Luminescence Detection of Latent Fingermarks on Non-porous Surfaces with Heavy-Metal-Free Quantum Dots

Abstract

<p>Current and proposed nanoparticle-based techniques for development of latent fingermarks suffer a number of drawbacks such as complicated, multi-step and time-consuming procedures, batch-to-batch variability, expensive reagents, large background noise and toxicity. Here, we introduce a promising green development technique based on heavy-metal-free quantum dots (QD) for the detection of latent fingermarks on non-porous surfaces. Red-near infrared luminescent Cu-In-S/ZnS core-shell QDs solution was produced in large scales using a water-based, simple and fast method using N-acetyl-cysteine as a biocompatible surfactant to coat the particles. The coated QDs were applied to the successful development of latent fingermarks deposited on a variety of surfaces, including highly patterned polymer banknotes and the sticky side of adhesive tape.<br></p>

Mind the gap: The challenges of sustainable forensic science service provision

“…The successful detection of latent fingermarks is a crucial forensic tool used in humanitarian and criminal investigations globally [ 13 , 34 ]. Over the last two decades there has been a significant increase in research improving existing techniques and developing novel techniques [ 13 , [35] , [36] , [37] ]. However, this research has largely focussed on improving performance relating to the quality and quantity of fingermarks detected, without considerations of sustainability or applications in jurisdictions with limited resources.…”

From nanomaterials to macromolecules: Innovative technologies for latent fingerprint development

“…One of most promising strategies for QD preparation for latent fingermark development is the core@shell approach, as can be demonstrated by Shahbazi et al (2020), who have reported the preparation of heavy metal-free QDs based on ternary metal complex chalcogenide (Cu-In-S/ZnS) core-shell for detection of latent fingermarks on nonporous surfaces. This material presented low toxicity and exhibited strong and broad absorption of ultraviolet (UV) and visible light, intense photoemission and reasonable stability under photoexcitation.…”

“…Most of the nanomaterials represented in the CIE 1931 diagram are blue or green emitters, which can result in low contrast on certain surfaces such as paper, plastic or glass, due to background fluorescence interference. Strategies to improve the quality of the developed fingermark image include use of nanoparticles that exhibit red emission (Chen et al, 2017;Dong et al, 2020;Niu et al, 2021;Shahbazi et al, 2020), that can be excited by infrared light (UCNM), that permit tunable emission (multicolor luminescence) (Xu et al, 2019) or that show phosphorescence (Feng et al, 2022).…”