Deep dive into structural and optical study of stuffed-tridymite rare earth (Sm3+, Eu3+) doped CsZnPO4

Abstract

This work used the most popular solid-state method to generate stuffed-tridymite CsZnPO₄ doped with rare-earth ions (Eu³⁺, Sm³⁺). The XRD analysis performed at room temperature and Rietveld refinement using the FullProf suit package has revealed that the combination CsZnPO₄ has crystallized into a monoclinic crystal structure with space group P121/a1. Crystallite size is determined using the Scherrer, modified Scherrer, and Williamson Hall procedures; a comparison study between the approaches was also conducted. In this work, the atomic positions (x, y, z) of Cs, Zn, P, and O in the unit cell, as well as the occupancy, have been estimated, and potential structural parameters such as a, b, c, α, β, and γ have been calculated. A comparative FTIR analysis was carried out between orthorhombic CsMnPO₄ with space group Pn a 21 and monoclinic CsZnPO₄ with space group P121/a1. The band gap for the synthesized material CsZnPO₄ was then determined using the P. Kubelka and Munk technique, and the estimated band gap energy for the compound was roughly 3.9 electron volts, which is very close to the actual band gap of the material. The PL spectra of CsZnPO₄:xSm³⁺ and CsZnPO₄:xEu³⁺ were recorded at the exact stimulation wavelengths of 401 nm and 396 nm, respectively. It is discovered that as the doping concentration rises, so does the emission intensity, and at a specific concentration of doping, it peaks, after which it begins to decline monotonically at greater concentrations. It is demonstrated that the concentration quenching process is caused by dipole-quadrupole interaction rather than the non-radiative cross-relaxation process in both the phosphor materials. The orange-red area (0.573, 0.423) and red region (0.624, 0.376) are where the chromaticity coordinates of the produced luminous material CsZnPO4:xSm³⁺ and CsZnPO4:xEu³⁺, respectively, are located. As the temperature increased, the relative PL intensities decreased by a negligible amount, but their peak locations did not alter. The remarkable thermal stability of the produced material is demonstrated by the emission behavior at increasing temperatures, and to explain this behavior, the configurational coordinate model is employed. The phosphor CsZnPO₄ doped with Eu³⁺ and Sm³⁺ shows excellent promise for usage as a red-emitting and orange-red-emitting phosphor in a range of applications, including white LEDs and displays, based on the study conducted in the present work.