Light-emitting devices, display panels and display devices

Abstract

This invention discloses a light-emitting device, a display panel, and a display apparatus. In one specific embodiment, the light-emitting device includes a first electrode, a second electrode, and an organic functional layer disposed between the first electrode and the second electrode. The organic functional layer includes a light-emitting layer and an organic material layer. The organic material layer includes polar molecules, and the dipole moment of the polar molecules in the organic material layer is greater than the dipole moment of the molecules in its adjacent film layers. This embodiment, by setting an organic material layer with strong molecular polarity, can enhance the induced capacitance of the device and reduce the magnitude of the first electrode potential rise caused by the leakage current of the thin-film transistor in the off-state pixel, thereby improving the pixel light leakage phenomenon.

Description

Technical Field

[0001] This invention relates to the field of displays. More specifically, it relates to a light-emitting device, a display panel, and a display apparatus. Background Technology

[0002] Currently, for Organic Light Emitting Diode (OLED) display panels, light leakage often occurs in pixels when they are off, affecting the display effect. Summary of the Invention

[0003] The purpose of this invention is to provide a light-emitting device, a display panel, and a display apparatus to solve at least one of the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The first aspect of the present invention provides a light-emitting device, including a first electrode, a second electrode, and an organic functional layer disposed between the first electrode and the second electrode; the organic functional layer includes a light-emitting layer and an organic material layer, the organic material layer including polar molecules, and the dipole moment of the polar molecules of the organic material layer being greater than the dipole moment of the molecules of its adjacent film layer.

[0006] Optionally, the dipole moment of the polar molecules in the organic material layer is greater than 1.3 Debye.

[0007] Optionally, the mobility of the organic material layer is less than or equal to the mobility of its adjacent film layer on the side closest to the light-emitting layer.

[0008] Optionally, the migration rate of the organic material layer is 5%-50% of the migration rate of the adjacent film layer on the side closest to the light-emitting layer.

[0009] Optionally, the thickness of the organic material layer is less than the thickness of its adjacent film layer on the side closer to the light-emitting layer, and / or the thickness of the organic material layer is less than the thickness of its adjacent film layer on the side farther from the light-emitting layer.

[0010] Optionally, the organic functional layer further includes a first hole transport layer and a second hole transport layer, wherein the first hole transport layer, the organic material layer, the second hole transport layer and the light-emitting layer are sequentially stacked on the first electrode.

[0011] Optionally, the organic functional layer further includes an electron transport layer located between the light-emitting layer and the second electrode.

[0012] Optionally, the organic functional layer further includes a hole injection layer and an electron injection layer, wherein the hole injection layer is located between the first electrode and the first hole transport layer, and the electron injection layer is located between the electron transport layer and the second electrode.

[0013] Optionally, the organic functional layer further includes an electron blocking layer and a hole blocking layer, wherein the electron blocking layer is located between the second hole transport layer and the light-emitting layer, and the hole blocking layer is located between the light-emitting layer and the electron transport layer.

[0014] A second aspect of the present invention provides a display panel including a red light-emitting device, a green light-emitting device and a blue light-emitting device, wherein at least one of the red light-emitting device, the green light-emitting device and the blue light-emitting device is the light-emitting device provided in the first aspect of the present invention.

[0015] Optionally, the red light-emitting device and / or the green light-emitting device are the light-emitting devices provided in the first aspect of the present invention.

[0016] Optionally, the display panel may further include low-temperature polycrystalline silicon thin-film transistors.

[0017] A third aspect of the present invention provides a display device comprising the display panel provided in the second aspect of the present invention.

[0018] The beneficial effects of this invention are as follows:

[0019] The technical solution described in this invention can enhance the induced capacitance of the device by setting a layer of organic material with strong molecular polarity, reduce the magnitude of the rise in the first electrode potential of the pixel in the off state due to the leakage current of the thin film transistor, and thus improve the pixel light leakage phenomenon. Attached Figure Description

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram of a polar molecule is shown.

[0022] Figure 2 A schematic diagram showing the positive and negative charge distribution of an organic material layer including polar molecules is shown.

