In this Letter, blue phosphorescence organic light-emitting diodes （PHOLEDs） employ structures for electron and/or hole confinement; 1,3,5-tris（N-phenylbenzimiazole-2-yl）benzene is used as a hole confinement layer...In this Letter, blue phosphorescence organic light-emitting diodes （PHOLEDs） employ structures for electron and/or hole confinement; 1,3,5-tris（N-phenylbenzimiazole-2-yl）benzene is used as a hole confinement layer and tris-（phenylpyrazole）iridium [Ir（ppz）3] is utilized for an electron confinement layer （ECL）. The electrical and optical properties of the fabricated blue PHOLEDs with various carrier-confinement structures are analyzed. Structures with a large ehergy offset between the carrier confinement and emitting layers enhance the charge-carrier balance in the emitting region, resulting from the effective carrier confinement. The maximum external quantum efficiency of the blue PHOLEDs with the double-ECLs is 24.02% at 1500 cd/m^2 and its luminous efficiency is 43.76 cd/A, which is 70.47% improved compared to the device without a carrier-confinement layer.展开更多
We fabricate white phosphorescent organic light-emitting diodes （PHOLEDs） with three dopants and double emissive layer （EML） to achieve color stability. The white PHOLEDs use FIrpic dopant for blue EML （B- EML）,...We fabricate white phosphorescent organic light-emitting diodes （PHOLEDs） with three dopants and double emissive layer （EML） to achieve color stability. The white PHOLEDs use FIrpic dopant for blue EML （B- EML）, and Ir（ppy）3：Ir（piq）3 dopants for green：red EML （GR-EML） with N,N＇-dicarbazolyl-3, 5-benzene （mCP） as host material. Thicknesses of B-EML and GR-EML are adjusted to form a narrow recombination zone at two EML＇s interface and charge trapping happens in EML according to wide highest occupied molecular orbital and/or lowest unoccupied molecular orbital energy band gap of mCP and smaller energy band gap of dopants. The total thickness of both EMLs is fixed at 30 nm in the device structure of ITO （150 nm）/MoO3 （2 nm）/N,N＇-diphenyl-N,N＇-bis（1-naphthyl-phenyl）-（1,1″-biphenyl）-4, 4＇-diamine （70 nm）/ meP：Firpic-8.0% （12 nm）/mCP：Ir（ppy）3-3.0%：Ir（piq）3-1.5% （18 nm）/2″,2＇,2＂＇-（1,3,5-benzinetriyl）-tris（1- phenyl-l-H-benzimidazole） （30 nm）/8-hydroxyquinolinolato-lithium （2 nm）/A1 （120 nm）. White PHOLED shows 18.25 cd/A of luminous efficiency and white color coordinates of （0.358 and 0.378） at 5000 cd/m2 and color stability with slight CIExy change of （0.028 and 0.002） as increasing luminance from 1000 to 5000 cd/m^2.展开更多
文摘In this Letter, blue phosphorescence organic light-emitting diodes （PHOLEDs） employ structures for electron and/or hole confinement; 1,3,5-tris（N-phenylbenzimiazole-2-yl）benzene is used as a hole confinement layer and tris-（phenylpyrazole）iridium [Ir（ppz）3] is utilized for an electron confinement layer （ECL）. The electrical and optical properties of the fabricated blue PHOLEDs with various carrier-confinement structures are analyzed. Structures with a large ehergy offset between the carrier confinement and emitting layers enhance the charge-carrier balance in the emitting region, resulting from the effective carrier confinement. The maximum external quantum efficiency of the blue PHOLEDs with the double-ECLs is 24.02% at 1500 cd/m^2 and its luminous efficiency is 43.76 cd/A, which is 70.47% improved compared to the device without a carrier-confinement layer.
文摘We fabricate white phosphorescent organic light-emitting diodes （PHOLEDs） with three dopants and double emissive layer （EML） to achieve color stability. The white PHOLEDs use FIrpic dopant for blue EML （B- EML）, and Ir（ppy）3：Ir（piq）3 dopants for green：red EML （GR-EML） with N,N＇-dicarbazolyl-3, 5-benzene （mCP） as host material. Thicknesses of B-EML and GR-EML are adjusted to form a narrow recombination zone at two EML＇s interface and charge trapping happens in EML according to wide highest occupied molecular orbital and/or lowest unoccupied molecular orbital energy band gap of mCP and smaller energy band gap of dopants. The total thickness of both EMLs is fixed at 30 nm in the device structure of ITO （150 nm）/MoO3 （2 nm）/N,N＇-diphenyl-N,N＇-bis（1-naphthyl-phenyl）-（1,1″-biphenyl）-4, 4＇-diamine （70 nm）/ meP：Firpic-8.0% （12 nm）/mCP：Ir（ppy）3-3.0%：Ir（piq）3-1.5% （18 nm）/2″,2＇,2＂＇-（1,3,5-benzinetriyl）-tris（1- phenyl-l-H-benzimidazole） （30 nm）/8-hydroxyquinolinolato-lithium （2 nm）/A1 （120 nm）. White PHOLED shows 18.25 cd/A of luminous efficiency and white color coordinates of （0.358 and 0.378） at 5000 cd/m2 and color stability with slight CIExy change of （0.028 and 0.002） as increasing luminance from 1000 to 5000 cd/m^2.
