Multimodal Luminescence in Ca₂InTaO₆:Pr³⁺ Phosphors: Applications in Dynamic Anticounterfeiting and Optical...

The advancement of phosphors with multiple capabilities has garnered significant interest, especially for applications in optical thermometry and dynamic anticounterfeiting technologies. In this work, we successfully synthesized a series of color-tunable Pr³⁺ single-doped Ca₂InTaO₆ (CITO:Pr³⁺) persistent luminescence (PersL) materials by using a high-temperature solid-state method. The crystal structure of the obtained CITO:Pr³⁺ phosphor was characterized by X-ray diffraction and Rietveld refinement. Concentration-, excitation wavelength-, and temperature-dependent optical properties were systematically studied, and the results revealed that these materials display versatile luminescence behaviors and possess excellent optical temperature sensing characteristics and remarkable anticounterfeiting capabilities. Furthermore, by incorporating defect energy levels through nonequivalent substitution of Pr³⁺ for Ca²⁺, the materials also exhibit red PersL emission. This multimodal luminescence capability underpins their potential for dynamic multiple anticounterfeiting applications. Additionally, the differential thermal quenching rates between the ³P₀ → ³H₄ and ¹D₂ → ³H₄ transitions of Pr³⁺ were leveraged for optical temperature sensing. The CITO:0.015Pr³⁺ phosphor, when excited at 318 nm, achieved maximum absolute sensitivity (S_a) and relative sensitivity (S_r) values of 20.42% K^-1 at 393 K and 2.37% K^-1 at 345 K, respectively. These results highlight the promising potential of CITO:Pr³⁺ materials for both multimodal dynamic anticounterfeiting and precise optical temperature measurement.