OLED devices and electronic devices

Abstract

The present disclosure provides an OLED device, comprising a substrate, a plurality of electrodes disposed on the substrate, and a light-emitting layer disposed between adjacent electrodes; the adjacent electrodes and the light-emitting layer sandwiched therebetween form a light-emitting unit; wherein in the plurality of electrodes, one of the electrode closest to the substrate and the electrode farthest from the substrate is a transmissive electrode, and the other is a reflective electrode, and the remaining electrodes are intermediate electrodes; the operating current density of each light-emitting unit monotonically decreases in the direction from the reflective electrode to the transmissive electrode.

Description

Technical Field

[0001] This disclosure belongs to the field of electronic device technology, specifically relating to an OLED device and an electronic device. Background Technology

[0002] In related technologies, lighting includes OLED (Organic Light-Emitting Diode) lighting and LED (Light-Emitting Diode) lighting. Compared to LED lighting, OLED lighting is a surface light source and is gentler. Most OLED desk lamps on the market are single-color temperature, adjustable brightness products, such as white light with a color temperature of 1800K~3200K (amber) or around 4000K, and cannot be infinitely adjusted in color temperature. OLED products that can achieve color temperature adjustment use multiple light-emitting layers of different colors placed in parallel. Different color light-emitting layers cannot share the same aperture ratio, which leads to problems such as reduced lifespan. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide an OLED device and an electronic device.

[0004] This disclosure provides an OLED device, which includes a substrate, a multilayer electrode disposed on the substrate, and a light-emitting layer located between adjacent electrodes; the adjacent electrodes and the light-emitting layer sandwiched between them constitute a light-emitting unit;

[0005] In the multilayer electrodes, one of the electrodes closest to the substrate and the electrode furthest from the substrate is a transmission electrode, the other is a reflection electrode, and the remaining electrodes are intermediate electrodes.

[0006] Along the direction from the reflective electrode to the transmissive electrode, the operating current density of each light-emitting unit decreases monotonically.

[0007] The intermediate electrode includes multiple sub-electrodes. Among the multiple sub-electrodes, the sub-electrode closest to the reflective electrode is the first sub-electrode, and the sub-electrode closest to the transmittance electrode is the second sub-electrode. The work function of the first sub-electrode is greater than that of the second sub-electrode.

[0008] The difference in work function between the first sub-electrode and the second sub-electrode is 1.2 to 2.5 eV.

[0009] Wherein, the work function of the first sub-electrode is greater than 4.8 eV, and / or the work function of the second sub-electrode is less than 4.3 eV.

[0010] The material of the first sub-electrode includes at least one of IZO and ITO; and / or

[0011] The material of the second sub-electrode includes at least one of magnesium, silver, and aluminum.

[0012] The intermediate electrode further includes a third sub-electrode sandwiched between the first sub-electrode and the second sub-electrode, wherein the work function of the third sub-electrode is less than that of the second sub-electrode.

[0013] The transmittance of the intermediate electrode is not less than 40%.

[0014] Wherein, the thickness of the first sub-electrode is 100–300 nm; and / or

[0015] The thickness of the second sub-electrode is 10–15 nm.

[0016] The light-emitting layers are multiple, and at least two of the light-emitting layers emit light of different colors.

[0017] This disclosure provides an electronic device including any of the OLED devices described above. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an OLED device in related technologies;

[0019] Figure 2 This is a schematic diagram of the structure of an OLED device according to an embodiment of the present disclosure;

[0020] Figure 3 This is a schematic diagram of the structure of the light-emitting unit of an OLED device according to an example of this disclosure;

[0021] Figure 4 This is a schematic diagram of the structure of the light-emitting unit of an OLED device, which is another example of this disclosure.

