Controllable Template Assisted In Situ Perovskite Growth for Display Application

Metal halide perovskites are compelling emitters for next-generation optoelectronics, yet their translation into flexible display architectures remains limited by interfacial optical losses, non-radiative recombination, and poor operational durability. Here we report a one-step, template-assisted in situ crystallization strategy that integrates CsPbX₃ (X = Cl, Br, I) directly within a porous polyethylene terephthalate (PET) membrane. A bifunctional diamine ligand molecularly bridges the perovskite and polymer, directing crystallization, promoting uniform pore filling and eliminating interfacial air gaps. This chemically defined interface suppresses non-radiative losses, increases light outcoupling from ∼13% to 36%, and yields a film-state photoluminescence quantum yield (PLQY) of 62%. The resulting perovskite-integrated porous PET membrane retains ∼82% of its initial photoluminescence after 150 days under ambient conditions and exhibits a projected T₅₀ of ∼10 000 h, establishing benchmark stability among in situ synthesized perovskite/polymer display-class systems. It further preserves >90% emission under repeated bending and enables inkjet-printed full-color RGB pixel arrays with 70% NTSC gamut. Using a highly porous PET membrane (0.5 µm pore diameter), a luminance of 1050 nits are achieved, confirming that brightness scales with pore density and is substrate limited. These results establish active encapsulation as a practical route to stable, efficient and mechanically compliant perovskite display platforms.