One‐Step Synthesis of Solid‐State Photoluminescent Carbon Nanodots from Grains for Latent Fingerprint Detection

Abstract

Employing grains (wheat, corn, sorghum and rice) as precursors, a series of carbon nanodots (CDs) have been prepared via one‐step hydrothermal treatment. All the CDs have narrow size distribution, roughly spherical shape and similar optical properties. The size depends on the precursors, which varies from 2 to 25 nm. The CDs without further treatment can overcome aggregation‐induced quenching effect, and emit stable bright blue luminescence under UV light irradiation in both colloidal and solid states. Additionally, the mechanism for the solid‐state fluorescence of CDs was also explored. Moreover, the feasibility of CDs as fluorescent labels for latent fingerprint detection was investigated and the results demonstrate well‐defined papillary ridges with higher sensitivity and wider applicability. The work provides a simple, low‐cost, and promising alternative for latent fingerprint detection in forensic science.

Nanocomposites of nitrogen-doped carbon dots/hydrotalcite with enhanced solid-state fluorescence for the recognition of latent fingerprints

“…10 Jiang and co-workers 11 used polyoxyethylene sorbitan monooleate and phosphoric acid as precursors to prepare CDs via one-step carbonization for enhancing the visualization of LFPs through interactions between the long alkyl chain of the developed CDs and fatty residues of LFPs. Wang and co-workers 12 prepared solid-state photoluminescent CDs from grains with blue luminescence emission under UV light irradiation via a one-step hydrothermal process to enhance the visualization of LFPs with well-defined papillary ridges and high sensitivity. CDs exhibit great potential in the visualization and detection of LFPs; however, there are still some problems during practical applications including the interference of self-fluorescence from the background on blue-emissive CDs, 13 fluorescence quenching of solid-state CDs because of aggregation-induced quenching effects during drying, 14 and unsuitable role of CD solutions for permeable substrates.…”

ZnO@SiO2 Nanocapsules: Efficient Fluorescence for Latent Fingerprint Detection

“…From an aspirational standpoint, the aim in developing LFPs is to achieve maximum sensitivity, contrast and selectivity. [11,12] An emerging area in enhanced images of LFPs is in the use of fluorescent nanomaterials. [13][14][15][16] Compared with conventional chemical methods, fluorescent materials typically offer high sensitivity and resolution on the pigments or patterns surface.…”

“…In the meantime, the researchers have developed the enhanced imaging of LFPs dates back more than a century, and the quantity and type of those techniques has regularly multiplied. From an aspirational standpoint, the aim in developing LFPs is to achieve maximum sensitivity, contrast and selectivity [11,12] …”

Construction, Mechanism, and Forensic Application of Green-Light-Excited Fluorescent Carbon Dots/Diatomite Composites

“…Many strategies focusing on optimizing usage modes of CDs have been explored to eliminate or at least reduce the first adverse impact. So far, three modes have proved to be effective, namely, liquid-dispersed CDs, − quenching-resistant CD powders, − and CD-based composite powders. − The last mode is considered the most practical and makes up the largest part of this research direction. Based on physical (blending, absorption, or embedding) or chemical (coating or intercalation) processes, various CDs and solid matrixes including silica, silicate, starch, boron oxide, and metallic oxides have been integrated to fabricate CD-based composite powders .…”