Light-emitting device, display panel and display device

Abstract

The invention discloses a light-emitting device, a display panel and a display device.The light-emitting device comprises a light-emitting layer and a film layer set located on one side of the light-emitting layer, the film layer set comprises a charge transmission layer, at least one adjusting layer and a charge blocking layer which are sequentially arranged in a stacked mode in the direction close to the light-emitting layer, and the adjusting layer is used for reducing capacitance of the light-emitting device. According to the design of the invention, the problems of dark smear and color cast caused by low brightness of the first frame can be improved.

Description

Technical Field

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

[0002] With the development and popularization of display technology in recent years, display panels have been applied to various electronic devices, such as mobile phones, tablet computers or other portable electronic devices.

[0003] However, the inventors of the present application have discovered that the display quality of current display panels needs to be further improved. Summary of the invention

[0004] The present application provides a light-emitting device, a display panel and a display apparatus, which can improve the problems of dark smear and color cast caused by low brightness of the first frame.

[0005] In a first aspect, the present application provides a light-emitting device, comprising: a light-emitting layer, and a film layer group located on one side of the light-emitting layer, wherein the film layer group comprises a charge transport layer, at least one adjustment layer, and a charge blocking layer stacked in sequence in a direction close to the light-emitting layer, and the adjustment layer is used to reduce the capacitance of the light-emitting device. .

[0006] In one embodiment, the charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, and the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the highest occupied molecular orbital energy level of the first adjustment layer is less than the highest occupied molecular orbital energy levels of the hole transport layer and the electron blocking layer.

[0007] In one embodiment, the absolute value of the difference between the highest occupied molecular orbital energy level of the first adjustment layer and the highest occupied molecular orbital energy level of the hole transport layer is greater than or equal to 0.2 eV; and / or the absolute value of the difference between the highest occupied molecular orbital energy level of the first adjustment layer and the highest occupied molecular orbital energy level of the electron blocking layer is greater than or equal to 0.2 eV.

[0008] In one embodiment, the highest occupied molecular orbital energy level of the first adjustment layer is less than or equal to -5.6 eV; and / or the minimum value of the highest occupied molecular orbital energy level of the hole transport layer and the highest occupied molecular orbital energy level of the electron blocking layer is less than or equal to -5.4 eV.

[0009] In one embodiment, the highest occupied molecular orbital energy level of the electron blocking layer is less than the highest occupied molecular orbital energy level of the hole transport layer.

[0010] In one embodiment, the charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, and the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the lowest unoccupied molecular orbital energy level of the second adjustment layer is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer and the lowest unoccupied molecular orbital energy level of the hole blocking layer.

[0011] In one embodiment, the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second adjustment layer and the lowest unoccupied molecular orbital energy level of the electron transport layer is greater than or equal to 0.2 eV; and / or the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second adjustment layer and the lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than or equal to 0.2 eV.

[0012] In one embodiment, the lowest unoccupied molecular orbital energy level of the second adjustment layer is greater than or equal to -2.8 eV; and / or the maximum value of the lowest unoccupied molecular orbital energy level of the electron transport layer and the lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than or equal to -3.0 eV.

[0013] In one embodiment, the lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer.

[0014] In one embodiment, the mobility of the adjustment layer is smaller than the mobility of the charge transport layer and the mobility of the charge blocking layer.

[0015] In one embodiment, the mobility of the adjustment layer is less than or equal to 1×10 -4 cm 2 / (V·s).

[0016] In one embodiment, the charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, and the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the hole mobility of the first adjustment layer is less than the hole mobility of the hole transport layer and the hole mobility of the electron blocking layer.

[0017] In one embodiment, the charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, and the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the electron mobility of the second adjustment layer is less than the electron mobility of the electron transport layer and the electron mobility of the hole blocking layer.

[0018] In one embodiment, the charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the material of the first adjustment layer includes a triphenylamine core structure material.

[0019] Preferably, the material of the first adjustment layer includes triphenylamine and / or benzocarbazole derivatives.

