Luminescence Properties of Yb3+/Ho3+ doped GdPO4 Nanocomposites Prepared by Hydrothermal Method using PEG(6000)

Abstract

By using hydrothermal synthesis, a novel Yb³⁺/Ho³⁺ co-doped GdPO₄ nanophosphors were prepared which shows both upconversion (UC) and downconversion (DC) with excellent luminescence properties. DC peaks were observed at ~460, ~550, ~650 and ~750 nm. By excitation at 300 nm, a very faint P-O charge transfer (CT) band of Ho³⁺ ions, as well as a tiny non-radiative resonance energy transfer was observed. It is discovered that GdPO₄: Yb³⁺/Ho³⁺, an upconversion (UC) nanophosphor, enables the production and enhancement of luminescence on a vast scale. On strong 980 nm laser illumination, the upconversion emission spectra show a conspicuous expectant peak of the Ho³⁺ ion at ~550 and ~650 nm. This process yields high-quality nanocrystalline materials with sizes between a few to tens of nm range. Considering the results of the study at 300 nm excitation, GdPO₄: Yb³⁺/Ho³⁺ produced a high quantum yield value. The findings are useful for creating efficient phosphors and it proves applications of nanophosphor materials covered by this method are numerous.