Thiol–yne crosslinked triarylamine hole transport layers for solution-processable organic light-emitting diodes

Ksenia Kutonova,Stefan Heißler,Bernd Ebenhoch,Alexander Colsmann,Stefan Bräse,Lorenz Graf Von Reventlow,Lukas Rothmann

doi:10.1039/d0tc03514a

Abstract

Formation of conjugated polymer thin-flim network by UV-triggered thiol–yne reaction of triarylamines and its use for hole transport in OLED.

Highlights

Triarylamine derivatives are widely used for hole transport in organic optoelectronic devices, but their excellent solubility in many common solvents limits their use for multi-layer device fabrication from solution
The synthesis of alkyne 3 was performed starting from tris(4-iodophenyl)amine 1, which was coupled with trimethylsilylacetylene (TMS acetylene) using the Sonogashira cross-coupling reaction,[66] followed by deprotection of the obtained tris(4-((trimethylsilyl)ethynyl)phenyl)amine 2 by tetrabutylammonium fluoride.[67]
Thin film blends of the two monomers tris(4-ethynylphenyl) amine 3 and tris(4-thiyphenyl)amine 5 were crosslinked under UV exposure, resulting in the hole-transport polymer network 6 (Scheme 2)

Summary

Introduction

Triarylamine derivatives are widely used for hole transport in organic optoelectronic devices, but their excellent solubility in many common solvents limits their use for multi-layer device fabrication from solution. We report on the synthesis of thiol- and alkyne-substituted triarylamines, the formation of conjugated crosslinked thin films and their implementation as HTLs in OLEDs followed by an analysis of performance and degradation. The thiol–yne reaction is initiated and controlled by UV exposure, it proceeds without the development of byproducts and leads to the formation of an insoluble conjugated polymer network thin film, which allows the deposition of subsequent layers from aromatic solvents.

Results

Conclusion