[0020] In one embodiment, the charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the material of the second adjustment layer includes at least one of a heteroaromatic ring derivative containing more than one N and a heterocyclic compound containing O and S.

[0021] In one embodiment, the thickness of the adjustment layer is greater than and less than or equal to

[0022] In one embodiment, the thickness of the adjustment layer is

[0023] In one implementation, the light emitting device is a red light emitting device, a green light emitting device or a blue light emitting device.

[0024] A second aspect of the present application provides a display panel, which includes the light-emitting device described in any one of the above embodiments.

[0025] A third aspect of the present application provides a display device, which includes the display panel according to any one of the above embodiments.

[0026] Different from the prior art, the beneficial effect of the present application is that the light-emitting device of the present application is provided with at least one adjustment layer between the charge transfer layer and the charge blocking layer, and the adjustment layer can reduce the capacitance of the light-emitting device. Based on this, the adjustment layer can be set by selecting the one with larger capacitance from the existing red light-emitting devices, green light-emitting devices and blue light-emitting devices. In this way, the capacitance of the red light-emitting device, the green light-emitting device and the blue light-emitting device can be made consistent, thereby ensuring the consistency of the start-up speed, thereby avoiding the ghosting caused by the low brightness of the first frame, thereby improving the problem of dark display and color cast. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0028] Figure 1 is a schematic structural diagram of a first embodiment of a light emitting device of the present application;

[0029] Figure 2 It is a schematic diagram of the structure of a light emitting device in the prior art;

[0030] Figure 3 yes Figure 1 A schematic structural diagram of a second embodiment of the light emitting device;

[0031] Figure 4 yes Figure 3 A schematic diagram of an implementation of the orbital energy levels of each film layer;

[0032] Figure 5 yes Figure 1 A schematic structural diagram of a third embodiment of the light emitting device;

[0033] Figure 6 yes Figure 5 A schematic diagram of an implementation of the orbital energy levels of each film layer;

[0034] Figure 7 yes Figure 1 A schematic structural diagram of a fourth embodiment of the light emitting device;

[0035] Figure 8 yes Figure 7 A schematic diagram of an implementation of the orbital energy levels of each film layer;

[0036] Fig. 9 yes Figure 1 The experimental test data curve of the adjustment layer in the light-emitting device under multiple thickness conditions;

[0037] Fig.10 is a schematic diagram of an embodiment of a display panel of the present application;

[0038] Fig.11 It is a schematic diagram of an embodiment of the display device of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] It should be noted that the terms "first" and "second" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0041] In the prior art, due to the different device performances of red, green and blue light-emitting devices, when the display panel switches from a black state to a display image, the red, green and blue light-emitting devices have different start-up speeds, and the brightness of the first frame is low, resulting in ghosting, which leads to problems of dark display and color cast.

[0042] See also Figure 1 In a first aspect, the present application provides a light-emitting device 10, which includes: a light-emitting layer 400 and a film layer group 1000 located on one side of the light-emitting layer 400, the film layer group 100 includes a charge transfer layer 100, at least one adjustment layer 300 and a charge blocking layer 200 stacked in sequence in a direction close to the light-emitting layer 400, and the adjustment layer 300 is used to reduce the capacitance of the light-emitting device 10.

[0043] Specifically, the function of the charge transport layer 100 is to transport charges, that is, to transport charges from an electrode (not shown) to the light-emitting layer 400, and the function of the charge blocking layer 200 is to block charges, that is, to block charges from the light-emitting layer 400 at the interface between the light-emitting layer 400 and the charge blocking layer 200. Generally speaking, the two sides of the light-emitting layer 400 are electrically connected to two electrodes, respectively, and the two electrodes are a cathode and an anode, respectively, and the cathode provides electrons to the light-emitting layer 400, and the anode provides holes to the light-emitting layer 400. It can be understood that since the direction in which the charge transport layer 100 transports charges is opposite to the direction in which the charge blocking layer 200 blocks charges, the charge types played by the charge transport layer 100 and the charge blocking layer 200 are also opposite. When the charge transport layer 100 is used to transport holes, the charge blocking layer 200 is used to block electrons, and when the charge transport layer 100 is used to transport electrons, the charge blocking layer 200 is used to block holes.

