Efficient triplet energy transfer in a 0D metal halide hybrid with long persistence room temperature phosphorescence for time-resolved anti-counterfeiting

Endowing metal halide hybrids (MHHs) with time-resolved emission and afterglow could significantly broaden their applications in fields such as information security and anti-counterfeiting. Nonetheless, there have been relatively few successes in developing organic cations with persistent room-temperature phosphorescence (RTP) to construct MHHs with afterglow. In this work, we synthesize a new polyazole, 3,5-di(1H-pyrazol-4-yl)-4H-1,2,4-triazol-4-amine (DPTA), with green persistent RTP up to 1.5 s. The afterglow of DPTA reaches up to similar to 1.0 s even after being assembled into 0D (DPTAH3)InCl6 center dot 2.5H2O (DIC). Due to strong overlap between the triplet emission of DPTA and 1S0 -> 3Px absorption of Sb3+, efficient triplet energy transfer (TET) with the highest yield of 65.3% and a near-unity photoluminescence quantum yield (PLQY) is achieved. More importantly, the afterglow persistence time of DIC:x% Sb can be easily tailored through Sb3+ doping. Given the Sb3+-dependent emission color and long persistence time, a series of DIC:x% Sb are successfully utilized to demonstrate high-security-level anti-counterfeiting application. This work shows an effective strategy for designing new MHHs with tunable emission and afterglow persistence time. Due to strong overlap between the triplet emission of DPTA and 1S0 -> 3Px absorption of Sb3+, efficient triplet energy transfer occurs between DPTA and Sb and the afterglow persistence time of DIC:x% Sb can be easily tailored through Sb3+ doping.

Automated summary

This work presents the synthesis of a new polyazole compound with green persistent phosphorescence and demonstrates its potential in applications such as information security and anti-counterfeiting. By doping Sb3+, the emission color and afterglow persistence time of the material can be easily adjusted.