All-Solution-Processed Inverted Quantum-Dot Light-Emitting Diodes

Quantum dots are a promising new candidate for the emissive material in light-emitting devices for display applications. The fabrication of such devices by solution processing allows considerable cost reduction and is therefore very attractive for industrial manufacturers. We report all solution-processed colloidal quantum-dot light-emitting diodes (QLEDs) with an inverted structure. The red, green, and blue devices showed maximum luminances of 12 510, 32 370, and 249 cd/m(2) and turn-on voltages of 2.8, 3.6, and 3.6 V, respectively. We investigate the effect of a surfactant addition in the hole injection layer (HIL), with the aim of facilitating layer deposition and thereby enhancing device performance. We demonstrate that in the device structure presented in this study, a small amount of surfactant in the HIL can significantly improve the performance of the QLED.