KR-102962650-B1 - Light emitting device having improved light emitting efficiency and display apparatus including the light emitting device

Abstract

An organic electroluminescent device and an organic electroluminescent display device having enhanced luminous efficiency are disclosed. The disclosed luminescent device comprises: a reflective layer; a first electrode disposed on the reflective layer; a second electrode disposed facing the first electrode; a partially transparent mirror disposed between the first electrode and the second electrode; a first light-emitting layer disposed between the first electrode and the partially transparent mirror; and a second light-emitting layer disposed between the partially transparent mirror and the second electrode; wherein the partially transparent mirror may be disposed such that a first-order or higher resonance mode is formed between the reflective layer and the partially transparent mirror and a second-order or higher resonance mode is formed between the reflective layer and the second electrode.

Inventors

• 주원제
• 구현
• 최아정

Assignees

• 삼성전자주식회사

Dates

Publication Date

20260507

Application Date

20210303

Claims (20)

1. Reflective layer; A first electrode disposed on the above-mentioned reflective layer; A second electrode positioned facing the first electrode; A partially transparent mirror disposed between the first electrode and the second electrode; A first light-emitting layer disposed between the first electrode and the partial transmission mirror; A second light-emitting layer disposed between the partial transmission mirror and the second electrode; and A transparent conductive layer disposed between the above-mentioned partial transmission mirror and the above-mentioned second light-emitting layer; comprising, The above transparent conductive layer comprises at least one transparent conductive oxide among ITO, IZO, and AZO, and The first light-emitting layer and the second light-emitting layer emit light of the same wavelength, and A light-emitting element in which the partial transmission mirror is arranged such that a first-order or higher resonance mode is formed between the reflective layer and the partial transmission mirror, and a second-order or higher resonance mode is formed between the reflective layer and the second electrode.
2. In Article 1, A light-emitting device, wherein the first electrode is a transparent electrode and the second electrode is a partially transparent electrode that reflects a portion of light and transmits a portion.
3. In Article 1, A light-emitting element in which the reflective layer and the second electrode form a microcavity having a resonant wavelength, and the partial transmission mirror is located at the node of the light wave resonating within the microcavity.
4. In Article 1, The above-mentioned partial transmission mirror is a light-emitting element made of silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy.
5. In Article 4, A light-emitting device having a thickness of 5 nm to 30 nm for the partial transmission mirror.
6. In Article 5, A light-emitting element in which the thickness of the second electrode and the thickness of the partial transmission mirror are different.
7. In Article 1, The first light-emitting layer above is: A first hole transport layer disposed on the first electrode; A first organic light-emitting material layer disposed on the first hole transport layer; and A first electron transport layer disposed on the first organic light-emitting material layer; comprising The second light-emitting layer above is: A second hole transport layer disposed on the above-mentioned partial transmission mirror; A second organic light-emitting material layer disposed on the second hole transport layer; and A light-emitting device comprising: a second electron transport layer disposed on the second organic light-emitting material layer.
8. delete
9. In Article 1, The light-emitting element further comprises a charge-generating layer disposed between the first light-emitting layer and the second light-emitting layer.
10. In Article 1, The light-emitting element further includes a third light-emitting layer disposed between the second light-emitting layer and the second electrode, and The above-mentioned partial transmission mirror comprises a first partial transmission mirror disposed between the first light-emitting layer and the second light-emitting layer, and a second partial transmission mirror disposed between the second light-emitting layer and the third light-emitting layer, forming a light-emitting element.
11. In Article 10, A light-emitting element in which the first and second partial transmission mirrors are arranged such that a first resonance mode is formed between the reflective layer and the first partial transmission mirror, a second resonance mode is formed between the reflective layer and the second partial transmission mirror, and a third resonance mode is formed between the reflective layer and the second electrode.
12. In Article 11, A light-emitting element, wherein the reflective layer and the second electrode form a microcavity having a resonant wavelength, the first partial transmission mirror is located at a first node of the light wave resonating within the microcavity, and the second partial transmission mirror is located at a second node of the light wave resonating within the microcavity.
13. Reflective layer; A first electrode disposed on the above-mentioned reflective layer; A second electrode positioned facing the first electrode; A phase correction layer disposed between the first electrode and the second electrode; A first light-emitting layer disposed between the first electrode and the phase correction layer; A second light-emitting layer disposed between the phase correction layer and the second electrode; A first partial transmission mirror disposed between the phase correction layer and the first light-emitting layer; and A second partial transmission mirror disposed between the phase correction layer and the second light-emitting layer; comprising A light-emitting element in which the first and second partial transmission mirrors are arranged such that a first or higher resonance mode is formed between the reflective layer and the first partial transmission mirror and a second or higher resonance mode is formed between the reflective layer and the second electrode.
14. In Article 13, A light-emitting device, wherein the first electrode is a transparent electrode and the second electrode is a partially transparent electrode that reflects a portion of light and transmits a portion.
15. In Article 13, A light-emitting element, wherein the reflection layer and the second electrode form a microcavity having a resonant wavelength, and the phase correction layer is located at the node of the light wave resonating within the microcavity.
16. In Article 13, A light-emitting element in which the reflective layer, the second electrode, the first partial transmission mirror, and the second partial transmission mirror cause phase modulation greater than 180 degrees with respect to reflected light.
17. In Article 13, A light-emitting device in which the above-mentioned phase correction layer is made of a transparent conductive material.
18. In Article 17, A light-emitting device having a phase correction layer thickness of 5 nm to 150 nm.
19. In Article 13, The light-emitting element, wherein the first and second portions of the transmission mirror are made of silver (Ag), aluminum (Al), a silver alloy, or an aluminum alloy.
20. In Article 19, A light-emitting device having thicknesses of the first and second partial transmission mirrors of 5 nm to 30 nm.

