Covalent Organic Polymers for Rapid Fluorescence Imaging of Latent Fingerprints

Rapid, simple and highly sensitive identification of latent fingerprints (LFPs) is an important issue related to national security and recognition of potential crimes. Here, we synthesize a series of covalent organic polymers (COPs) with colorful fluorescence (from blue to green, pale yellow, bright yellow, and red) and further investigate their performance for fluorescence imaging of LFPs. Results indicate that the COP materials can be used as fluorescence probes to rapidly visualize the precision substructure of LFPs within 5 s by simply spraying method, and tunable fluorescent color makes the COP probes have a high contrast and low interference for fluorescence imaging of LFPs on different substrates (including glass slides, paper, aluminum foil, plastic, ironware) in different backgrounds. We also further reveal the mechanism of COP probes for fluorescence imaging of LFPs. Importantly, the COP probes show high stability and could successfully achieve the fluorescence imaging for LFPs after aged for 45 days or washed by water. In short, this is the first report on the porous polymers for fluorescence imaging of LFPs and expected that it can be also applied to the fluorescence imaging of other fields.