[0023] Figure 3 A schematic diagram of a light-emitting device provided in an embodiment of the present invention is shown.

[0024] Figure 4 Another schematic diagram of the light-emitting device provided in an embodiment of the present invention is shown.

[0025] Figure 5 Another schematic diagram of the light-emitting device provided in an embodiment of the present invention is shown.

[0026] Figure 6 A schematic diagram of an existing display panel is shown.

[0027] Figure 7 Show Figure 6 The graphs shown represent the device-induced capacitance of the red, green, and blue light-emitting devices in an existing display panel as a function of the potential of the first electrode (anode).

[0028] Figure 8 A schematic diagram of a display panel provided in an embodiment of the present invention is shown.

[0029] Figure 9 Show Figure 8 The graphs shown represent the device-induced capacitance of the red, green, and blue light-emitting devices in the display panel as a function of the potential of the first electrode (anode).

[0030] Figure 10 Another schematic diagram of a display panel provided in an embodiment of the present invention is shown.

[0031] Figure 11 Show Figure 10 The graphs shown represent the device-induced capacitance of the red, green, and blue light-emitting devices in the display panel as a function of the potential of the first electrode (anode).

[0032] Figure 12 Another schematic diagram of a display panel provided in an embodiment of the present invention is shown.

[0033] Figure 13 Show Figure 12 The graphs shown represent the device-induced capacitance of the red, green, and blue light-emitting devices in the display panel as a function of the potential of the first electrode (anode). Detailed Implementation

[0034] In this invention, "on," "formed on," and "set on" can mean that one layer is directly formed or set on another layer, or that one layer is indirectly formed or set on another layer, meaning that there are other layers between the two layers.

[0035] It should be noted that although the terms "first," "second," etc., may be used herein to describe various components, members, elements, regions, layers, and / or portions, these components, members, elements, regions, layers, and / or portions should not be limited by these terms. Rather, these terms are used to distinguish one component, member, element, region, layer, and / or portion from another. Thus, for example, the first component, first member, first element, first region, first layer, and / or first portion discussed below may be referred to as a second component, second member, second element, second region, second layer, and / or second portion without departing from the teachings of the invention.

[0036] In this invention, unless otherwise stated, the term "co-layer arrangement" refers to two layers, components, members, elements, or portions that can be formed by the same fabrication process (e.g., patterning process), and that these two layers, components, members, elements, or portions are generally formed of the same material. For example, co-layer arrangement of two or more functional layers means that these co-layered functional layers can be formed using the same material layer and the same fabrication process, thereby simplifying the fabrication process of the display substrate.

[0037] In this invention, unless otherwise stated, the term "patterning process" generally includes steps such as photoresist coating, exposure, development, etching, and photoresist stripping. The term "one-step patterning process" refers to a process of forming patterned layers, components, or parts using a single photomask.

[0038] Currently, OLED display panels often exhibit light leakage in pixels when they are off, affecting display quality, especially low grayscale image quality. The inventors discovered that the cause of this phenomenon is that in existing designs using a common cathode for all pixels, the leakage current of the thin-film transistor (TFT) raises the anode potential of the off-state pixels. The voltage difference between the cathode and anode promotes the injection of a small number of holes and electrons into the light-emitting layer, resulting in light leakage.

[0039] Especially for OLED display panels that use low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) as pixel circuit switches, LTPS TFTs are commonly used as pixel circuit switches to reduce power consumption and improve circuit response speed. However, the high mobility of LTPS TFTs leads to high leakage current. As a result, in OLED display panels using LTPS TFTs, the anode potential of pixels in the off state rises significantly due to the high leakage current of the LTPS TFTs, resulting in severe light leakage.

[0040] Table 1 shows a comparison of the mobility and leakage current of low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) and oxide thin-film transistors (Oxide TFTs). It can be seen that LTPS PMOS transistors and LTPS NMOS transistors have higher mobility and larger leakage current compared to oxide thin-film transistors (referred to as Oxide in Table 1).

