Fluorescent‐Dye‐Doped Nanoporous Silica Powder for Imaging of Latent Fingerprints (Levels 1–3) and Case Studies

Abstract

Novel naphthalimide based fluorescent dye NI‐1 possess (i) high quantum yield, (ii) blue emission (λem=450 nm), (iii) CIE coordinate (x=0.21, y=0.35) with 39 % blue colour purity in solid state, (iv) photochemical and thermal stability up to 200 oC and (v) low cytotoxicity to normal cells L929. NI‐1 was doped in nano porous silica and used as fluorescent powder for imaging of latent fingerprints (LFPs) on coloured surfaces, barcode, wood, brick, leaf and engraved steel beside other common household porous and nonporous surfaces. We demonstrated visibility of levels 1–3 on ceramic tile, glass, paper, steel, iron and compact disc using NI‐1 doped fluorescent silica powder. Furthermore, LFPs developed with NI‐1 were successfully lifted from different surfaces using adhesive tape for documentation and archiving purposes. To mimic the automated fingerprint identification system (AFIS), we manually screened fingerprints from 16 subjects to identify the unknown subject. The unique minutiae points such as long hook, opposite bifurcation, crossbar, cross over, dock, triple bifurcation, lake and spikes were observed beside other 16 minutiae points.