Light-emitting device, manufacturing method thereof and display device

Abstract

The invention provides a light-emitting device, a manufacturing method thereof and a display device. The light-emitting device comprises an anode, a light-emitting layer and a cathode which are sequentially stacked, the functional stacked film layers are arranged between the anode and the light-emitting layer and between the cathode and the light-emitting layer, and the functional stacked film layers comprise at least two functional film layers of a hole injection layer, a hole transmission layer, an electron blocking layer, an electron injection layer, an electron transmission layer and the hole blocking layer; wherein in the functional stacked film layers, except between the hole blocking layer and the light-emitting layer and between the electron blocking layer and the light-emitting layer, at least one first interface transition layer is arranged between at least two adjacent functional film layers with different functions, and the material components of the first interface transition layer comprise a material A and a material B, the material A and the material B are material components of the two functional film layers adjacent to the first interface transition layer respectively. The light-emitting device, the manufacturing method thereof and the display device can improve the comprehensive performance of a product.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a light-emitting device, a method for manufacturing the same, and a display apparatus. Background Technology

[0002] Organic light-emitting diode (OLED) technology, as the core of next-generation display and lighting technology, directly determines the competitiveness of end products. Among these, luminous efficiency, lifetime, and driving voltage (trans-voltage) are the most critical technical indicators for measuring OLED device performance, directly affecting the device's energy consumption, stability, and cost. In related technologies, OLED devices still face many performance challenges, such as a series of display defects related to device capacitance, specifically manifested as issues like motion blur and viewing angle dependence. Summary of the Invention

[0003] In order to solve at least one of the technical problems in the above-mentioned related technologies, this disclosure provides a light-emitting device, a method for manufacturing the same, and a display device.

[0004] The technical solution provided in this disclosure is as follows:

[0005] In a first aspect, this disclosure provides a light-emitting device, comprising:

[0006] The anode, light-emitting layer, and cathode are stacked sequentially; and

[0007] A functional stacked film layer is disposed between the anode and the light-emitting layer, and between the cathode and the light-emitting layer, wherein the functional stacked film layer includes at least two functional film layers selected from the following: a hole injection layer, a hole transport layer, an electron blocking layer, an electron injection layer, an electron transport layer, and a hole blocking layer; wherein,

[0008] In the functional stacked film layer, except between the hole blocking layer and the light-emitting layer, and between the electron blocking layer and the light-emitting layer, at least one first interface transition layer is provided between at least two functionally different and adjacent functional film layers. The material composition of the first interface transition layer includes material A and material B, where material A and material B are the material compositions of the two functional film layers adjacent to the first interface transition layer, respectively.

[0009] For example, at least one of the first interface transition layers is a hybrid layer whose material composition comprises a mixture of material A and material B.

[0010] For example, in the hybrid layer, the mixing ratio of material A and material B is 1:9 to 9:1.

[0011] For example, at least one of the first interface transition layers is a gradient layer, the material composition of which changes continuously from the side closer to the previous film layer to the side closer to the next film layer, wherein the previous film layer and the next film layer are two functional film layers adjacent to the first interface transition layer.

[0012] For example, the at least two functionally distinct and adjacent functional film layers are selected from any pair of the following combinations: between the hole injection layer and the hole transport layer, between the hole transport layer and the electron blocking layer, between the electron blocking layer and the light-emitting layer, between the light-emitting layer and the hole blocking layer, between the hole blocking layer and the electron transport layer, and between the electron transport layer and the electron injection layer.

[0013] For example, the light-emitting device is a stacked light-emitting device, including at least two light-emitting units connected by at least one charge-generating layer CGL, wherein a second interface transition layer is provided between the charge-generating layer and the functional film layer of the adjacent light-emitting unit; the material composition of the second interface transition layer includes material C and material D, wherein material C and material D are the material compositions of the charge-generating layer and the adjacent functional film layer, respectively.

[0014] Secondly, this disclosure provides a display device that includes the light-emitting device described above.

[0015] Thirdly, this disclosure provides a method for manufacturing a light-emitting device, used to manufacture the light-emitting device as described above, the method comprising the following steps:

[0016] The anode, the light-emitting layer, the cathode, and the functional stacked film layer are formed, wherein the first interface transition layer is formed by vapor deposition.

[0017] For example, when at least one of the first interface transition layers is a hybrid layer, the process of forming the first interface transition layer by vapor deposition specifically includes:

[0018] Simultaneously, the evaporation sources of two functional films adjacent to the first interface transition layer are turned on for co-evaporation to form the first interface transition layer.

[0019] For example, when at least one of the first interface transition layers is a gradient layer, the process of forming the first interface transition layer by vapor deposition specifically includes:

[0020] During the deposition of the first film layer material, the evaporation source for the second film layer material is turned on, and the evaporation rates of the two evaporation sources are gradually adjusted so that the composition ratio of the second film layer material gradually increases and the composition ratio of the first film layer material gradually decreases until the second film layer is completely transitioned to form the first interface transition layer.

