Ultra-violet to visible quantum cutting in YPO4: Gd3+, Tb3+ phosphor via down conversion

Abstract

The green emitting phosphor was YPO₄ co-doped with Gd³⁺, Tb³⁺ and synthesized by the precipitation method. The X-ray diffraction (XRD) analysis shows structural purity of as-synthesized phosphors. The photoluminescence (PL) properties including excitation (PLE) and emission (PL) spectra in the vacuum ultraviolet (VUV) or ultraviolet region were measured. From the emission spectra monitored at different excitation wavelengths, the two-step energy transfer process was confirmed with theoretical visible quantum efficiency was found to be 155%, 159% and 162% under excitation wavelengths of 150, 185 and 224 nm respectively.