[0041] Table 1

[0042]

[0043] In view of this, embodiments of the present invention provide a light-emitting device, including a first electrode, a second electrode, and an organic functional layer disposed between the first electrode and the second electrode; the organic functional layer includes a light-emitting layer and an organic material layer, the organic material layer including polar molecules, and the dipole moment of the polar molecules in the organic material layer is greater than the dipole moment of the molecules in its adjacent film layer.

[0044] In this device, the first electrode is, for example, an anode, and the second electrode is, for example, a cathode. The light-emitting principle is as follows: holes generated by the first electrode (anode) and electrons generated by the second electrode (cathode) recombine in the light-emitting layer (EML) to form excitons, which emit light. The material of the first electrode (anode) is, for example, indium tin oxide (ITO), and the material of the second electrode (cathode) is, for example, a magnesium (Mg) or silver (Ag) alloy.

[0045] Organic materials can be classified into polar molecules and nonpolar molecules according to their polarization properties, such as... Figure 1 As shown, the positive and negative charge centers of polar molecules do not coincide. Therefore, there is always one positive charge center and one negative charge center in a polar molecule. This inherent dipole moment of the polar molecule itself is called the intrinsic dipole or permanent dipole. The dipole moment is the product of the distance between the positive and negative charge centers and the charge carried by the charge center. The dipole moment is a vector, and its direction is from the positive charge center to the negative charge center. It is represented by the symbol μ and the unit is D (Debye).

[0046] like Figure 2 As shown, when polar molecules are deposited on the lower film layer to form an organic material layer, due to the mutual repulsion of polar molecules, the molecular arrangement tends to be more ordered. The organic material layer 201 formed by the orderly arrangement of molecules macroscopically exhibits a positive and negative charge distribution in the same direction as the molecular dipole moment.

[0047] In a specific example, the light-emitting device provided in this embodiment is as follows: Figure 3 As shown, it includes a first electrode 301 (anode), a second electrode 302 (cathode), and an organic functional layer disposed between the first electrode 301 and the second electrode 302; the organic functional layer includes a light-emitting layer 303 and an organic material layer 304, the organic material layer 304 includes polar molecules, and the dipole moment of the polar molecules in the organic material layer 304 is greater than the dipole moment of the molecules in its adjacent film layer. Figure 3 As shown, the positive and negative charges generated at the interface of the organic material layer 304 composed of polar molecules will induce the first electrode 301 (anode) and the second electrode 302 (cathode), which serve as OLED devices, to generate an equal number of positive and negative charges with opposite polarities. The induced charges and the positive and negative charges separated from the polar molecules form the device induced capacitance, which is a spontaneous and permanent capacitance.

[0048] In existing light-emitting devices, the films in the organic functional layers are either films containing nonpolar molecules or films containing polar molecules with small dipole moments and weak polarity. Therefore, existing light-emitting devices have no device-induced capacitance or have small device-induced capacitance. However, the light-emitting device provided in this embodiment, by setting an organic material layer with large dipole moments and strong molecular polarity, can enhance the device-induced capacitance formed by the spontaneous orientation of the film layer while ensuring the device's response speed and other performance. A large device-induced capacitance can be generated without an external electric field or a small electric field, which enhances the device's ability to store charge before lighting up. This reduces the magnitude of the rise in the first electrode (anode) potential of the pixel in the off state due to the leakage current of the thin-film transistor, making the rise in the first electrode (anode) potential slower. This reduces the probability that holes injected from the first electrode (anode) and electrons injected from the second electrode (cathode) of the pixel in the off state will overcome the potential barrier and meet in the light-emitting layer to cause light emission, thereby improving the pixel light leakage phenomenon.

[0049] Furthermore, the organic material layer in this embodiment can also be referred to as a capacitance control layer or a capacitance enhancement layer.

[0050] In one possible implementation, the dipole moment of the polar molecules in the organic material layer of the light-emitting device provided in this embodiment is greater than 1.3 Debye. This ensures that the molecular polarity of the organic material layer is sufficiently strong, so that the enhancement of the device's induced capacitance meets the requirements, and the reduction in the magnitude of the rise in the first electrode (anode) potential of the pixel in the off-state due to the leakage current of the thin-film transistor meets the requirements, thus ensuring the improvement effect on pixel light leakage.

