AUTHOR=Li Hui , Komatsu Ryutaro , Hankache Jihane , Sasabe Hisahiro , Lawson Daku Latevi Max , Özen Bilal , Chen Songjie , Hauser Jürg , Hauser Andreas , Decurtins Silvio , Kido Junji , Liu Shi-Xia 

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

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.721272

DOI=10.3389/fchem.2021.721272

ISSN=2296-2646

ABSTRACT=<p>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 (<bold>1</bold>) and single bonds (<bold>2</bold>) respectively, or at 2,6-positions through double bonds (<bold>3</bold>). Their electronic absorption and photoluminescence properties as well as redox behaviour have been investigated in detail, indicating that the π-extended conjugation <italic>via</italic> vinyl linkers in <bold>1</bold> and <bold>3</bold> leads to comparatively strong electronic interactions between the relevant redox moieties TPA and BDF. Due to intriguing electronic properties and structural planarity, <bold>3a</bold> 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.</p>