) into practical flexible optoelectronic devices requires high‐resolution multicolor patterning techniques that are compatible with post‐fabrication processing. However, such a capability has remained elusive. Here, we introduce a mask‐free continuous‐wave (CW) laser patterning technique that simultaneously crystallizes and compositionally tunes CsPb(Br 1‐ x I x ) 3 perovskite nanocrystals (PNCs) within a polyvinylidene difluoride (PVDF) film. By modulating the irradiation time and power density, we achieve precise control over halide composition, enabling continuous photoluminescence (PL) shift from green (520 nm) to red (630 nm) and a corresponding bandgap reduction from 2.31 to 1.89 eV. This approach enables high‐resolution multicolor patterning with micron‐scale features suitable for flexible optoelectronics. Furthermore, the patterned perovskite–PVDF films exhibit excellent water stability and mechanical flexibility, supporting applications in high‐resolution X‐ray imaging and dynamic biomimetic devices. We demonstrate scalable fabrication of vivid, bendable patterns, and integrate laser‐patterned perovskite motifs into a humidity‐responsive polyurethane copolymer to create bionic butterflies that mimic natural wing motion. This mask‐free single‐step laser patterning method offers a versatile and post‐fabrication‐compatible route for spatially precise optoelectronic integration, advancing the application of perovskite nanomaterials in flexible displays, scintillators, and biomimetic robotics.