Red, green, and blue quantum dot LEDs with solution processable ZnO nanocrystal electron injection layers

ZnO nanocrystals are presented as an electron injection layer for red, green, and blue light-emitting diodes (LEDs) based on core–shell CdSe/ZnS quantum dots (QDs). The deposition of ZnO nanocrystals from isopropanol permits fabricating multilayer QD-LEDs that include both hole and electron transport layers by simple solution processing. The ZnO nanocrystals improve electron injection in the light-emitting QD layer as evidenced from a decreased turn-on voltage and a reduction of emission originating from other layers than the QD layer of the LEDs.