Highly Efficient, Color-Reproducible Full-Color Electroluminescent Devices Based on Red/Green/Blue Quantum Dot-Mixed Multilayer

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• 作者：Ki-Heon Lee ; Chang-Yeol Han ; Hee-Don Kang ; Heejoo Ko ; Changho Lee ; Jonghyuk Lee ; NoSoung Myoung ; Sang-Youp Yim ; Heesun Yang
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：November 24, 2015
• 年：2015
• 卷：9
• 期：11
• 页码：10941-10949
• 全文大小：625K
• ISSN：1936-086X

文摘

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-enabling white QLED still remains nearly unexplored. Using red, green, and blue quantum dots (QDs), herein, we fabricate bichromatic and trichromatic QLEDs through sequential solution-processed deposition of poly(9-vinlycarbazole) (PVK) hole transport layer, two or three types of QDs-mixed multilayer, and ZnO nanoparticle electron transport layer. The relative electroluminescent (EL) spectral ratios of constituent QDs in the above multicolored devices are found to inevitably vary with applied bias, leading to the common observation of an increasing contribution of a higher-band gap QD EL over low-band gap one at a higher voltage. The white EL from a trichromatic device is resolved into its primary colors through combining with color filters, producing an exceptional color gamut of 126% relative to National Television Systems Committee (NTSC) color space that a state-of-the-art full-color organic LED counterpart cannot attain. Our trichromatic white QLED also displays the record-high EL performance such as the peak values of 23鈥?52 cd/m² in luminance, 21.8 cd/A in current efficiency, and 10.9% in external quantum efficiency.