[0044] Furthermore, the present application provides at least one adjustment layer 300 between the charge transport layer 100 and the charge blocking layer 200. The number of the adjustment layer 300 is not specifically limited, and may be one, two or three layers. The adjustment layer 300 is used to reduce the capacitance of the light-emitting device 10. Its specific function is to reduce the charge transfer to the light-emitting layer 400 by blocking at least part of the charge from the electrode. Therefore, the adjustment layer 300 and the charge transport layer 100 have the same charge type. When the charge transport layer 100 is used to transport holes, the adjustment layer 300 is used to block at least part of the holes. When the charge transport layer 100 is used to transport electrons, the adjustment layer 300 is used to block at least part of the electrons. To explain more clearly, combined with the capacitance formula Wherein, C is the capacitance of the light emitting device, ε is the dielectric constant, S is the relative area of ​​the two plates of the capacitor, k is the electrostatic force constant, and d is the distance between the two plates of the capacitor. Figure 2, most of the electrons and holes will be concentrated on the interface on both sides of the light-emitting layer 400. Therefore, the interface on both sides of the light-emitting layer 400 is equivalent to the two plates of the capacitor, and the distance between the two plates is approximately d1. The present application can block at least part of the charges by setting the adjustment layer 300, so that at least part of the charges cannot be transmitted to the interface of the light-emitting layer 400, but are blocked at the interface between the adjustment layer 300 and the charge transfer layer 100, so that the distance between the two plates of the capacitor increases to approximately the distance d2. According to the above capacitance formula, the increase in the distance between the two plates will reduce the capacitance. The present application is to increase the distance between the two plates of the capacitor by setting the adjustment layer 300, so as to achieve the improvement effect. It can be understood that by setting the adjustment layer 300 for the device with the larger capacitance among the red light-emitting device, the green light-emitting device and the blue light-emitting device, the light-emitting devices of each color have the same light-up speed, so that the smear can be improved, thereby avoiding the problem of dark display and color cast. At the same time, by reducing the capacitance of the larger one, the light-up speed can also be increased, and the response speed of the light-emitting device can be increased.

[0045] It can be understood that the light emitting device 10 of the present application includes an organic light emitting device, and the adjustment layer 300 is applicable to at least one of a red light emitting device, a green light emitting device, and a blue light emitting device.

[0046] In one embodiment, see Figure 3 and Figure 4 The charge transport layer 100 includes a hole transport layer 110, the charge blocking layer 200 includes an electron blocking layer 210, and the at least one adjustment layer 300 includes a first adjustment layer 310, the first adjustment layer 310 is located between the hole transport layer 110 and the electron blocking layer 210, and the highest occupied molecular orbital energy level of the first adjustment layer 310 is less than the highest occupied molecular orbital energy level of the hole transport layer 110 and the electron blocking layer 210.

[0047] Specifically, the frontier orbital energy level includes the highest occupied molecular orbital energy level (HOMO energy level) and the lowest unoccupied molecular orbital energy level (LUMO energy level). In the process of holes being transferred from the hole transport layer 110 to the light-emitting layer 400, it is necessary to overcome the barrier of the highest occupied molecular orbital energy level between different film layers. Since the highest occupied molecular orbital energy level of the first adjustment layer 310 is less than the highest occupied molecular orbital energy level of the hole transport layer 110 and the electron blocking layer 210, the energy level barrier between the hole transport layer 110 and the first adjustment layer 310 is wider than the energy level barrier between the hole transport layer 110 and the electron blocking layer 210. The provision of the first adjustment layer 310 increases the difficulty of hole transmission. Therefore, some holes will stay at the interface between the hole transport layer 110 and the first adjustment layer 310, which will reduce the capacitance of the light-emitting device 10. It should be noted that in some embodiments, the electron blocking layer 210 can also be called a compensation layer (Prime). It should be noted that the two sides of the first adjustment layer 310 may be adjacent to the hole transport layer 110 and the electron blocking layer 210 respectively, or may not be in direct contact with each other, and other film layers may be provided in between, which is not limited in the present application.

