Light emitting device and display device

Abstract

The present invention provides a light-emitting device and a display device. The light-emitting device includes a substrate and an active layer, a gate layer, a source-drain layer, a first electrode layer, an organic material layer, and a second electrode layer arranged above the substrate, the organic material layer is located between the first electrode layer and the second electrode layer, the second electrode layer is located on the side of the first electrode layer away from the substrate, the first electrode layer is located on the side of the source-drain layer away from the substrate, the first electrode layer and the source-drain layer are arranged in corresponding positions, the width of the source-drain layer is greater than or equal to the width of the first electrode layer, and a resonant cavity is formed between the source-drain layer and the second electrode layer. The light-emitting device and display device provided by the present invention increase the cavity length of the resonant cavity and weaken the resonant cavity effect, thereby achieving wide-spectrum emission and improving the performance of the light-emitting device.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a light-emitting device and a display apparatus. Background Art

[0002] With the rapid development of display technology, organic light-emitting diodes (OLEDs) have made qualitative leaps in material synthesis, device preparation, and process integration. OLEDs have many advantages, such as high efficiency, high brightness, high contrast, low power consumption, fast response speed, and flexible display. It can be said that OLEDs will become the most powerful competitor of the next generation of mainstream flat panel display technology. Especially in the field of active matrix displays, OLEDs have opened up a new way to achieve high-resolution, large-area, and low-power display devices.

[0003] In order to improve the aperture ratio of active-matrix organic light emitting diode (AMOLED), AMOLED usually adopts a top emission structure. Top emitting organic light emitting diode (TEOLED) has a strong microcavity effect, so it has a strong selectivity for luminescent color. Although this is beneficial to improve color purity and brightness, it will narrow the emission spectrum and make it difficult to achieve wide-spectrum emission. Therefore, the preparation of white light top emitting organic light emitting diode (TEWOLED) is a difficult point in OLED research.

[0004] In the prior art TEWOLED, a resonant cavity is formed between the anode and the cathode. Since the cavity length of the resonant cavity formed between the anode and the cathode is short, light interference is enhanced, resulting in an enhanced resonant cavity effect, which leads to a narrowing of the spectrum of the emitted light and reduces the performance of the OLED. Summary of the invention

[0005] The present invention provides a light emitting device and a display device, which are used to weaken the resonant cavity effect in the light emitting device, thereby realizing wide spectrum emission of the light emitting device and improving the performance of the light emitting device.

[0006] To achieve the above-mentioned purpose, the present invention provides a light-emitting device, including a substrate and an active layer, a gate layer, a source-drain layer, a first electrode layer, an organic material layer and a second electrode layer arranged above the substrate, the organic material layer is located between the first electrode layer and the second electrode layer, the second electrode layer is located on the side of the first electrode layer away from the substrate, the first electrode layer is located on the side of the source-drain layer away from the substrate, the first electrode layer and the source-drain layer are arranged in corresponding positions, the width of the source-drain layer is greater than or equal to the width of the first electrode layer, and a resonant cavity is formed between the source-drain layer and the second electrode layer.

[0007] Preferably, the optical path of the resonant cavity is not equal to k*2πλ, wherein k is a positive integer and λ is the wavelength of the emitted light.

[0008] Preferably, the device further comprises: a planarization layer and a passivation layer, wherein the planarization layer and the passivation layer are located between the source and drain electrode layer and the first electrode layer.

[0009] Preferably, the optical path of the resonant cavity is equal to the sum of the product of the thickness of the planarization layer and the refractive index of the planarization layer, the product of the thickness of the passivation layer and the refractive index of the passivation layer, the product of the thickness of the first electrode layer and the refractive index of the first electrode layer, and the product of the thickness of the organic material layer and the refractive index of the organic material layer.

[0010] Preferably, the source and drain layers are made of Mo or Ni.

[0011] Preferably, the material of the first electrode layer is a transparent conductive material.

[0012] Preferably, the light emitting device according to claim 1 is characterized in that the thickness of the source and drain layers is in the range of to

[0013] Preferably, the thickness of the first electrode layer is in the range of to

[0014] Preferably, the thickness of the planarization layer is in the range of to

[0015] The present invention also provides a display device, comprising the light-emitting device.

