Synthesis of D-A typed AIE luminogens in isomeric architecture and their application in latent fingerprints imaging

Among the emitters in powder dusting to visualize the latent fingerprints (LFPs), aggregation-induced emission luminogens (AIEgens) are well employed for their high brightness and resistance to photo-bleaching. However, the serious background interference and low resolution still limit their fast development. Therefore, to further enhance the signal-to-noise ratio in LFPs imaging, especially to improve the analysis for level 3 details, donor-acceptor (D-A) typed AIEgens of DTPA-2,3-P, DTPA-2,5-P and DTPA-2,6-P are designed here. It is observed that strong emission covering from 450 nm to 650 nm can be obtained for all these molecules, especially that a high PLQY value of 10.06% in solids is achieved in DTPA-2,3-P. This is much higher than that of the other two cases (0.80% and 0.51%). By utilizing the DTPA-2,3-P in powder dusting, fluorescence imaging of LFPs can be clearly captured on both smooth and rough substrates. Moreover, confocal laser scanning microscope (CLSM) enables us to achieve high-resolution LFPs imaging in both 2D and 3D views, providing more detailed information of fingerprints pores in width, distance, distribution, and shapes. The results here demonstrate that highly emissive AIEgen of DTPA-2,3-P could be an excellent candidate for the visualization of fingerprints, thus providing the potential application in criminal investigation in the future.