title: N-heterocyclic carbazole-based hosts for simplified single-layer phosphorescent OLEDs with high efficiencies.
abstract: Highly efficient single-layer organic light-emitting diodes (OLEDs) are demonstrated using new N-heterocyclic carbazole-based host materials. Phosphorescent OLEDs with a structure of ITO/MoO(3) /host/host:dopant/host/Cs(2) CO(3) /Al are fabricated in which the new materials act simultaneously as electron-transport, hole-transport, and host layer. Devices with maximum current and external quantum efficiencies of 92.2 cd A(-1)  and 26.8% are achieved, the highest reported to date for a single-layer OLED.
authors.affiliation: Department of Chemistry, Queen's University, Kingston, Ontario, Canada.
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Hudson
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Wang
authors.forename: Michael G
authors.initials: MG
authors.lastname: Helander
authors.forename: Zheng-Hong
authors.initials: ZH
authors.lastname: Lu
authors.forename: Suning
authors.initials: S
authors.lastname: Wang
mesh_terms: D000535:Aluminum / Q000737:chemistry; D002227:Carbazoles / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D002586:Cesium / Q000737:chemistry; D018360:Crystallography, X-Ray; D004579:Electron Transport; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D011789:Quantum Theory; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D002227:Carbazoles; D002254:Carbonates; D010087:Oxides; D017971:Tin Compounds; C041514:carbazole; D002586:Cesium; C082290:molybdenum trioxide; C109984:indium tin oxide; D008982:Molybdenum; D000535:Aluminum; C545311:cesium carbonate