[0022] Figure 5 for Figure 2 The equivalent circuit diagram of the OLED device is shown. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0025] like Figure 1 As shown, in related technologies, an OLED device includes a substrate 10, a pixel defining layer 20 disposed on the substrate 10, and two light-emitting units L. The two light-emitting units L emit different colors of light. Each unit includes a first electrode 30, a light-emitting layer, and a second electrode 50 sequentially disposed along a direction away from the substrate 10. The first electrodes 30 of the two light-emitting units L are not connected to each other. The two light-emitting units L emit different colors, therefore their light-emitting layers have different colors. The pixel defining layer 20 has pixel openings corresponding to the light-emitting units L. The first electrode 30 of the light-emitting unit L is located on the side of the pixel defining layer 20 closest to the substrate 10. The light-emitting layer of the light-emitting unit L at least covers the pixel opening and is in contact with the first electrode 30. The second electrode 50 covers the side of the light-emitting layer away from the first electrode 30. For each light-emitting unit L, one of the first electrode 30 and the second electrode 50 is an anode, and the other is a cathode. Figure 1 This example uses only the first electrode 30 as the anode and the second electrode 50 as the cathode. In some examples, to facilitate voltage application and fabrication, the cathodes of the two light-emitting units L are designed as a single molded structure. In an OLED device, one of the cathode and anode is the transmission electrode, and the other is the reflection electrode. Figure 1 In OLED devices, taking the cathode as the reflective electrode and the anode as the transmittance electrode as an example.

[0026] It should be noted that, Figure 1Taking an OLED device with two light-emitting units L as an example, for ease of description, the two light-emitting units L are referred to as the first light-emitting unit L1 and the second light-emitting unit L2, respectively. The light-emitting layer of the first light-emitting unit L1 is represented by the first light-emitting layer 41, and the light-emitting layer of the second light-emitting unit L2 is represented by the second light-emitting layer 42. To prevent water and oxygen from affecting the light-emitting layer of the light-emitting unit L, an encapsulation layer 60 is covered on the side of the cathode of the light-emitting unit L that faces away from the substrate 10.

[0027] for Figure 1 The OLED device is driven by applying corresponding voltages to the cathode and anode of the first light-emitting unit L1, causing L1 to emit light of a first color. Similarly, applying corresponding voltages to the cathode and anode of the second light-emitting unit L2 causes L2 to emit light of a second color. The first and second colors are then mixed to produce a third color light emitted by the OLED device. Furthermore, the color temperature of the third color light emitted by the OLED device can be adjusted by regulating the voltage applied to the anodes of the first and second light-emitting units L1 and L2, thereby regulating the light intensity of each unit.

[0028] The inventors discovered that because the light-emitting units L in the OLED device are arranged in parallel, that is, one pixel opening corresponds to only one light-emitting unit L, and the pixel openings of each light-emitting unit L cannot be shared, the OLED device cannot achieve color temperature adjustment when a light-emitting unit L has a problem. At the same time, the inability of each light-emitting unit L to share an opening is not conducive to improving the aperture ratio, resulting in a relatively small projected area of ​​the first electrode 30 and / or the second electrode 50 of each light-emitting unit L on the substrate 10. This leads to a larger operating current density when achieving the same brightness, which reduces the lifespan of the light-emitting device.

[0029] To address the problems existing in OLED devices in the aforementioned related technologies, this disclosure provides a new OLED device structure.

[0030] like Figure 2 As shown, the OLED device provided in this embodiment includes a substrate 10, multiple layers of electrodes, and a light-emitting layer. The multiple layers of electrodes are disposed on the substrate 10, and the light-emitting layer is located between adjacent electrodes; the adjacent electrodes and the light-emitting layer sandwiched between them constitute a light-emitting unit. Among the multiple layers of electrodes, one of the electrodes closest to the substrate 10 and the electrode furthest from the substrate 10 is a transmission electrode, the other is a reflection electrode, and the remaining electrodes are intermediate electrodes 70; along the direction from the reflection electrode to the transmission electrode, the operating current density of each light-emitting unit monotonically decreases.

