Effect of monovalent, divalent, and trivalent ions codoped with LaOCl: Eu3+ phosphors and its Judd-Ofelt analysis for display device applications

In this work, Lanthanum oxychloride LaOCl: Eu3+ (0–9 mol%) was synthesized using a conventional solid-state approach over the course of relatively low temperature (400 °C) and a shorter duration of 1 h. To investigate the phase purity of phosphors, crystallographic studies were performed using PXRD, which revealed the tetragonal structure with space group P4/nmm (No. 129). Morphological investigations were made using FESEM which unveils the agglomeration of phosphors. Photoluminescence spectra reveals that, the intensity of the 5D0→7F2 transition (618 nm), which increases with an increase in Eu3+ concentration (1–9 mol%), rises to a maximum of 7 mol% before quenching causes it to fall. The reason behind the quenching concentration of Eu3+ ions at 7 mol% was dipole-quadruple interaction which is determined using the Van Uitert equation. To improve luminescence efficiency metal ions like Li+, Na+, K+, Ca2+, and Bi3+ were exploited, among these LaOCl: Eu3+ co-doped with Li+ ion exhibit the highest PL intensity (39 times that of Eu3+). The Commission International de I'Eclairage (CIE) chromaticity coordinates of LaOCl: Eu3+ co-doped with Li+ phosphor is (0.590, 0.346) which is close to commercial red light-emitting phosphors. These phosphor materials were mixed with PVA and developed a flexible phosphor polymer composite, which can be used for flexible display device applications. Spectral parameters like J-O intensity parameters are used to analyze optical materials, these parameters were determined with the help of luminescence spectra.