Dual-Mode Afterglow of Organic-Inorganic Hybrid Metal Halides for Multi-Dimensional Information Encryption.

Abstract

Organic and organic-inorganic hybrid materials exhibiting room-temperature phosphorescence (RTP) and long persistent luminescence (LPL) materials have attracted growing attention for various time-resolved optoelectronic applications. To date, realizing intrinsically distinct RTP and LPL emissions within a single material system remains elusive, yet it is crucial for unlocking multifunctional applications such as multilevel optical encryption. Here, a Mn²⁺-doped organic-inorganic hybrid metal halide is presented that exhibits bright yellow phosphorescence under UV excitation and a long-lasting red afterglow persisting for over 600 s under X-ray irradiation. These contrasting emission behaviors originate from distinct recombination pathways: triplet exciton emission from the organic ligand governs RTP, while LPL arises from Mn²⁺-centered emission. The latter is enabled by the thermally activated release of charge carriers trapped at radiation-induced defects. This excitation-dependent divergence in luminescence offers temporal and spectral control over optical signals, enabling a multidimensional time-space-energy encoded optical encryption platform. The findings introduce a pathway-engineered strategy for multi-mode phosphorescent materials, paving the way for further materials design for emerging intelligent optoelectronic devices.