Disilanyl Double-Pillared Bisanthracene: A Bipolar Carrier Transport Material for Organic Light-Emitting Diode Devices

摘要

The first direct-current electroluminescent material, anthracene, has been the cornerstone molecule for organic electronics. The first reports on the electroluminescence with single crystals of anthracene demonstrated the potential use of organic molecules as emission materials as well as hole- and electron-transport materials. Vacuum deposition of anthracene also paved the way for thin-film devices functioning at a low driving voltage (ca. 30 V) albeit at a low quantum efficiency (ca. 0.05%) and low substrate temperature (ca. —50°C). However, the molecule was quickly replaced with aryl amine derivatives for the hole-transport layer (HTL), such as N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (α-NPD) and with tris(8-hydroxyquinoline)alu-minum (Alq3) for the electron-transport layer (ETL) after the discovery of layered organic light-emitting diodes (OLEDs) with superior performance and stability. Although several derivatives for the emission layer (EML) were accumulated by varying functional groups at the 9- and 10-positions,the further application of anthracene derivatives as carrier transport materials in layered OLEDs has been rarely explored, despite the renewed interest in these materials for thin-film organic field-effect transistors (OFETs). We report herein on the design and synthesis of an anthracene derivative, disilanyl double-pillared bisanthracene (~(Si)DPBA, 1, Scheme 1), which effectively functions as a bipolar carrier transport material in OLEDs. The device performance using ~(Si)DPBA as both an HTL and ETL material is reasonably high and highlights a new strategy for the molecular design of organic electronic materials.