Up-Converting K₂Gd(PO₄)(WO₄):20%Yb³⁺,Ho³⁺ Phosphors for Temperature Sensing.

ABSTRACT: Inorganic luminescent materials that can be excited with NIR radiation and emit in the visible spectrum have recently gained much scientific interest. Such materials can be utilized as anti-counterfeiting pigments, luminescent thermometers, bio-imaging agents, etc. In this work, we report the synthesis and optical properties of K₂Gd(PO₄)(WO₄):Ho³⁺ and K₂Gd(PO₄)(WO₄):20%Yb³⁺,Ho³⁺ powders. The single-phase samples were prepared by the solid-state reaction method, and the Ho³⁺ concentration was changed from 0.5% to 10% with respect to Gd³⁺. It is interesting to note that under 450 nm excitation, no concentration quenching was observed in K₂Gd(PO₄)(WO₄):Ho³⁺ (at least up to 10% Ho³⁺) samples. However, adding 20% Yb³⁺ has caused a gradual decrease in Ho³⁺ emission intensity with an increase in its concentration. It turned out that this phenomenon is caused by the increasing probability of Ho³⁺ → Yb³⁺ energy transfer when Ho³⁺ content increases. K₂Gd(PO₄)(WO₄):20%Yb³⁺,0.5%Ho³⁺ sample showed exceptionally high up-conversion (UC) emission stability in the 77-500 K range. The UC emission intensity reached a maximum at ca. 350 K, and the intensity at 500 K was around four times stronger than the intensity at 77 K. Moreover, the red/green emission ratio gradually increased with increasing temperature, which could be used for temperature sensing purposes.

SUBMITTER: Grigorjevaite J 

PROVIDER: S-EPMC9917978 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature