ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

AI-authenticated latent fingerprint developed using ultra-bright nitrogen-doped carbon dots-intercalated Zn(OH)₂ nanosheets

G. Gnanamani Simiyon, Mary Vergheese Thomas, B. Nivetha, and Mariya Jiji Parakkal

Department of Chemistry, Madras Christian College (Affiliated to University of Madras), Chennai, India

E-mail: maryvergheese@mcc.edu.in

Received: 7 March 2024  Accepted: 24 May 2024

Abstract:

The identification and development of latent fingerprints (LFs) is a challenging task that serves as vital evidence to identify crime activities during criminal investigations. Fluorescent powders provide better contrast than conventional powders to develop LFs. From the literature, the shortcomings of fluorescent materials to develop LFs are their toxicity, high-cost precursors and preparation method, background hindrance, and low stability. Though carbon dots (CDs) possess excellent fluorescence property, its application is limited due to low emission quantum yield. Intercalations of CDs into layered structure enhance the emission quantum yield by minimizing the internal quenching. In this work, we successfully intercalated nitrogen-doped carbon dots (NCDs) in layers of zinc hydroxide (NCLZH) using simple and low-cost microwave method. The red shift of the UV–Vis absorption peak in NCLZH confirms the intercalation of NCDs to layered zinc hydroxide (LZH). XRD data show peak at lower angle indicating formation of inorganic layers, and increase in interlayer spacing from 14.3 Å (LZH) to 14.9 Å (NCLZH) substantiates the intercalation of NCDs into LZH, which is also confirmed by HRSEM image. NCLZH is biocompatible and exhibits bright fluorescent emissions under UV light (400 nm). Our current work addresses the challenges reported earlier to develop LFs on porous and non-porous surfaces by powder dusting method. NCLZH provides high-quality LFs image due to electrostatic interaction between the positively charged NCLZH and negatively charged functional groups present in LFs residue. The high-quality LFs image is obtained without background hindrance due to bright fluorescence emission and validated using AI tools. LFs developed using synthesized material provide detailed information about all the categories of ridge patterns without background hindrance making it the best for forensic fingerprint detection. NCLZH has higher shelf life as it retains the emission intensity even after a year.

Graphical abstract

Keywords: N-doped carbon dots; Latent fingerprints; Ridge information; Layered zinc hydroxide; Microwave synthesis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03535-x

Chemical Papers 78 (10) 6179–6189 (2024)