Zinc Germanate Nanophosphors with Persistent Luminescence for Multi-Mode Imaging of Latent Fingerprints

Fluorescence latent fingerprinting (LFP) imaging is a convenient and frequently used in situ detection technique. In recent years, various types of phosphors have been widely used for LFP imaging. However, traditional phosphor powders are suffering from a formidable challenge to design effective fluorescent LFP powders with low background interference and high detection sensitivity. In this work, we have synthesized Zn2GeO4:Mn,Li,K (ZGO:Mn,Li,K) nanophosphors with the high persistent luminescence (PersL) brightness and long duration using hydrothermal method by optimizing synthesis conditions. The ZGO:Mn,Li,K phosphors, with a perceptible green PersL, have been successfully used for developing LFPs on non-fluorescent substrate, fluorescent substrate, and PersL substrate without special equipment. Besides the level 1 and level 2 details, the other details of LFPs even exceeding level 3 details including the ridge width and boundary streamline of LFPs and the sweat pore feature are distinguishable. These findings show that the ZGO:Mn,Li,K phosphors, with multimode luminescence and high detection sensitivity, will promise a more sophisticated luminescent label for LFP detection on various substrates.