[0051] In one possible implementation, the mobility of the organic material layer in the light-emitting device provided in this embodiment is less than or equal to the mobility of the adjacent film layer on the side closest to the light-emitting layer. This is more conducive to ensuring that the enhancement of the device's induced capacitance meets the requirements, and that the reduction in the magnitude of the rise in the first electrode (anode) potential of the pixel in the off-state due to the leakage current of the thin-film transistor meets the requirements, further guaranteeing the improvement effect on pixel light leakage.

[0052] In one possible implementation, the mobility of the organic material layer in the light-emitting device provided in this embodiment is 5%-50% of the mobility of the adjacent film layer on the side closest to the light-emitting layer. This is more conducive to ensuring that the enhancement of the device's induced capacitance meets the requirements, and that the reduction in the magnitude of the rise in the first electrode (anode) potential of the pixel in the off-state due to the leakage current of the thin-film transistor meets the requirements, further guaranteeing the improvement effect on pixel light leakage.

[0053] Furthermore, the mobility of the organic material layer in the light-emitting device provided in this embodiment is 10% of the mobility of the adjacent film layer on the side closest to the light-emitting layer.

[0054] In one possible implementation, the thickness of the organic material layer in the light-emitting device provided in this embodiment is less than the thickness of the adjacent film layer on the side closer to the light-emitting layer, and / or the thickness of the organic material layer is less than the thickness of the adjacent film layer on the side farther from the light-emitting layer. This is more conducive to ensuring that the enhancement of the device's induced capacitance meets the requirements, and that the reduction in the magnitude of the rise in the first electrode (anode) potential of the pixel in the off-state due to the leakage current of the thin-film transistor meets the requirements, further guaranteeing the improvement effect on pixel light leakage.

[0055] In one possible implementation, the light-emitting device provided in this embodiment further includes a first hole transport layer (HTL) and a second hole transport layer in the organic functional layer. The first hole transport layer, the organic material layer, the second hole transport layer and the light-emitting layer are sequentially stacked on the first electrode.

[0056] In one possible implementation, the light-emitting device provided in this embodiment further includes a first hole transport layer, a second hole transport layer, and a third hole transport layer in the organic functional layer. The first hole transport layer, the third hole transport layer, the organic material layer, the second hole transport layer, and the light-emitting layer are sequentially stacked on the first electrode.

[0057] The above implementation method, by designing the interface where holes accumulate to be far away from the light-emitting layer, can further reduce the probability of holes and electrons meeting under low voltage, thereby further improving the pixel light leakage phenomenon.

[0058] In one possible implementation, the organic functional layer of the light-emitting device provided in this embodiment further includes a first electron transport layer (ETL) located between the light-emitting layer and the second electrode (cathode).

[0059] In one possible implementation, the organic functional layer of the light-emitting device provided in this embodiment further includes a second electron transport layer located between the first electron transport layer and the second electrode (cathode).

[0060] In a specific example, combining the above implementation methods, the light-emitting device is as follows: Figure 4As shown, the device includes a first electrode 401 (anode), a second electrode 402 (cathode), and an organic functional layer disposed between the first electrode 401 and the second electrode 402. The organic functional layer includes a first hole transport layer 405, a third hole transport layer 406, an organic material layer 404, a second hole transport layer 407, a light-emitting layer 403, a first electron transport layer 408, and a second electron transport layer 409, which are sequentially stacked on the first electrode 401. The dipole moment of the polar molecules in the organic material layer 404 is greater than the dipole moment of the molecules in the third hole transport layer 406 and the second hole transport layer 407. Furthermore, the hole mobility of the organic material layer 404 is less than or equal to the hole mobility of the second hole transport layer 407. Furthermore, the thickness of the organic material layer 404 is less than the thickness of the third hole transport layer 406 and the second hole transport layer 407.

[0061] In one possible implementation, the organic functional layer of the light-emitting device provided in this embodiment further includes a hole injection layer (HIL) and an electron injection layer (EIL). The hole injection layer is located between the first electrode (anode) and the first hole transport layer. When only the first electron transport layer is provided, the electron injection layer is located between the first electron transport layer and the second electrode (cathode). When both the first and second electron transport layers are provided, the electron injection layer is located between the second electron transport layer and the second electrode (cathode).