[0031] In this embodiment of the present disclosure, the electrode sandwiched between adjacent light-emitting layers simultaneously serves as the electrode of two adjacent light-emitting units. In other words, if the number of light-emitting layers is N, that is, the number of light-emitting units is N, along the direction away from the substrate 10, the electrode on the side of the i-th light-emitting unit away from the substrate 10 and the electrode on the side of the (i+1)-th light-emitting unit close to the substrate 10 are the same electrode, where i = 1 to N, and N is a positive integer.

[0032] In this embodiment, the light-emitting units are stacked, and the stacked light-emitting units share a common aperture ratio. Compared to the parallel arrangement of light-emitting units in related technologies, the aperture ratio of each light-emitting unit in this embodiment is larger. This helps to reduce the operating current density flowing through each light-emitting unit while achieving the same luminous brightness, thus extending the lifespan of the OLED device. Furthermore, in this embodiment, since the operating current density of each light-emitting unit monotonically decreases along the direction from the reflective electrode to the transmission electrode, the overall operating voltage drop of the OLED device can be reduced. This reduces the IR drop between the middle and edge portions of the intermediate electrode 70, resulting in more uniform luminous brightness of the light-emitting units and improving the luminous quality of the OLED device.

[0033] In this embodiment, the electrode closest to the substrate 10 in the multilayer electrode is used as the transmission electrode, and the electrode furthest from the substrate 10 is used as the reflection electrode. Of course, in other embodiments, the electrode closest to the substrate 10 in the multilayer electrode can also be configured as the reflection electrode, and the electrode furthest from the substrate 10 as the transmission electrode.

[0034] In this embodiment, the electrode closest to the substrate 10 in the multilayer electrode is used as the anode, and the electrode furthest from the substrate 10 is used as the cathode. Of course, in other embodiments, the electrode closest to the substrate 10 in the multilayer electrode can also be configured as the cathode and the electrode furthest from the substrate 10 as the anode.

[0035] The OLED device in this embodiment will be described in detail below with specific examples.

[0036] In the embodiments disclosed herein, for ease of description, the following examples will use an OLED device comprising three electrode layers and two light-emitting layers as an example, but this shall not constitute a limitation of the present disclosure.

[0037] like Figure 2As shown, the OLED device in this example includes a substrate 10, and a pixel defining layer 20, three electrode layers, and two light-emitting layers disposed on the substrate 10. The three electrode layers include a first electrode 30, an intermediate electrode 70, and a second electrode 50. The two light-emitting layers include a first light-emitting layer 41 and a second light-emitting layer 42. The pixel defining layer 20 has an opening extending through its thickness direction. The first electrode 30, the first light-emitting layer 41, the intermediate electrode 70, the second light-emitting layer 42, and the second electrode 50 are sequentially arranged in a direction away from the substrate 10, and these five elements are corresponding to the opening. The first electrode 30, the first light-emitting layer 41, and the intermediate electrode 70 constitute a first light-emitting unit, and the intermediate electrode 70, the second light-emitting layer 42, and the second electrode 50 constitute a second light-emitting unit. The second electrode 50 is a reflective electrode, and the first electrode 30 is a transmissive electrode. The operating current density of the second light-emitting unit is greater than that of the first light-emitting unit.

[0038] In this example, a first driving voltage applied between the first electrode 30 and the intermediate electrode 70 drives the first light-emitting unit to emit light, and a second driving voltage applied between the intermediate electrode 70 and the second electrode 50 drives the second light-emitting unit to emit light. By setting the operating current density of the second light-emitting unit to be greater than that of the first light-emitting unit, the overall operating voltage drop of the OLED device can be reduced, thereby reducing the IRDrop between the middle and edge portions of the intermediate electrode 70. This results in more uniform brightness of the first and second light-emitting units, improving the luminous quality of the OLED device.

