Colloidal quantum-dot LEDs with a solution-processed copper oxide (CuO) hole injection layer

Abstract Solution-processed copper oxide (CuO) thin films are introduced as a hole injection layer (HIL) for quantum dot-based light-emitting diodes (QD-LEDs). AFM, XPS and UPS measurements are utilized for the characterization of the thermally-annealed CuO films. The optimized CuO-based QD-LEDs exhibited an external quantum efficiency (EQE) of 5.37% with a maximum brightness over 70,000 cd/m 2 . The key parameters including the current efficiency and power efficiency of CuO-based QD-LEDs are comparable to the commonly-used PEDOT:PSS-based QD-LEDs using the same structure, further demonstrating that CuO is an effective hole injection layer for QD-LED applications.