Light emitting device, display device
By employing a three-layer emitting layer design in OLED display devices, the electron-hole ratio is balanced, solving the problems of short lifetime and low acceleration factor, and achieving a longer LT95 duration and stable low-brightness lifetime.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BOE TECHNOLOGY GROUP CO LTD
- Filing Date
- 2022-05-26
- Publication Date
- 2026-07-21
AI Technical Summary
Existing OLED display devices suffer from shorter lifespans, insufficient brightness, and low acceleration factors due to differences in materials and device structures, resulting in LT overshoot and impacting user experience.
The design employs a three-layer light-emitting layer. The second sublayer contains both host and guest materials, with the highest exciton concentration, and is located in the middle. The first and third sublayers contain host materials with lower exciton concentrations. By controlling the energy value and thickness difference, the main light-emitting region is located in the middle, balancing the electron-hole ratio.
It significantly improves the lifespan of OLED display devices, reduces LT overshoot, increases the acceleration factor, and ensures lifespan stability at low brightness.
Smart Images
Figure CN117598041B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, and in particular to a light-emitting device and a display apparatus. Background Technology
[0002] With the development of technology, OLED (Organic Light Emitting Diode) display devices have been widely used. Currently, users have increasingly higher performance requirements for OLED display devices, such as wanting longer product lifespans.
[0003] However, due to differences in existing materials and device structures, OLED display devices cannot achieve a long lifespan in actual use, resulting in a poor user experience. Summary of the Invention
[0004] The embodiments of this application adopt the following technical solutions:
[0005] On one hand, embodiments of this application provide a light-emitting device, including:
[0006] The light-emitting layer includes a first sublayer, a second sublayer, and a third sublayer, with the second sublayer disposed between the first and third sublayers; the second sublayer includes a host material and a guest material; and excitons are recombinated in the second sublayer under the influence of external energy.
[0007] The first sublayer and the third sublayer both include the host material; the concentration of excitons in the second sublayer is greater than the concentration of excitons in the first sublayer, and the concentration of excitons in the second sublayer is greater than the concentration of excitons in the third sublayer.
[0008] Optionally, both the first sub-layer and the third sub-layer are single-layer structures and both include the main material.
[0009] Optionally, the light-emitting device further includes a hole injection layer disposed on the side of the first sub-layer away from the second sub-layer;
[0010] The absolute value of the difference between the energy value of the highest molecular occupied orbital HOMO of the first sublayer and the energy value of the highest molecular occupied orbital HOMO of the second sublayer ranges from 0.1 to 0.5 eV.
[0011] Optionally, the light-emitting device further includes an electron injection layer disposed on the side of the third sub-layer away from the second sub-layer;
[0012] The absolute value of the difference between the energy value of the lowest unoccupied orbital LUMO of the third sublayer and the energy value of the lowest unoccupied orbital LUMO of the second sublayer ranges from 0.1 to 0.5 eV.
[0013] Optionally, along a direction perpendicular to the light-emitting layer, the thickness of the second sub-layer is greater than the thickness of the first sub-layer, and the thickness of the second sub-layer is greater than the thickness of the third sub-layer.
[0014] Optionally, the thickness of the first sub-layer is the same as the thickness of the third sub-layer along a direction perpendicular to the light-emitting layer.
[0015] Optionally, the first sublayer includes a first auxiliary sublayer and a first electron blocking sublayer, wherein the first electron blocking sublayer is disposed between the first auxiliary sublayer and the second sublayer;
[0016] The third sublayer includes a second auxiliary sublayer and a first hole-blocking sublayer, wherein the first hole-blocking sublayer is disposed between the second auxiliary sublayer and the second sublayer.
[0017] Optionally, both the first auxiliary sublayer and the second auxiliary sublayer include the main material and the object material;
[0018] The first hole blocking sublayer includes a hole blocking material; the first electron blocking sublayer includes an electron blocking material.
[0019] Optionally, both the first auxiliary sublayer and the second auxiliary sublayer include the main material and the object material;
[0020] The first hole-blocking sublayer includes the host material, the guest material, and the hole-blocking material; the first electron-blocking sublayer includes the host material, the guest material, and the electron-blocking material.
[0021] Optionally, along a direction perpendicular to the light-emitting layer, the thickness of the second sub-layer is greater than the thickness of the first hole-blocking sub-layer, and the thickness of the second sub-layer is greater than the thickness of the first electron-blocking sub-layer.
[0022] Optionally, along a direction perpendicular to the light-emitting layer, the thickness of the first hole-blocking sublayer is the same as the thickness of the first electron-blocking sublayer.
[0023] Optionally, the first sublayer further includes a second electron blocking sublayer, which is disposed on the side of the first electron blocking sublayer away from the second sublayer and divides the first auxiliary sublayer into two parts.
[0024] Optionally, the second electron blocking sublayer includes the host material, the guest material, and the electron blocking material;
[0025] The doping concentration of the electron blocking material in the second electron blocking sublayer in the host material is greater than the doping concentration of the electron blocking material in the first electron blocking sublayer in the host material.
[0026] Optionally, the third sublayer further includes a second hole-blocking sublayer, which is disposed on the side of the first hole-blocking sublayer away from the second sublayer and divides the second auxiliary sublayer into two parts.
[0027] Optionally, the second hole-blocking sublayer includes the host material, the guest material, and the hole-blocking material;
[0028] The doping concentration of the hole-blocking material in the second hole-blocking sublayer in the host material is greater than the doping concentration of the hole-blocking material in the first hole-blocking sublayer in the host material.
[0029] Optionally, the light-emitting device further includes an electron blocking layer and a hole blocking layer, wherein the electron blocking layer is disposed on the side of the first sub-layer away from the second sub-layer, and the hole blocking layer is disposed on the side of the third sub-layer away from the second sub-layer;
[0030] The distance between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer is the same as the distance between the first hole blocking sublayer and the interface between the second auxiliary sublayer and the hole blocking layer.
[0031] On the other hand, embodiments of this application provide a display device including the above-described light-emitting device.
[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1This is a schematic diagram of the structure of a light-emitting device in a related art, provided as an embodiment of this application;
[0035] Figure 2 This is a schematic diagram of the structure of a light-emitting device in another related technology provided in an embodiment of this application;
[0036] Figure 3 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this application;
[0037] Figure 4 This is a schematic diagram of another light-emitting device provided in an embodiment of this application;
[0038] Figure 5 This is a schematic diagram of the structure of another light-emitting device provided in the embodiments of this application;
[0039] Figure 6 A comparative example of the duration of LT95 provided for an embodiment of this application;
[0040] Figure 7 A comparative example of the overshoot phenomenon provided for embodiments of this application;
[0041] Figure 8 A comparison chart of acceleration factors between the embodiments of this application and those of the embodiments of this application is provided for illustration.
