▎ 摘　　要

We fabricated organic light emitting diodes (OLEDs) with PdCo alloy nanoparticles supported on polypropylenimine dendrimer-grafted graphene (PdCo/PPI-g-G) that was doped at different concentrations (0, 0.02, 0.03, 0.06 and 2 wt%) in a poly(3,4-ethylene dioxythiophene): polystyrene sulfonic acid (PEDOT:PSS) as a host layer. PdCo PPI-g-G and PEDOT:PSS were studied as hole injection layers in OLEDs. The efficiency of hole injection from the anode is strongly dependent on the concentration of the PdCo/PPI-g-G. While a graphene oxide and pure PEDOT:PSS layer leads to higher driving voltage and decreased luminescence efficiency. PdCo/PPI-g-G of 0.02 wt% noticeably enhanced the hole injection and resulted in lower turn-on voltage, increased luminance, and current efficiencies. The 0.02 wt% PdCo/PPI-g-G based device has also a luminance of 3705 cd/m(2) and maximum efficiency of 1.9 cd/A at 13 V which are the highest values among other PdCo/ PPI-g-G based devices.