Three distinct concentration-dependent chromophores of non-traditional intrinsic luminescence: The mechanism and special properties

Non-traditional intrinsic luminescence (NTIL) have presented many unique properties, which are quite different from traditional fluorescent materials. In this work, using non-aromatic amines, we found three distinct fluorescent peaks at 400 nm, 440 nm and 500 nm, respectively, in a concentration increasing process. The direct proofs obtained from NMR and other techniques suggested that these peaks might originate from different concentration-dependent aggregates. On the other hand, our results well explained the weird phenomena that NTIL systems presented the excitation-dependent fluorescence (EDF) or excitation-independent fluorescence (EIF) in various cases. We proposed a strategy to prepare fluorescent systems with unique property of tunable emission and controllable EDF or EIF, which would be useful in multi-color imaging applications. • For amine-containing NTIL systems, three concentration-dependent fluorescent peaks were firstly detected, which varied from one to another in a “peak-jump” mode. • Simple aliphatic amines (i.e., TETA) were adopted to prove that the fluorescence might originate from three kinds of concentration-dependent aggregates. • Our results explained the prolonged puzzle that amine-containing NITL systems presented the excitation-dependent/independent fluorescence in different circumstances. • A strategy was proposed to explore applications of multi-color fluorescent imaging based on the unique properties of NTIL.