[0062] In one possible implementation, the organic functional layer of the light-emitting device provided in this embodiment further includes an electron blocking layer (EBL) and a hole blocking layer (HBL), with the electron blocking layer located between the second hole transport layer and the light-emitting layer, and the hole blocking layer located between the light-emitting layer and the first electron transport layer.

[0063] For example, combining the above implementation, the light-emitting principle of the light-emitting device is as follows: The first electrode (anode) generates holes, and the hole injection layer (HIT) injects holes into the hole transport layer (HTL). The hole transport layer (HTL) accelerates the transport of holes to the electron blocking layer (EBL). The electron blocking layer (EBL) blocks the transport of electrons and transports holes to the light-emitting layer (EML). The second electrode (cathode) generates electrons, and the electron injection layer (EIL) injects electrons into the electron transport layer (ETL). The electron transport layer (ETL) accelerates the transport of electrons to the hole blocking layer (HBL). The hole blocking layer (HBL) blocks the transport of holes and transports electrons to the (EML). Holes and electrons recombine in the (EML) to form excitons, which emit light.

[0064] In a specific example, combining the above implementation methods, the light-emitting device is as follows: Figure 5As shown, the device includes a first electrode 501 (anode), a second electrode 502 (cathode), and an organic functional layer disposed between the first electrode 501 and the second electrode 502. The organic functional layer includes, in sequence, a hole injection layer 510, a first hole transport layer 505, a third hole transport layer 506, an organic material layer 504, a second hole transport layer 507, an electron blocking layer 511, a light-emitting layer 503, a hole blocking layer 512, a first electron transport layer 508, a second electron transport layer 509, and an electron injection layer 513 disposed on the first electrode 401. The dipole moment of the polar molecules in the organic material layer 504 is greater than the dipole moment of the molecules in the third hole transport layer 506 and the second hole transport layer 507. Furthermore, the hole mobility of the organic material layer 504 is less than or equal to the hole mobility of the second hole transport layer 507. Furthermore, the thickness of the organic material layer 504 is less than the thickness of the third hole transport layer 506 and the second hole transport layer 507.

[0065] Another embodiment of the present invention provides a display panel including a red light-emitting device, a green light-emitting device and a blue light-emitting device, wherein at least one of the red light-emitting device, the green light-emitting device and the blue light-emitting device is a light-emitting device provided in the above embodiment having an organic material layer.

[0066] In one possible implementation, the red and / or green light-emitting devices in the display panel provided in this embodiment are the light-emitting devices with organic material layers provided in the above embodiments. Since light leakage is more severe in red and green pixels in OLED display panels, while light leakage in blue pixels is usually not significant, this implementation uses red and / or green light-emitting devices with organic material layers provided in the above embodiments to specifically improve the light leakage of red and green pixels.

[0067] In one possible implementation, the display panel provided in this embodiment further includes a low-temperature polycrystalline silicon thin-film transistor, or in other words, the thin-film transistor in the display panel provided in this embodiment is a low-temperature polycrystalline silicon thin-film transistor.

[0068] The following will provide a detailed description of the display panel provided in this embodiment, using specific examples of existing display panels as references and three specific examples of the display panel provided in this embodiment.

[0069] I. Specific examples of existing display panels:

[0070] like Figure 6 As shown, an existing display panel includes, for example, a substrate and a driving circuit layer, a light-emitting device layer, and a light extraction layer 620 sequentially disposed on the substrate, wherein, as Figure 6As shown, the light-emitting device layer includes a red pixel anode 601, a green pixel anode 602, a blue pixel anode 603, a first hole transport layer 604, a third hole transport layer 605, a red hole transport layer 606, a green hole transport layer 607, a blue hole transport layer 608, a red light-emitting layer 609, a green light-emitting layer 610, a blue light-emitting layer 611, a first electron transport layer 612, a second electron transport layer 613, and a cathode 614.

