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

Abstract

Triarylamine derivatives are widely used for hole transport in organic optoelectronic devices, but their excellent solubility in many common solvents limits their use for device fabrication from solution. In this...

Construction of a fully conjugated cross-linked hole-transport film based on ethynyl to enable high mobility for efficient solution-processed OLEDs

“…37 Unfortunately, the reported ethynyl-based HTMs could not form an overall conjugated structure after cross-linking due to the non-integral conjugation of the molecule itself or the non-conjugated units introduced by the cross-linking process, resulting in low mobility and failing to meet the requirements of high-performance devices. Kutonova et al 38 used the rapid reaction of ethynyl with sulfhydryl groups to obtain a highly cross-linked polymer network. Due to the interrupted conjugation by the C–S bond and poor planarity, the hole mobility of the cross-linked film was only 2 × 10 −8 cm 2 V −1 s −1 .…”

Highly Refractive Polyimides Derived from Efficient Catalyst-Free Thiol–Yne Click Polymerization

“…28−31 In recent years, thiol−yne click polymerization has emerged as a high-efficiency technique that can fabricate highly refractive functional polymers owing to the introduction of abundant sulfur atoms. 32−34 The number of reported advanced functional polymers via thiol−yne click polymerization has increased dramatically, such as poly(vinyl sulfide)s (PVSs) with linear and hyperbranched structures 34−37 and functional elastomers, 31 while almost all have been synthesized under similar conditions that employ 2,2dimethoxy-2-phenylacetophenone or 2,2′-azobis(2-methylpropionitrile) as an initiator, 29,38 or the reaction must proceed under UV radiation 33,39 and the catalysis of organic/inorganic base or transition metal complexes, 31,35,36,40 ultimately affording polymer networks with different functionalities. These studies provide important insights into the formation of PVSs through thiol−yne click polymerization, but it still remains desirable to further simplify the experimental conditions.…”

“…Developing a powerful polymerization strategy to produce polymers with definite molecular structures and elaborate properties is the ultimate goal in polymer chemistry. Click chemistry, featured as the reactions with atom economy, high efficiency, high yield, and mild reaction conditions, has exerted a profound influence on polymer and material science since it was coined by Sharpless for the synthesis of biologically active molecules in 2001. , Among numerous click reactions, thiol-based click polymerizations have attracted recent interest because of their broad monomer scope and desirable functionalities. − In recent years, thiol–yne click polymerization has emerged as a high-efficiency technique that can fabricate highly refractive functional polymers owing to the introduction of abundant sulfur atoms. − The number of reported advanced functional polymers via thiol–yne click polymerization has increased dramatically, such as poly­(vinyl sulfide)­s (PVSs) with linear and hyperbranched structures − and functional elastomers, while almost all have been synthesized under similar conditions that employ 2,2-dimethoxy-2-phenylacetophenone or 2,2′-azobis­(2-methylpropionitrile) as an initiator, , or the reaction must proceed under UV radiation , and the catalysis of organic/inorganic base or transition metal complexes, ,,, ultimately affording polymer networks with different functionalities. These studies provide important insights into the formation of PVSs through thiol–yne click polymerization, but it still remains desirable to further simplify the experimental conditions.…”

Effect of Bis-diazirine-Mediated Photo-Crosslinking on Polyvinylcarbazole and Solution-Processed Polymer LEDs

“…Poly­(9-vinylcarbazole) (PVK), is a well-known hole-transporting material and host commonly used in polymer-based LEDs (PLEDs). − However, the application of this polymer in solution-processed devices is limited due to its relatively low hole mobility (2.5 × 10 –6 cm 2 V –1 s –1 ), the need to blend it with other materials, , and its high solubility in most halogenated and aromatic solvents that are also used to deposit common materials utilized in subsequent device layers. To circumvent the latter problem, cross-linking is a very promising strategy to convert soluble organic layers into a highly cross-linked insoluble network. − There are few cross-linking strategies previously reported in the literature, such as temperature-induced thermal cross-linking (e.g., trifluorovinylethers, , benzocyclobutenes, styrenes, , or diacetylenes), strong UV-induced (400 W mercury lamp/wavelength shorter than 280 nm 37 ) photo-cross-linking (e.g., cinnamates − or acrylates − ), or both light- and heat-mediated cross-linking (e.g., oxetane , ). All of these methods suffer from potential drawbacks such as the generation of undesirable byproducts or harsh conditions (>150 °C or <280 nm UV) required for cross-linking.…”