[0016] Beneficial effects of the present invention:

[0017] In the light-emitting device and display device provided by the present invention, a resonant cavity is formed between the source-drain layer and the second electrode layer, the first electrode layer and the source-drain layer are arranged in corresponding positions, and the width of the source-drain layer is greater than or equal to the width of the first electrode layer, thereby increasing the cavity length of the resonant cavity and weakening the resonant cavity effect, thereby achieving wide-spectrum emission and improving the performance of the light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a light emitting device provided in Embodiment 1 of the present invention;

[0019] Figure 2 A schematic diagram of the structure of an organic material layer in a light-emitting device provided in Embodiment 1 of the present invention;

[0020] Figure 3 A schematic diagram of the spectrum of the light-emitting device provided in the first embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the light emitting device and the display device provided by the present invention are described in detail below with reference to the accompanying drawings.

[0022] Figure 1 A schematic diagram of the structure of a light emitting device provided in Embodiment 1 of the present invention is shown in FIG. Figure 1 As shown, the light-emitting device includes a base substrate 1 and an active layer 3, a gate layer 5, a source-drain electrode layer 7, a first electrode layer 10, an organic material layer 11 and a second electrode layer 12 arranged above the base substrate 1, the organic material layer 11 is located between the first electrode layer 10 and the second electrode layer 12, the second electrode layer 12 is located on the side of the first electrode layer 10 away from the base substrate 1, the first electrode layer 10 is located on the side of the source-drain electrode layer 7 away from the base substrate 1, the first electrode layer 10 and the source-drain electrode layer 7 are arranged in corresponding positions, the width of the source-drain electrode layer 7 is greater than or equal to the width of the first electrode layer 10, and a resonant cavity is formed between the source-drain electrode layer 7 and the second electrode layer 12.

[0023] In this embodiment, the first electrode layer 10 is an anode, and the second electrode layer 12 is a cathode.

[0024] In this embodiment, preferably, the width of the source-drain electrode layer 7 is equal to the width of the first electrode layer 10 .

[0025] In this embodiment, the width of the second electrode layer 12 is equal to the width of the first electrode layer 10 .

[0026] Figure 2 for Figure 1 Schematic diagram of the structure of the organic material layer, such as Figure 2As shown, specifically, the organic material layer 11 includes: a first hole injection layer (Hole Injection Layer, HIL) 111, a second hole injection layer (Hole Injection Layer, HIL) 112, a red light emitting layer (Red Emitting Material Layer, R-EML) 113, a green light emitting layer (Green Emitting Material Layer, G-EML) 114, a first electron transport layer (Electron Transport Layer, ETL) 115, a first charge generating layer (Charge Generating Layer, CGL) 116, a third hole injection layer 117, a hole transport layer (HTL) 118, a blue light emitting layer (Blue Emitting Material Layer, B-EML) 119, a second electron transport layer 120 and a second charge generating layer 121, which are sequentially arranged on the first electrode layer 10.

[0027] Furthermore, the light emitting device further comprises a buffer layer 2 , wherein the buffer layer 2 is located on the base substrate 1 , and the active layer 3 is located on the buffer layer 2 .

[0028] Furthermore, the light emitting device further comprises a gate insulating layer 4 , the gate insulating layer 4 is located on the active layer 3 and covers the base substrate 1 , and the gate layer 5 is located on the gate insulating layer 4 .

[0029] Furthermore, the light emitting device further comprises an interlayer insulating layer 6 , which is located on the gate layer 5 and covers the base substrate 1 , and the source-drain electrode layer 7 is located on the interlayer insulating layer 6 .

[0030] Furthermore, the light emitting device further comprises a protective layer 13 , which is located on the second electrode layer 12 and covers the base substrate 1 .

[0031] Further, the light emitting device further includes: a planarization layer 8 and a passivation layer 9, and the planarization layer 8 and the passivation layer 9 are located between the source-drain electrode layer 7 and the first electrode layer 10. Specifically, the planarization layer 8 is located on the source-drain electrode layer 7, the passivation layer 9 is located on the planarization layer 8, and the first electrode layer 10 is located on the passivation layer 9.

[0032] In this embodiment, a first via hole 14 is provided in the interlayer insulating layer 6 and the gate insulating layer 4. Specifically, the first via hole 14 is located above the active layer 3 to expose a portion of the active layer 3. A portion of the source and drain layer 7 is filled in the first via hole 14 to achieve connection with the active layer 3.

[0033] In this embodiment, second via holes 15 are provided in the passivation layer 9 and the planarization layer 8. Specifically, the second via holes 15 are located on the source-drain electrode layer 7 to expose a portion of the source-drain electrode layer 7. A portion of the first electrode layer 10 is filled in the second via holes 15 to achieve connection with the source-drain electrode layer 7.