[0039] In this example, the first electrode can serve as the anode of the first light-emitting unit, the intermediate electrode can serve as both the cathode of the first light-emitting unit and the anode of the second light-emitting unit, and the second electrode can serve as the cathode of the second light-emitting unit. In other examples, the first electrode can serve as the cathode of the first light-emitting unit, the intermediate electrode can serve as both the anode of the first light-emitting unit and the cathode of the second light-emitting unit, and the second electrode can serve as the anode of the second light-emitting unit.

[0040] In this example, the operating current density of the second light-emitting unit can be made greater than that of the first light-emitting unit by adjusting the area and material of the first electrode 30, the intermediate electrode 70 and the second electrode 50 in the direction parallel to the substrate 10.

[0041] In some examples, the intermediate electrode 70 can be designed to make the operating current density of the second light-emitting unit greater than that of the first light-emitting unit.

[0042] like Figure 3As shown, in one example, the intermediate electrode layer 70 includes a second sub-electrode 72 and a first sub-electrode 71 stacked sequentially in a direction away from the substrate 10. The work function of the first sub-electrode 71 is greater than that of the second sub-electrode 72. In this case, by setting the intermediate electrode 70 to include a first sub-electrode 71 and a second sub-electrode 72 with different work functions, the overall sheet resistance of the intermediate electrode 70 can be effectively reduced, thereby helping to reduce the overall operating voltage drop of the OLED device, reduce the IR drop between the middle and edge portions of the intermediate electrode 70, and make the luminous brightness of the first and second light-emitting units more uniform, thus improving the luminous quality of the OLED device. Figure 3 The arrow in the diagram indicates the direction of the current.

[0043] In this example, the first electrode 30 serves as the anode of the first light-emitting unit, the second sub-electrode 72 serves as the cathode of the first light-emitting unit, the first sub-electrode 71 serves as the anode of the second light-emitting unit, and the second electrode 50 serves as the cathode of the second light-emitting unit.

[0044] Furthermore, the difference in work function between the first sub-electrode 71 and the second sub-electrode 72 is 1.2–2.5 eV. For example, the work function of the first sub-electrode 71 is greater than 4.8 eV, and / or the work function of the second sub-electrode 72 is less than 4.3 eV. Further, the work function of the first sub-electrode 71 can be 5.5 eV, 6.2 eV, etc., and the work function of the second sub-electrode 72 can be 4.0 eV, 3.5 eV, etc., without specific limitations here.

[0045] Furthermore, the first sub-electrode 71 can be made of a material with good light transmittance, such as IZO (Indium Zinc Oxide) or ITO (Indium Tin Oxide), and the second sub-electrode 72 can be made of a material with good conductivity, such as magnesium, silver, or aluminum. For example, the second sub-electrode 72 can be a film layer formed by co-evaporation deposition of magnesium and silver.

[0046] like Figure 4As shown, in another example, the intermediate electrode 70 includes a second sub-electrode 72, a third sub-electrode 73, and a first sub-electrode 71 stacked sequentially in a direction away from the substrate 10. The work function of the first sub-electrode 71 is greater than that of the second sub-electrode 72, and the work function of the second sub-electrode 72 is greater than that of the third sub-electrode 73. In this case, by placing the third sub-electrode 73 between the first sub-electrode 71 and the second sub-electrode 72, the overall sheet resistance of the intermediate electrode 70 can be further reduced, thereby helping to further reduce the overall operating voltage drop of the OLED device, reduce the IR drop between the middle and edge portions of the intermediate electrode 70, and make the luminous brightness of the first and second light-emitting units more uniform, thus improving the luminous quality of the OLED device. Figure 4 The arrow in the diagram indicates the direction of the current.

[0047] In this example, the first electrode 30 serves as the anode of the first light-emitting unit, the second sub-electrode 72 and the third sub-electrode 73 serve as the cathodes of the first light-emitting unit, the first sub-electrode 71 serves as the anode of the second light-emitting unit, and the second electrode 50 serves as the cathode of the second light-emitting unit.

