Photoinduced anion exchange for spatially patterned perovskite ASE: Enabling full-color pixelated lasing displays

Laser displays are pivotal next-generation technologies for augmented/virtual reality, wearables, and optical communications. To realize full-color patterned lasing displays, we propose an effective‌ photoinduced vapor-solid anion exchange (PVAE) strategy, enabling unprecedented amplified spontaneous emission (ASE) control via precise temporal modulation. It regulates photoswitchable anion exchange in CsPbX₃ (X = Cl, Br, I) perovskites, with exchange rates tuned by illumination wavelength and intensity. Under optimized 1561.8 microwatts per square centimeter ultraviolet activation, PVAE drives complete compositional transitions (CsPbIBr₂ → CsPbBr₃ → CsPbClBr₂), inducing linear ASE peak shifts across 470- to 710-nanometer full-color spectra. Spatially modulated multicolor ASE patterns further verify its adaptability. We achieve precise, wide microscale emission wavelength modulation of CsPbX₃ films in both temporal and spatial domains. These advantages establish PVAE as a dual-mode platform for high-precision pixelated laser displays, offering practical solutions for cutting-edge photonic applications such as programmable high-resolution lasing displays and dynamic laser anticounterfeiting labels.