Nanocomposites of Cu9s5 Nanoclusters Conjugated Silica with Orange Emission for Visualization Latent Fingerprints

Abstract

Latent fingerprints (LFPs) which can be used as the accurate and dependable tool for identification of individuals at the crime scene are not easily discernible to distinguish with the naked eye, and require some physiochemical techniques to effectively enhance the quality of the LFPs images. In this work, we have designed a simple strategy for preparing the nanocomposites by in-situ anchoring the luminescent Cu9S5 nanoclusters onto the surface of the sulfide-functionalized silica (Cu9S5/silica), which are used for the detection of the fresh and aged LFPs on the surfaces of various substrates. The Cu9S5/silica exhibits a fluorescence emission at 606 nm upon 386 nm excitation. The fluorescence quantum yield of the Cu9S5/silica in the solid state can reach 1.43%, and an excited state lifetime is found to be 863.3 ns. Orange clear bright ridge patterns of LFPs with primary, secondary and tertiary features can be identified by the Cu9S5/silica using traditional powder-dusting method with good sensitivity and high contrast. Furthermore, the Cu9S5/silica as a phosphor is successfully used to detect the fresh and aged LFPs on a variety of substrates with non-porous and semi-porous surfaces. These satisfactory results illustrate that the Cu9S5/silica has great potential for applications in forensic science.

Keywords: Latent Fingerprints, Nanoclusters, Hybrid