An organic light-emitting diode device and a display panel

Abstract

The present invention discloses an organic light-emitting diode device and a display panel. The organic light-emitting diode device includes: a first electrode layer, a first light-emitting layer, an intermediate layer, a second light-emitting layer, and a second electrode layer that are sequentially stacked; wherein, the intermediate layer at least includes a first transition layer and a second transition layer; in a first direction, the first transition layer and the second transition layer are sequentially stacked between the first light-emitting layer and the second light-emitting layer; the host material doped in the first transition layer is the same as the first host material of the first light-emitting layer; the host material doped in the second transition layer is the same as the second host material of the second light-emitting layer; wherein, the first direction is the direction from the first electrode layer to the second electrode layer. The present invention provides an organic light-emitting diode device and a display panel, which can improve the transmission rates of holes and electrons, avoid the annihilation of electrons or holes, balance charge transport, and enhance the light-emitting brightness of the device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of optoelectronic devices, and in particular, to an organic light-emitting diode device and a display panel. Background Art

[0002] An organic light-emitting diode (OLED) device, also known as an organic electroluminescent diode device, has attracted wide attention due to its advantages of self-luminescence, rich colors, fast response speed, wide viewing angle, light weight, thin thickness, low power consumption, and flexible display, etc., and has broad market and application prospects.

[0003] The basic structure of an organic light-emitting diode device is a sandwich structure composed of an anode, a cathode, and an organic layer located between the anode and the cathode. The organic layer is usually composed of one or two or more light-emitting layers with complementary light colors. When a voltage is applied to the organic light-emitting diode device, the holes output from the anode and the electrons output from the cathode need to travel a certain distance to reach the opposite light-emitting layer. The transport of holes and electrons occurs at the interface of the light-emitting layer, which easily causes the annihilation of electrons or holes, resulting in an imbalance between holes and electrons, and the device efficiency deteriorates, thus affecting the light-emitting brightness of the device. Summary of the Invention

[0004] The present invention provides an organic light-emitting diode device and a display panel, which can improve the transport rate of holes and electrons, avoid the annihilation of electrons or holes, balance charge transport, and enhance the light-emitting brightness of the device.

[0005] In a first aspect, embodiments of the present invention provide an organic light-emitting diode device, including: a first electrode layer, a first light-emitting layer, an intermediate layer, a second light-emitting layer, and a second electrode layer, which are sequentially stacked;

[0006] Wherein, the intermediate layer at least includes a first transition layer and a second transition layer; in a first direction, the first transition layer and the second transition layer are sequentially stacked between the first light-emitting layer and the second light-emitting layer; the host material doped in the first transition layer is the same as the first host material of the first light-emitting layer; the host material doped in the second transition layer is the same as the second host material of the second light-emitting layer; wherein, the first direction is the direction from the first electrode layer to the second electrode layer.

[0007] Optionally, the intermediate layer at least includes one intermediate transition layer;

[0008] The intermediate transition layer is arranged between the first transition layer and the second transition layer; the host material doped in the intermediate transition layer is a mixed material of the first host material and the second host material;

[0009] Along the first direction, the proportion of the first main material of the intermediate transition layer decreases successively; along the second direction, the proportion of the second main material of the intermediate transition layer decreases successively; wherein, the second direction is the direction from the second electrode layer to the first electrode layer.

[0010] Optionally, the intermediate layer includes one layer of the intermediate transition layer;

[0011] The intermediate transition layer is disposed between the first transition layer and the second transition layer, and the doping ratio of the first main material and the second main material in the main material doped in the intermediate transition layer is 1:1.

[0012] Optionally, the thickness of the first transition layer is 1.5 nm, the thickness of the second transition layer is 3 nm, and the thickness of the third transition layer is 1.5 nm.

[0013] Optionally, the thickness of the intermediate layer is less than or equal to 10 nm.

[0014] Optionally, the organic light-emitting diode device further includes an electron transport layer, a hole blocking layer, an electron blocking layer, a hole transport layer, and a hole injection layer;

[0015] The first electrode layer, the hole injection layer, the hole transport layer, the electron blocking layer, the first light-emitting layer, the intermediate layer, the second light-emitting layer, the hole blocking layer, the electron transport layer, and the second electrode layer are sequentially stacked.

[0016] Optionally, the materials of the first electrode layer and the second electrode layer are at least one of a metal, a metal oxide, and a polymer.

[0017] Optionally, the first light-emitting layer is a monochromatic light-emitting layer or a mixed-color light-emitting layer; the second light-emitting layer is a mixed-color light-emitting layer or a monochromatic light-emitting layer.

