In Situ Synthesis of Core–Shell Structured Perovskite Nanofibers for Stretchable Color-Conversion Film

Recently, stretchable color-conversion films encapsulating organic–inorganic halide perovskite nanocrystals (PeNCs) have been developed. However, reported methods for fabricating stretchable perovskite films require multistep process, including the synthesis of PeNCs and their encapsulation within a protective matrix, followed by their incorporation into a stretchable matrix. To address these challenges, we introduce a one-step fabrication process based on coaxial electrospinning to produce stretchable perovskite fiber films. In this approach, PeNCs are in situ synthesized within a protective poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) core, which is subsequently encapsulated by a stretchable styrene–butadiene-ethylene-styrene (SEBS) shell. To investigate the effect of the SEBS shell, we also fabricated MAPbBr 3 @PVDF-HFP fiber films without the SEBS shell. We observed that the SEBS shell enhances photoluminescence quantum yield (PLQY), stability and stretchability. The resulting MAPbBr 3 @PVDF-HFP@SEBS fiber film exhibits superior optical properties (full width at half-maximum of ∼23 nm, PLQY of 61.4%), stability (retaining 94% of its emission intensity after 9 days in water), and stretchability (140% strain at break). We expect that this one-step fabrication method for stretchable color-conversion films can be applied to wearable displays in the future.