Optical and Upconversion Properties of A<sub>3</sub>Y(PO<sub>4</sub>)<sub>3</sub>:Pr<sup>3+</sup> (A = Sr, Ba) Phosphors
Nadiia Rebrova, Radosław Lisiecki, Patrycja Zdeb, Yu. Zorenko, A. Voloshinovskiĭ, Andriy Pushak, P.J. Dereń
Abstract
High Resolution Image Download MS PowerPoint Slide The development of new ultraviolet (UV) phosphors is critical to unlocking the full potential of UV technologies to address global challenges related to healthcare, indoor air quality, and environmental sustainability. This work presents effective UV-C phosphors Sr 3 Y(PO 4 ) 3:Pr 3+ and Ba 3 Y(PO 4 ) 3:Pr 3+, synthesized by the solid-state method. The luminescent properties, including both down- and upconversion, were investigated under X-ray, UV, and visible excitation. Crystallites of A 3 Y(PO 4 ) 3 (A = Sr, Ba) activated by Pr 3+ demonstrate effective ultraviolet 5d–4f emission and weak 4f–4f emission (mainly red 1 D 2 → 3 H 4 luminescence) upon ultraviolet excitation. Selective excitation of the 3 P J level of the Pr 3+ ion in the crystallites leads to emissions in the blue, red-orange, and near-infrared regions, as well as broadband ultraviolet upconverted luminescence. The dependence of the integral intensity of Stokes and anti-Stokes emission on the concentration of the activator has been studied. The optimal concentrations of Pr 3+ ions are determined to be 1 and 1.5 mol %, and the mechanisms of concentration quenching are discussed. To elucidate the upconversion mechanism, the intensity of upconversion emission was analyzed as a function of pumping. Ba 3 Y(PO 4 ) 3:Pr 3+ shows a 6-fold increase in upconversion emission compared to YPO 4:Pr 3+ known from the literature, while Sr 3 Y(PO 4 ) 3:Pr 3+ exhibits a 3.5-fold increase over the same material. The spectral-luminescent and luminescence-kinetic properties of pure and Pr 3+ -doped A 3 Y(PO 4 ) 3 (A = Sr, Ba) crystallites under excitation by X-rays up to 40 keV have been studied. The mechanism of energy transfer to Pr 3+ ions in the crystallites upon X-ray excitation is discussed. Additionally, in the temperature range of 80–730 K, the optical thermometric characteristics of A 3 Y(PO 4 ) 3:Pr 3+ crystallites were studied using the luminescence intensity ratio between two Pr 3+ emission bands ( 3 P 1 → 3 H 5 and 3 P 0 → 3 H 6 ).