Bis(Triphenylamine)Benzodifuran Chromophores: Synthesis, Electronic Properties and Application in Organic Light-Emitting Diodes

Abstract

A series of bis(triphenylamine)benzodifuran chromophores have been synthesized and fully characterised. Starting from suitably functionalized benzodifuran (BDF) precursors, two triphenylamine (TPA) moieties are symmetrically coupled to a central BDF unit either at 4,8-positions through double bonds (1) and single bonds (2) respectively, or at 2,6-positions through double bonds (3). Their electronic absorption and photoluminescence properties as well as redox behaviour have been investigated in detail, indicating that the π-extended conjugation via vinyl linkers in 1 and 3 leads to comparatively strong electronic interactions between the relevant redox moieties TPA and BDF. Due to intriguing electronic properties and structural planarity, 3a has been applied as a dopant emitter in organic light-emitting diodes. A yellowish-green OLED exhibits a high external quantum efficiency (EQE) of 6.2%, thus exceeding the theoretical upper limit most likely due to energy transfer from an interface exciplex to an emissive layer and/or favorable horizontal orientation.

Buchwald–Hartwig Amination of Aryl Halides with Heterocyclic Amines in the Synthesis of Highly Fluorescent Benzodifuran-Based Star-Shaped Organic Semiconductors

“…Benzodifurans ( BDFs ), due to their p-type organic semiconductor properties, excellent light absorption and emission capability, and high hole mobility, are a group of compounds with a great potential application as luminescent and electroluminescent materials. − In addition, they are much less studied compared to benzodithiophenes widely used in optoelectronics. The appropriate molecular design of the BDF -based semiconductors allows for their application in many fields, including molecular switches and electrical regulators, − high-affinity fluorescent probes, potential therapeutic agents, dye-sensitized solar cell sensitizers, − polymer materials in polymer solar cells, − organic solar cells, , organic thin-film transistor materials, , and different layers in organic light-emitting diodes (LEDs). − …”