Description

Light emitting device having improved light emitting efficiency and display apparatus including the light emitting device The disclosed embodiments relate to a light-emitting element and a display device including the same, and more specifically, to an organic electroluminescent element and an organic electroluminescent display device having improved light-emitting efficiency. An organic light emitting device (OLED) is a display device that forms an image by emitting light through the combination of holes supplied from an anode and electrons supplied from a cathode within an organic light-emitting layer. Such organic light emitting devices can exhibit excellent display characteristics such as a wide viewing angle, fast response speed, thin thickness, low manufacturing cost, and high contrast. Furthermore, by selecting a suitable material as the organic light-emitting layer material in an organic electroluminescent device, it is possible to emit a desired color. Based on this principle, it is possible to realize a color display device using an organic electroluminescent device. FIG. 1 is a cross-sectional view schematically showing the structure of a light-emitting element according to one embodiment. Figure 2 is a conceptual diagram showing the microcavity structure of the light-emitting element illustrated in Figure 1. FIGS. 3a and 3b exemplarily show the resonance modes of the microcavity of the light-emitting element shown in FIG. 1. FIG. 4 is a cross-sectional view schematically showing the structure of a light-emitting element according to another embodiment. FIG. 5 is a cross-sectional view schematically showing the structure of a light-emitting element according to another embodiment. Figure 6 is a conceptual diagram showing the microcavity structure of the light-emitting element illustrated in Figure 5. FIGS. 7a to 7c exemplarily show the resonance modes of the microcavity of the light-emitting element shown in FIG. 5. FIG. 8 is a graph that exemplarily shows the change in the luminescence characteristics of a light emitter according to the resonance order in the light-emitting element shown in FIG. 5, compared with comparative examples. FIG. 9 is a graph that exemplarily shows the change in the light emission characteristics of a light-emitting element according to the resonance order in the light-emitting element shown in FIG. 5, compared with comparative examples. FIG. 10 is a cross-sectional view schematically showing the structure of a light-emitting element according to another embodiment. FIG. 11 is a cross-sectional view schematically showing the structure of a light-emitting element according to another embodiment. FIGS. 12a to 12c exemplarily show the resonance modes of the microcavity of the light-emitting element shown in FIG. 11. FIG. 13 exemplarily shows the change in the resonance wavelength of the second resonator according to the change in the thickness of the phase correction layer in the light-emitting element shown in FIG. 11. FIG. 14 is a graph that exemplarily shows the change in the luminescence characteristics of a light emitter according to the resonance order in the light-emitting element shown in FIG. 11, compared with comparative examples. FIG. 15 is a conceptual diagram showing the microcavity structure of a light-emitting element according to another embodiment. FIG. 16 is a cross-sectional view schematically showing the structure of a light-emitting element according to another embodiment. FIG. 17 is a cross-sectional view schematically showing the structure of a display device according to one embodiment. Hereinafter, a light-emitting element having enhanced luminous efficiency and a display device including the same will be described in detail with reference to the attached drawings. In the drawings below, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, the embodiments described below are merely illustrative, and various modifications are possible from these embodiments. In the following, terms designated as "upper" or "upper" may include not only those directly above in contact but also those above non-contact. Singular expressions include multiple expressions unless the context clearly indicates otherwise. Furthermore, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. The use of the term "for example" and similar descriptive terms may apply to both the singular and the plural. Unless there is an explicit description of the order of the steps constituting the method, these steps may be performed in a suitable order and are not necessarily limited to the described order. Additionally, terms such as "...part," "module," etc., as described in the specification refer to a unit that processes at leas