[0048] Furthermore, the difference in work function between the first sub-electrode 71 and the second sub-electrode 72 is 1.2 to 2.5 eV. The specific setting of the difference in work function between the first sub-electrode 71 and the second sub-electrode 72 can be referred to the example above, and will not be repeated here.

[0049] In this example, the first sub-electrode 71 and the second sub-electrode 72 can be made of the same materials as described above, and the third sub-electrode 73 can be made of a material with better conductivity than the second sub-electrode 72, such as silver, but the purity of the silver used in the third sub-electrode 73 must be higher than the purity of the silver used in the second sub-electrode 72.

[0050] In some examples, the first electrode 30 can be a single-layer structure or a composite-layer structure. The first electrode can be a transmission electrode, and the material of the transmission electrode can include at least one of ITO and IZO; the first electrode can also be a reflection electrode, and the material of the reflection electrode can include aluminum, silver, etc.

[0051] In some examples, the second electrode 50 can be a single-layer structure or a composite-layer structure. The second electrode can be a reflective electrode, and the material of the reflective electrode can include aluminum, silver, etc.; the second electrode can also be a transmission electrode, and the material of the transmission electrode can include at least one of ITO and IZO.

[0052] In some examples, there are two light-emitting layers, namely a first light-emitting layer 41 and a second light-emitting layer 42. The first light-emitting layer 41 emits light of a first color, and the second light-emitting layer 42 emits light of a second color. The first color light and the second color light are mixed and then emitted. The materials of the first light-emitting layer 41 and the second light-emitting layer 42 can be organic electroluminescent materials.

[0053] In some examples, the substrate 10 can be made of rigid or flexible light-transmitting material. Rigid light-transmitting materials include quartz glass, silicon substrate, germanium substrate, etc., while flexible light-transmitting materials include polyimide, flexible glass, etc.

[0054] In some examples, the material of the pixel limiting layer 20 can be a material with a light transmittance lower than a preset threshold, such as black rubber material. The size of the preset threshold can be set as needed and is not specifically limited here.

[0055] like Figure 2 As shown, the OLED device also includes an encapsulation layer 60 disposed on the side of the second electrode 50 facing away from the substrate 10.

[0056] In some examples, the encapsulation layer 60 can be a single-layer structure or a composite layer structure. For example, the encapsulation layer 60 may include an organic encapsulation layer, an inorganic encapsulation layer, and another organic encapsulation layer stacked sequentially. The material of the organic encapsulation layer may include epoxy resin, polyimide, polyamide, etc. The material of the inorganic encapsulation layer may include plastic, ceramic, etc. By setting the encapsulation layer 60, water and oxygen can be blocked, extending the lifespan of the OLED device.

[0057] like Figure 2 As shown, the multilayer electrode includes a first electrode 30, an intermediate electrode 70, and a second electrode 50. The multilayer light-emitting layer includes a first light-emitting layer 41 and a second light-emitting layer 42. The first electrode 30, the first light-emitting layer 41, and the intermediate electrode 70 constitute a first light-emitting unit, and the intermediate electrode 70, the second light-emitting layer 42, and the second electrode 50 constitute a second light-emitting unit.

[0058] like Figure 5 The diagram shows a schematic of the circuit principle for driving the first and second light-emitting units to emit light. The first light-emitting layer 41 can be equivalent to a first diode EL1, and the second light-emitting layer 42 can be equivalent to a second diode EL2. By applying a first driving voltage V1 between the first electrode 30 and the intermediate electrode 70, the first light-emitting layer 41 (equivalent to the first diode EL1) is driven to emit light. By applying a second driving voltage V2 between the intermediate electrode 70 and the second electrode 50, the second light-emitting layer 42 (equivalent to the second diode EL2) is driven to emit light. The first driving voltage V1 is greater than the turn-on voltage of the first light-emitting layer 41, and the second driving voltage V2 is greater than the turn-on voltage of the second light-emitting layer 42.

