Green Emitting Phosphor of Praseodymium Doped La(OH)₃ Nanoparticles Synthesized Via Sol-Gel Combustion Technique

In this study, pure and Pr³⁺ ions doped La(OH)₃ phosphor for different concentrations (2, 5, and 10 wt%) is produced via the sol-gel combustion route, and its crystal structure, vibrational, morphological, optical, and photoluminescent properties were studied. XRD investigations confirmed that the hexagonal phase, which matches the standard lattice constants a = b = 6.518 Å and c = 3.841 Å for the as-synthesized pure and Pr³⁺ doped La(OH)₃ nanoparticles. The particle size confirmed from the TEM image is 37 nm and is nearly identical to the crystallite size as measured by XRD measurements. The average band gap of Pr³⁺ doped La(OH)₃ nanoparticles is found to be 3.5 eV. The PL emission spectrum of 2 wt% of Pr doped La(OH)₃ nanoparticles show high emission intensity, which confirms the green emission around 511 nm with transition ³P₀→³H₄. The CIE coordinates could confirm that the presence of Pr³⁺ ion-doped La(OH)₃ phosphors is beneficial for green emission phosphors as cool white light. The lifetimes of Pr³⁺ ions doped in La(OH)₃ nanoparticles are determined to be 2.166 ms, 1.982 ms, and 2.143 ms for 2, 5, and 10 wt% of Pr³⁺ ions, respectively. Through this research, the doping effects of rare earth ions are better comprehended, and new design ideas for enhanced luminescent materials that can be utilized in light-emitting diodes and display systems.