Dynamic room-temperature phosphorescence enabled by boronic acid group-mediated 2D perovskite heterojunctions for time-resolved multidimensional anti-counterfeiting and encryption

Abstract

Dynamic room-temperature phosphorescence (RTP) materials with color-tunable afterglow characteristics hold great promise for advanced anti-counterfeiting and multidimensional encryption applications. In this work, we successfully synthesized a novel two-dimensional phenylammonium cadmium chloride perovskite (B-PACC) with enhanced RTP efficiency via boronic acid group-assisted crystallization. Furthermore, a precise doping strategy was employed to introduce Mn²⁺, which assembled into Mn²⁺ pairs forming a Mn²⁺-based inorganic layer. This layer, together with B-PACC, constructed a heterojunction structure with different interlayer spacings, enabling dynamic afterglow emission color modulation from red to blue. Moreover, tuning the Mn²⁺ concentration enables precise modulation of the energy transfer rates from the singlet and triplet states of the organic moieties to the Mn²⁺ layer, thereby allowing fine control over the dynamic RTP behavior. Benefiting from the minimal background interference and large chromaticity contrast associated with the red-to-blue phosphorescence transition, the system exhibited high visual detectability. Based on this dynamic afterglow behavior, we successfully developed time-resolved anti-counterfeiting patterns and constructed dynamic room-temperature phosphorescence-based four-dimensional (4D) codes, providing new insights into the design of dynamic RTP materials and highly secure encryption strategies.