[0018] Optionally, the organic light-emitting diode device further includes a third light-emitting layer; the third light-emitting layer is in contact with the first light-emitting layer or the second light-emitting layer.

[0019] In a second aspect, an embodiment of the present invention provides a display panel, at least including the organic light-emitting diode device according to any one of the embodiments of the present invention.

[0020] The technical solution provided by the embodiment of the present invention is to arrange an intermediate layer between the first light-emitting layer and the second light-emitting layer. The intermediate layer at least includes a first transition layer and a second transition layer. The material doped in the first transition layer is the same as the first host material of the first light-emitting layer, and the material doped in the second transition layer is the same as the second host material of the second light-emitting layer. By using the first transition layer and the second transition layer, the transport rate of holes and electrons is increased, so that holes or electrons can quickly jump to the adjacent transition layer and then be transported to the interface of the light-emitting layer by the transition layer, avoiding the annihilation of electrons or holes, balancing the charge transport, and thus improving the light-emitting brightness of the device. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of an organic light-emitting diode device provided by an embodiment of the present invention.

[0022] Figure 2 It is a schematic structural diagram of another organic light-emitting diode device provided by an embodiment of the present invention.

[0023] Figure 3 It is a schematic structural diagram of another organic light-emitting diode device provided by an embodiment of the present invention. Detailed Embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Figure 1 It is a schematic structural diagram of an organic light-emitting diode device provided by an embodiment of the present invention. Refer to Figure 1 , including: a first electrode layer 110, a first light-emitting layer 120, an intermediate layer 130, a second light-emitting layer 140, and a second electrode layer 150 that are sequentially stacked;

[0026] Among them, the intermediate layer 130 at least includes a first transition layer and a second transition layer; in the first direction A, the first transition layer 131 and the second transition layer 132 are sequentially stacked between the first light-emitting layer 120 and the second light-emitting layer 140; the host material doped in the first transition layer 131 is the same as the first host material of the first light-emitting layer 120; the host material doped in the second transition layer 132 is the same as the second host material of the second light-emitting layer 140; wherein, the first direction A is the direction from the first electrode layer 110 to the second electrode layer 150.

[0027] Specifically, a first light-emitting layer 120, an intermediate layer 130, and a second light-emitting layer 140 are sequentially stacked between the first electrode layer 110 and the second electrode layer 150. The direction from the first electrode layer 110 to the second electrode layer 150 is the first direction A. Among them, the first light-emitting layer 120 is in contact with the first electrode layer 110, and the second light-emitting layer 140 is in contact with the second electrode layer 150.

[0028] Exemplarily, the first electrode layer 110 and the second electrode layer 150 are disposed relatively parallel to each other. Electrons and holes are combined in the first light-emitting layer 120 and the second light-emitting layer 140 to excite corresponding colored light. Among them, the first electrode layer 110 can be an anode, and the second electrode layer 150 is a cathode. Or, the second electrode layer 150 is an anode, and the first electrode layer 110 is a cathode.

[0029] The first light-emitting layer 120 and the second light-emitting layer 140 are doped with different host materials respectively. Electrons and holes can excite lights of different colors in the first light-emitting layer 120 and the second light-emitting layer 140 respectively. After mixing the lights, white light with a certain brightness can be obtained. The host materials doped in the first light-emitting layer 120 and the second light-emitting layer 140 can be light-emitting materials for red light, blue light or green light. In the embodiments of the present invention, the host material of the first light-emitting layer 120 is called the first host material, and the host material of the second light-emitting layer 140 is called the second host material. A first transition layer 131 and a second transition layer 132 are stacked between the first light-emitting layer 120 and the second light-emitting layer 140. One side of the first transition layer 131 is in contact with the first light-emitting layer 120, and one side of the second transition layer 132 is in contact with the second light-emitting layer 140. The host material doped in the first transition layer 131 is the same as the first host material of the first light-emitting layer 120, and the host material doped in the second transition layer 132 is the same as the second host material of the second light-emitting layer 140. Exemplarily, in the embodiments of the present invention, taking the first electrode layer 110 as the anode and the second electrode layer 150 as the cathode as an example, the first host material of the first light-emitting layer 120 is a hole-biased host material, and the second host material of the second light-emitting layer 140 is an electron-biased host material. By using the first transition layer 131 and the second transition layer 132 to reduce the transport barriers of holes and electrons, after the cathode and the anode are respectively powered on, electrons are injected into the second light-emitting layer 140 through the cathode. A part of the electrons are injected into the first light-emitting layer 120 through the second transition layer 132 and the first transition layer 131. Holes are injected into the first light-emitting layer 120 through the anode. A part of the holes are injected into the second light-emitting layer 140 through the first transition layer 131 and the second transition layer 132. Electrons and holes recombine in their respective light-emitting layers to emit light. That is to say, by doping the same host material as the first host material of the first light-emitting layer 120 in the first transition layer 131 and doping the same host material as the second host material of the second light-emitting layer 140 in the second transition layer 132, the transport rates of holes and electrons are increased, so that holes or electrons can quickly jump to the adjacent transition layer, and then be transported to the light-emitting layer interface by the transition layer, balancing the charge transport, thereby improving the light-emitting brightness of the device.

