Hydrogen bonding triggered tunable high temperature phosphorescence.

Due to the luminescence quenching at elevated temperature, the development of high temperature phosphorescent (HTP) materials with tunable emission remains a formidable challenge. Herein, a hydrogen bonding (HB) triggered strategy to achieve color-tunable and thermally robust room temperature phosphorescence (RTP) was demonstrated. Using a triazine derivative (TRZ) as a luminescent core and HB acceptor and a series of acids, o-pyridinesulfonic acid (OPS), ethanesulfonic acid (ESA), or trifluoroacetic acid (TFA), as HB donors, a series of stable HB luminescent systems were constructed, which not only exhibited RTP activity, but also enabled continuous wavelength tuning from 528 to 585 nm through varying acid strength. Remarkably, these HB systems exhibited phosphorescence that persisted up to 463 K, owing to the exceptional thermal stability, which was one of the highest reported working temperatures for tunable organic phosphors. By doping TRZ and ESA into a PMMA matrix, the material reveals promoted aggregation and stabilized triplet excitons, which lead to photoactivated RTP and a pronounced photothermal effect. Results also reveal that HB enhances spin-orbit coupling, promotes charge-transfer character, and restricts molecular motions, thereby suppressing thermal quenching. This work establishes a versatile strategy for designing tunable HTP materials with secondary interaction, broadening avenues for applications in high temperature optoelectronics and sensing.