Excellent luminescent thermal stability of Dy3+/Sm3+ co-activated multifunctional titanate single-phase phosphors

Abstract

Nowadays, the development of phosphors with excellent luminescent thermal stability for various applications has become a research hotspot. Therefore, the Dy³⁺/Sm³⁺ co-activated multifunctional NaYTiO₄ phosphors with excellent comprehensive performance in the field of non-contact optical measurement and white LED solid-state lighting were reported in this paper, and their crystal structure, elemental composition, optical bandgap and photoluminescence properties were systematically studied. Remarkably, the reason why NaYTiO₄:Dy³⁺,Sm³⁺ phosphors achieved color-controlled emission from yellow to orange-red and even to white at the excitation wavelength of 363 nm was not based on the energy transfer process from Dy³⁺ to Sm³⁺ but on co-excitation. When the temperature reached 475 K, the luminescence intensity of the phosphor still maintained 96.75% of the initial intensity, demonstrating excellent thermal quenching property. Furthermore, the temperature sensing performance was evaluated by FIR technique according to the differential decreasing trend of Dy³⁺ and Sm³⁺ emission intensity with increasing temperature. Finally, we also certified the applicability of NaYTiO₄:Dy³⁺,Sm³⁺ phosphors in white LEDs for indoor health lighting. These results indicate that NaYTiO₄:Dy³⁺,Sm³⁺ multifunctional phosphors are promising dual functional luminescent platforms that can be used for non-contact optical thermometers and white LED device applications.