Phosphorescent Materials with Extreme Temperature Stability via a Dehydration-Shrinkage Strategy.

Phosphorescence, stemming from triplet excitons, is highly susceptible to thermal quenching as elevated temperatures trigger nonradiative transitions. Achieving efficient and persistent organic phosphorescence under extreme heat remains a formidable challenge. We introduce a dehydration-shrinkage strategy to obtain doped organic phosphorescence systems with extreme-temperature tolerance, which achieves gradual anchoring of the phosphors within the ionic network of hydrated sodium borate. These doped systems exhibit efficient phosphorescence spanning 400 to 680 nm at room temperature and 573 K, achieving a phosphorescence quantum yield of 81.2% and a lifetime of 1.64 s at room temperature. Remarkably, the doped systems can remain operational for at least 6 months at 573 K. Mechanistic studies reveal that temperature-induced water departure triggers network shrinkage, which rigidifies the local environment and suppresses triplet exciton deactivation, thereby stabilizing the phosphorescence. This strategy opens a perspective for constructing high-temperature phosphorescent materials, safety indicators, and information security devices.