A thermally cured 9,9-diarylfluorene-based triaryldiamine polymer displaying high hole mobility and remarkable ambient stability

Abstract

We have synthesized and characterized a novel thermally polymerizable triaryldiamine monomer (VB-FNPD) possessing a styrene-functionalized 9,9-diarylfluorene core and have used time-of-flight transient photocurrent techniques to investigate the hole transport properties of its solution-processed and subsequently thermally cured (170 °C) polymer films. This novel polymeric material exhibits non-dispersive hole transport behavior with a high hole drift mobility (up to 10⁻⁴ cm²V⁻¹ s⁻¹). The film displayed remarkable ambient stability, even when exposed to air for one month. We tested the thermally generated polymer film as a hole transport material in organic light-emitting diodes incorporating tris(8-hydroxyquinolate) aluminium (Alq₃) as the emission and electron transport layer. The device exhibited a maximum external quantum efficiency (η_ex) of 1.4%, significantly better than that of the device prepared using the corresponding model compound VB-model (η_ex = 1.1%).