[0059] In a specific example, the first electrode 30 serves as the anode of the first light-emitting unit, and the second sub-electrode 72 serves as the cathode of the first light-emitting unit. A first driving voltage V1 is applied between the first electrode 30 and the intermediate electrode 70, which is equivalent to the first driving voltage V1 applied between the first electrode 30 and the second sub-electrode 72, to drive the first light-emitting unit to emit light. The first sub-electrode 71 serves as the anode of the second light-emitting unit, and the second electrode 50 serves as the cathode of the second light-emitting unit. A second driving voltage V2 is applied between the intermediate electrode 70 and the second electrode 50, which is equivalent to the second driving voltage V2 applied between the first sub-electrode 71 and the second electrode 50, to drive the second light-emitting unit to emit light. The voltages applied to the first electrode 30, the intermediate electrode 70, and the second electrode 50 can decrease sequentially.

[0060] The operating current density of the second light-emitting unit is greater than that of the first light-emitting unit, i.e., I EL2 >I EL1 By adjusting the first driving voltage V1, the luminous intensity of the first light-emitting unit can be adjusted, thereby adjusting the brightness of the first color. By adjusting the second driving voltage V2, the luminous intensity of the second light-emitting unit can be adjusted, thereby adjusting the brightness of the second color. By adjusting the brightness of the first color and the second color respectively, the color temperature of the emitted light from the OLED device can be adjusted.

[0061] The above is an introduction to OLED devices that include two light-emitting units. In other examples, OLED devices may include more light-emitting units. For example, an OLED device may include three light-emitting units. By individually adjusting the luminous intensity of each light-emitting unit, the color temperature of the emitted light from the OLED device can be adjusted, and more emitted light of different color temperatures can be obtained.

[0062] In some examples, the intermediate electrode may include not only the two or three sub-electrodes mentioned above, but also more sub-electrodes. In the multi-layer sub-electrodes, the sub-electrode closest to the reflecting electrode is the first sub-electrode, and the sub-electrode closest to the transmitting electrode is the second sub-electrode, as long as the work function of the first sub-electrode is greater than that of the second sub-electrode, and the work function of the other sub-electrodes sandwiched between the first and second sub-electrodes is less than that of the second sub-electrode.

[0063] Furthermore, the difference in work function between the first sub-electrode and the second sub-electrode is 1.2–2.5 eV. For example, the work function of the first sub-electrode is greater than 4.8 eV, and / or the work function of the second sub-electrode is less than 4.3 eV. Further, the work function of the first sub-electrode can be 5.5 eV, 6.2 eV, etc., and the work function of the second sub-electrode can be 4.0 eV, 3.5 eV, etc., without specific limitations.

[0064] In this embodiment of the disclosure, the difference in work function between the first sub-electrode and the second sub-electrode can be made to meet a preset requirement by selecting the materials of the first sub-electrode and the second sub-electrode. For specific material selection, please refer to the above example, which will not be repeated here.

[0065] In some examples, the intermediate electrode can be not only a single layer, but also multiple layers. When the intermediate electrode is multiple layers, the number of sub-electrodes included in the intermediate electrodes located in different layers can be the same or different. The difference in work function between the first sub-electrode and the second sub-electrode can be the same or different. No specific limitation is made here.

[0066] In some examples, the transmittance of the intermediate electrode can be set to no less than 40% to form a microcavity between the reflective electrode and the intermediate electrode, and between the intermediate electrodes.

[0067] In this embodiment, the transmittance of the intermediate electrode can be controlled by controlling the film structure and / or material composition of the intermediate electrode. For example, the intermediate electrode may include a two-layer structure, namely a first sub-electrode closest to the reflective electrode and a second sub-electrode closest to the transmissive electrode. The material of the first sub-electrode can be IZO, which has good transmittance, and the material of the second sub-electrode can be magnesium and silver, which have good conductivity, thereby giving the intermediate electrode a certain transmittance. Furthermore, by controlling the thickness ratio of the first sub-electrode and the second sub-electrode, the transmittance of the intermediate electrode can be controlled. For example, the thickness of the first sub-electrode can be greater than the thickness of the second sub-electrode, or the thickness ratio of the first sub-electrode to the second sub-electrode can be controlled to be different ratios such as 6:4 or 7:3, to increase or decrease the transmittance of the intermediate electrode. The transmittance of the intermediate electrode can be selected, for example, 45%, 53%, etc., without specific limitation.

