Magical fluorescent powder and ink for instantaneous imaging of latent fingerprints (level 1–3) and anti-counterfeiting labels

Abstract

In the fingerprint research area, development of ‘old’ fingerprints (FPs) or FPs taken on porous, smooth surfaces, preservation of developed FPs and visualization of sweat pores are unsolved issues. In this report, we have synthesized and explored 4,5-bis(diethylene glycol) functionalized 1,8-naphthalimide (Naph-DG) dye for addressing these issues. The Naph-DG possesses high quantum yield (φ = 4.22) in solid-state suitable for the development of latent, old, stained FPs using powder dusting method on porous, non-porous and coloured surfaces up to levels 1–3. Depending upon the hydrophobicity of the surface, Naph-DG Chameleon emits blue, blue-greenish and greenish fluorescence on the ridges of the FPs. The practical applicability of Naph-DG was demonstrated using case studies. The FPs developed with Naph-DG can be lifted with scotch tape for preservation. The Naph-DG was also used (i) as a fluorescent ink for the development of anti-counterfeiting labels and (ii) for molecular recognition of Fe3+ as low as 42 nM in CH3CN.