Dual-Encrypted Ultraviolet Optical Communication Driven by Opto-Piezoelectric Coupling in Two-Dimensional Flexible Ferroelectric Single-Crystalline Thin-Films.

The rapid development of flexible wearable electronics has triggered an urgent demand for high-security and miniaturized encrypted optical communication systems. However, conventional optical encryption strategies predominantly rely on dual-wavelength excitation, tunable light sources, or software-based algorithms, leading to bulky configurations and vulnerable hardware-level security. Herein, we report a dual-encrypted ultraviolet optical communication system based on BA2EA2Pb3Br10 (1, where BA is n-butylamine and EA is ethylamine) ferroelectric single-crystalline thin-films (SCFs). The 1 ferroelectric SCFs show a photoresponsivity that reaches 230% of the original level under +1.13% tensile strain. Notably, we innovatively define the strain-ratio key (ε1/ε2, ε2/ε3, ε3/ε4) induced by distinct bending states as the intrinsic unclonable hardware secret key, and construct a 4-bit combined coding scheme based on four distinguishable photocurrent levels modulated by these strain ratios to realize secure transmission of the message "FJIRSM." This strain ratio-based system avoids complex optical modulation, ensuring ultrahigh security, and expands the application of two-dimensional ferroelectrics in advanced encrypted optoelectronics.