[0048] Of course, there is no limitation on the number of the first adjustment layers 310 , which may be one layer, two layers, or three layers.

[0049] In one embodiment, the absolute value of the difference between the highest occupied molecular orbital energy level of the first adjustment layer 310 and the highest occupied molecular orbital energy level of the hole transport layer 110 is greater than or equal to 0.2 eV. Specifically, the absolute value may be 0.2 eV, 0.3 eV or 0.5 eV, etc., and this application does not impose any specific restrictions. That is, the highest occupied molecular orbital energy level of the first adjustment layer 310 is at least 0.2 eV deeper than the highest occupied molecular orbital energy level of the hole transport layer 110.

[0050] In one embodiment, the absolute value of the difference between the highest occupied molecular orbital energy level of the first adjustment layer 310 and the highest occupied molecular orbital energy level of the electron blocking layer 210 is greater than or equal to 0.2 eV. Specifically, the absolute value may be 0.2 eV, 0.3 eV, or 0.5 eV, etc., and the present application does not impose any specific restrictions. That is, the highest occupied molecular orbital energy level of the first adjustment layer 310 is at least 0.2 eV deeper than the highest occupied molecular orbital energy level of the electron blocking layer 210.

[0051] In one embodiment, the highest occupied molecular orbital energy level of the first adjustment layer 310 is less than or equal to -5.6 eV. Specifically, the highest occupied molecular orbital energy level of the first adjustment layer 310 may be -5.6 eV, -5.8 eV or -6.0 eV, etc., which is not specifically limited in the present application.

[0052] In one embodiment, the minimum value of the highest occupied molecular orbital energy level of the hole transport layer 110 and the highest occupied molecular orbital energy level of the electron blocking layer 210 is less than or equal to -5.4 eV. Specifically, the minimum value may be -5.4 eV, -5.6 eV or -5.8 eV, etc., and the present application does not impose any specific restrictions. In other words, if the highest occupied molecular orbital energy level of the hole transport layer 110 is less than the highest occupied molecular orbital energy level of the electron blocking layer 210, the highest occupied molecular orbital energy level of the hole transport layer 110 is less than or equal to -5.4 eV, and if the highest occupied molecular orbital energy level of the electron blocking layer 210 is less than the highest occupied molecular orbital energy level of the hole transport layer 110, the highest occupied molecular orbital energy level of the electron blocking layer 210 is less than or equal to -5.4 eV.

[0053] Of course, the numerical limits for the highest occupied molecular orbital energy levels of the hole transport layer 110 , the first adjustment layer 310 , and the electron blocking layer 210 may also be other.

[0054] In one embodiment, see Figure 4 , the highest occupied molecular orbital energy level of the electron blocking layer 210 is less than the highest occupied molecular orbital energy level of the hole transport layer 110. This allows the energy levels of the hole transport layer 110 and the electron blocking layer 210 to be better matched. In other embodiments, the highest occupied molecular orbital energy level of the electron blocking layer 210 may also be greater than or equal to the highest occupied molecular orbital energy level of the hole transport layer 110. In short, the present application does not impose any restrictions on the comparison of the highest occupied molecular orbital energy level of the electron blocking layer 210 and the highest occupied molecular orbital energy level of the hole transport layer 110.

[0055] In one embodiment, see Figure 5 and Figure 6 The charge transport layer 100 includes an electron transport layer 120, the charge blocking layer 200 includes a hole blocking layer 220, and the at least one adjustment layer 300 includes a second adjustment layer 320, the second adjustment layer 320 is located between the electron transport layer 120 and the hole blocking layer 220, and the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer 120 and the lowest unoccupied molecular orbital energy level of the hole blocking layer 220.

