LAUSR

Abstract Polycrystalline powders of the triphosphate of ammonium hydrogen and erbium NH 4 ErHP 3 O 10 are grown by flux method. The obtained sample was characterized by X-Ray Diffraction, Infrared and Raman spectroscopies. It was found that this compound is isostructural with NH 4 BiHP 3 O 10 . It crystallizes in the triclinic system, with space group P-1. The spectroscopic properties have been investigated in the UV–Vis and IR region via absorption, excitation, and emission spectra at room temperature. Also, the particle size distribution was investigated and the average crystallite size of HNH 4 ErP 3 O 10 was 124.08 nm. The optical band gap energy (Eg ≈ 4.24 eV) was calculated from the diffuse reflectance by using the Kubelka–Munk function and Tauc's relation. The time-resolved luminescence of 4 F 9/2 emission has also been studied. The decay time was shown to be exponential with a pure radiative transition and the lifetime value for the transition 4 F 9/2  →  4 I 15/2 is found equal to 15, 4 μs. The effects of the crystal structure, NH 4 + and OH groups on the lifetime have been revealed. The CIE chromaticity coordinates reveal that this phosphor can be a promising Yellow-orange emitting material.