Te4+-doped Cs3In2Cl9 zero-dimensional perovskite for high-sensitivity optical thermometry

Halide perovskite materials have garnered considerable interest due to their distinctive optical properties and their promise in optoelectronic applications. In this study, we reported the synthesis novel zero-dimensional halide perovskite Cs₃In₂Cl₉:Te⁴⁺ via an ultrasonic-assisted method. The structural and photoluminescent properties of the resulting polycrystalline sample were meticulously characterized using X-ray powder diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. Experimental findings reveal that upon excitation with near-ultraviolet light at 390 nm, the Cs₃In₂Cl₉:Te⁴⁺ sample exhibits a bright orange-yellow emission centered at 585 nm, primarily attributed to self-trapped exciton (STE) luminescence. Temperature-dependent emission spectra and decay curves imply that the material holds great potential for temperature sensing applications, showcasing a maximum relative sensitivity (S_r) of 6.27 % K⁻¹ at 300 K within the range of 300–350 K. Moreover, the Cs₃In₂Cl₉:Te⁴⁺ material has been found to possess outstanding thermal and color stability, maintain its integrity through multiple heating and cooling cycles as well as during extended measurement periods. This reliability is crucial for the development of fluorescence-based temperature detection technologies.