[0034] In this embodiment, the material of the source-drain electrode layer 7 is Mo or Ni. Preferably, the material of the source-drain electrode layer 7 is Mo. Since the reflectivity of Mo or Ni is low, the resonant cavity effect of the light-emitting device can be further weakened. In this embodiment, optionally, the structure of the source-drain electrode layer 7 can also be a three-layer structure, and the materials of the three-layer structure are Ti / Al / Ti in sequence.

[0035] The material of the first electrode layer 10 is a transparent conductive oxide material, preferably, the material of the first electrode layer 10 is ITO. Since the material of the first electrode layer 10 is a transparent conductive oxide material, the reflectivity of the first electrode layer 10 is further reduced, and the resonant cavity effect of the light emitting device is further weakened.

[0036] The material of the planarization layer 8 can be a polymer material with a low refractive index. Preferably, the material of the planarization layer 8 is polydimethylsiloxane (PDMS). Using a polymer material with a low refractive index as the planarization layer can further reduce the refractive index of the source and drain layer 7, thereby obtaining a metal reflective surface with a low reflectivity, thereby weakening the resonant cavity effect of the light-emitting device.

[0037] The material of the passivation layer 9 is SiNx.

[0038] The material of the second electrode layer 12 is magnesium-silver alloy (Mg:Ag). Since the second electrode layer 12 is made of Mg:Ag material, it is not necessary to form the second electrode layer 12 by sputtering technology during the preparation process, thereby avoiding the damage of the organic material layer 11 under the second electrode layer 12 by the sputtering technology, thereby simplifying the preparation process and improving the efficiency, life and yield rate of the device.

[0039] In this embodiment, the thickness range of the buffer layer 2 is to Preferably, the thickness of the buffer layer 2 is

[0040] In this embodiment, the thickness range of the active layer 3 is to Preferably, the thickness of the active layer 3 is

[0041] In this embodiment, the thickness of the gate insulating layer 4 is in the range of to Preferably, the thickness of the gate insulating layer 4 is

[0042] In this embodiment, the thickness range of the gate layer 5 is to Preferably, the thickness of the gate layer 5 is

[0043] In this embodiment, the thickness range of the interlayer insulating layer 6 is to Preferably, the thickness of the interlayer insulating layer 6 is

[0044] In this embodiment, the thickness range of the source and drain electrode layer 7 is to Preferably, the thickness of the source-drain electrode layer 7 is

[0045] In this embodiment, the thickness range of the planarization layer 8 is to Preferably, the thickness of the planarization layer 8 is

[0046] In this embodiment, the thickness range of the passivation layer 9 is to Preferably, the thickness of the passivation layer 9 is

[0047] In this embodiment, the thickness range of the first electrode layer 10 is to Preferably, the thickness of the first electrode layer 10 is

[0048] In this embodiment, preferably, the thickness of the first hole injection layer 111 is The thickness of the second hole injection layer 112 is The thickness of the red light emitting layer 113 is The thickness of the green light emitting layer 114 is The thickness of the first electron transport layer 115 is The thickness of the first charge generation layer 116 is The thickness of the third hole injection layer 117 is The thickness of the hole transport layer 118 is The thickness of the blue light emitting layer 119 is The thickness of the second electron transport layer 120 is The thickness of the second charge generation layer 121 is

[0049] In this embodiment, preferably, the refractive index of the planarization layer 8 is 1.5, the refractive index of the passivation layer 9 is 2.0, the refractive index of the first electrode layer 10 is 1.8, and the refractive index of each layer structure in the organic material layer is 1.8.

[0050] In this embodiment, the planarization layer 8 may further include a plurality of sub-planarization layers, and the refractive index of each sub-planarization layer is different. Preferably, the refractive index of each sub-planarization layer changes in a step-by-step manner or changes linearly. In practical applications, the remaining layers may also include a plurality of sub-layers, and the refractive index of each sub-layer of the remaining layers may also change in a step-by-step manner or change linearly, which will not be described in detail here.

[0051] In this embodiment, preferably, the optical path of the resonant cavity is not equal to k*2πλ, wherein k is a positive integer and λ is the wavelength of the emitted light, so that the phase change of the emitted light in the round-trip optical path between the source and drain layer 7 and the second electrode layer 12 is not equal to an integer multiple of 2π, thereby effectively weakening the resonant cavity effect of the light-emitting device.

[0052] Specifically, the optical path of the resonant cavity is equal to the sum of the product of the thickness of the flattening layer 8 and the refractive index of the flattening layer 8, the product of the thickness of the passivation layer 9 and the refractive index of the passivation layer 9, the product of the thickness of the first electrode layer 10 and the refractive index of the first electrode layer 10, and the product of the thickness of the organic material layer 11 and the refractive index of the organic material layer 11.

