An AIEE-active Triphenylethylene Derivative with Photoresponsive Character for Latent Fingerprints Detection via a Simple Soaking Method

Latent fingerprints (LFPs) is one of the most important physical evidence in the criminal scene, playing an important role in forensic investigations. Therefore, developing highly sensitive and convenient materials for the visualization of LFPs is of great significance. We designed and synthesized an organic fluorescent molecule TP-PH with aggregation-induced enhanced emission (AIEE) activity. By simply soaking, blue fluorescent images with high contrast and resolution are readily developed on various surfaces including tinfoil, steel, glass and plastic. Remarkably, LFPs can be visualized within 5 min including the first-, second- and tertiary-level details. In addition, TP-PH exhibits interesting photoactivated fluorescence enhancement properties. Under irradiation of 365 nm UV light with a power density of 382 mW/cm², the fluorescence quantum yield displays approximately 21.5-fold enhancement. Mechanism studies reveals that the photoactivated fluorescence is attributed to the irreversible cyclodehydrogenation reactions under UV irradiation. This work provides a guideline for the design of multifunctional AIEE fluorescent materials.