Tunable emission in aggregated T-Shaped 2H-Benzo[d][1,2,3]triazoles with waveguide behaviour

Abstract

Symmetrical Donor-Acceptor-Donor (D-A-D) 2H-benzo[d][1,2,3]triazole derivatives have been designed by DFT calculations and prepared by a multistep synthetic protocol. The design strategy involved the identification of a suitable acceptor benzotriazole core and modification of the steric volume and donor strength of the branches in order to modulate the Intramolecular Charge Transfer (ICT) process and, consequently, the band gap. Self-assembly of the reported triazoles afforded organized supramolecular structures, the morphologies of which were visualized by SEM imaging. The outcomes demonstrated the effect that the donor moiety has on the emission properties and the morphologies of the aggregates. The aggregates that had a crystal-like structure, with smooth surfaces and flat end facets, exhibited optical waveguide behaviour with tunable colour emission. Depending on the initial design, the different emission wavelengths are related to the band gap of the benzotriazole derivatives.