[0053] Specifically, Among them, D PLN8 is the thickness of the planarization layer 8, N PLN8 is the refractive index of the planarization layer 8, D PVX9 is the thickness of the passivation layer 9, N PVX9 is the refractive index D of the passivation layer 9 IT010 is the thickness of the first electrode layer 10, N ITO10 is the refractive index of the first electrode layer 10, D HIL111 is the thickness of the first hole injection layer 111, N HIL111 is the refractive index of the first hole injection layer 111, D HIL112 is the thickness of the second hole injection layer 112, N HIL112 is the refractive index of the second hole injection layer 112, D REML113 is the thickness of the red light emitting layer 113, N REML113 is the refractive index of the red light emitting layer 113, D GEML114 is the thickness of the green light emitting layer 114, N GEML114 is the refractive index of the green light emitting layer 114, D ETL115 is the thickness of the first electron transport layer 115, NETL115 is the refractive index of the first electron transport layer 115, D CGL116 is the thickness of the first charge generation layer 116, N CGL116 is the refractive index of the first charge generation layer 116, D HIL117 is the thickness of the third hole injection layer 117, N HIL117 is the refractive index of the third hole injection layer 117, D HTL118 is the thickness of the hole transport layer 118, N HTL118 is the refractive index of the hole transport layer 118, D BEML119 is the thickness of the blue light emitting layer 119, N BEML119 is the refractive index of the blue light emitting layer 119, D ETL120 is the thickness of the second electron transport layer 120, N ETL120 is the refractive index of the second electron transport layer 120, D CGL121 is the thickness of the second charge generation layer 121, N CGL121 is the refractive index of the second charge generation layer 121, k is a positive integer, and λ is the wavelength of the emitted light.

[0054] In this embodiment, if the planarization layer 8 includes a plurality of sub-planarization layers, the product of the thickness of the planarization layer 8 and the refractive index of the planarization layer 8 is equal to the sum of the products of the thickness of each sub-planarization layer and the refractive index of each sub-planarization layer. If the remaining layers of the light-emitting device in this embodiment also include a plurality of sub-layers, the product of the thickness of the remaining layers and the refractive index is equal to the sum of the products of the thickness of each sub-layer and the refractive index of each sub-layer, which will not be described in detail here.

[0055] In this embodiment, the optical path of the resonant cavity is not equal to k*2πλ by setting the refractive index of the material of each layer structure and the thickness of each layer structure arranged between the source and drain electrode layer 7 and the second electrode layer 12. Since the optical path of the resonant cavity is not equal to k*2πλ, that is, the phase change of the round-trip optical path of the emitted light between the source and drain electrode layer 7 and the second electrode layer 12 is not equal to an integer multiple of 2π, the interference of light cannot be enhanced, thereby effectively weakening the resonant cavity effect of the light-emitting device.

[0056] Figure 3 for Figure 1 Schematic diagram of the spectrum of the light-emitting device, such as Figure 3 As shown, compared with the emission spectrum of the light-emitting device in the prior art, the emission spectrum of the light-emitting device in this embodiment is wider because the resonant cavity length of the light-emitting device in this embodiment is longer and the resonant cavity effect is weaker. On the basis of weakening the resonant cavity effect, the present invention provides a light-emitting device with a stable full-band spectrum, thereby achieving wide-spectrum emission.

[0057] In the light-emitting device provided in the present embodiment, a resonant cavity is formed between the source-drain electrode layer and the second electrode layer, the first electrode layer and the source-drain electrode layer are arranged at corresponding positions, and the width of the source-drain electrode layer is greater than or equal to the width of the first electrode layer, thereby increasing the cavity length of the resonant cavity and weakening the resonant cavity effect, thereby achieving wide-spectrum emission and improving the performance of the light-emitting device; in the present embodiment, the first electrode layer adopts a transparent conductive oxide material, thereby reducing the reflectivity of the first electrode layer and further weakening the resonant cavity effect; the second electrode layer adopts a metal material, and there is no need to adopt a sputtering technology to form the second electrode layer, thereby avoiding the damage of the sputtering technology to the organic material layer under the second electrode layer, thereby simplifying the preparation process and improving the efficiency, life and yield of the device; by setting the thickness of each layer between the source-drain electrode layer and the second electrode layer and setting the refractive index of each layer structure, the optical path of the resonant cavity is not equal to k*2πλ, so the phase change of the round-trip optical path of the emitted light between the second electrode layer and the source-drain electrode layer is not an integer multiple of 2π, so that the interference effect of light cannot be enhanced, further weakening the resonant cavity effect of the light-emitting device.

