Overcoming ACQ: DPA-modified TICT-type AIEgens for high-resolution and multilevel latent fingerprint visualization
Liangxin Fan, Xinxin Zhu, Wanjin Wu, Xingxiao Wang, Sheng Zhang, Jingwei Wan, Song Jiang, Lin Lü, Haoyu Gao, Jinjin Wang, Zhanqi Cao, Zhenliang Pan, Zhihong Xu, Lijie Liu · Materials Horizons · 2025
Latent fingerprints (LFPs), as critical carriers of personal identification information, present a long-standing challenge for high-resolution imaging in forensic science. Aggregation-induced emission luminogens (AIEgens), known for their superior luminescence in aggregated or high-viscosity environments, have emerged as ideal candidates for high-contrast fingerprint visualization. In this study, we designed a series of novel AIEgens by introducing diphenylamine (DPA) donor groups at the 3- and 11-positions of a quinazolinone core, effectively constructing twisted intramolecular charge transfer (TICT) systems. This design strategy successfully transformed traditional aggregation-caused quenching (ACQ) behavior into pronounced AIE characteristics. The resulting molecules exhibit intense blue fluorescence, ultralong phosphorescence lifetimes, and a distinct "turn-on" fluorescence response in the presence of lipids secreted by eccrine glands. These features enable high-resolution visualization of level 1-3 fingerprint details on various smooth substrates, offering a promising approach for sensitive and nondestructive fingerprint identification.