[0030] The technical solution provided by the embodiments of the present invention is to set an intermediate layer between the first light-emitting layer and the second light-emitting layer. The intermediate layer at least includes a first transition layer and a second transition layer. The material doped in the first transition layer is the same as the first host material of the first light-emitting layer, and the material doped in the second transition layer is the same as the second host material of the second light-emitting layer. By using the first transition layer and the second transition layer, the transport barriers of holes and electrons are reduced, the transport rates of holes and electrons are increased, so that holes or electrons can quickly jump to the adjacent transition layer, and then be transported to the light-emitting layer interface by the transition layer, avoiding the annihilation of electrons or holes, balancing the charge transport, thereby improving the light-emitting brightness of the device.

[0031] Figure 2 This is a schematic structural diagram of another organic light-emitting diode device provided by an embodiment of the present invention. Refer to Figure 2 , the intermediate layer 130 includes at least one intermediate transition layer 133;

[0032] An intermediate transition layer 133 is provided between the first transition layer 131 and the second transition layer 132; the host material doped in the intermediate transition layer 133 is a mixed material of a first host material and a second host material;

[0033] Along the first direction A, the proportion of the first host material in the intermediate transition layer 133 decreases successively; along the second direction B, the proportion of the second host material in the intermediate transition layer 133 decreases successively; wherein, the second direction B is the direction from the second electrode layer 150 to the first electrode layer 110.

[0034] Specifically, at least one intermediate transition layer 133 may be provided between the first transition layer 131 and the second transition layer 132. The host material doped in the intermediate transition layer 133 is a mixed material of the first host material and the second host material. Exemplarily, the first host material is selected as a blue host material, and the second host material is selected as a green host material. Then, the first transition layer 131 is also doped with the blue host material, the second transition layer 132 is doped with the green host material, and three intermediate transition layers 133 are provided between the first transition layer 131 and the second transition layer 132. The doping material of the intermediate transition layer 133 is a mixed material of the blue host material and the green host material. The proportion of the blue host material in the intermediate transition layer 133 adjacent to the first transition layer 131 is relatively large, and along the first direction A, the proportion of the blue host material in each intermediate transition layer 133 decreases in sequence. Similarly, the proportion of the green host material in the intermediate transition layer 133 adjacent to the second transition layer 132 is relatively large, and along the second direction B, the proportion of the green host material in each intermediate transition layer 133 decreases in sequence. For the sake of illustration, exemplarily, the proportion of the blue host material in the first transition layer 131 is 1, then the ratio of the blue host material to the green host material in the first intermediate transition layer 210 adjacent to the first transition layer 131 is 3:1, the ratio of the blue host material to the green host material in the second intermediate transition layer 220 is 1:1, the ratio of the blue host material to the green host material in the third intermediate transition layer 230 is 1:3, and the proportion of the green host material in the second transition layer 132 is 1. Through the gradient concentration mixing change of the first transition layer 131, the intermediate transition layer 133, and the second transition layer 132, the transport barriers of holes and electrons are further reduced, the transport rates of holes and electrons are increased, and the charge transport is balanced, thereby improving the light emission brightness of the device. It should be noted that the colors of the host materials of the first light-emitting layer 120 and the second light-emitting layer 140, as well as the number of layers and specific mixing ratios of the intermediate transition layer 133, are only for illustrative purposes and are not specifically limited.

[0035] Figure 3 This is a schematic structural diagram of another organic light-emitting diode device provided by an embodiment of the present invention. Refer to Figure 3 , the intermediate layer 130 includes one intermediate transition layer 133;

[0036] The intermediate transition layer 133 is disposed between the first transition layer 131 and the second transition layer 132, and the doping ratio of the first host material and the second host material in the host material doped in the intermediate transition layer 133 is 1:1.

