Stable blue phosphorescent organic light emitting devices
First Claim
1. A method depositing an emissive layer for an organic light emitting device, comprising:
- providing a source of a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm in a sublimation crucible having an original charge, whereinthe phosphorescent emissive dopant comprises a cyclometallated N,C-donor imidazophenanthridine ligand comprising at least one 2,2,2 trialkylethyl substituent;
the source has a purity in excess of 99.5% as determined by high pressure liquid chromatography;
the source further has a combined concentration of halide and metal impurities below 100 ppm; and
the source being sufficiently pure that a residue corresponding to less than 5 wt % of the original charge in the sublimation crucible remains after the original charge is decreased; and
depositing the phosphorescent emissive dopant via sublimation, along with a host, whereinthe phosphorescent emissive dopant is deposited in an environment having less than 10 ppm oxygen, and in the near absence of light having a wavelength less than 600 nm.
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Abstract
Novel combination of materials and device architectures for organic light emitting devices are provided. In some aspects, specific charge carriers and solid state considerations are features that may result in a device having an unexpectedly long lifetime. In some aspects, emitter purity is a feature that may result in devices having unexpectedly long lifetime. In some aspects, structural and optical considerations are features that may result in a device having an unexpectedly long lifetime. In some aspects, an emissive layer including an organic phosphorescent emissive dopant and an organic carbazole host material results in devices having an unexpectedly long lifetime.
44 Citations
7 Claims
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1. A method depositing an emissive layer for an organic light emitting device, comprising:
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providing a source of a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm in a sublimation crucible having an original charge, wherein the phosphorescent emissive dopant comprises a cyclometallated N,C-donor imidazophenanthridine ligand comprising at least one 2,2,2 trialkylethyl substituent; the source has a purity in excess of 99.5% as determined by high pressure liquid chromatography; the source further has a combined concentration of halide and metal impurities below 100 ppm; and the source being sufficiently pure that a residue corresponding to less than 5 wt % of the original charge in the sublimation crucible remains after the original charge is decreased; and depositing the phosphorescent emissive dopant via sublimation, along with a host, wherein the phosphorescent emissive dopant is deposited in an environment having less than 10 ppm oxygen, and in the near absence of light having a wavelength less than 600 nm. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification
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- Resources
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Current AssigneeUniversal Display Corporation
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Original AssigneeUniversal Display Corporation
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InventorsD'Andrade, Brian, Mackenzie, Peter B., Weaver, Michael S., Brown, Julia J.
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Primary Examiner(s)Leong, Nathan T
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Application NumberUS14/023,345Publication NumberTime in Patent Office987 DaysField of SearchNoneUS Class Current1/1CPC Class CodesH10K 2101/10 Triplet emissionH10K 2101/30 Highest occupied molecular ...H10K 50/11 characterised by the electr...H10K 50/18 Carrier blocking layersH10K 71/10 Deposition of organic activ...H10K 71/311 Purifying organic semicondu...H10K 85/342 comprising iridiumH10K 85/657 Polycyclic condensed hetero...H10K 85/6572 comprising only nitrogen in...
