A high T_g small-molecule arylamine derivative as a doped hole-injection/ transport material for stable organic light-emitting diodes

摘要

High performant hole-injection materials find important applications in organic electronics. In this contribution we report a simple small-molecule organic hole-injection/transport materialN,N,N′,N′-tetra(4-methoxyphenyl)-[2,2′-binaphthalene]-6,6′-diamine for organic light-emitting diodes (OLEDs). It shows a high thermal and morphological stability with aTgof 99 °C. The ultraviolet photoelectron spectroscopy measurements reveal a favorable HOMO level of −5.05 eV p-Doping with tetrafluorotetracyanoquinodimethane (F4-TCNQ) increases the hole conductivity up to 2.64 × 10−4 S m−1vs. 1.68 × 10−4 S m−1of the neat film. The characterization of the red and green phosphorescent OLEDs suggests that introducing this thick p-doped hole-injection layer may yield high electroluminescent efficiency and operational stability. Moreover the new compound shows enhanced thermal and conducting properties and thus better performances in contrast with a conventional hole-injection materialN,N,N′,N′-tetra(4-methoxyphenyl)-[1,10-biphenyl]-4,4′- diamine (MeO-TPD) in the OLEDs.