Bright-blue electroluminescence from a silyl-substituted ter-(phenylene–vinylene) derivative

A bright-blue electroluminescent device has been fabricated by using an emissive dopant and an electron-transporting host. The dopant was a highly photoluminescent silyl-substituted ter-(phenylene–vinylene) derivative [1,4-bis[4-(2-trimethylsilylvinly) styryl]-2,5-dibutoxybenzene (BTSB)]. BTSB was doped into a trimer of N-arylbenzimidazoles (TPBI) which functioned as the host and electron transporter. ${\mathrm{N,N}}^{\mathrm{\prime }}{\mathrm{-bis-(1-naphthyl)-N,N}}^{\mathrm{\prime }}{\mathrm{-diphenyl-1,1}}^{\mathrm{\prime }}{\mathrm{-biphenyl-4-4}}^{\mathrm{\prime }}\mathrm{-diamine}$ (NPB) was used as the hole transporter. The device, with a structure of indium tin oxide\NPB\TPBI:10%BTSB\TPBI\Mg:Ag, shows a bright blue emission of $\text{11000\hspace{0.05em}}{\mathrm{cd/m}}^{\mathrm{2}}$ at a current density of $\text{360\hspace{0.05em}}{\mathrm{mA/cm}}^{\mathrm{2}}.$ The current efficiency of this device is about 3.2 cd/A at $\text{20\hspace{0.05em}}{\mathrm{mA/cm}}^{\mathrm{2}}.$