Patternable Stimuli-Responsive Perovskite Fiber Membranes for Underwater Anti-Counterfeiting and Information Encryption

Abstract

All-inorganic lead halide perovskites are favored for next-generation optoelectronic devices due to their exceptional photoluminescence quantum yields (PLQYs), wide color gamut, and structural tunability. However, their application in intelligent materials, especially for dynamic optical encryption and anti-counterfeiting in aqueous or humid environments, remains challenging owing to their poor water stability and lack of tunable response under external stimuli. Here, we reported a scalable strategy to fabricate large-area (15 cm × 25 cm), hierarchically porous perovskite fiber membranes (PFMs) that enabled water-responsive, reversible fluorescence modulation. By developing a dual-ligand surface passivation approach, combining hydrophilic supramolecular cyclodextrins and hydrophobic long-chain alkylamines, we simultaneously achieved surface passivation, water resistance, as well as dynamic bandgap modulation and defect engineering within a single material platform. The resulting blue-emitting PFMs demonstrated a high PLQY of 86.3%, narrow-band emission (full-width at half-maximum value of ~20 nm), enhanced color purity up to 96.4%, and long-term stability (> 4000 h) under ambient conditions. More interestingly, moisture-induced ligand reorganization enabled reversible fluorescence shifts from deep-blue (461.1 nm) to cyan-green (504.9 nm) across multiple cycles (with > 95% photoluminescence intensity retention) and in a wide pH range (3–13). We further demonstrated an ASCII-encoded microdots array and dual-mode optical encryption system that allowed orthogonal decoding via moisture and ultraviolet stimuli, highlighting the potential of these materials for underwater anti-counterfeiting and dynamic information encryption. This work provides a new paradigm for integrating intelligent stimulus responsiveness with stable optoelectronic performance in perovskites, paving the way for their application in secure information technologies and smart photonic devices in harsh environments.