Stable blue phosphorescent organic light emitting devices
First Claim
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1. An organic light emitting device, comprising:
- an anode;
a cathode;
an emissive layer disposed between the anode and the cathode, the emissive layer including a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm;
whereinthe phosphorescent emissive dopant is deposited from a source that has a purity in excess of 99.5% as determined by high pressure liquid chromatography, the source further having a combined concentration of halide and metal impurities below 100 ppm;
the phosphorescent emissive dopant leaves a residue corresponding to less than 5 wt % of the original charge in the sublimation crucible; and
the phosphorescent emissive dopant has a sublimation temperature less than 350°
C. and is deposited via sublimation;
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 <
600 nm;
the phosphorescent emissive dopant comprises a cyclometallated N,C-donor imidazophenanthridine ligand comprising at least one 2,2,2-trialkylethyl substituent.
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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.
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Citations
25 Claims
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1. An organic light emitting device, comprising:
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an anode; a cathode; an emissive layer disposed between the anode and the cathode, the emissive layer including a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm; wherein the phosphorescent emissive dopant is deposited from a source that has a purity in excess of 99.5% as determined by high pressure liquid chromatography, the source further having a combined concentration of halide and metal impurities below 100 ppm; the phosphorescent emissive dopant leaves a residue corresponding to less than 5 wt % of the original charge in the sublimation crucible; and the phosphorescent emissive dopant has a sublimation temperature less than 350°
C. and is deposited via sublimation;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 <
600 nm;the phosphorescent emissive dopant comprises a cyclometallated N,C-donor imidazophenanthridine ligand comprising at least one 2,2,2-trialkylethyl substituent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification