Time-Resolved Physically Unclonable Functions Enabled by Solvent-Free Scalable Boron-Based Ultralong Phosphorescent Systems for Machine-Learning-Resilient Optical Encryption.

Abstract

Anti-counterfeiting technologies are increasingly challenged by advances in imaging and machine learning, exposing the fundamental limitations of conventional static optical security systems. Here, a time-resolved physically unclonable function (TR-PUF) system is established, transforming optical authentication from static pattern recognition to high-dimensional temporal encoding. Central to this approach, boron-based room-temperature phosphorescent (RTP) materials are developed via covalent coupling with coumarin derivatives using a solvent-free strategy that is readily scalable to kilogram-level production, exhibiting a maximum phosphorescence lifetime of over 2 s, an ultralong afterglow visible for up to 30 s, and color-tunable emission. The formation of rigid B-O-C linkages spatially isolates emissive centers, suppressing energy transfer and preserving temporally independent decay channels-an essential prerequisite for high-entropy time-resolved encoding. Randomly embedding these multi-emissive RTP units into a polymer matrix forms a complex encryption structure that enables a dual-entropy encoding mechanism with both spectral and temporal dimensions, generating dynamic time keys for authentication. Moreover, we propose a matched time-gated authentication framework that achieves >99% identification accuracy within 1.2 s while exhibiting resistance against the tested generative machine-learning attacks. This work proposes a practical materials platform and a time-gated authentication strategy, offering a scalable technological path for the development of dynamic optical encryption tags.