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KR-20260065789-A - ENERGY LEVELS AND DEVICE STRUCTURES FOR PLASMONIC OLEDS

KR20260065789AKR 20260065789 AKR20260065789 AKR 20260065789AKR-20260065789-A

Abstract

An organic light-emitting device is provided that includes a host structure having electron and/or hole transport components having specific energy levels that promote excellent charge balance and enhanced charge trapping. The disclosed energy level structure provides a host system that intentionally includes exciplex formation to promote improved internal quantum efficiency and stability of the device by reducing exciplex formation, or to modify the mean orientation of the dipoles.

Inventors

  • 퓨셀라 마이클
  • 톰슨 니콜라스 제이

Assignees

  • 유니버셜 디스플레이 코포레이션

Dates

Publication Date
20260511
Application Date
20260428
Priority Date
20211015

Claims (14)

  1. As an organic light-emitting device, Substrate; A first electrode disposed on a substrate; A light-emitting stack disposed on a first electrode and comprising the following: A first organic light-emitting layer (EML) comprising one or more host materials and an organic light-emitting material; and Hole blocking layer (HBL), electron blocking layer (EBL), or both; A second electrode placed on a light-emitting stack; and The first enhancement layer comprises a plasmonic material that non-radiatively couples to an organic light-emitting material of an organic light-emitting layer and exhibits surface plasmon resonance, which transfers excited state energy from the organic light-emitting material to a non-radiative mode of surface plasmon polaritons of the enhancement layer; Here, the light-emitting stack is, The luminescence stack includes an EBL in which the highest occupied molecular orbital (HOMO) energy level is within 0.4 eV of the HOMO energy level of the organic luminescent material; The light-emitting stack comprises an EBL whose triplet energy is less than or equal to the triplet energy of at least one of one or more host materials; The luminescent stack comprises an HBL in which the lowest unoccupied molecular orbital (LUMO) energy level is within 0.3 eV of at least one of one or more host materials; At least one of one or more host materials forms an exciplex with an organic light-emitting material; The luminescent stack comprises an HTL in which the HOMO energy level is 0.5 eV or less of at least one of one or more host materials; E ET ≤ |HOMO Emitter - LUMO EML | + δ, where E ET is the lowest triplet energy level among all matter in the EML, LUMO EML is the deepest LUMO among all matter in the EML, and δ is at least 0.01 eV. An organic light-emitting device that meets one or more of the criteria.
  2. A device according to claim 1, wherein one or more host materials comprise an electron-transport material.
  3. A device according to claim 1, wherein one or more host materials comprise a hole-transport material.
  4. A device according to paragraph 3, wherein one or more host materials comprise an electron-transport material.
  5. A device according to claim 1, wherein the light-emitting stack comprises an EBL having a highest occupied molecular orbital (HOMO) energy level within 0.4 eV of the HOMO energy level of the organic light-emitting material.
  6. A device according to claim 1, wherein the light-emitting stack comprises an EBL having a triplet energy of at least one triplet energy or less of one of the one or more host materials.
  7. A device according to claim 1, wherein the light-emitting stack comprises an HBL having at least one of one or more host materials having a lowest unoccupied molecular orbital (LUMO) energy level within 0.3 eV.
  8. A device according to claim 1, wherein at least one of the one or more host materials forms an exciplex with an organic light-emitting material.
  9. A device according to claim 1, wherein the light-emitting stack comprises an HTL having at least one HOMO energy level of 0.5 eV or less among one or more host materials.
  10. A device according to claim 1, wherein E ET ≤ |HOMO emitter - LUMO EML | + δ, where E ET is the lowest triplet energy level among all materials in the EML, LUMO EML is the deepest LUMO among all materials in the EML, and δ is at least 0.01 eV.
  11. In claim 10, the device is one in which δ is at least 0.11 eV.
  12. In claim 11, a device in which δ is at least 0.21 eV.
  13. In paragraph 1, E ET ≤ |HOMO EML - LUMO EML | + δ, wherein E ET is the lowest triplet energy level among all matter in the EML, LUMO EML is the deepest LUMO among all matter in the EML, HOMO EML is the shallowest HOMO among all matter in the EML, and δ is at least 0.01 eV; The organic light-emitting material is a device having the shallowest HOMO within the EML.
  14. In paragraph 1, E ET ≤ |HOMO EML - LUMO EML | + δ, wherein E ET is the lowest triplet energy level among all matter in the EML, LUMO EML is the deepest LUMO among all matter in the EML, HOMO EML is the shallowest HOMO among all matter in the EML, and δ is at least 0.01 eV; A device in which one or more host materials have the shallowest HOMO within the EML.