[0058] Embodiment 2 of the present invention provides a light-emitting device. The light-emitting device provided in this embodiment is different from the above-mentioned embodiment 1 in that the light-emitting device provided in this embodiment does not include a passivation layer, and the planarization layer is located between the source and drain electrode layer and the first electrode layer. Specifically, the planarization layer is located on the source and drain electrode layer, and the first electrode layer is located on the planarization layer. In this embodiment, a second via hole is formed in the planarization layer to expose a portion of the source and drain electrode layer, and a portion of the first electrode layer is filled in the second via hole to achieve connection with the source and drain electrode layer.

[0059] For the rest of the description of the light emitting device in this embodiment, please refer to the above-mentioned embodiment 1, which will not be repeated here.

[0060] A third embodiment of the present invention provides a display device, which includes the light-emitting device provided by the first or second embodiment, which will not be described in detail here.

[0061] In this embodiment, preferably, the light emitting device may be a white light emitting device, and the white light emitting device may be a TEWOLED, and the display device further comprises a color filter film, which is located on the light emitting surface of the light emitting device. Specifically, an encapsulation layer is provided on the light emitting surface of the light emitting device, and the color filter film is located on the encapsulation layer.

[0062] In the display device provided by the embodiment of the present invention, a resonant cavity is formed between the source-drain electrode layer and the second electrode layer, the first electrode layer and the source-drain electrode layer are arranged in corresponding positions, and the width of the source-drain electrode layer is greater than or equal to the width of the first electrode layer, thereby increasing the cavity length of the resonant cavity and weakening the resonant cavity effect, thereby achieving wide-spectrum emission and improving the performance of the light-emitting device; in this embodiment, the first electrode layer adopts a transparent conductive oxide material, thereby reducing the reflectivity of the first electrode layer and further weakening the effect of the resonant cavity; the second electrode layer adopts a metal material, and there is no need to adopt a sputtering technology to form the second electrode layer, thereby avoiding the sputtering technology on the second electrode layer. The organic material layer below the electrode layer is destroyed, thereby simplifying the preparation process and improving the efficiency, life and yield of the device; by setting the thickness of each layer between the source and drain electrode layer and the second electrode layer and setting the refractive index of each layer structure, the optical path of the resonant cavity is not equal to k*2πλ, so the phase change of the round-trip optical path of the emitted light between the second electrode layer and the source and drain electrode layer is not an integer multiple of 2π, so that the interference effect of light cannot be enhanced, and the resonant cavity effect of the light-emitting device is further weakened; the display device provided in this embodiment realizes wide-spectrum emission of the light-emitting device and improves the performance of the light-emitting device and the display device.

[0063] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A light emitting device, comprising a substrate and an active layer, a gate layer, a source-drain layer, a first electrode layer, an organic material layer, and a second electrode layer arranged above the substrate, wherein the organic material layer is located between the first electrode layer and the second electrode layer, and the second electrode layer is located on a side of the first electrode layer away from the substrate, characterized in that: The first electrode layer is located on a side of the source-drain layer away from the substrate, the first electrode layer and the source-drain layer are arranged in corresponding positions, the width of the source-drain layer is greater than or equal to the width of the first electrode layer, a resonant cavity is formed between the source-drain layer and the second electrode layer, and the optical path of the resonant cavity is not equal to k*2πλ, where k is a positive integer and λ is the wavelength of the emitted light; The light emitting device further includes a gate insulating layer and an interlayer insulating layer.

2. The light emitting device according to claim 1, characterized in that: Also includes: A planarization layer and a passivation layer, wherein the planarization layer and the passivation layer are located between the source and drain electrode layer and the first electrode layer.

3. The light emitting device according to claim 2, characterized in that: The optical path of the resonant cavity is equal to the sum of the product of the thickness of the planarization layer and the refractive index of the planarization layer, the product of the thickness of the passivation layer and the refractive index of the passivation layer, the product of the thickness of the first electrode layer and the refractive index of the first electrode layer, and the product of the thickness of the organic material layer and the refractive index of the organic material layer.

4. The light emitting device according to claim 1, characterized in that: The material of the source and drain layers is Mo or Ni.

5. The light emitting device according to claim 1, characterized in that: The material of the first electrode layer is a transparent conductive material.

6. The light emitting device according to claim 1, characterized in that: The thickness range of the source and drain layer is to 7. The light emitting device according to claim 1, characterized in that: The thickness of the first electrode layer is in the range of to 8. The light emitting device according to claim 2, characterized in that: The thickness of the planarization layer is in the range of to 9. A display device, characterized in that: include: A light emitting device as claimed in any one of claims 1 to 8.

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