[0042] Figure 9 A schematic diagram of vapor deposition in a related technology provided in an embodiment of this application;
[0043] Figure 10 This is a schematic diagram of vapor deposition provided for an embodiment of this application. Detailed Implementation
[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0045] For clarity, the thickness of regions and layers may be exaggerated in the figures. The same reference numerals in the figures denote the same or similar structures, and therefore their detailed descriptions are omitted. Furthermore, the figures are merely illustrative of this application and are not necessarily drawn to scale.
[0046] In the embodiments of this application, unless otherwise stated, "a plurality of" means two or more; the orientation or positional relationship indicated by the term "above" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the structure or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0047] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific feature, structure, material, or characteristic may be included in any suitable manner in any one or more embodiments or examples.
[0048] In the embodiments of this application, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect, only for the purpose of clearly describing the technical solution of the embodiments of this application, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated.
[0049] With the development of technology, OLED displays are finding increasingly widespread application due to their numerous advantages, including self-emissiveness, low driving voltage, high luminous efficiency, short response time, high clarity and contrast, wide viewing angle, wide operating temperature range, and the ability to achieve flexible and large-area full-color displays. Currently, electronic products such as mobile phones equipped with OLED displays are gradually moving from high-end flagship models to mid-range products to meet the needs of more ordinary consumers. In pursuit of maximum profit and product differentiation, mobile phone manufacturers are placing increasingly higher demands on the performance of OLED displays, requiring them to have excellent color reproduction, long lifespan, high reliability, and minimal performance fluctuations over extended periods of use.
[0050] However, due to differences in material degradation and device structure, various problems arise during actual use. In the actual production stage, to solve these problems, the thickness of certain film layers in the OLED display device is altered according to actual needs, which leads to further issues such as… Figure 1 and Figure 2 The problem shown, in which Figure 1 and Figure 2 These are all schematic diagrams of OLED display devices in related technologies. (Reference) Figure 1 As shown, the OLED display device includes an HTL (Hole Transporting Layer) 101, a Prime layer 102, an EML (Emitting Layer) 103, and an HBL (Hole Blocking Layer) 104. When energized, holes 105 and electrons 106 in the EML layer 103 recombine primarily at the interface between the Prime layer 102 and the EML layer 103 to form excitons. Similarly, refer to... Figure 2 As shown, the OLED display device includes an HTL layer 101, an EML layer 103 and an HBL layer 104. When powered on, holes and electrons in the EML layer 103 mainly recombine near the HTL layer 101 to form excitons 107. Figure 1 and Figure 2 All of these make the main light-emitting region closer to the edge of EML layer 103 ( Figure 1 and Figure 2 The area within the dotted lines represents the main light-emitting area, which can cause many screen defects, such as a short T95 duration, LT overshoot, and color shift after prolonged use. The T95 duration refers to the time it takes for the OLED display's brightness to decrease to 95% of its initial brightness; the LT overshoot phenomenon refers to the phenomenon where the OLED display's brightness initially increases and then decreases over time.
[0051] Furthermore, users typically use OLED displays at relatively low brightness levels. However, testing product lifespan at low brightness is extremely time-consuming and impractical. Generally, to ensure accuracy and efficiency in lifespan testing, aging tests are conducted on OLED displays using medium to high brightness images. The lifespan of the OLED display at low brightness is then calculated by the ratio of the aging rates at medium / high brightness to those at low brightness (i.e., the acceleration factor). Therefore, assuming the same lifespan at medium and high brightness, a higher acceleration factor indicates a longer lifespan at low brightness. However, due to factors such as differences in the degradation of different OLED materials and variations in device structure, the acceleration factor is currently very low.
[0052] Based on the above, embodiments of this application provide a light-emitting device, with reference to... Figure 3 , Figure 4 and Figure 5 As shown, it includes: a light-emitting layer 1, including a first sublayer 11, a second sublayer 12 and a third sublayer 13, the second sublayer 12 being disposed between the first sublayer 11 and the third sublayer 13; the second sublayer 12 includes a host material and a guest material; under the action of external energy, excitons 107 are composited in the second sublayer 12.
[0053] Among them, reference Figure 3 , Figure 4 and Figure 5 As shown, both the first sublayer 11 and the third sublayer 13 include the host material; the concentration of exciton 107 in the second sublayer 12 is greater than the concentration of exciton 107 in the first sublayer 11, and the concentration of exciton 107 in the second sublayer 12 is greater than the concentration of exciton 107 in the third sublayer 13.
[0054] The aforementioned light-emitting layer can be any one of a red, green, or blue light-emitting layer, in which case the light-emitting layer can be used to emit light of a single color. The light-emitting device can simultaneously include three light-emitting layers: a red light-emitting layer, a green light-emitting layer, or a blue light-emitting layer; of course, it can also include only one type of light-emitting layer, for example, only multiple red light-emitting layers, or only multiple green light-emitting layers, or only multiple blue light-emitting layers. The specific design can be determined according to actual requirements.
[0055] The structure of the first sub-layer is not specifically limited here. For example, the first sub-layer may include a single-layer structure; or, the first sub-layer may include a multi-layer structure. Figure 3 The first sub-layer 11, which includes a two-layer structure, is illustrated as an example. Figure 4 The diagram is illustrated using the first sub-layer 11, which includes one layer of structure. Figure 5 The illustration is based on the first sub-layer 11, which includes a four-layer structure. In cases where the first sub-layer includes multiple layers, the structure of each layer is not limited; the specific details depend on the actual application.
[0056] The structure of the second sub-layer mentioned above is not specifically limited here. For example, the second sub-layer may include, for instance, the structure of the second sub-layer mentioned above. Figure 3-5 The single-layer structure shown may vary depending on the actual application.
[0057] The structure of the third sub-layer is not specifically limited here. For example, the third sub-layer may include a single-layer structure; or, the third sub-layer may include a multi-layer structure. Figure 3 The third sub-layer 13, which includes a two-layer structure, is illustrated as an example. Figure 4 The diagram is illustrated using the third sub-layer 13, which includes one layer of structure. Figure 5 The diagram is illustrated using the third sub-layer 13, which comprises a four-layer structure. In cases where the third sub-layer includes multiple layers, the structure of each layer is not limited; the specific details depend on the actual application.
