Water-Operable Photochromic Perovskite-Like Materials for Rewritable Anti-Counterfeiting and Display

Stimuli-responsive solid-state photochromic materials are attractive for information encryption and smart displays, yet purely organic systems often suffer from high water solubility, while fully inorganic counterparts are constrained by cost-effective and scalable fabrication. These limitations highlight the challenge of developing water-stable, water-operable photochromic materials for underwater information writing and wet-environment anti-counterfeiting. Herein, we report a water-stable 1D perovskite-like lead chloride hybrid, (AeBpy)₂Pb₃Cl₁₀, constructed with a viologen-based organic dication (AeBpy²⁺: N-(2-aminoethyl)-4,4'-bipyridinium). The structure features a negatively charged 1D inorganic backbone electrostatically balanced by AeBpy²⁺, a structural motif characteristic of low-dimensional organic-inorganic perovskite-like materials. Upon light irradiation, efficient photoinduced electron transfer enables rapid photochromism, with coloration occurring within 10 s and complete thermal decoloration achieved at 160°C within 10 min, supporting robust photo-writing/erasing cycles. Importantly, the photochromic response remains operable directly in water, enabling aqueous information writing and on-demand thermal erasing. This work provides a viable materials design strategy to address the challenge of water-stable and water-operable photochromic systems, enabling underwater information writing, wet-environment anti-counterfeiting, and rewritable displays.