title: Phosphorescent PtAu2 Complexes with Differently Positioned Carbazole-Acetylide Ligands for Solution-Processed Organic Light-Emitting Diodes with External Quantum Efficiencies of over 20.
abstract: 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.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Liang-Jin
authors.initials: LJ
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Xian-Chong
authors.initials: XC
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Jin-Yun
authors.initials: JY
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Li-Yi
authors.initials: LY
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Low Carbon Energy Research Center, National Tsing Hua University , Hsinchu 30013, Taiwan.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chi
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors.forename: Zhong-Ning
authors.initials: ZN
authors.lastname: Chen
keywords: electroluminescence; gold; organic light-emitting diode; phosphorescence; platinum; solution process