Description

Energy Levels and Device Structures for Plasmonic OLEDs Cross-reference regarding related applications This application claims the benefit of priority of U.S. Patent Application No. 63/093,987 filed on October 20, 2020, the entire contents of which are incorporated herein by reference. field The present invention relates to an organic light-emitting device, such as an organic light-emitting diode, having a plasmon enhancement layer and a related structure, and to a device and technique including the same. Optoelectronic devices using organic materials are becoming increasingly important for various reasons. Since many of the materials used to manufacture such devices are relatively inexpensive, organic optoelectronic devices have potential in terms of cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, make them highly suitable for specific applications, such as fabrication on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic phototransistors, organic photocells, and organic photodetectors. In the case of OLEDs, organic materials can have performance advantages over conventional materials. For example, the wavelength at which the organic light-emitting layer emits light can generally be easily controlled with a suitable dopant. OLEDs use organic thin films that emit light when voltage is applied across the device. OLEDs are a technology that is becoming increasingly important for applications such as flat panel displays, lighting, and backlighting. Various OLED materials and compositions are described in U.S. Patents No. 5,844,363, 6,303,238, and 5,707,745, the full text of which is incorporated herein by reference. One application of phosphorescent emitting molecules is full-color displays. Industrial standards for such displays require pixels tuned to emit specific colors referred to as "saturated" colors. Specifically, these standards require saturated red, green, and blue pixels. Alternatively, OLEDs can be designed to emit white light. In conventional liquid crystal displays, emissions from a white backlight are filtered using absorption filters to produce red, green, and blue emissions. The same technique can also be applied to OLEDs. White OLEDs can be single EML devices or stacked structures. Color can be measured using CIE coordinates known in the art. As used herein, the term “organic” includes not only polymeric materials that can be used to fabricate organic optoelectronic devices, but also small molecule organic materials. “Small molecule” refers to any organic material that is not a polymer, and “small molecule” can actually be quite large. Small molecules may contain repeating units in some situations. For example, using a long-chain alkyl group as a substituent does not exclude the molecule from the “small molecule” type. Small molecules may also be incorporated into the polymer, for example, as pendant groups on the polymer main chain or as part of the main chain. Small molecules may also act as the core moiety of a dendrimer, which consists of a series of chemical shells formed on the core moiety. The core moiety of the dendrimer may be a fluorescent or phosphorescent small molecule emitter. A dendrimer may be a “small molecule,” and all dendrimers currently used in the OLED field are considered to be small molecules. As used herein, "top part" means furthest from the substrate, and "bottom part" means closest to the substrate. If the first layer is described as being "placed on top of" the second layer, the first layer is placed far from the substrate. If the first layer is not specified as being "in contact" with the second layer, other layers may exist between the first layer and the second layer. For example, even if various organic layers exist between the cathode and the anode, the cathode may be described as being "placed on top of" the anode. As used herein, "solution processability" means that it can be dissolved, dispersed, or transported in a liquid medium in the form of a solution or suspension, or can be deposited from a liquid medium. If a ligand is considered to directly contribute to the photoactive properties of a luminescent material, the ligand may be referred to as "photoactive." If a ligand is considered not to contribute to the photoactive properties of the luminescent material, even though an auxiliary ligand may alter the properties of the photoactive ligand, the ligand may be referred to as "auxiliary." As used herein and as generally understood by those skilled in the art, when the first energy level is closer to the vacuum energy level, the first "highest occupied molecular orbital (HOMO)" or "lowest unoccupied molecular orbital (LUMO)" energy level is "greater" or "higher" than the second HOMO or LUMO energy level. Since the ionization potential (IP) is measured as negative energy with respect to the vacuum level, a highe