[0058] The aforementioned second sub-layer includes a host material and a guest material, with the guest material typically mixed within the host material. This explanation uses the blue emitting layer as an example; other colored emitting layers can be understood similarly to the blue emitting layer, and will not be elaborated upon further here. The blue emitting layer includes a host material and a guest material that emits blue light.
[0059] The main material is not specifically limited here. For example, the main material may include a hole-type main material, which is an organic semiconductor material that can achieve directional and orderly controllable migration of charge carriers under the action of an electric field when holes are injected, thereby achieving charge transfer; or, for example, the main material may include an electronic main material, which is an organic semiconductor material that can achieve directional and orderly controllable migration of charge carriers under the action of an electric field when electrons are injected, thereby achieving charge transfer.
[0060] The doping ratio of the aforementioned guest material in the host material is not specifically limited here. For example, the doping ratio of the aforementioned guest material in the host material may include 1-10%, specifically, the doping ratio may be 2%, 4%, 6%, 8% or 10%, etc.
[0061] The types of external energy mentioned above are not specifically limited here. For example, the external energy mentioned above can include light, electricity, etc.
[0062] The concentration of excitons in the first sublayer is not specifically limited here. For example, there may be no excitons in the first sublayer; or, there may be excitons in the first sublayer, and the concentration of excitons in the first sublayer is less than the concentration of excitons in the second sublayer.
[0063] The concentration of excitons in the third sublayer is not specifically limited here. For example, there may be no excitons in the third sublayer; or, there may be excitons in the third sublayer, and the concentration of excitons in the third sublayer is less than the concentration of excitons in the second sublayer.
[0064] The fabrication processes for the first, second, and third sublayers are not specifically limited here. For example, these processes may include vapor deposition, coating, etc. Among them, vapor deposition is highly feasible and has no significant adverse effects on other characteristics of the light-emitting device.
[0065] The type of light-emitting device mentioned above is not specifically limited here. For example, the light-emitting device mentioned above may include a single OLED light-emitting device, that is, a single OLED; or, the light-emitting device mentioned above may include a Tandem OLED light-emitting device, that is, a series OLED.
[0066] Modern mass-produced OLED light-emitting devices typically consist of a host material (RH) and a guest material (RD). Under the influence of external energy sources such as light and electricity, the host material can transfer energy to the guest material, causing the guest material to emit light through radiative transitions. Specifically, under electroexcitation, holes and electrons form excitons on the host material. The energy levels of these excitons are transferred from the host material to the guest material, and then radiative transitions occur in the guest material, thus enabling the light-emitting device to emit light.
[0067] The light-emitting device provided in this application includes a light-emitting layer comprising a first sublayer, a second sublayer, and a third sublayer, with the second sublayer disposed between the first and third sublayers. The second sublayer comprises a host material and a guest material. Under the influence of external energy, excitons recombine in the second sublayer. Both the first and third sublayers comprise the host material. The concentration of excitons in the second sublayer is greater than that in the first sublayer, and the concentration of excitons in the second sublayer is greater than that in the third sublayer. Since neither the first nor the third sublayer comprises a guest material, and the concentration of excitons is highest in the second sublayer, under the influence of external energy, excitons are forced to recombine in the second sublayer. Figure 3 and Figure 5 Most of the holes 105 and electrons 106 shown recombine within the second sublayer 12, forming as shown in the diagram. Figure 4 The exciton 107 shown represents the highest exciton content within the second sublayer. The energy levels of the excitons in the second sublayer are transferred from the host material to the guest material, and then emit light through radiative transitions in the guest material. This results in the main emitting region of the light-emitting device provided in this embodiment being located in the second sublayer, i.e., in the middle of the emitting layer. This makes the relative proportions of electrons and holes more balanced, thereby effectively improving the lifetime of the light-emitting device, such as increasing the LT95 duration and reducing or even avoiding LT overshoot.
[0068] Furthermore, since the lifespan of the light-emitting device provided in this application embodiment is significantly improved, the problem of the low lifetime acceleration factor of OLED is largely improved, the acceleration factor is effectively improved, and thus the lifespan level of the light-emitting device at low brightness is guaranteed.
[0069] The above-mentioned LT95 duration can be obtained from Figure 6 see, Figure 6 For comparison ( Figure 1 The diagram shows a comparison of the LT95 duration of the light-emitting device structure shown and the light-emitting device of the embodiment of this application, where curve L1 is the LT95 duration curve of the light-emitting device provided in the embodiment of this application, and curve L2 is the LT95 duration curve of the comparative example. Figure 6 In the graph, the horizontal axis represents duration in hrs, and the vertical axis represents brightness percentage. (Reference) Figure 6As shown, under the same brightness, the LT95 duration of the light-emitting device provided in this application embodiment is much longer than the LT95 duration of the comparative example.
[0070] The above-mentioned LT overshoot phenomenon can be seen from Figure 7 see, Figure 7 For comparison ( Figure 1 The diagram shows a comparison of the LT overshoot phenomenon between the light-emitting device structure shown and the light-emitting device of the embodiment of this application, where curve L4 is the curve of the light-emitting device provided in the embodiment of this application, and curve L3 is the curve of the comparative example. Figure 7 In the graph, the horizontal axis represents duration in hrs, and the vertical axis represents brightness percentage. (Reference) Figure 7 As shown, the L3 curve exhibits a significant overshoot phenomenon from duration 0 to duration 500-600hrs, while the L4 curve shows a continuous decrease in brightness from duration 0 to duration 500-600hrs without any overshoot phenomenon.
[0071] The above-mentioned acceleration factors can be obtained from Figure 8 see, Figure 8 For comparison ( Figure 2 The graph shows a comparison of the acceleration factors of the light-emitting device structure shown and the light-emitting device of the embodiment of this application, where the L5 curve is the curve of the light-emitting device (after improvement) provided in the embodiment of this application, and the L6 curve is the curve of the comparative example (before improvement). Figure 8 In the graph, the horizontal axis represents the logarithm of brightness, and the vertical axis represents the logarithm of lifetime. (Reference) Figure 8 As shown, after fitting the L5 curve, the improved acceleration factor n = 1.0 was obtained, and after fitting the L6 curve, the unimproved acceleration factor n = 0.62 was obtained. Obviously, the acceleration factor of the improved light-emitting device is significantly increased.
