Preparation and Characterization of Carbazole-Based Luminogen with Efficient Emission in Solid and Solution States

Abstract

Organic luminescent materials with high luminescence efficiency in both solution and solid states, namely dual-state emission (DSE), have attracted considerable attention due to their promising applications in various fields. In order to enrich the variety of DSE materials, carbazole, similar to triphenylamine (TPA), was utilized to construct a novel DSE luminogen named 2-(4-(9H-carbazol-9-yl)phenyl)benzo[d]thiazole (CZ-BT). CZ-BT exhibited DSE characteristics with fluorescence quantum yields of 70, 38 and 75% in solution, amorphous and crystalline states, respectively. CZ-BT shows thermochromic and mechanochromic properties in solution and solids, respectively. Theoretical calculations show that there is a small conformational difference between the ground state and the lowest singly excited state of CZ-BT and that it exhibits a low non-radiative transition characteristic. The oscillator strength during the transition from the single excited state to the ground state reaches 1.0442. CZ-BT adopts a distorted molecular conformation with intramolecular hindrance effects. The excellent DSE properties of CZ-BT can be explained well using theoretical calculations and experimental results. In terms of application, the CZ-BT has a detection limit for the hazardous substance picric acid of 2.81 × 10−7 mol/L.

Monophenyl luminescent material with dual-state emission and pH sensitivity for cell imaging

“…The novel organic luminescent material, currently referred to as dual-state emission (DSE) luminescent materials, 17 combines the advantages of ACQ and AIE active luminescent materials and is effective in dilute solutions, at high concentrations and in the solid state. 18 The unique optical properties of DSE luminophores allow for a wide range of applications in cell imaging. 19,20 Several DSE luminophores have been developed by modification of triphenylamine, 20 phtalamides, 21 benzo[1,2,5]thiadiazole, 22 boron complexes, 23,24 and arenes et al In addition, in recent years, a number of excited-state proton transfer DSE-active luminescent materials have also been reported.…”