Influence of vanadium concentration on up-conversion luminescence in Er3+–Yb3+ and Tm3+–Yb3+ ions pair co-doped YVxP1−xO4 solid state solution

Highlights: • Co-precipitation synthesis method lead to obtaining pure YV_xP_1-xO₄ co-doped with Tm³⁺–Yb³⁺ and Er³⁺–Yb³⁺ ions. • Structural and morphological analysis confirmed that materials were nanosized and in accordance with the Vegard's law. • Influence of changing V⁵⁺ ion concentration on up-conversion luminescence of Tm³⁺–Yb³⁺ and Er³⁺–Yb³⁺ was investigated. • Energy level scheme with proposed up-conversion processes (ETU, ESA, CS and CR) was presented. -- Abstract: The paper is focused on an influence of vanadium ions on the up-conversion processes in nanosized YV_xP_1−xO₄ solid state solution. As a consequence, two series of YV_xP_1−xO₄ (where x = 0–1) materials has been obtained via co-precipitation method. Yttrium orthovanadate-phosphate has been co-doped with the up-converting Er³⁺-Yb³⁺ and Tm³⁺-Yb³⁺ lanthanide ion pairs. Obtained series of nanosized materials has been investigated for phase purity, chemical composition, morphology by the means of X-Ray Powder Diffraction (XRD) and Scanning Electron Microscope (SEM). Photoluminescence properties of 0.25 mol% Tm³⁺, 20 mol% Yb³⁺:YV_xP_1−xO₄ (x = 0, 0.3, 0.4, 0.5, 0.6, 0.7, 1), and 1 mol% Er³⁺, 20 mol% Yb³⁺:YV_xP_1−xO₄ (x = 0, 0.3, 0.4, 0.5, 0.6, 0.7, 1) were investigated in detail. It has been found that increase of the vanadium content leading to better up-conversion luminescence.