Tunable-emission and AIPE-active heteroleptic Ir(iii) complexes for fingermark detection via a spraying technique

Latent fingermark detection has been a high profile issue in the field of identity authentication. In the present work, three cationic heteroleptic Ir(iii) complexes with the same ancillary ligand (N^N) and different cyclometalated ligands (C^N) were designed and synthesized. The complexes exhibited different solid-state emission colors and aggregation-induced phosphorescent emission (AIPE) properties, all of which could be tuned by modifying the substituent and conjugation groups. Additionally, owing to excellent AIPE and lipophilicity properties, these complexes were also used to detect partial and aged latent fingermarks on vertical surfaces and porous paper, obtaining clearly-defined third level details.