Highly Efficient Blue鈥揋reen Quantum Dot Light-Emitting Diodes Using Stable Low-Cadmium Quaternary-Alloy ZnCdSSe/ZnS Core/Shell Nanocrystals

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• 作者：Huaibin Shen ; Sheng Wang ; Hongzhe Wang ; Jinzhong Niu ; Lei Qian ; Yixing Yang ; Alexandre Titov ; Jake Hyvonen ; Ying Zheng ; Lin Song Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：May 22, 2013
• 年：2013
• 卷：5
• 期：10
• 页码：4260-4265
• 全文大小：426K
• 年卷期：v.5,no.10(May 22, 2013)
• ISSN：1944-8252

文摘

High-quality blue鈥揼reen emitting Zn_xCd_1鈥?i>xS_1鈥?i>ySe_y/ZnS core/shell quantum dots (QDs) have been synthesized by a phosphine-free method. The quantum yields of as-synthesized Zn_xCd_1鈥?i>xS_1鈥?i>ySe_y/ZnS core/shell QDs can reach 50鈥?5% with emissions between 450 and 550 nm. The emissions of such core/shell QDs are not susceptible to ligand loss through the photostability test. Blue-green light-emitting diodes (LEDs) based on the low-cadmium Zn_xCd_1鈥?i>xS_1鈥?i>ySe_y/ZnS core/shell QDs have been successfully demonstrated. Composite films of poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB) and ZnO nanoparticle layers were chosen as the hole-transporting and the electron-transporting layers, respectively. Highly bright blue鈥揼reen QD-based light-emitting devices (QD-LEDs) showing maximum luminance up to 10000 cd/m², in particular, the blue QD-LEDs show an unprecedentedly high brightness over 4700 cd/m² and peak external quantum efficiency (EQE) of 0.8%, which is the highest value ever reported. These results signify a remarkable progress in QD-LEDs and offer a practicable platform for the realization of QD-based blue鈥揼reen display and lighting.

Keywords:

ZnCdSSe/ZnS; alloy; core/shell; blue鈭抔reen; QD-LEDs; electroluminescence