[0056] Specifically, in the process of electrons being transmitted from the electron transport layer 120 to the light-emitting layer 400, it is necessary to overcome the barrier of the lowest unoccupied molecular orbital energy level between different film layers. Since the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer 120 and the hole blocking layer 220, the energy level barrier between the electron transport layer 120 and the second adjustment layer 320 is wider than the energy level barrier between the electron transport layer 120 and the hole blocking layer 220. The provision of the second adjustment layer 320 increases the difficulty of electron transmission. Therefore, some electrons will stay at the interface between the electron transport layer 120 and the second adjustment layer 320, which will reduce the capacitance of the light-emitting device 10. It should be noted that the two sides of the second adjustment layer 320 may be adjacent to the electron transport layer 120 and the hole blocking layer 220, or may not be in direct contact, and other film layers may be provided in the middle, which is not limited in this application.

[0057] Of course, there is no limitation on the number of the second adjustment layers 320 , and it can be one layer, two layers, or three layers.

[0058] In one embodiment, the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 and the lowest unoccupied molecular orbital energy level of the electron transport layer 120 is greater than or equal to 0.2 eV. Specifically, the absolute value may be 0.2 eV, 0.3 eV, or 0.5 eV, etc., and the present application does not impose any specific restrictions. That is, the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is at least 0.2 eV shallower than the lowest unoccupied molecular orbital energy level of the electron transport layer 120.

[0059] In one embodiment, the absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 and the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 is greater than or equal to 0.2 eV. Specifically, the absolute value may be 0.2 eV, 0.3 eV, or 0.5 eV, etc., and the present application does not make specific restrictions. That is, the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is at least 0.2 eV shallower than the lowest unoccupied molecular orbital energy level of the hole blocking layer 220.

[0060] In one embodiment, the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is greater than or equal to -2.8 eV. Specifically, the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 may be -2.8 eV, -2.6 eV or -2.4 eV, etc., which is not specifically limited in this application.

[0061] In one embodiment, the maximum value of the lowest unoccupied molecular orbital energy level of the electron transport layer 120 and the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 is greater than or equal to -3.0 eV. Specifically, the maximum value may be -3.0 eV, -2.8 eV or -2.6 eV, etc., and this application does not impose specific restrictions. In other words, if the lowest unoccupied molecular orbital energy level of the electron transport layer 120 is greater than the lowest unoccupied molecular orbital energy level of the hole blocking layer 220, the lowest unoccupied molecular orbital energy level of the electron transport layer 120 is greater than or equal to -3.0 eV, and if the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer 120, the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 is greater than or equal to -3.0 eV.

[0062] Of course, the numerical limits for the lowest unoccupied molecular orbital energy level of the electron transport layer 120 , the second adjustment layer 320 , and the hole blocking layer 220 may also be other values.

[0063] In one embodiment, the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer 120. This allows the energy levels of the electron transport layer 120 and the hole blocking layer 220 to be better matched. In other embodiments, the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 may also be less than or equal to the lowest unoccupied molecular orbital energy level of the electron transport layer 120. In short, the present application does not limit the comparison of the lowest unoccupied molecular orbital energy level of the hole blocking layer 220 and the lowest unoccupied molecular orbital energy level of the electron transport layer 120.

[0064] In some other embodiments, see Figure 7 and Figure 8 The light emitting device 10 further includes an anode 610, a hole injection layer 510, a hole transport layer 520, a first adjustment layer 310, an electron blocking layer 210, a light emitting layer 400, a hole blocking layer 220, a second adjustment layer 320, an electron transport layer 120, an electron injection layer 520 and a cathode 620 stacked in sequence. In this embodiment, the first adjustment layer 310 may be disposed between the hole transport layer 110 and the electron blocking layer 210, or the second adjustment layer 320 may be disposed between the electron transport layer 120 and the hole blocking layer 220, wherein the highest occupied molecular orbital energy level of the first adjustment layer 310 is lower than the highest occupied molecular orbital energy levels of the hole transport layer 110 and the electron blocking layer 210, and the lowest unoccupied molecular orbital energy level of the second adjustment layer 320 is higher than the lowest unoccupied molecular orbital energy level of the electron transport layer 120 and the lowest unoccupied molecular orbital energy level of the hole blocking layer 220.

