All-solution-processed fabrication of electroluminescent devices with stacked blue, green and red quantum dot layers

Over the past few years the performance of colloidal quantum dot-light-emitting diode (QLED) has been progressively improved. However, most of QLED work has been fulfilled in the form of monochromatic device, while full-color-capable white QLED still remains nearly unexplored. Using red, green, and blue quantum dots (QDs), herein, we for the first time demonstrate all-solution-processed fabrication of full-color QLED with an RGB-QD stacked structure. The interlayer mixing-free formation of such stacked RGB emitting layer is enabled by applying a buffer layer of ZnO nanoparticles located at the interfaces between different-colored QD layers, which effectively prevents the underlying QD layer from being damaged upon solution-processing the following another QD layer.

1. Introduction

Fascinating fluorescent properties of colloidal semiconductor quantum dots (QDs), including outstanding photoluminescent (PL) quantum yield (QY), facile emission tunability, and narrow emission bandwidth, render them suitable as visible emitters for the application to display and lighting devices. In particular, a high degree of color purity enabled by QD emission bandwidths as sharp as < 30 nm is readily obtainable, consequently expecting an excellent color gamut from QD-based display device.