A novel fluorene derivative containing four triphenylamine groups: Highly thermostable blue emitter with hole-transporting ability for organic light-emitting diode (OLED)

Four triphenylamine groups-substituted fluorene with rather high glass transition temperature, Tg, of 165 °C, was prepared and employed together with TPD as a composite hole-transporting layer to give a device with very low turn-on voltage and high efficiency. When a hole block layer was fabricated, the new compound can be used as a light-emitting layer for OLED to give a device emitting blue color.