A preparation strategy for multicolor carbon dots embedded in silicone for latent fingermarks and detection of AcO−

Abstract

A convenient and mild method for preparing multicolor carbon dots (CDs) using the solvothermal process and extraction has been developed. After doping CDs as the cross-linking agent into γ-(2,3-epoxypropoxy)propytrimethoxysilane solution, orange, yellow, and blue emitting powders were fabricated, which effectively avoid aggregation-caused quenching and emit bright luminescence. By introducing oily chain segments, the interaction between the fluorescent powder and fingerprint residue is improved as well as the imaging ability of latent fingerprints. Level 1–3 features can be extracted using the CD powder developed fingerprints. Additionally, seven substrates with different surface appearance, colours, and interference were chosen to deposit on fingerprints, in which all the substrates have a good combination with the CD powder and showed excellent contrast and visibility. Notably, the as-prepared CDs can be used for acetate ion (AcO⁻) sensing. The CDs exhibit an efficient response to AcO⁻ by an ‘‘on–off’’ switching strategy. As a sensing probe, the CDs exhibit a wide concentration range (3 × 10⁻⁷–3 × 10⁻³ M) of response to AcO⁻ with a low fluorescence response threshold (0.3 μM).