CsPbBr3/EuPO4 dual-phase devitrified glass for highly sensitive self-calibrating optical thermometry

Abstract

Despite possessing admirable features for optical thermometry, a semiconductor (SC) nanocrystal based material has the innate shortcomings of poor stability towards environmental variation, complicated/unfriendly preparation procedures, low production, and the necessity of a delicate structural design to achieve dual-emission. To well address these issues, a kind of dual-phase devitrified glass (DG) strategy is proposed. In the case of dual-phase DG embedded with CsPbBr₃ SC and EuPO₄, fabricated via a glass self-crystallization route, it has been found that the spatial isolation of two emitting species enables non-interfering luminescence with different temperature-responsive behaviors. Utilizing the fluorescence intensity ratio (FIR) between the Eu³⁺: 4f → 4f emission from EuPO₄ and the exciton emission from CsPbBr₃, a self-calibrating thermometer with ultra-high sensitivity (S_a = 0.082 K⁻¹ and S_r = 1.80% K⁻¹, 303–483 K) is achieved. Importantly, the introduction of a CsPbBr₃ perovskite SC into the inert glass matrix greatly improves its thermal stability, and so highly repeatable thermometry in the dual-phase DG is achieved (97.12% for 10 heating–cooling cycles). This work demonstrates an effective pathway for accurate, reliable and robust thermometry by integrating SC nanocrystals and rare-earth-ions into an inorganic glassy composite.