Stretchable Metal Halide Perovskite Color Conversion Layers with Block Copolymer Dispersant

Stretchable luminescent nanocomposites with metal halide perovskite (MHP) emitters are in high demand as deformable color‐conversion layers (CCLs) for vivid‐colored form‐factor free displays. However, the immiscibility of the MHP crystals with an elastomeric polymer matrix induces particle aggregation with resultant luminescence quenching, hindering the development of MHP‐based CCLs. Herein, a simple method is proposed to produce highly luminescent MHP nanoparticles (NPs) and stably disperse them in an elastomeric poly(dimethylsiloxane) (PDMS) polymer matrix with block copolymer (BCP) dispersant. The nanocomposites are developed through sequential steps of synthesis of MHP‐NP dispersion solution with BCP and blending with PDMS followed by thermal curing. It is revealed that Lewis basic poly(2‐vinylpyridine)‐block‐poly(dimethylsiloxane) (P2VP‐b‐PDMS) BCP added in the synthesis step promotes crystallization of the MHPs as nanocrystals with an average diameter of 5.9 ± 1.2 nm, whereas MHPs with hundreds of nm are produced without BCP. The resultant MHP‐NPs with P2VP‐b‐PDMS exhibit excellent photophysical properties, such as narrow band emission, high photoluminescence (PL) quantum yield, and long PL lifetime. The MHP‐NPs are stably dispersed in the PDMS matrix by P2VP‐b‐PDMS without particle aggregation, leading to highly deformable and stretchable nanocomposites with stable PL emission upon repetitive stretching, and excellent environmental stability. A simple but robust strategy to develop stretchable metal halide perovskite (MHP) nanocomposites is proposed. Lewis basic block copolymer is a key material for the synthesis of MHP nanocrystals and dispersion in an elastomer matrix. The resultant luminescent nanocomposite shows excellent photophysical properties, environmental stability, and mechanical deformability.