Intense red emission from trivalent Eu3+ doped Ca9La(VO4)7 nanophosphor for lighting and latent fingerprinting applications

A quick, efficient, and environment-friendly solution combustion approach was used to develop intense red light emitting Eu³⁺ activated Ca₉La(VO₄)₇ nanophosphor. Rietveld’s refinement of patterns obtained from XRD validated the trigonal structure & (R3c 161 space group) of the crystallized nanophosphors. Elemental analysis and surface morphology of the red phosphors were investigated by EDAX and SEM techniques. Tauc’s theory was used to determine the band gap of the host & optimized nanosample. The excitation spectra at 331 nm indicate energy transfer between VO₄³⁻ → Eu³⁺ ions, which is confirmed by photoluminescence lifetime measurements. The designated nanophosphors emit bright red light due to the ⁵D₀ → ⁷F₂ radiative transition. Dexter’s hypothesis and I–H model were used to demonstrate that dipole–dipole interactions are a true phenomenon for concentration quenching. Furthermore, the optical properties of Ca₉La_0.6Eu_0.4(VO₄)₇ nanophosphor exhibit quantum efficacy (58.67%), CIE co-ordinates (0.5192, 0.3313), and color-temperature (1717 K), making it suitable for use in wLEDs, photonic devices and based on the previously mentioned results, the optimum (i.e. Ca₉La_(1-x)Eu_x(VO₄)₇ (x = 0.4 mol%)) nanophosphor was shown to be useful for LFP (latent fingerprinting).