[0072] Optionally, refer to Figure 4 As shown, both the first sublayer 11 and the third sublayer 13 are single-layer structures and both include a host material. This divides the traditional light-emitting layer into three parts: the first sublayer, the second sublayer, and the third sublayer of this application. By designing a host material layer without guest light-emitting molecules near the interface between the light-emitting layer and adjacent layers, most excitons can be forced to reside in the second sublayer under the influence of external energy. This allows the main light-emitting region of the light-emitting device provided in this embodiment to be located in the middle of the light-emitting layer, resulting in a more balanced relative ratio of electrons and holes. This avoids disrupting the electron-hole balance due to excitons being close to the interface between the light-emitting layer and adjacent layers, thereby effectively improving the lifetime of the light-emitting device, such as increasing the LT95 duration, reducing or even avoiding LT overshoot, and ensuring a high acceleration factor, thus maintaining a high lifetime of the light-emitting device at low brightness.
[0073] The fabrication processes for the first, second, and third sublayers are not specifically limited here. For example, the fabrication processes may include vapor deposition, coating, etc. Among them, vapor deposition is highly feasible and has no significant adverse effects on other characteristics of the light-emitting device.
[0074] The following uses vapor deposition as an example to illustrate a specific fabrication process of the light-emitting device in an embodiment of the present invention. Figure 9 In the vapor deposition process of related technologies, the current method involves simultaneous vapor deposition of both the host material (BH) and the guest material (BD) from the same vapor deposition source. The angle plate is adjusted to ensure that the two materials are deposited in the same area at a specific vapor deposition rate and ratio. (Reference) Figure 9 As shown, it includes a host material (BH) evaporation source and a guest material (BD) evaporation source. Along the Scan Direction, for example, first scanning to the left and then scanning to the right, in the left scanning stage, since the BH evaporation source and the BD evaporation source are deposited simultaneously, the formed layer contains both BH material and BD material.
[0075] Figure 10 The vapor deposition process described in this application embodiment involves adjusting the vapor deposition angle plates for BH and BD materials. As the plate moves along the scanning direction, at the beginning and end of each scanning cycle, a portion of the film may contain only one of either BH or BD materials. See details... Figure 10 As shown, for example, in the leftward scanning phase, BH material can be deposited first to form the first sublayer. After a period of time, such as 2 seconds, BD material can be deposited simultaneously to form the second sublayer. In the rightward scanning phase, both BH and BD materials are deposited to form the second sublayer. In the period of time before the end, such as 2 seconds, only BH material is deposited to form the third sublayer, and so on.
[0076] Optionally, refer to Figure 4 As shown, the light-emitting device further includes a hole injection layer 18 disposed on the side of the first sub-layer 11 away from the second sub-layer 12; the absolute value range of the difference between the energy value of the highest molecular occupied orbital (HOMO) of the first sub-layer 11 and the energy value of the highest molecular occupied orbital (HOMO) of the second sub-layer 12 is 0.1-0.5 eV. Thus, by coordinating the HOMO energy values of the first and second sub-layers, under the influence of external energy, more excitons are further forced to reside in the second sub-layer. In other words, the main light-emitting region of the light-emitting device provided in this embodiment is located in the middle of the light-emitting layer, avoiding disruption of the electron-hole balance near the interface, making the relative proportion of electrons and holes more balanced, thereby further effectively improving the lifetime of the light-emitting device and further increasing the acceleration factor.
[0077] The highest occupied molecular orbital (HOMO) refers to the molecular orbital with the highest energy among the electron-occupied molecular orbitals. The energy value of the highest occupied molecular orbital is also known as the HOMO value.
[0078] Here, there is no specific limitation on the absolute value of the difference between the energy value of the highest molecular occupancy orbital HOMO of the first sublayer and the energy value of the highest molecular occupancy orbital HOMO of the second sublayer. For example, the absolute value of the difference between the energy value of the highest molecular occupancy orbital HOMO of the first sublayer and the energy value of the highest molecular occupancy orbital HOMO of the second sublayer can be 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV or 0.5 eV, etc.
[0079] Optionally, refer to Figure 4 As shown, the light-emitting device also includes an electron injection layer 19 disposed on the side of the third sublayer 13 away from the second sublayer 12; the absolute value range of the difference between the energy value of the lowest molecular unoccupied orbital LUMO of the third sublayer 13 and the energy value of the lowest molecular unoccupied orbital LUMO of the second sublayer 12 includes 0.1-0.5 eV. Thus, by coordinating the LUMO energy values of the third sublayer and the second sublayer, under the influence of external energy, more excitons are further forced to reside in the second sublayer. In other words, the main light-emitting region of the light-emitting device provided in this embodiment is located in the middle of the light-emitting layer, avoiding disruption of the electron-hole balance near the interface, making the relative proportion of electrons and holes more balanced, thereby further effectively improving the lifetime of the light-emitting device and further increasing the acceleration factor.
[0080] The lowest unoccupied molecular orbital (LUMO) is the molecular orbital with the lowest energy among those that are not occupied by electrons. The energy value of the lowest unoccupied molecular orbital is also known as the LUMO value.
[0081] Here, there is no specific limitation on the absolute value of the difference between the energy value of the lowest unoccupied orbital LUMO of the third sublayer and the energy value of the lowest unoccupied orbital LUMO of the second sublayer. For example, the absolute value of the difference between the energy value of the lowest unoccupied orbital LUMO of the third sublayer and the energy value of the lowest unoccupied orbital LUMO of the second sublayer can be 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, or 0.5 eV, etc.
[0082] Optionally, refer to Figure 4As shown, along the direction perpendicular to the light-emitting layer (OA direction shown in the figure), the thickness of the second sub-layer 12 is greater than the thickness of the first sub-layer 11, and the thickness of the second sub-layer 12 is greater than the thickness of the third sub-layer 13. This results in the first and third sub-layers being much thinner than the second sub-layer, and the amount of bulk material in both the first and third sub-layers being less than that in the second sub-layer. Under the influence of external energy, more excitons can be forced to reside in the second sub-layer. In other words, the main light-emitting region of the light-emitting device provided in this embodiment is located in the middle of the light-emitting layer, avoiding disruption of the electron-hole balance near the interface, thus making the relative proportion of electrons and holes more balanced, effectively improving the lifetime of the light-emitting device and increasing the acceleration factor.