[0037] Specifically, the intermediate layer 130 includes an intermediate transition layer 133, so the structure of the intermediate layer 130 is a stacked structure of a first transition layer 131, an intermediate transition layer 133 and a second transition layer 132, and the doping material of the intermediate transition layer 133 is a mixture of a first main material and a second main material, wherein the mixing ratio is 1:1. The first transition layer 131, the intermediate transition layer 133 and the second transition layer 132 are used to reduce the transmission barrier of holes and electrons. After the cathode and the anode are energized respectively, electrons are injected into the second light-emitting layer 140 through the cathode, and a portion of electrons are injected into the first light-emitting layer 120 through the second transition layer 132, the intermediate transition layer 133 and the first transition layer 131, holes are injected into the first light-emitting layer 120 through the anode, and a portion of holes are injected into the second light-emitting layer 140 through the first transition layer 131, the intermediate transition layer 133 and the second transition layer 132, and the electrons and holes are recombined in their respective light-emitting layers to emit light.

[0038] In the test experiment of equal voltage brightness, the middle layer 130 is set to a single-layer structure and doped with a single main material as the first comparison group, and the middle layer 130 is set to a single-layer structure and doped with the first main material and the second main material as the second comparison group. In this embodiment, the structure of the middle layer 130 is a stacked structure of a first transition layer 131, an intermediate transition layer 133 and a second transition layer 132. The first transition layer 131 is the first main material, the intermediate transition layer 133 is a mixture of the first main material and the second main material, and the mixing ratio is 1:1. The second transition layer 132 is the second main material. According to the experimental results, the brightness of this embodiment is>12000cd / m 2 , compared with the first comparison group and the second comparison group, the brightness is improved.

[0039] Optionally, the overall thickness of the intermediate layer 130 is less than or equal to 10 nm. When the structure of the intermediate layer 130 is a stacked structure of a first transition layer 131, an intermediate transition layer 133, and a second transition layer 132, preferably, the thickness of the first transition layer 131 is 1.5 nm, the thickness of the intermediate transition layer 133 is 3 nm, and the thickness of the third transition layer is 1.5 nm.

[0040] Continue to see Figure 1 , Figure 2 and Figure 3 Optionally, the organic light emitting diode device further includes an electron transport layer 310, a hole blocking layer 320, an electron blocking layer 350, a hole transport layer 340 and a hole injection layer 330;

[0041] The first electrode layer 110, the hole injection layer 330, the hole transport layer 340, the electron blocking layer 350, the first light-emitting layer 120, the intermediate layer 130, the second light-emitting layer 140, the hole blocking layer 320, the electron transport layer 310, and the second electrode layer 150 are stacked in sequence.

[0042] Specifically, the hole injection layer 330 reduces the barrier for injecting holes from the anode, enabling holes to be effectively injected from the anode into the light-emitting device. Generally, the hole transport rate is greater than the electron transport rate. To ensure that the recombination of electrons and holes injected from the electrodes occurs in the light-emitting layer, an electron transport layer 310 and a hole transport layer 340 can also be provided. When electrons and holes migrate into the light-emitting layer, due to the presence of an electric field, electrons can continue to migrate towards the anode, and holes can continue to migrate towards the cathode, resulting in a decrease in the concentration of electrons and holes in the light-emitting region and a reduction in the light-emitting efficiency. By providing an electron blocking layer 350 and a hole blocking layer 320, due to their special energy level structures, they can form barriers for the migration of electrons or holes and prevent their further migration.

[0043] Optionally, the materials of the first electrode layer 110 and the second electrode layer 150 are at least one of a metal, a metal oxide, and a polymer.

[0044] Specifically, the first electrode layer 110 and the second electrode layer 150 serve as the anode or the cathode, and their materials are selected from at least one of a metal, a metal oxide, and a polymer. For the anode, since holes need to be injected into the device, it requires a relatively high work function. Commonly used anode materials include ITO, IZO, Au, Pt, Si, etc. For the cathode, materials with a low work function are used. Commonly used cathode materials include Ag, Al, Li, Mg, Ca, Mg:Ag, Li:Al, ITO, NPD, AlQ, and AlQ(Li)Al, etc.

[0045] Optionally, the first light-emitting layer 120 is a single-color light-emitting layer or a mixed-color light-emitting layer; the second light-emitting layer 140 is a mixed-color light-emitting layer or a single-color light-emitting layer.

