The effect of C60 doping on the electroluminescent performance of organic light-emitting devices

Organic light-emitting devices (OLEDs) with the PVK hole transport layer were fabricated. The effect of C60 doping in the hole transport PVK layer on the performance of the devices was investigated by changing the C60 content from 0 to 3.0 wt%. The OLEDs had a structure of ITO/PEDOT:PSS/PVK:C60 (0, 0.5, 1.0, 2.0, 3.0 wt%)/AlQ/LiF/Al. The doping led to a higher conductivity in C60-doped PVK layer and the hole mobility of PVK was improved from 4.5x10-7 to 2.6x10-6 cm2/Vs with the doping concentration of C60 changing from 0 to 3.0 wt%. Moreover, the doping led to a high density of equilibrium charges carriers, which facilitated hole injection and transport. Doping of C60 in PVK resulted in efficient hole injection and low drive voltage at high luminance