OLEDs utilizing direct injection to the triplet state
First Claim
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1. An organic light emitting device comprising:
- a) an anode;
b) a cathode;
c) an emissive layer disposed between the anode and the cathode, the emissive layer comprisingi) a phosphorescent dopant having a phosphorescent dopant HOMO energy level, a phosphorescent dopant LUMO energy level, a triplet energy, and a singlet energy; and
ii) an emissive layer host having an emissive layer host HOMO energy level and an emissive layer host LUMO energy level; and
d) a transport layer disposed adjacent to the emissive layer, the transport layer comprising a first material having a first material HOMO energy level and a first material LUMO energy level, wherein electrons and holes introduced into the emissive layer have an energy difference less than the energy required to form a singlet on the dopant, such that the energy difference is sufficient for formation of triplets on the dopant and energetically unfavorable for formation of singlets on the dopant.
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Abstract
The present invention relates to OLEDs utilizing direct injection to the triplet state. The present invention also relates to OLEDs utilizing resonant injection and/or stepped energy levels.
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Citations
10 Claims
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1. An organic light emitting device comprising:
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a) an anode; b) a cathode; c) an emissive layer disposed between the anode and the cathode, the emissive layer comprising i) a phosphorescent dopant having a phosphorescent dopant HOMO energy level, a phosphorescent dopant LUMO energy level, a triplet energy, and a singlet energy; and ii) an emissive layer host having an emissive layer host HOMO energy level and an emissive layer host LUMO energy level; and d) a transport layer disposed adjacent to the emissive layer, the transport layer comprising a first material having a first material HOMO energy level and a first material LUMO energy level, wherein electrons and holes introduced into the emissive layer have an energy difference less than the energy required to form a singlet on the dopant, such that the energy difference is sufficient for formation of triplets on the dopant and energetically unfavorable for formation of singlets on the dopant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An organic light emitting device, comprising:
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a) an anode; b) a cathode; c) an emissive layer disposed between the anode and the cathode, the emissive layer comprising i) a phosphorescent dopant having a phosphorescent dopant HOMO energy level, a phosphorescent dopant LUMO energy level, a triplet energy, and a singlet energy; and ii) an emissive layer host having an emissive layer host HOMO energy level and an emissive layer host LUMO energy level; and d) a transport layer disposed adjacent to the emissive layer, wherein the transport layer comprising comprises a plurality of materials, each material having a HOMO energy level and a LUMO energy level, wherein at least one energy level of each of the plurality of materials together form a series of energy steps leading to at least one energy level in the emissive layer, wherein each step in the series of energy steps is no more than 0.2 eV.
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Specification