Enhanced brightness and efficiency in organic electroluminescent devices using SiO2 buffer layers

Organic electroluminescent devices using ${\mathrm{SiO}}_{\mathrm{2}}$ as a hole-injecting buffer have been fabricated. With the presence of the buffer, the luminance of the device reaches $\text{1820\hspace{0.05em}}{\mathrm{cd/m}}^{\mathrm{2}}$ at the current density of $\text{20\hspace{0.05em}}{\mathrm{mA/cm}}^{\mathrm{2}},$ which corresponds to an efficiency of 9.1 cd/A. The enhancements in brightness and efficiency are attributed to an improved balance of hole and electron injections due to blocking of the injected holes by the buffer layer and a more homogeneous adhesion of the hole transporting layer to the anode.