[0065] In one embodiment, see Figure 1 and Figure 2, the mobility of the adjustment layer 300 is smaller than the mobility of the charge transport layer 100 and the mobility of the charge blocking layer 200 .

[0066] Specifically, the greater the mobility, the faster the charge moves. In this embodiment, an adjustment layer 300 having a smaller mobility than the charge transport layer 100 and the charge blocking layer 200 is used. When the charge is transferred from the charge transport layer 100 to the light-emitting layer 400, the charge moves more slowly in the adjustment layer 300, so that at least part of the charge is relatively further away from the light-emitting layer 400, which is equivalent to increasing the distance between the two electrodes, thereby reducing the capacitance of the light-emitting device 10.

[0067] In one embodiment, the mobility of the adjustment layer 300 is less than or equal to 1×10 -4 cm 2 / (V·s). Specifically, the value of mobility can be 1×10 -4 ,9×10 -4 or 8×10 -4 Etc., this application does not make specific limitations.

[0068] In one embodiment, see Figure 3 The charge transport layer 100 includes a hole transport layer 110, the charge blocking layer 200 includes an electron blocking layer 210, and the at least one adjustment layer 300 includes a first adjustment layer 310, the first adjustment layer 310 is located between the hole transport layer 110 and the electron blocking layer 210, and the hole mobility of the first adjustment layer 310 is less than the hole mobility of the hole transport layer 110 and the hole mobility of the electron blocking layer 210.

[0069] Specifically, by setting the first adjustment layer 310, the hole mobility of the hole in the first adjustment layer 310 is smaller than the hole mobility in the hole transport layer 110 and the hole mobility in the electron blocking layer 210, so that some holes are further away from the light-emitting layer 400, which is equivalent to increasing the distance between the two electrodes of the electrode, thereby reducing the capacitance of the light-emitting device 10. In addition, the relationship between the hole mobility of the hole transport layer 110 and the hole mobility of the electron blocking layer 210 is not limited. It should be noted that the two sides of the first adjustment layer 310 can be adjacent to the hole transport layer 110 and the electron blocking layer 210, or they can be in direct contact, and other film layers are provided in the middle, which is not limited in this application.

[0070] In one embodiment, see Figure 5The charge transport layer 100 includes an electron transport layer 120, the charge blocking layer 200 includes a hole blocking layer 220, and the at least one adjustment layer 300 includes a second adjustment layer 320, the second adjustment layer 320 is located between the electron transport layer 120 and the hole blocking layer 220, and the electron mobility of the second adjustment layer 320 is less than the electron mobility of the electron transport layer 120 and the electron mobility of the hole blocking layer 220.

[0071] Specifically, by providing the second adjustment layer 320, the electron mobility of the electrons in the second adjustment layer 320 is smaller than the electron mobility in the electron transport layer 120 and the electron mobility in the hole blocking layer 220, so that some electrons are further away from the light-emitting layer 400, which is equivalent to increasing the distance between the two plates of the electrode, thereby reducing the capacitance of the light-emitting device 10. In addition, the magnitude relationship between the electron mobility of the electron transport layer 120 and the electron mobility of the hole blocking layer 220 is not limited. It should be noted that the two sides of the second adjustment layer 320 may be adjacent to the electron transport layer 120 and the hole blocking layer 220, or may not be in direct contact, and other film layers may be provided in the middle, which is not limited in this application.

[0072] In some other embodiments, see Figure 7 A first adjustment layer 310 may be provided between the hole transport layer 110 and the electron blocking layer 210, or a second adjustment layer 320 may be provided between the electron transport layer 120 and the hole blocking layer 220, wherein the hole mobility of the first adjustment layer 310 is smaller than the hole mobility of the hole transport layer 110 and the hole mobility of the electron blocking layer 210, and the electron mobility of the second adjustment layer 320 is smaller than the electron mobility of the electron transport layer 120 and the electron mobility of the hole blocking layer 220.

