Electrochromic Encryption and Decryption Smart Films Fabricated by Selective Photopolymerization of Polarization‐Dependent Triphenylamine‐Based Thin Films

Abstract The newly designed triphenylamine (TPA) based asymmetric monomer (TPA‐A) is synthesized for the development of a high‐security information encryption system. TPA‐A exhibits photoluminescence (PL) emission and redox‐active electrochromic (EC) properties, highlighting its potential as a smart encryptable ink. Introducing a methyl group to one side branch of the TPA‐A induces a steric hindrance effect, enabling TPA‐A to form a self‐assembled lamello‐columnar structure. This structural modification reduces the phase transition temperature and simultaneously allows for the uniaxial orientation of TPA‐A by a simple shear‐coating process. The uniaxially oriented and self‐assembled TPA‐A thin films exhibits polarization‐dependent PL properties and electrofluorochromic (EFC) characteristics combined with redox‐responsive EC properties. The selective photopolymerization of polarization‐dependent TPA‐A thin film generates a dual‐mode information encryption system. The newly developed EC smart film can open a new door for optoelectronic information encryption and anti‐counterfeiting technologies.