[0071] In this display panel, the red, green, and blue pixels share a common cathode 614, meaning the cathodes of the red, green, and blue pixels are at the same potential. Charge injection and light emission are controlled by the change in the potential of the red pixel anode 601, green pixel anode 602, and blue pixel anode 603 via thin-film transistors in the driving circuit layer. However, because thin-film transistors have off-state leakage current, positive charge accumulates on the anode before the transistors are turned on, causing light leakage. Figure 7 As shown, during the period of 0-1V anode voltage before the thin-film transistor is turned on, the device-induced capacitance (or conversion capacitance) of red, green and blue pixels is low, especially the device-induced capacitance of red and green pixels. As a result, the leakage current of the thin-film transistor in the off state will cause the anode potential to rise by a large margin and rise by a fast pace, resulting in severe light leakage of pixels in the off state.

[0072] For example, due to factors such as differences in luminous efficiency, the area ratio of red, green, and blue pixels on a display panel can be designed to be 1:1.2:1.8. Furthermore, it should be noted that... Figure 6 As shown, the sum of the thicknesses of the red hole transport layer 606 and the red emitting layer 609, the sum of the thicknesses of the green hole transport layer 607 and the green emitting layer 610, and the sum of the thicknesses of the blue hole transport layer 608 and the blue emitting layer 611 decrease in that order. In reality, under these conditions, the morphology of some upper layers, such as the first electron transport layer 612, will not be as... Figure 6 The flatness shown Figure 6 For illustrative purposes only.

[0073] II. A first specific example of the display panel provided in this embodiment:

[0074] The first specific example of the display panel provided in this embodiment includes a substrate and a driving circuit layer, a light-emitting device layer, and a light extraction layer 620 sequentially disposed on the substrate, such as... Figure 8As shown, unlike existing display panels, the light-emitting device layer in the first specific example of the display panel provided in this embodiment includes a red pixel anode 601, a green pixel anode 602, a blue pixel anode 603, a first hole transport layer 604, a third hole transport layer 605, a red hole transport layer 606, a green hole transport layer 607', a green pixel organic material layer 615, a blue hole transport layer 608, a red light-emitting layer 609, a green light-emitting layer 610, a blue light-emitting layer 611, a first electron transport layer 612, a second electron transport layer 613, and a cathode 614. For example, the organic material layer in the light-emitting device layer is formed on the anode by a vapor deposition process, such as... Figure 8 and Figure 6 As shown, in the first specific example of the display panel provided in this embodiment, after adding the green pixel organic material layer 615, the sum of the thicknesses of the green pixel organic material layer 615 and the green hole transport layer 607 is equal to the thickness of the green hole transport layer 607 in the existing specific example of the display panel.

[0075] The first specific example of the display panel provided in this embodiment shows the performance difference between the green pixel organic material layer 615 added between the third hole transport layer 605 and the green hole transport layer 607' and the third hole transport layer 605 and the green hole transport layer 607' as shown in Table 2. In Table 2, HOMO represents the highest occupied molecular orbital energy level.

[0076] Table 2

[0077] Membrane label Dipole moment (D) Molecular polarity film thickness HOMO(ev) migration rate 607` <1.1 weak 20 nanometers 5.5 <![CDATA[e -05 ~e -06 ]]> 615 >1.3 powerful 10 nanometers 5.0～5.5 <![CDATA[e -04 ~e -05 ]]> 605 <1.1 weak 100 nanometers 5.0 <![CDATA[e -04 ]]>

[0078] See Figure 9 and Figure 7 In comparison, the first specific example of the display panel provided in this embodiment adds a green pixel organic material layer 615 between the third hole transport layer 605 and the green hole transport layer 607'. During the period of 0-1V anode voltage before the thin film transistor is turned on, the device-induced capacitance of the green pixel is significantly enhanced, which enhances the ability of the green pixel device to store charge before it is turned on. This reduces the magnitude of the potential rise of the green pixel anode 602 caused by the leakage current of the thin film transistor in the off state, thereby improving the light leakage phenomenon of the green pixel in the off state. Specifically, as shown in Table 3, compared with the specific example of the existing display panel (hereinafter referred to as the reference example in Table 3), the magnitude of the potential rise of the green pixel anode 602 in the first specific example of the display panel provided in this embodiment (hereinafter referred to as Example 1 in Table 3) with the addition of the green pixel organic material layer 615 is reduced from 34% to 21%, a reduction of up to 38%. In Table 3, the anode potential rise is a percentage of the device turn-on potential.

