Detection of Latent Fingerprints with Simple AIE-Active p-Phenylenediamine Schiff Bases

Detection of latent fingerprints (LFPs) is pivotal in recognizing the individuals involved in the crime. To achieve this, many attempts have been made to obtain highly sensitive fluorophores with low adhesiveness; however, this remains a challenge. The present research explores the synthesis and application of aggregation-induced emission active phenylenediamine-based Schiff bases 3a and 3b for latent fingerprint detection. The Schiff base, exhibiting enhanced fluorescence upon aggregation, demonstrates remarkable sensitivity and selectivity towards latent fingerprints. The synthesized compounds offer a unique approach, capitalizing on the aggregation-induced enhanced emission phenomenon, providing clear and vivid visualization of latent fingerprints on various surfaces, including rubber, plastic, glass, metals, aluminum foil, and ceramics. A simple powder dusting method was utilized to visualize the latent fingerprints. This technique successfully produced high-resolution images, giving all the 1-3 levels of specifications of the developed fingerprints. The photostability of the synthesized molecule was also evaluated by checking the emission produced by the compounds after storing them for a longer period under ambient conditions. The AIE Active Phenylenediamine-based Schiff bases provide a simple tool to visualize LFPs. The CIE (x, y) coordinates for 3a and 3b were (0.416, 0.556) and (0.317, 0.452), respectively, indicating green-yellow emission under UV 365 nm illumination.