[0068] In this embodiment of the disclosure, by setting the transmittance of the intermediate electrode to be not less than 40%, a microcavity can be formed between the reflective electrode and the intermediate electrode, and between the intermediate electrodes, so that the light emitted by the light-emitting layer can form a resonance in the microcavity through interference, thereby enhancing the propagation of light.

[0069] In some examples, when there are multiple intermediate electrodes, the multiple intermediate electrodes may have the same transmittance or different transmittances, without being specifically limited here.

[0070] For the scheme of stacking multiple light-emitting units in the embodiments of this disclosure, the overall thickness of the OLED device can be controlled by controlling the thickness of the intermediate electrode.

[0071] In some examples, the thickness of the intermediate electrode is 150–300 nm. The thickness of the first sub-electrode is 100–300 nm; and / or, the thickness of the second sub-electrode is 10–15 nm.

[0072] In this embodiment, the thickness of the intermediate electrode can be 160nm, 180nm, 240nm, 290nm, etc. The intermediate electrode should not be too thick so that the overall thickness of the OLED device is relatively small. In other embodiments, the intermediate electrode may also have other thicknesses. The specific thickness of the intermediate electrode can be set as needed and is not specifically limited here.

[0073] In this embodiment, the thickness of the first sub-electrode can be 120nm, 150nm, 260nm, etc., and the thickness of the second sub-electrode can be 11nm, 13nm, 14nm, etc. Compared to the second sub-electrode, the first sub-electrode has a larger work function and a larger thickness, which is beneficial for reducing the sheet resistance of the first sub-electrode, thereby reducing the overall sheet resistance of the intermediate electrode, reducing the IR drop between the middle and edge parts of the intermediate electrode, making the luminous brightness of the first and second light-emitting units more uniform, and improving the luminous quality of the OLED device.

[0074] In some examples, when there are multiple intermediate electrodes, these electrodes may have the same thickness or different thicknesses; no specific limitation is made here. In the intermediate electrodes of different layers, the thickness of each first sub-electrode may be the same or different, the thickness of each second sub-electrode may be the same or different, and the thickness ratio between the first and second sub-electrodes may be the same or different; no specific limitation is made here.

[0075] In some examples, there can be more than two light-emitting layers, such as three or four, with at least two of the light-emitting layers emitting light of different colors. The material of the light-emitting layers can be an organic electroluminescent material, which can emit light through carrier injection and recombination under an electric field.

[0076] In some examples, for each light-emitting unit, between two adjacent electrode layers, along the direction away from the substrate, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer may be included. That is, for each light-emitting unit, a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer may also be included to improve the injection rate and amount of holes and electrons, reduce the energy barrier for holes to be injected into the light-emitting layer from the anode and the energy barrier for electrons to be injected into the light-emitting layer from the cathode, thereby improving the luminous efficiency and performance of the OLED device.

[0077] In some examples, along a direction perpendicular to the surface of the substrate 10 and pointing towards the substrate 10, except for the electrodes disposed between the pixel defining layer and the substrate, the projected area of ​​each film layer on the substrate 10 monotonically decreases. For example, with Figure 2 The example shown illustrates that the projected areas of the second electrode, the second light-emitting layer, the intermediate electrode, and the first light-emitting layer on the substrate decrease monotonically.

[0078] In other examples, the size of the projected area of ​​each film layer on the substrate can be set as needed, which is beneficial for setting up power lines for each electrode so as to drive each light-emitting unit to emit light and to adjust the light intensity of each light-emitting unit, thereby achieving color temperature adjustment of the emitted light.

