The effectiveness of CdSe nanoparticle suspension for developing latent fingermarks

Abstract

Utilization of CdSe nanoparticle suspension for latent fingermarks on a multitude of non-porous and semi-porous surfaces has been demonstrated in this paper. Whether it is dark or light, the color of adhesives has no effect on the results of developing, because of the strong fluorescence excited by irradiation with UV LEDs. Enough contrast could be obtained for imaging. As an effective stabilizer for suspension which is commonly used in fingermark developing, Tween 20 with different concentration was also applied for better results. However, it did not work for nanometer-sized particles, which have already been stable in suspension. To broaden the scope of its application, different excitation systems were adopted. Well-contrast images could be obtained when 365 nm UV light, 440 nm blue light and daylight were applied. TiO2 SPR (small particle reagent) and gentian violet were used to compare with CdSe nanoparticle suspension under daylight. The results indicated that it produced significantly less background development and better contrast.

Keywords

• CdSe nanoparticle suspension
• Latent fingermark development
• TiO2 SPR
• Excitation system