Red emissive nanocomposite with high quantum yield for ultrasensitive and selective detection of latent fingerprints

Abstract

Level 1–3 minutiae of latent fingerprints (LFPs) play essential roles in the identification of individuals. The level 3 details of sweat pores are especially important for accurate LFPs recognition, as they can provide microscopic features. Fluorescent materials with high quantum yield and red emission are advantageous in the LFPs detection, due to the associated potential of elevated sensitivity and contrast. Herein, a highly fluorescent red emissive nanocomposite material (PPDCDs@ZIF-8) was successfully prepared by combining carbonized polymer dots of PPDCDs with zeolitic imidazolate framework ZIF-8 in situ. The obtained material displays a strong and stable red emission at solid state with the maximum peak located at 630 nm, and the fluorescence quantum yield of PPDCDs is significantly improved from 17.8% to 43.5% after conjugation with ZIF-8. This nanocomposite material was successfully applied to detect LFPs on glass, metal, marble and other substrates with ultrahigh sensitivity. The obtained fluorescent images clearly revealed the detailed LFPs features from level 1 to level 3. Therefore, PPDCDs@ZIF-8 possesses great potential applications in crime scenes as it provides an easy and accurate strategy to visual the sweat pores in LFPs.