High Efficiency Electron Transfer Layer based on Ag-Al Co-Doped ZnS in Organic Lighting Emission Devices

Electron transmission improvement in organic light-emitting devices with Ag-Al co-doped ZnS has been demonstrated. The electroluminescence (EL) of device with co-doped ZnS electron transfer layer (ETL) is more than that of devices without ETL and the co-doped ZnS ETL device performs higher EL compared to pure ZnS ETL device. The using of co-doped ZnS can reduce the thickness of ETL from 40 nm to 8 nm and performs comparable efficiency and higher EL. According to the PL spectra studies and current density-voltage characters, the improved electron transmission is attributed to the introduction of impurity energy level and the increased concentration of electron.