Inverted All-Inorganic Nanorod-Based Light-Emitting Diodes via Electrophoretic Deposition

High performance and high stability in all-inorganic solution processed nanocrystal-based light-emitting diodes (LEDs) are highly attractive for large area devices compared to organic material-based LEDs. In this work, an inverted all-inorganic LED structure is designed to have an easy integration with thin-film transistors. Adopting robust inorganic materials such as Ni_1-xO nanoparticle films as a hole transport layer (HTL) is beneficial for the performance of LED. Herein, we have optimized the HTL by introducing Mg into Ni_1-xO to bridge the difference in energy offset between the nanorod emissive layer and the HTL, in addition to the advantages of low temperature solubility of Ni_1-xO:Mg nanoparticles. Furthermore, CdSe/CdS-based nanorods via electrophoretic deposition (EPD) are amassed in a vertically aligned (VA-NR) fashion as an emissive layer to facilitate the carrier transportation. Fostering these approaches enabled an EQE of 1.2% of the fabricated device, establishing the viability for further development of efficient and highly stable nanocrystal-based LEDs.