[0046] Specifically, the first light-emitting layer 120 and the second light-emitting layer 140 are doped with a host material that emits red, blue, or green light. The first light-emitting layer 120 and the second light-emitting layer 140 can also incorporate a guest dye, with the guest dye doped within the host material. The host material is a fluorescent host material or a phosphorescent host material, and the guest dye is a fluorescent guest dye or a phosphorescent guest dye. Exemplarily, the first light-emitting layer 120 or the second light-emitting layer 140 includes only a single-color host material and a single-color guest dye, which can form a corresponding single-color light-emitting layer. For example, if the host material of the first light-emitting layer 120 is blue and a blue guest dye is added, then the first light-emitting layer 120 is a single-color light-emitting layer. If the host material of the first light-emitting layer 120 is green and green and red guest dyes are added respectively, then the first light-emitting layer 120 can form a mixed-color light-emitting layer. Similarly, the second light-emitting layer 140 can also form a single-color light-emitting layer or a mixed-color light-emitting layer.

[0047] Optionally, the organic light-emitting diode device further includes a third light-emitting layer; the third light-emitting layer is in contact with the first light-emitting layer 120 or the second light-emitting layer 140.

[0048] Specifically, multiple light-emitting layers can be provided in the organic light-emitting diode device. Exemplarily, the third light-emitting layer can be provided on the surface of the first light-emitting layer 120 close to the first electrode layer 110, or on the surface of the first light-emitting layer 120 close to the second electrode layer 150. Similarly, the third light-emitting layer can also be provided on the surface of the second light-emitting layer 140 close to the first electrode layer 110, or on the surface of the second light-emitting layer 140 close to the second electrode layer 150. By the color light of the multiple light-emitting layers, the uniformity of white light emission is improved.

[0049] An embodiment of the present invention further provides a display panel, which at least includes any organic light-emitting diode device of the embodiment of the present invention. Since the display panel includes the organic light-emitting diode device of the embodiment of the present invention, it has the same beneficial effects, which will not be elaborated here.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An organic light-emitting diode device, characterized in that, Comprising: A first electrode layer, a first light-emitting layer, an intermediate layer, a second light-emitting layer, and a second electrode layer stacked in sequence; Wherein, the intermediate layer at least includes a first transition layer and a second transition layer; in a first direction, the first transition layer and the second transition layer are stacked in sequence between the first light-emitting layer and the second light-emitting layer; the host material doped in the first transition layer is the same as the first host material of the first light-emitting layer; the host material doped in the second transition layer is the same as the second host material of the second light-emitting layer; wherein, the first direction is the direction from the first electrode layer to the second electrode layer; Three intermediate transition layers are provided between the first transition layer and the second transition layer; the host material doped in the intermediate transition layer is a mixed material of the first host material and the second host material; along the first direction, the proportion of the first host material in the intermediate transition layer decreases in sequence; along a second direction, the proportion of the second host material in the intermediate transition layer decreases in sequence; wherein, the second direction is the direction from the second electrode layer to the first electrode layer; The proportion of the first host material in the first transition layer is 1, the ratio of the first host material to the second host material of the first intermediate transition layer adjacent to the first transition layer is 3:1, the ratio of the first host material to the second host material of the second intermediate transition layer is 1:1, the ratio of the first host material to the second host material of the third intermediate transition layer is 1:3, and the proportion of the second host material in the second transition layer is 1; It further includes a third light-emitting layer; the third light-emitting layer is in contact with the first light-emitting layer or the second light-emitting layer.

2. The organic light-emitting diode device according to claim 1, characterized in that, The thickness of the first transition layer is 1.5 nm, the thickness of the second transition layer is 3 nm, and the thickness of the third transition layer is 1.5 nm.

3. The organic light emitting diode device according to claim 1, wherein The thickness of the intermediate layer is less than or equal to 10 nm.

4. The organic light-emitting diode device according to claim 1, characterized in that, It further includes an electron transport layer, a hole blocking layer, an electron blocking layer, a hole transport layer, and a hole injection layer; The first electrode layer, the hole injection layer, the hole transport layer, the electron blocking layer, the first light-emitting layer, the intermediate layer, the second light-emitting layer, the hole blocking layer, the electron transport layer, and the second electrode layer are stacked in sequence.

5. The organic light emitting diode device according to claim 1, characterized in that, The materials of the first electrode layer and the second electrode layer are at least one of metal, metal oxide, and polymer.

6. The organic light emitting diode device according to claim 1, characterized in that, The first light-emitting layer is a monochromatic light-emitting layer or a mixed-color light-emitting layer; the second light-emitting layer is a mixed-color light-emitting layer or a monochromatic light-emitting layer.

7. A display panel, characterized in that, At least including the organic light-emitting diode device according to any one of claims 1-6.

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