[0083] The thicknesses of the first, second, and third sublayers are not specifically limited here. For example, the ratio of the thickness of the first sublayer to the thickness of the second sublayer can range from 20% to 30%, specifically 20%, 25%, or 30%, etc. Similarly, the ratio of the thickness of the third sublayer to the thickness of the second sublayer can range from 20% to 30%, specifically 20%, 25%, or 30%, etc. For example, the thickness of the second sublayer is... At that time, the thickness of the first sublayer and the thickness of the third sublayer can both be 1.
[0084] There is no specific limitation on the thickness of the first sublayer and the third sublayer. For example, the thickness of the first sublayer and the third sublayer can be the same; or the thickness of the first sublayer and the third sublayer can be different.
[0085] Optionally, for ease of production and to save on processes, refer to Figure 4 As shown, along the direction perpendicular to the light-emitting layer, the thickness of the first sub-layer 11 is the same as the thickness of the third sub-layer 13.
[0086] Optionally, refer to Figure 3 and Figure 5 As shown, the first sublayer 11 includes a first auxiliary sublayer 111 and a first electron blocking sublayer 112, with the first electron blocking sublayer 112 disposed between the first auxiliary sublayer 111 and the second sublayer 12.
[0087] refer to Figure 3 and Figure 5As shown, the third sublayer 13 includes a second auxiliary sublayer 131 and a first hole-blocking sublayer 132, with the first hole-blocking sublayer 132 disposed between the second auxiliary sublayer 131 and the second sublayer 12. This results in a five-layer structure for the light-emitting device. The first electron-blocking sublayer restricts electrons from escaping from the second sublayer, and the first hole-blocking sublayer restricts holes from escaping from the second sublayer. This forces most electrons and holes to recombine in the second sublayer, placing the main light-emitting region of the device in the middle of the second sublayer, effectively extending the device's lifetime and increasing the acceleration factor.
[0088] The aforementioned first auxiliary sublayer refers to a layer used for emitting light. The material of the aforementioned first auxiliary sublayer is not specifically limited here. For example, the material of the aforementioned first auxiliary sublayer may include a host material and a guest material; or, the material of the aforementioned first auxiliary sublayer may include only the host material.
[0089] The thickness of the first auxiliary sublayer is not specifically limited here. For example, along the direction perpendicular to the light-emitting layer, the thickness of the first auxiliary sublayer can be less than the thickness of the second sublayer; or, along the direction perpendicular to the light-emitting layer, the thickness of the first auxiliary sublayer can be the same as the thickness of the second sublayer.
[0090] The aforementioned first electron-blocking sublayer has a strong ability to block electrons and has almost no effect on hole migration. It can prevent electrons in the second sublayer from escaping, ensuring that more electrons recombine with holes in the second sublayer, thereby increasing the number of excitons and thus improving luminescence efficiency. The material of the aforementioned first electron-blocking sublayer is not specifically limited here. For example, the material of the aforementioned first electron-blocking sublayer may only include an electron-blocking material; or, the material of the aforementioned first electron-blocking sublayer may include an electron-blocking material and a host material; or, the material of the aforementioned first electron-blocking sublayer may include an electron-blocking material, a host material, and a guest material.
[0091] The thickness of the first electron blocking sublayer is not specifically limited here. For example, along the direction perpendicular to the light-emitting layer, the thickness of the first electron blocking sublayer can be much smaller than the thickness of the second sublayer. This not only ensures that electrons are blocked from passing through the second sublayer, thus confining more electrons in the second sublayer to recombine with holes, so that the main light-emitting area of the light-emitting device is located in the middle of the second sublayer, but also avoids the energy level difference at the interface between the electron blocking sublayer and the second sublayer due to the excessive thickness of the first electron blocking sublayer, which would cause excitons to recombine at the interface between the first electron blocking sublayer and the second sublayer, thus reducing the lifetime of the light-emitting device.
[0092] The aforementioned second auxiliary sublayer refers to a layer used for emitting light. The material of the aforementioned second auxiliary sublayer is not specifically limited here. For example, the material of the aforementioned second auxiliary sublayer may include both host material and guest material; or, the material of the aforementioned second auxiliary sublayer may include only host material.
[0093] The thickness of the second auxiliary sublayer is not specifically limited here. For example, the thickness of the second auxiliary sublayer can be less than the thickness of the second sublayer in the direction perpendicular to the light-emitting layer; or, the thickness of the second auxiliary sublayer can be the same as the thickness of the second sublayer in the direction perpendicular to the light-emitting layer.
[0094] The aforementioned first hole-blocking sublayer has a strong ability to block holes and has almost no effect on hole migration. It can prevent holes in the second sublayer from escaping the second sublayer, ensuring that more holes recombine with electrons in the second sublayer, thereby increasing the number of excitons and thus improving luminescence efficiency. The material of the aforementioned first hole-blocking sublayer is not specifically limited here. For example, the material of the aforementioned first hole-blocking sublayer may only include a hole-blocking material; or, the material of the aforementioned first hole-blocking sublayer may include a hole-blocking material and a host material; or, the material of the aforementioned first hole-blocking sublayer may include a hole-blocking material, a host material, and a guest material.
[0095] The thickness of the first hole-blocking sublayer is not specifically limited here. For example, along the direction perpendicular to the light-emitting layer, the thickness of the first hole-blocking sublayer can be much smaller than the thickness of the second sublayer. This not only ensures that the blocked holes can pass through the second sublayer, thereby confining more holes in the second sublayer to recombine with electrons, so that the main light-emitting area of the light-emitting device is located in the middle of the second sublayer, but also avoids the energy level difference at the interface between the first hole-blocking sublayer and the second sublayer due to the excessive thickness of the first hole-blocking sublayer, which would cause excitons to recombine at the interface of the first hole-blocking sublayer and the second sublayer, thus reducing the lifetime of the light-emitting device.
[0096] Optionally, both the first auxiliary sublayer and the second auxiliary sublayer include a host material and an object material.
[0097] The first hole-blocking sublayer includes a hole-blocking material; the first electron-blocking sublayer includes an electron-blocking material. In this configuration, the first electron-blocking sublayer effectively restricts electrons from escaping from the second sublayer, and the first hole-blocking sublayer effectively restricts holes from escaping from the second sublayer. This forces most electrons and holes to recombine in the second sublayer, resulting in the main light-emitting region of the light-emitting device being located in the middle of the second sublayer. This effectively extends the lifetime of the light-emitting device and improves the acceleration factor.
