High‐Security and High‐Efficiency Information Encryption/Decryption Based on 2D Hybrid Organic–Inorganic Perovskites via Delicate Organic‐Cation Engineering

Optical encryption based on stimuli-responsive luminescence (SRL) materials has received enormous interest in the field of information security. Metal-halide perovskites, as a newly emerging SRL material, have shown great potential for confidential information encryption/decryption (InfoED) applications. However, it is rather challenging to ensure high security and achieve high readout efficiency in perovskite SRL-based InfoED. Herein, we present a unique InfoED strategy using 2D hybrid organic-inorganic perovskites via delicate organic-cation engineering, benefiting from the high contrast and quick response of their photoluminescence behaviors. Indistinguishably encrypted information can be efficiently decrypted through triple-key implementation (i.e., ultraviolet-light irradiation, temperature control, and narrow-bandpass filtering) that operates in multiple switching modes, enabling us to demonstrate extremely high security by adopting dot-matrix patterning scenarios that are virtually uncrackable. As a proof of principle, a simple 2 × 2 patterning can yield a code dictionary with random variants as high as ∼10⁴⁷, which will take as long as ∼10²² years to crack using the hitherto fastest supercomputer, El Capitan. Our perovskite SRL-based InfoED strategy provides a promising solution for information security based on optical encryption.