New Hole Transporting Materials Based on Tetraphenylbenzene and Aromatic Amine Derivatives for OLEDs

Abstract

Three different new hole transport compounds, namely,2-[1-{4-(N,N-diphenylamino) phenyl}-3,4,5,6-tetraphenylbenzene-2-yl]5-N,N-diphenylaminopyridine(DPAP-TB), 2-[1-{4-(N-phenylnaphthalene-1-amino)phenyl}-3,4,5,6-tetraphenylbenzene-2-yl]5- (N-phenylnaphthalen-1-amino)pyridine(1-PNAP-TB) and 2-[1{4-(N-phenylnaphthal- en-1-amino)phenyl}-3,4-,5,6-tetraphenylbenzene-2-yl]-5-(N-phenylnaphthalen-2-amino)pyridine(2-PNAP-TB) were synthesized. Optical and electronic properties were examined by UV-Visible absorption spectrum and cyclic voltammetry. Luminance efficiencies and external quantum efficiencies of DPAP-TB, 1-PNAP-TB and 2-PNAP-TB were 3.72, 2.82, 3.30 cd/A, and 1.29, 0.97, 1.12% at 10 mA/cm2, respectively. Synthesized materials exhibited high Tg in the range of 118 to 133°C. These values are higher than that of NPB which is commonly used as a hole transporting material.