[0079] Table 3

[0080]

[0081]

[0082] III. A second specific example of the display panel provided in this embodiment:

[0083] The second specific example of the display panel provided in this embodiment includes a substrate and a driving circuit layer, a light-emitting device layer, and a light extraction layer 620 sequentially disposed on the substrate, such as... Figure 10 As shown, unlike existing display panels, the light-emitting device layer in the second specific example of the display panel provided in this embodiment includes a red pixel anode 601, a green pixel anode 602, a blue pixel anode 603, a first hole transport layer 604, a third hole transport layer 605, a red hole transport layer 606', a red pixel organic material layer 616, a green hole transport layer 607, a blue hole transport layer 608, a red light-emitting layer 609, a green light-emitting layer 610, a blue light-emitting layer 611, a first electron transport layer 612, a second electron transport layer 613, and a cathode 614.

[0084] The second specific example of the display panel provided in this embodiment shows the performance difference between the red pixel organic material layer 616 added between the third hole transport layer 605 and the red hole transport layer 606' and the third hole transport layer 605 and the red hole transport layer 606', as shown in Table 4.

[0085] Table 4

[0086] Membrane label Dipole moment (D) Molecular polarity film thickness HOMO(ev) migration rate 606` <1.1 weak 70 nanometers 5.5 <![CDATA[e -05 ~e -06 ]]> 616 >1.3 powerful 10 nanometers 5.5～6.0 <![CDATA[e -04 ~e -05 ]]> 605 <1.1 weak 100 nanometers 5.0 <![CDATA[e -04 ]]>

[0087] See Figure 11 and Figure 7 In comparison, the second specific example of the display panel provided in this embodiment adds a red pixel organic material layer 616 between the third hole transport layer 605 and the red hole transport layer 606'. During the period of 0-1V anode voltage before the thin film transistor is turned on, the device-induced capacitance of the red pixel is significantly enhanced, which enhances the ability of the red pixel device to store charge before it is turned on. This reduces the magnitude of the potential rise of the red pixel anode 601 caused by the leakage current of the thin film transistor in the off state, thereby improving the light leakage phenomenon of the red pixel in the off state. Specifically, as shown in Table 5, compared with the specific example of the existing display panel (hereinafter referred to as the reference example in Table 5), the magnitude of the potential rise of the red pixel anode 601 in the second specific example of the display panel provided in this embodiment (hereinafter referred to as Example 2 in Table 5) with the addition of the red pixel organic material layer 616 is reduced from 51% to 43%, a reduction of up to 16%.

[0088] Table 5

[0089]

[0090] IV. A third specific example of the display panel provided in this embodiment:

[0091] The third specific example of the display panel provided in this embodiment includes a substrate and a driving circuit layer, a light-emitting device layer, and a light extraction layer 620 sequentially disposed on the substrate, such as... Figure 12 As shown, unlike existing display panels, the light-emitting device layer in the second specific example of the display panel provided in this embodiment includes a red pixel anode 601, a green pixel anode 602, a blue pixel anode 603, a first hole transport layer 604, a third hole transport layer 605, a red hole transport layer 606', a red pixel organic material layer 616, a green hole transport layer 607', a green pixel organic material layer 615, a blue hole transport layer 608, a red light-emitting layer 609, a green light-emitting layer 610, a blue light-emitting layer 611, a first electron transport layer 612, a second electron transport layer 613, and a cathode 614.

[0092] The third specific example of the display panel provided in this embodiment shows the performance difference between the red pixel organic material layer 616 added between the third hole transport layer 605 and the red hole transport layer 606' and the third hole transport layer 605 and the red hole transport layer 606', and the performance difference between the green pixel organic material layer 615 added between the third hole transport layer 605 and the green hole transport layer 607' and the third hole transport layer 605 and the green hole transport layer 607', as shown in Table 6.

