Fluorescent variant of silica nanoparticle powder synthesised from rice husk for latent fingerprint development

Abstract

Background: Fingerprint, though still remains one of the best possible means of individual identification, is often lost during the recovery process. The successful utilisation of developed fingerprint for identification relies on the contrast between the ridges and substrate which allows for the minutiae recognition and characterisation. However, the contrast is difficult to be achieved on challenging or difficult surfaces such as reflective, multicoloured and patterned materials. Methodology: Silica nanoparticles (SNP) were synthesised from rice husk using thermochemical treatment and incorporated with natural dyes. The photoluminescence of the powders was recorded and characterised using field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis and forensic alternative light source. The effectiveness of three fluorescent variant of the SNP powders and commercial fluorescent powder (CFP) was investigated by developing latent fingerprints deposited on different multicoloured substrates. Results: Spherical fluorescent silica nanoparticles were successfully synthesised from rice husk. Characterisation studies of coloured silica nanoparticles showed amorphous spherical silica nanoparticle with a mean particle size of approximately 200 nm. Silica nanoparticle doped with curcumin pigment exhibited strongest fluorescence and good stability when exposed to heat and aged at room temperature. The efficiency of the coloured silica nanoparticle was not compromised by the dye doping process as determined using electron microscope and surface tests on various surfaces. Conclusion: Findings demonstrated that fluorescent silica powder synthesised from rice husk and curcumin dye extract exhibited good photoluminescence and hence providing sufficient contrast for the fingerprint analysis on difficult and challenging surfaces. Additionally, the spherical mono-dispersed nanoparticles enhanced the clarity and selectivity of the powder.