[0079] This disclosure provides an electronic device including any of the OLED devices described above.

[0080] In the embodiments of this disclosure, the electronic device can be any product or component with lighting or display functions, such as a lighting device, mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator.

[0081] In some examples, the electronic device may also include the driving circuitry for the OLED device described above.

[0082] This disclosure provides a method for fabricating an OLED device, comprising: providing a substrate; forming an electrode on the substrate, which may be referred to as a first electrode for ease of description; forming a pixel defining layer, the pixel defining layer including a plurality of openings exposing at least a portion of the first electrode; subsequently forming a plurality of alternately stacked light-emitting layers and electrodes in the openings; referring to the electrode furthest from the substrate relative to the first electrode as a second electrode; referring to other electrodes sandwiched between the first electrode and the second electrode as intermediate electrodes; and forming an encapsulation layer on the side of the second electrode facing away from the substrate. Adjacent electrodes and the light-emitting layers between them constitute a light-emitting unit. In the OLED device, there are at least two light-emitting layers and at least one intermediate electrode.

[0083] In one example, forming the intermediate electrode may include sequentially forming a second sub-electrode and a first sub-electrode along a direction away from the substrate. The work function of the first sub-electrode is greater than the work function of the second sub-electrode.

[0084] In one example, forming the intermediate electrode may include sequentially forming a second sub-electrode, a third sub-electrode, and a first sub-electrode along a direction away from the substrate. The work function of the first sub-electrode, the second sub-electrode, and the third sub-electrode decreases sequentially.

[0085] In one example, for each light-emitting unit, the electrode closer to the substrate is the anode and the electrode farther from the substrate is the cathode. A hole injection layer and a hole transport layer can also be formed sequentially between the anode and the light-emitting layer, and an electron transport layer and an electron injection layer can be formed sequentially between the light-emitting layer and the cathode.

[0086] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled 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. An OLED device, comprising a substrate, a multilayer electrode disposed on the substrate, and a light-emitting layer located between adjacent electrodes; the adjacent electrodes and the light-emitting layer sandwiched between them constitute a light-emitting unit; for each light-emitting unit, the light-emitting layer is driven to emit light by applying a driving voltage between two adjacent electrodes; In the multilayer electrode, one of the electrode closest to the substrate and the electrode furthest from the substrate is a transmission electrode, and the other is a reflection electrode; the remaining electrodes are intermediate electrodes. The intermediate electrode includes multiple sub-electrodes, in which the sub-electrode closest to the reflection electrode is the first sub-electrode, and the sub-electrode closest to the transmission electrode is the second sub-electrode. The work function of the first sub-electrode is greater than that of the second sub-electrode. The intermediate electrode also includes a third sub-electrode sandwiched between the first sub-electrode and the second sub-electrode. The work function of the third sub-electrode is less than that of the second sub-electrode. The material of the first sub-electrode includes at least one of IZO and ITO; and / or, the material of the second sub-electrode includes at least one of magnesium, silver, and aluminum. Along the direction from the reflective electrode to the transmission electrode, the operating current density of each light-emitting unit decreases monotonically.

2. The OLED device according to claim 1, wherein, The difference in work function between the first sub-electrode and the second sub-electrode is 1.2~2.5eV.

3. The OLED device according to claim 1 or 2, wherein, The work function of the first sub-electrode is greater than 4.8 eV, and / or the work function of the second sub-electrode is less than 4.3 eV.

4. The OLED device according to claim 1, wherein, The transmittance of the intermediate electrode is not less than 40%.

5. The OLED device according to claim 1 or 2, wherein, The thickness of the first sub-electrode is 100~300 nm; and / or The thickness of the second sub-electrode is 10~15nm.

6. The OLED device according to claim 1, wherein, The light-emitting layers are multiple, of which at least two light-emitting layers emit light of different colors.

7. An electronic device comprising an OLED device as claimed in any one of claims 1 to 6.

Images