[0093] Table 6

[0094]

[0095]

[0096] See Figure 13 and Figure 7In comparison, the third specific example of the display panel provided in this embodiment adds a red pixel organic material layer 616 between the third hole transport layer 605 and the red hole transport layer 606', and adds a green pixel organic material layer 615 between the third hole transport layer 605 and the green hole transport layer 607'. During the period of 0-1V anode voltage before the thin-film transistor is turned on, the device-induced capacitance of the red and green pixels is significantly enhanced. This enhances the ability of the red and green pixel devices to store charge before being turned on, and reduces the red image caused by the leakage current of the thin-film transistor in the off state. The potential rise of the red pixel anode 601 and the green pixel anode 602 is increased, thereby improving the light leakage phenomenon of the red and green pixels in the off state. Specifically, as shown in Table 7, compared with the specific examples of existing display panels (hereinafter referred to as the reference scale in Table 7), in the third specific example of the display panel provided in this embodiment (hereinafter referred to as Example 3 in Table 7) with the addition of the red pixel organic material layer 616 and the green pixel organic material layer 615: the potential rise of the red pixel anode 601 is reduced from 51% to 43%, a decrease of up to 16%; the potential rise of the green pixel anode 602 is reduced from 34% to 21%, a decrease of up to 38%.

[0097] Table 7

[0098]

[0099] Another embodiment of the present invention provides a display device including the aforementioned display panel. The display device can be any product or component with display functionality, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator; this embodiment does not limit the scope of the application.

[0100] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A light emitting device, characterized by, The organic functional layer comprises a light-emitting layer and an organic material layer, the organic material layer comprises polar molecules, and a dipole moment of the polar molecules of the organic material layer is greater than a dipole moment of molecules of an adjacent film layer adjacent to the organic material layer; The dipole moment of the polar molecules of the organic material layer is greater than 1.3 debye; The organic functional layer further comprises a first hole transport layer and a second hole transport layer, the first hole transport layer, the organic material layer, the second hole transport layer, and the light-emitting layer are sequentially stacked on the first electrode.

2. The light emitting device of claim 1, wherein, The mobility of the organic material layer is less than or equal to the mobility of an adjacent film layer adjacent to a side of the organic material layer close to the light-emitting layer.

3. The light emitting device of claim 2, wherein, The mobility of the organic material layer is 5%-50% of the mobility of an adjacent film layer adjacent to a side of the organic material layer close to the light-emitting layer.

4. The light emitting device of claim 1, wherein, The thickness of the organic material layer is less than the thickness of an adjacent film layer adjacent to a side of the organic material layer close to the light-emitting layer, and / or the thickness of the organic material layer is less than an adjacent film layer adjacent to a side of the organic material layer away from the light-emitting layer.

5. The light emitting device of claim 1, wherein, The organic functional layer further comprises an electron transport layer between the light-emitting layer and the second electrode.

6. The light emitting device of claim 5, wherein, The organic functional layer further comprises a hole injection layer between the first electrode and the first hole transport layer, and an electron injection layer between the electron transport layer and the second electrode.

7. The light emitting device of claim 5, wherein the first and second light emitting devices are arranged in a vertical stack. The organic functional layer further comprises an electron blocking layer between the second hole transport layer and the light-emitting layer, and a hole blocking layer between the light-emitting layer and the electron transport layer.

8. A display panel, characterized by, The display panel comprises a red light-emitting device, a green light-emitting device, and a blue light-emitting device, at least one of the red light-emitting device, the green light-emitting device, and the blue light-emitting device is the light-emitting device as claimed in any one of claims 1-7.

9. The display panel of claim 8, wherein, The red light-emitting device and / or the green light-emitting device is the light-emitting device as claimed in any one of claims 1-7.

10. The display panel of claim 8, wherein, The display panel further comprises a low-temperature polysilicon thin-film transistor.

11. A display device, characterized by comprising: The display panel comprises the display panel as claimed in any one of claims 8-10.

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