Comparative study of luminescence in alkali‐metal‐based yttrium fluoride nanophosphor for biophotonic applications

Alkali‐metal‐based yttrium fluoride host (AY 1‒ x F 4 : x Eu 3+ ; A: Li/Na/K) nanophosphors were developed using co‐precipitation method. Phase analysis and emission spectral behavior were established for the said nanophosphors. The highest emission observed for NaYF 4 doped with Eu 3+ was then optimized to achieve maximum photoluminescence (PL) emission for varied dopant amount. The downconversion and upconversion PL studies revealed pure red emission under n‐ultraviolet and infrared excitations. The CIE coordinates are observed to be lie in the red hue of the CIE diagram. The PL decay curves reported to study lifetime of the emitting state and to identify quantum efficiency using Auzel's model for the said nanophosphor. Thermal stability was also evaluated from temperature‐sensitive luminescent spectra. The studies conducted on AYF 4 :.05Eu 3+ (A: Li/Na/K) nanophosphors contemplates that NaYF 4 nanophosphors doped with Eu 3+ ions are best suited for biophotonic applications as the later one show relatively high emission.