Don′t sweat it: “Negative” fingermarks are developed on paper by the application of gold nanoparticles (gold circles) that are capped by a bifunctional ligand, and then silver precipitation. In this process, paper is the substrate and the fingermarks serve as a mask. This approach may contribute to the successful recovery of latent fingermarks by law enforcement agencies.

No abstract

Preis ohne Schweiß: „Negative“ von Fingerabdrücken lassen sich auf Papier mithilfe von Goldnanopartikeln (Kreise) mit einem difunktionellen Liganden und anschließende Silberabscheidung gewinnen. Dabei ist das Papier das Substrat und der Fingerabdruck die Maske. Die Unterschiede in der Schweißzusammensetzung individueller Personen spielen keine Rolle, sodass dieser Ansatz zur Entdeckung latenter Fingerabdrücke für Behörden nützlich sein könnte.

Gold nanoparticles, AuNPs, capped with mercaptocarboxylic acids followed by silver precipitation develop latent fingermarks on paper as high quality "negative" impressions. This effect stems from hydrogen bonding between the carboxylic group and the paper cellulose and may improve the yield of latent fingermarks since the results are less dependent on sweat composition.

The calculations of polarization diagrams of photoluminescence for pair centres in azincblende lattice, e.g. donor-acceptorpairs, are presented. Theclassical dipoleapproximation is applied for three types of pair spectra. The extreme values of the polarization diagram are expressed via coordinates of the corresponding pair centre in a lattice. I1 is possible to identify the different typesof pair spectra and to provide enumeration ofthe pairs from their polarization characteristics. The calculations represent a theoretical basis for the new method of selectively excited polarized luminescence of pair lines.