A single-phase white emitting nanophosphor with refined crystal structure and extremely luminescent characteristics for WLEDs and latent fingerprint detection

Abstract

Rare earth (RE) elements activated luminescent phosphor materials play a critical role in optoelectronics and advanced forensic applications. For white light-emitting diodes (WLEDs) and latent fingerprints (LFPs) detection, we employed a wet chemical approach to synthesize Bi3+/Eu3+ coactivated Y2O3 single-phase white emitting nanophosphor at low temperatures. Experiments are carried out on the photoluminescence (PL) behavior of the nanophosphor as well as the qualitative and quantitative structural characterizations of two different symmetric sites of the crystal. The nanophosphor emitted blue, green, and a strong red emission bands with optimal intensity when exposed to ultraviolet (UV) radiation, resulting in white light when these three emission bands were combined. The observed PL-spectra of the Bi3+ ion is fragmented into two sub-bands occupying Bi3+(I) and Bi3+(II) sites, with stokes shifts of 2.94 × 103 cm−1 and 9.06 × 103 cm−1 respectively. The efficient energy transfer mechanism of Bi3+(I)/Bi3+(II)→Eu3+ was investigated using the PL-emission spectra. Under excitations at 326 and 342 nm, the Commission Internationale de l'Eclairage (CIE) 1931 chromaticity coordinates and correlated color temperature (CCTs) exhibited the tunable white color. Furthermore, the nanophosphor was utilized to observe the clear skin ridge pattern of the fingerprints under 254 UV nm light. The findings of these experiments revealed that the produced nanophosphor could be a suitable candidate for WLEDs and LFP imaging applications.