[0073] Of course, in some other implementations, see Figure 7 A first adjustment layer 310 may be provided between the hole transport layer 110 and the electron blocking layer 210, or a second adjustment layer 320 may be provided between the electron transport layer 120 and the hole blocking layer 220, wherein one of the first adjustment layer 310 and the second adjustment layer 320 may be provided according to the energy level relationship in the above-mentioned embodiment, and the other may be provided according to the mobility relationship in the above-mentioned embodiment.

[0074] In one embodiment, see Figure 3 The charge transport layer 100 includes a hole transport layer 110, the charge blocking layer 200 includes an electron blocking layer 210, and the at least one adjustment layer 300 includes a first adjustment layer 310, the first adjustment layer 310 is located between the hole transport layer 110 and the electron blocking layer 210, and the material of the first adjustment layer 310 includes a triphenylamine core structure material.

[0075] In one implementation, the material of the first adjustment layer 310 includes at least one of triphenylamine and / or benzocarbazole derivatives.

[0076] In one embodiment, see Figure 5 The charge transport layer 100 includes an electron transport layer 120, the charge blocking layer 200 includes a hole blocking layer 220, and at least one adjustment layer 300 includes a second adjustment layer 320. The second adjustment layer 320 is located between the electron transport layer 120 and the hole blocking layer 220. The material of the second adjustment layer 320 includes at least one of a heteroaromatic ring derivative containing more than one N and a heterocyclic compound containing O and S.

[0077] In one embodiment, see Figure 1 , the thickness H of the adjustment layer 300 is greater than and less than or equal to For example, the thickness of the adjustment layer 300 may be or Specifically, the thickness range of the adjustment layer 300 is set to Therefore, within this thickness range, the capacitance of the light-emitting device 10 can be reduced by the adjustment layer 300 while ensuring the lifespan, luminous efficiency, start-up voltage, operating voltage and other characteristics of the light-emitting device 10.

[0078] In one embodiment, see Fig. 9 , the horizontal axis is the start-up voltage of the light emitting device 10, and the vertical axis is the capacitance of the light emitting device 10. It can be seen that when the thickness of the adjustment layer 300 is When the capacitance of the light emitting device 10 is the smallest, and the capacitance growth is not obvious at low voltage, so the capacitance can be effectively reduced and the display quality of the display panel can be improved.

[0079] In one embodiment, the thickness of the adjustment layer 300 in the red light-emitting device, the thickness of the adjustment layer 300 in the green light-emitting device, and the thickness of the adjustment layer 300 in the blue light-emitting device are the same or different, and can be set according to needs, and this application does not impose specific restrictions on this.

[0080] See also Fig.10 In a second aspect, the present application further provides a display panel 20, which includes the light-emitting device 10 of any one of the above-mentioned embodiments.

[0081] In one embodiment, there are multiple light emitting devices 10 .

[0082] See also Fig.11In a third aspect, the present application further provides a display device 30, which includes a display panel 20 according to any one of the above-mentioned embodiments.

[0083] Specifically, the display device 30 provided in the embodiment of the present invention can be a smart phone, a notebook, a tablet computer, a computer, a wearable device, etc., and the present invention does not make any specific limitations on this.

[0084] The above are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A light emitting device, characterized in that: include: A light-emitting layer, and a film layer group located on one side of the light-emitting layer, wherein the film layer group includes a charge transport layer, at least one adjustment layer and a charge blocking layer stacked in sequence in a direction close to the light-emitting layer, and the adjustment layer is used to reduce the capacitance of the light-emitting device.

2. The light emitting device according to claim 1, characterized in that: The charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, and the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the highest occupied molecular orbital energy level of the first adjustment layer is less than the highest occupied molecular orbital energy levels of the hole transport layer and the electron blocking layer.