[0098] The fabrication processes for the first auxiliary sublayer, second auxiliary sublayer, first electron blocking sublayer, and first hole blocking sublayer are not specifically limited here. For example, the above fabrication processes may include vapor deposition, coating, etc. Among them, vapor deposition is highly feasible and has no significant adverse effects on other characteristics of the light-emitting device.
[0099] The following uses vapor deposition as an example to illustrate a fabrication process for the light-emitting device of this invention.
[0100] First, the vapor deposition sources for both the host material (BH) and the guest material (BD) are simultaneously turned on, and BH and BD materials are deposited simultaneously to form a first auxiliary sublayer. After the first auxiliary sublayer of a predetermined thickness is formed, the vapor deposition sources for both BH and BD materials are simultaneously turned off, and the vapor deposition source for the electron blocking material is turned on to form a first electron blocking layer. After the first electron blocking sublayer of a predetermined thickness is formed, the vapor deposition source for the electron blocking material is turned off, and the vapor deposition sources for both BH and BD materials are simultaneously turned on to form a second sublayer. After the second sublayer of a predetermined thickness is formed, the vapor deposition sources for both BH and BD materials are simultaneously turned off, and the vapor deposition source for the hole blocking material is turned on to form a first hole blocking sublayer. After the first hole blocking sublayer of a predetermined thickness is formed, the vapor deposition source for the hole blocking material is turned off, and the vapor deposition sources for both BH and BD materials are simultaneously turned on to form a second auxiliary sublayer.
[0101] Optionally, both the first auxiliary sublayer and the second auxiliary sublayer include a host material and an object material;
[0102] The first hole-blocking sublayer comprises a host material, a guest material, and a hole-blocking material; the first electron-blocking sublayer comprises a host material, a guest material, and an electron-blocking material. In this configuration, the first electron-blocking sublayer effectively restricts electrons from escaping from the second sublayer, and the first hole-blocking sublayer effectively restricts holes from escaping from the second sublayer. This forces most electrons and holes to recombine in the second sublayer, resulting in the main light-emitting region of the light-emitting device being located in the middle of the second sublayer. This effectively extends the lifetime of the light-emitting device and improves the acceleration factor.
[0103] The fabrication processes for the first auxiliary sublayer, second auxiliary sublayer, first electron blocking sublayer, and first hole blocking sublayer are not specifically limited here. For example, the above fabrication processes may include vapor deposition, coating, etc. Among them, vapor deposition is highly feasible and has no significant adverse effects on other characteristics of the light-emitting device.
[0104] The following uses vapor deposition as an example to illustrate a fabrication process for the light-emitting device of this invention.
[0105] First, the vapor deposition sources for both the host material (BH) and the guest material (BD) are simultaneously turned on, and BH and BD materials are deposited simultaneously to form a first auxiliary sublayer. After the first auxiliary sublayer of a predetermined thickness is formed, the vapor deposition source for the electron blocking material is also turned on to form a first electron blocking layer. After the first electron blocking sublayer of a predetermined thickness is formed, the vapor deposition source for the electron blocking material is turned off to form a second sublayer. After the second sublayer of a predetermined thickness is formed, the vapor deposition source for the hole blocking material is also turned on to form a first hole blocking sublayer. After the first hole blocking sublayer of a predetermined thickness is formed, the vapor deposition source for the hole blocking material is turned off to form a second auxiliary sublayer.
[0106] Optionally, refer to Figure 3 and Figure 5 As shown, along the direction perpendicular to the light-emitting layer, the thickness of the second sublayer 12 is greater than the thickness of the first hole-blocking sublayer 132, and the thickness of the second sublayer 12 is greater than the thickness of the first electron-blocking sublayer 112. This makes the thicknesses of the first hole-blocking sublayer and the first electron-blocking sublayer thinner than the thickness of the second sublayer. Under the influence of external energy, this forces more excitons to reside in the second sublayer. Simultaneously, it avoids the formation of energy levels at the interfaces between the second sublayer and the first hole-blocking sublayer and the first electron-blocking sublayer due to excessive thickness of the first hole-blocking sublayer and the first electron-blocking sublayer, respectively. This ensures that the main light-emitting region of the light-emitting device provided in this embodiment is located in the middle of the light-emitting layer, preventing the electron-hole balance from being disrupted near the interface, resulting in a more balanced relative proportion of electrons and holes, thereby effectively improving the lifetime of the light-emitting device and increasing the acceleration factor.
[0107] The thicknesses of the first hole-blocking sublayer, the second sublayer, and the first electron-blocking sublayer are not specifically limited here. For example, the ratio of the thickness of the first hole-blocking sublayer to the thickness of the second sublayer ranges from 1% to 5%, specifically, it includes 1%, 2%, 3%, 4%, or 5%, etc. Similarly, the ratio of the thickness of the first electron-blocking sublayer to the thickness of the second sublayer ranges from 1% to 5%, specifically, it includes 1%, 2%, 3%, 4%, or 5%, etc. For example, the thickness of the second sublayer is... At that time, the thickness of the first hole-blocking sublayer and the thickness of the first electron-blocking sublayer can both be 1 / 2.
[0108] The thickness of the first hole blocking sublayer and the thickness of the first electron blocking sublayer are not specifically limited here. For example, the thickness of the first hole blocking sublayer and the thickness of the first electron blocking sublayer can be the same; or, the thickness of the first hole blocking sublayer and the thickness of the first electron blocking sublayer can be different.
[0109] Optionally, for ease of production and to save on processes, refer to Figure 3 and Figure 5 As shown, along the direction perpendicular to the light-emitting layer, the thickness of the first hole blocking sublayer 132 is the same as the thickness of the first electron blocking sublayer 112.
[0110] Optionally, refer to Figure 5 As shown, the first sub-layer 11 also includes a second electron blocking sub-layer 1111. The second electron blocking sub-layer 1111 is disposed on the side of the first electron blocking sub-layer 112 away from the second sub-layer 12 and divides the first auxiliary sub-layer 111 into two parts. This makes the light-emitting layer of the light-emitting device include a seven-layer structure. The first electron blocking sub-layer in this seven-layer structure can restrict electrons from passing through the second sub-layer. However, a small number of electrons may still pass through the second sub-layer and enter the first auxiliary sub-layer. Therefore, the second electron blocking sub-layer can restrict electrons from passing through the first auxiliary sub-layer, thereby making the main light-emitting area of the light-emitting device as close to the center of the light-emitting layer as possible, effectively extending the lifetime of the light-emitting device and improving the acceleration factor.
