SATS@CdTe hierarchical structures emitting green to red colors developed for latent fingerprint applications

Abstract In this work, a photoluminescent fingerprint developer was prepared, based on quantum dots (QDs) stabilized by mercaptopropionic acid (MPA). CdTe-MPA QDs were synthesized in electrochemical cavity cell, with tunable optical properties. Green to red fluorescences were obtained with QY reaching 13%. The QDs were embedded to Luna® silica microspheres with surface modified by [3-(2-aminoethylamino)propyl]trimethoxysilane (SATS), yielding the SATS@CdTe composite. Luminescence was preserved after CdTe-MPA anchoring on the chemically modified silica. The hierarchical SATS@CdTe composite was successfully applied as powder dusting method for development of latent fingerprints on different non-porous surfaces, such as glass, steel and plastic, with high sensitivity and contrast. However, the developing contrast for paper (porous surface) was low, due to the unavoidable background fluorescence interference from the substrate under UV light. The results showed that the hierarchical SATS@CdTe composite has potential to be applied as developer, to enhancement of latent fingerprints, making it a candidate for forensic science application.