Enhanced efficiency of white polymer light-emitting diodes with inorganic nanodots

Enhanced efficiency of white polymer light-emitting diodes (PLEDs) was observed by incorporating polysilicic acid (PSA) nanodots into the hole-injection layer (HIL). The PLEDs employed three different phosphorescent dyes in a single emissive layer with a host polymer of poly(vinylcarbazole) (PVK). The optimal composition of the phosphorescent dyes has been found to accomplish the white emission. By incorporating 1.5 wt% of PSA nanodots into the HIL, the maximum efficiency has been found to increase about 65%, from 13.7 cd/A to 22.9 cd/A. This remarkable improvement in efficiency may be attributed to the introduction of the PSA nanodots, which leads to the better carrier balance in the PLEDs.