[0111] The aforementioned second electron blocking sublayer has a strong ability to block electrons and has almost no effect on hole migration. It can prevent electrons in the first auxiliary sublayer from escaping the first auxiliary sublayer, ensuring that more electrons recombine with holes in the first auxiliary sublayer, thereby increasing the number of excitons and thus improving luminescence efficiency. The material of the aforementioned second electron blocking sublayer is not specifically limited here. For example, the material of the aforementioned second electron blocking sublayer may only include an electron blocking material; or, the material of the aforementioned second electron blocking sublayer may include an electron blocking material and a host material; or, the material of the aforementioned second electron blocking sublayer may include an electron blocking material, a host material, and a guest material.
[0112] The thickness of the second electron blocking sublayer is not specifically limited here. For example, along the direction perpendicular to the light-emitting layer, the thickness of the second electron blocking sublayer can be much smaller than the thickness of the first sublayer; or, the thickness of the second electron blocking sublayer can be the same as the thickness of the first electron blocking sublayer. The specific application shall prevail.
[0113] It should be noted that the reference Figure 5 As shown, the second electron-blocking sublayer 1111 divides the first auxiliary sublayer 111 into two parts: a first part 1112 and a second part 1113. The specific materials of the first part 1112 and the second part 1113 are not limited here. For example, the materials of both the first part 1112 and the second part 1113 may include both the host material and the guest material; or, the materials of both the first part 1112 and the second part 1113 may include both the host material, depending on the actual application.
[0114] Optionally, the second electron blocking sublayer includes a host material, a guest material, and an electron blocking material; the doping concentration of the electron blocking material in the second electron blocking sublayer in the host material is greater than the doping concentration of the electron blocking material in the first electron blocking sublayer in the host material. This allows the first electron blocking sublayer to restrict electrons from escaping through the second sublayer. However, a small number of electrons may still escape from the second sublayer into the first auxiliary sublayer. Since the electron blocking material in the second electron blocking sublayer has a higher doping concentration in the host material, it can further restrict electrons from escaping through the first auxiliary sublayer, thereby maximizing the location of the main emitting region of the light-emitting device in the center of the emitting layer, effectively extending the lifetime of the light-emitting device, and improving the acceleration factor.
[0115] Optionally, refer to Figure 5 As shown, the third sub-layer 13 also includes a second hole-blocking sub-layer 1311. The second hole-blocking sub-layer 1311 is disposed on the side of the first hole-blocking sub-layer 132 away from the second sub-layer 12 and divides the second auxiliary sub-layer 131 into two parts. This makes the light-emitting layer of the light-emitting device include a nine-layer structure. The first hole-blocking sub-layer in this nine-layer structure can restrict holes from passing through the second sub-layer. However, a small number of holes may still pass through the second sub-layer and enter the second auxiliary sub-layer. Therefore, the second hole-blocking sub-layer can restrict electrons from passing through the second auxiliary sub-layer, thereby making the main light-emitting area of the light-emitting device as close to the center of the light-emitting layer as possible, effectively extending the lifetime of the light-emitting device and improving the acceleration factor.
[0116] The aforementioned second hole-blocking sublayer has a strong ability to block holes and has almost no effect on electron migration. It can prevent electrons in the second auxiliary sublayer from escaping, ensuring that more holes recombine with electrons in the second auxiliary sublayer, thereby increasing the number of excitons and thus improving luminescence efficiency. The material of the aforementioned second hole-blocking sublayer is not specifically limited here. For example, the material of the aforementioned second hole-blocking sublayer may only include a hole-blocking material; or, the material of the aforementioned second hole-blocking sublayer may include a hole-blocking material and a host material; or, the material of the aforementioned second hole-blocking sublayer may include a hole-blocking material, a host material, and a guest material.
[0117] The thickness of the second hole-blocking sublayer is not specifically limited here. For example, along the direction perpendicular to the light-emitting layer, the thickness of the second hole-blocking sublayer can be much smaller than the thickness of the second sublayer; or, the thickness of the second hole-blocking sublayer can be the same as the thickness of the first hole-blocking sublayer. The specific application shall prevail.
[0118] It should be noted that the reference is... Figure 5As shown, the second hole-blocking sublayer 1311 divides the second auxiliary sublayer 131 into two parts: a third part 1312 and a fourth part 1313. The specific materials of the third part 1312 and the fourth part 1313 are not limited here. For example, the materials of both the third part 1312 and the fourth part 1313 may include both the host material and the object material; or, the materials of both the third part 1312 and the fourth part 1313 may include both the host material, depending on the actual application.
[0119] Optionally, the second hole-blocking sublayer includes a host material, a guest material, and a hole-blocking material. The doping concentration of the hole-blocking material in the second hole-blocking sublayer in the host material is greater than the doping concentration of the hole-blocking material in the first hole-blocking sublayer in the host material. This allows the first hole-blocking sublayer to restrict holes from escaping through the second sublayer. However, a small number of holes may still escape through the second sublayer and enter the second auxiliary sublayer. Since the hole-blocking material in the second hole-blocking sublayer has a higher doping concentration in the host material, it can further restrict holes from escaping through the second auxiliary sublayer. This ensures that the main light-emitting region of the light-emitting device is located in the middle of the light-emitting layer, effectively extending the lifetime of the light-emitting device and improving the acceleration factor.
[0120] Optionally, refer to Figure 3 and Figure 5 As shown, the light-emitting device also includes an electron blocking layer 14 and a hole blocking layer 15. The electron blocking layer 14 is disposed on the side of the first sub-layer 11 away from the second sub-layer 12, and the hole blocking layer 15 is disposed on the side of the third sub-layer 13 away from the second sub-layer 12.
[0121] The distance between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer is the same as the distance between the first hole blocking sublayer and the interface between the second auxiliary sublayer and the hole blocking layer.
[0122] The aforementioned electron blocking layer can prevent electrons in the light-emitting layer from passing through the light-emitting layer, ensuring that more electrons recombine with holes in the light-emitting layer, thereby increasing the number of excitons and thus improving the luminescence efficiency.
[0123] The hole blocking layer described above can prevent holes in the light-emitting layer from escaping the light-emitting layer, ensuring that more holes recombine with electrons in the light-emitting layer, thereby increasing the number of excitons and thus improving the luminescence efficiency.