3. The light emitting device according to claim 2, characterized in that: The absolute value of the difference between the highest occupied molecular orbital energy level of the first adjustment layer and the highest occupied molecular orbital energy level of the electron blocking layer is greater than or equal to 0.2 eV; And / or, an absolute value of a difference between a highest occupied molecular orbital energy level of the first adjustment layer and a highest occupied molecular orbital energy level of the hole transport layer is greater than or equal to 0.2 eV.

4. The light emitting device according to claim 2, characterized in that: The highest occupied molecular orbital energy level of the first adjustment layer is less than or equal to -5.6 eV; And / or, a minimum value of the highest occupied molecular orbital energy level of the hole transport layer and the highest occupied molecular orbital energy level of the electron blocking layer is less than or equal to -5.4 eV.

5. The light emitting device according to claim 2, characterized in that: The highest occupied molecular orbital energy level of the electron blocking layer is lower than the highest occupied molecular orbital energy level of the hole transport layer.

6. The light emitting device according to any one of claims 1 to 5, characterized in that: The charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the lowest unoccupied molecular orbital energy level of the second adjustment layer is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer and the lowest unoccupied molecular orbital energy level of the hole blocking layer.

7. The light emitting device according to claim 6, characterized in that: The absolute value of the difference between the lowest unoccupied molecular orbital energy level of the second adjustment layer and the lowest unoccupied molecular orbital energy level of the electron transport layer is greater than or equal to 0.2 eV; And / or, an absolute value of a difference between a lowest unoccupied molecular orbital energy level of the second adjustment layer and a lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than or equal to 0.2 eV.

8. The light emitting device according to claim 6, characterized in that: The lowest unoccupied molecular orbital energy level of the second adjustment layer is greater than or equal to -2.8 eV; And / or, a maximum value of the lowest unoccupied molecular orbital energy level of the electron transport layer and the lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than or equal to -3.0 eV.

9. The light emitting device according to claim 6, characterized in that: The lowest unoccupied molecular orbital energy level of the hole blocking layer is greater than the lowest unoccupied molecular orbital energy level of the electron transport layer.

10. The light emitting device according to claim 1, characterized in that: The mobility of the adjustment layer is smaller than the mobility of the charge transport layer and the mobility of the charge blocking layer.

11. The light emitting device according to claim 10, characterized in that: The mobility of the adjustment layer is less than or equal to 1×10 -4 cm 2 / (V·s).

12. The light emitting device according to claim 10, characterized in that: The charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the hole mobility of the first adjustment layer is less than the hole mobility of the hole transport layer and the hole mobility of the electron blocking layer.

13. The light emitting device according to any one of claims 10 to 12, characterized in that: The charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the electron mobility of the second adjustment layer is less than the electron mobility of the electron transport layer and the electron mobility of the hole blocking layer.

14. The light emitting device according to claim 1, characterized in that: The charge transport layer includes a hole transport layer, the charge blocking layer includes an electron blocking layer, the at least one adjustment layer includes a first adjustment layer, the first adjustment layer is located between the hole transport layer and the electron blocking layer, and the material of the first adjustment layer includes a triphenylamine mother core structure material; Preferably, the material of the first adjustment layer includes triphenylamine and / or benzocarbazole derivatives.

15. The light emitting device according to claim 1, characterized in that: The charge transport layer includes an electron transport layer, the charge blocking layer includes a hole blocking layer, the at least one adjustment layer includes a second adjustment layer, the second adjustment layer is located between the electron transport layer and the hole blocking layer, and the material of the second adjustment layer includes at least one of a heteroaromatic ring derivative containing more than one N and a heterocyclic compound containing O and S.

16. The light emitting device according to claim 1, characterized in that: The thickness of the adjustment layer is greater than and less than or equal to 17. The light emitting device according to claim 16, characterized in that: The thickness of the adjustment layer is 18. The light emitting device according to claim 1, characterized in that: The light emitting device is a red light emitting device, a green light emitting device or a blue light emitting device.

19. A display panel, characterized in that: The display panel comprises the light emitting device according to any one of claims 1 to 18.

20. A display device, characterized in that: The display device comprises the display panel as claimed in claim 19.

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