Application research on the development of latent fingermarks using color tunable LiZnPO4:Eu3+ phosphors

Abstract

High brightness LiZnPO4:Eu3+(LZP:Eu3+)phosphors were prepared using state reaction, the emission of this phosphor at 592 nm is dominant due to there being symmetric center in the crystal structure of LiZnPO4, which corresponds to the 5D0→7F1 transition of Eu3+. The emission intensity is up to maximum when Eu3+ content is 12at. %. The excitation spectrum consists of a broad band extending 200∼280 nm and a series of sharp peaks extending 310∼500 nm, centered at 395 nm, corresponding to the charge transfer band of O2-→Eu3+ and f→f transition of Eu3+, respectively. The phosphor is excitable efficiently by 395 nm UV and short wave UV, and then was applied in the detection and imaging of lipid fingermarks on common non-porous and semi-porous substrates such as colored paper, glass, porcelain, leather, etc. All results illustrated that LZP:Eu3+ phosphor was an ideal detection powder for reduction of background interferences due to its high fluorescence brightness, offered high contrast images and applicable to the development of fingermarks on the common non-porous and semi-porous substrates