Fluorescent Carbon Dots from Cassava Peel Biomass for Enhanced Latent Fingerprint Visualization

Latent fingerprint (LFP) visualization requires effective strategies to enhance ridge contrast on nonporous substrates. In this work, fluorescent carbon dots (CDs) derived from cassava peel biomass were synthesized via rapid microwave-assisted pyrolysis (360 W, 9 min) and evaluated for LFP visualization. The CDs exhibited strong blue emission at 470 nm under 365 nm excitation with a quantum yield of 31.0%. To enable practical application, the CDs were incorporated into a small particle reagent (SPR) formulation for fingerprint development. The resulting CDs-SPR system enabled clear fluorescence-assisted ridge visualization on glass substrates, with SPR serving as a particle-adhesion matrix and CDs providing the fluorescence signal. A minutiae-based evaluation demonstrated comparable or enhanced fingerprint visualization performance under UV illumination, with good repeatability across tested conditions. The method also offers rapid processing, low background interference, and operational simplicity. These results highlight the potential of biomass-derived CDs as sustainable fluorescent materials for latent fingerprint visualization.