Phosphorescent PtAu2 Complexes with Differently Positioned Carbazole–Acetylide Ligands for Solution-Processed Organic Light-Emitting Diodes with External Quantum Efficiencies of over 20%

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• 作者：Liang-Jin Xu ; Xian-Chong Zeng ; Jin-Yun Wang ; Li-Yi Zhang ; Yun Chi ; Zhong-Ning Chen
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：8
• 期：31
• 页码：20251-20257
• 全文大小：425K
• 年卷期：0
• ISSN：1944-8252

文摘

The utilization of phosphorescent metal cluster complexes as new types of emitting materials in organic light-emitting diodes (OLEDs) is becoming an alternative and viable approach for achieving high-efficiency electroluminescence. We report herein the design of cationic PtAu₂ cluster complexes with differently positioned 9-phenylcarbazole–acetylides to serve as phosphorescent emitters in OLEDs. The rigid structures of PtAu₂ complexes cause intense phosphorescence with quantum yields of over 85%, which originates from ³[π(phenylcarbazole–acetylide) → π*(dpmp)] ligand-to-ligand and ³[π(phenylcarbazole–acetylide) → p/s(PtAu₂)] ligand-to-metal charge-transfer triplet excited states. When 8 wt % PtAu₂ is doped to blended host materials of TCTA and OXD-7 (2:1 weight ratio) as light-emitting layers, solution-processed OLEDs give a current efficiency of 78.2 cd A^–1 and an external quantum efficiency (EQE) of 21.5% at a practical luminance of 1029 cd m^–2 with a slow efficiency roll-off upon increasing luminance. This represents the best device performance and the highest efficiency recorded at practical luminance for solution-processed OLEDs.