[0124] Here, no specific limitations are made on the distances between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer, or the distances between the first hole blocking sublayer and the interface between the second auxiliary sublayer and the hole blocking layer. For example, the distance between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer can range from 10% to 30%. Specifically, if the thickness of the light-emitting layer is... The distance between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer can be... or Etc. For example, the distance between the first hole-blocking sublayer and the interface between the second auxiliary sublayer and the hole-blocking layer can range from 10% to 30%. Specifically, if the thickness of the luminescent layer is... The distance between the interface between the first hole-blocking sublayer and the second auxiliary sublayer and the hole-blocking layer can be... or etc.
[0125] Optionally, refer to Figure 2 , Figure 3 and Figure 5 As shown, the light-emitting device also includes an anode 20 and a cathode 21. The anode 20 is disposed on the side of the hole injection layer 18 away from the first sub-layer 11, and the cathode 21 is disposed on the side of the electron injection layer 19 away from the third sub-layer 13.
[0126] refer to Figure 2 , Figure 3 and Figure 5 As shown, the light-emitting device also includes a hole transport layer 16 and an electron transport layer 17. The hole transport layer 16 is disposed between the hole injection layer 18 and the electron blocking layer 14, and the electron transport layer 17 is disposed between the electron injection layer 19 and the hole blocking layer 15.
[0127] The material of the anode is not specifically limited here. For example, the material of the anode may include ITO (Indium Tin Oxides).
[0128] The specific manufacturing process of the anode is not limited here. For example, a glass plate with ITO can be ultrasonically treated in deionized water and then dried at 100°C to obtain the anode.
[0129] Optionally, the light-emitting device also includes an encapsulation layer, which is disposed on the side of the cathode away from the light-emitting layer and covers the light-emitting layer. This allows the light-emitting device to be effectively encapsulated by the encapsulation layer, preventing it from being corroded by moisture and oxygen.
[0130] The structure of the encapsulation layer is not specifically limited here. For example, the encapsulation layer can be a single-layer structure, such as an encapsulation layer that includes only one inorganic layer; or, the encapsulation layer can be a multi-layer structure, such as an encapsulation layer that includes a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer. The specific structure depends on the actual application.
[0131] On the other hand, embodiments of this application also provide a display device including the above-described light-emitting device.
[0132] The aforementioned display device may be a touch-enabled display device, or a foldable or rollable display device, or a display device that simultaneously has touch and foldable functions; no limitation is made here. The display device may be a flexible display device (also known as a flexible screen) or a rigid display device (i.e., a display screen that cannot be bent); no limitation is made here.
[0133] The aforementioned display device may be an OLED display device, a Micro LED display device, or a Mini LED display device.
[0134] The aforementioned display device can be any product or component with a display function, such as a television, digital camera, mobile phone, or tablet computer. It can also be applied to fields such as identity recognition and medical devices. Products that have been promoted or have good prospects for promotion include security identity authentication, smart door locks, and medical image acquisition. This display device has advantages such as long lifespan, low cost, good display effect, high stability, high contrast, good imaging quality, and high product quality.
[0135] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.
[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A light emitting device, wherein, include: The light-emitting layer includes a first sublayer, a second sublayer, and a third sublayer, wherein the second sublayer is disposed between the first sublayer and the third sublayer; The second sublayer comprises a host material and a guest material; under the influence of external energy, excitons are compounded in the second sublayer; Wherein, both the first sublayer and the third sublayer include the host material; the concentration of excitons in the second sublayer is greater than the concentration of excitons in the first sublayer, and the concentration of excitons in the second sublayer is greater than the concentration of excitons in the third sublayer; The first sub-layer includes a first auxiliary sub-layer and a first electron blocking sub-layer, wherein the first electron blocking sub-layer is disposed between the first auxiliary sub-layer and the second sub-layer; The third sublayer includes a second auxiliary sublayer and a first hole-blocking sublayer, wherein the first hole-blocking sublayer is disposed between the second auxiliary sublayer and the second sublayer; Both the first auxiliary sublayer and the second auxiliary sublayer include the main material and the object material; The first hole-blocking sublayer includes the host material, the guest material, and the hole-blocking material; the first electron-blocking sublayer includes the host material, the guest material, and the electron-blocking material.
2. The light-emitting device according to claim 1, wherein Along the direction perpendicular to the light-emitting layer, the thickness of the second sub-layer is greater than the thickness of the first hole-blocking sub-layer, and the thickness of the second sub-layer is greater than the thickness of the first electron-blocking sub-layer.
3. The light-emitting device according to claim 2, wherein, Along the direction perpendicular to the light-emitting layer, the thickness of the first hole blocking sublayer is the same as the thickness of the first electron blocking sublayer.
4. The light-emitting device according to claim 1, wherein, The first sublayer further includes a second electron blocking sublayer, which is disposed on the side of the first electron blocking sublayer away from the second sublayer and divides the first auxiliary sublayer into two parts.
5. The light-emitting device according to claim 4, wherein, The second electron blocking sublayer includes the host material, the guest material, and the electron blocking material; The doping concentration of the electron blocking material in the second electron blocking sublayer in the host material is greater than the doping concentration of the electron blocking material in the first electron blocking sublayer in the host material.
6. The light-emitting device according to claim 1, wherein, The third sublayer further includes a second hole-blocking sublayer, which is disposed on the side of the first hole-blocking sublayer away from the second sublayer and divides the second auxiliary sublayer into two parts.
7. The light-emitting device according to claim 6, wherein, The second hole-blocking sublayer includes the host material, the guest material, and the hole-blocking material; The doping concentration of the hole-blocking material in the second hole-blocking sublayer in the host material is greater than the doping concentration of the hole-blocking material in the first hole-blocking sublayer in the host material.
8. The light-emitting device according to claim 1, wherein, The light-emitting device further includes an electron blocking layer and a hole blocking layer. The electron blocking layer is disposed on the side of the first sub-layer away from the second sub-layer, and the hole blocking layer is disposed on the side of the third sub-layer away from the second sub-layer. The distance between the first electron blocking sublayer and the interface between the first auxiliary sublayer and the electron blocking layer is the same as the distance between the first hole blocking sublayer and the interface between the second auxiliary sublayer and the hole blocking layer.
9. A display device, wherein, Includes the light-emitting device according to any one of claims 1-8.