Study on synthesis and properties of novel luminescent hole transporting materials based on N,N′-di(p-tolyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine core

Four novel blue luminescent hole transporting materials with N,N'-di(p-tolyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine as the core, containing triphenylamine units and olefinic linkers were synthesized and characterized by FT-IR, H-1 NMR and HRMS. Their optical, electrochemical and thermal properties were investigated. Quantum-chemical calculations were performed to obtain their optimized structures and the electron distribution of the molecular orbital energy levels, and the experimental findings suggest that monosubstituted compounds have a similar energy gap to the bisubstituted compounds. The UV-Vis and photoluminescence spectra indicate that these compounds are blue luminescent materials. Cyclic voltammetry measurements show that the four compounds embody suitable highest occupied molecular orbital levels (in a range of -5.08 similar to -5.14 eV) for hole injection. All of the compounds have excellent thermal stability, with decomposition temperatures above 400 degrees C and glass transition temperatures above 100 degrees C, which is of benefit to form stable amorphous glassy states. (C) 2012 Elsevier Ltd. All rights reserved.