Spectrally camouflaged radiative pathway switching in all-inorganic perovskite derivatives for efficient optical encryption

The growing demand for high-level information security necessitates advanced photonic materials with programmable, multidimensional optical responses. However, conventional research predominantly optimizes the performance of static, predefined luminescent centers, leaving the dopant-programmed switching of dominant radiative pathways largely unexplored. Herein, we propose and demonstrate a novel strategy of spectrally camouflaged switching of the dominant radiative pathway within CsCdCl 3 perovskite microcrystals via a sequential Zr 4+ /Mn 2+ doping protocol. Zr 4+ initially acts as a structural modifier to tailor lattice strain and optimize self-trapped excitons (STEs) as an energy donor. The subsequent introduction of Mn 2+ drives a highly efficient (with an apparent efficiency >97.6%) energy transfer, covertly shifting the dominant emission pathway from STE recombination to the Mn 2+ 4 T 1 → 6 A 1 transition. While both the steady-state and persistent luminescence colors remain unchanged in the orange region, the internal quantum efficiency increases to 99.4%, accompanied by a fundamental reconfiguration of carrier dynamics. Exploiting this hidden photophysical transformation, we construct a dynamic optical information storage platform where the underlying luminescence mechanism itself serves as an invisible, advanced encryption dimension. This transition from conventional property tuning to mechanism programming establishes a robust material design principle for next-generation anti-counterfeiting technologies. Inspired by the traditional Chinese art of ‘Face-Changing’, a novel strategy of spectrally camouflaged luminescence mechanism switching is demonstrated in CsCdCl 3 :Zr 4+ /Mn 2+ microcrystals. By actively switching the internal emission engine from self-trapped excitons to Mn 2+ d-d transitions under an identical orange color, a high-security multi-dimensional optical encryption platform is achieved. Download: Download high-res image (415KB) Download: Download full-size image