[0021] For example, the material ratio of material A to material B in co-evaporation or gradient evaporation can be controlled by adjusting the heating temperature of the evaporation source of the two functional film layers adjacent to the first interface transition layer.

[0022] The beneficial effects of this disclosure are at least as follows:

[0023] By setting a first interface transition layer between adjacent functional films with different functions in the functional stacked film layers, and the material composition of the first interface transition layer includes the material composition of the two adjacent functional films, the first interface transition layer can play a core role in energy level buffering and charge bridging, thereby systematically optimizing the overall performance of the device. Attached Figure Description

[0024] Figure 1 This diagram illustrates the stacked structure of light-emitting devices in some embodiments of this disclosure.

[0025] Figure 2 This diagram illustrates the stacked structure of light-emitting devices in some other embodiments of this disclosure.

[0026] Figure 3 This diagram illustrates the overlap of electron clouds between adjacent film layers in light-emitting devices in related technologies and in some embodiments of the light-emitting devices disclosed herein.

[0027] Figure 4 A schematic diagram illustrating the carrier transport and interface charge accumulation of light-emitting devices in related technologies and some embodiments of this disclosure;

[0028] Figure 5 A schematic diagram of CV curves representing the accumulation of charge at the film interface;

[0029] Figure 6 This is one of the schematic diagrams illustrating the fabrication process of the light-emitting device in some embodiments of this disclosure;

[0030] Figure 7 This is the second schematic diagram illustrating the fabrication process of the light-emitting device in some embodiments of this disclosure;

[0031] Figure 8 This is the third schematic diagram illustrating the fabrication process of the light-emitting device in some embodiments of this disclosure;

[0032] Figure 9 This diagram illustrates the stacked structure of light-emitting devices in some other embodiments of this disclosure. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0034] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0035] The features such as "parallel," "perpendicular," and "identical" used in the embodiments of this disclosure include features in the strict sense of "parallel," "perpendicular," and "identical," as well as cases where "approximately parallel," "approximately perpendicular," and "approximately identical" include certain tolerances. Taking into account the measurement and the tolerances associated with the measurement of a specific quantity (e.g., limitations of the measurement system), they represent the acceptable deviation range for a specific value as determined by a person skilled in the art. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of said value.

[0036] Furthermore, throughout this document, unless otherwise defined, the terms “substantially,” “essentially,” “approximately,” and “about” are used to describe and explain small variations. When used with an event or situation, these terms can cover situations where the event or situation occurs precisely or approximately. For example, when used with a numerical value, these terms can include a range of variation of the value less than or equal to 10%, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term “substantially coplanar” can refer to two surfaces arranged along the same plane within a micrometer range, such as within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm.

[0037] It should be understood that, in the exemplary embodiments of this disclosure, when a layer or element is referred to as being on another layer or substrate, it may mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate. "A and B are set in the same layer" means that after A and B are formed using the same film deposition process to form a film layer for forming a specific pattern, the layer structure is formed in one patterning process using the same photomask.

[0038] Before providing a detailed description of the light-emitting device and its manufacturing method, as well as the display device, provided in the embodiments of this disclosure, the following description of related technologies is given:

[0039] In related technologies, OLED devices still face many performance challenges, such as a series of display defects related to device capacitance, specifically manifested as issues like motion blur and viewing angle dependence. Motion blur refers to the phenomenon where, when displaying rapidly changing dynamic images, the afterimage of the previous frame lingers on the screen, causing a blurry image. Viewing angle dependence refers to color shift phenomena, such as a greenish tint to white images displayed at specific viewing angles.

[0040] The inventors of this application have discovered through research that motion blur in dynamic images is closely related to the low percentage of pixels in the first frame, and its physical root cause lies in the charge accumulation effect during the charging and discharging process of the device's capacitor. Viewing angle dependence is also closely related to the charge distribution and capacitance characteristics within the device. The aforementioned problems are closely related to the inherent stacked structure of OLED devices.

[0041] For example, a typical OLED device can be composed of multiple functional layers stacked sequentially, including an anode, a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode. Because different functional layers use different organic materials, energy level differences (energy barriers) generally exist between these layers. These energy level differences lead to difficulties in carrier transport. When electrons and holes cross the interfaces between different layers, they need to overcome this energy barrier in a hopping mode. This not only causes an increase in the driving voltage (transition voltage), leading to increased power consumption, but also results in low carrier injection and transport efficiency, ultimately limiting the device's luminous efficiency.

[0042] Furthermore, this energy level difference also disrupts charge transfer, leading to charge accumulation at the interface. For example... Figure 5 As shown, the phenomenon of interface charge accumulation can be visually observed through CV curve testing. Due to the presence of energy barriers, charge carriers (electrons and holes) are easily blocked and accumulate at the film interface. This continuous accumulation of charge directly leads to an increase in device capacitance, which in turn causes the aforementioned dynamic ghosting phenomenon and green radiance in the RA, resulting in poor image quality. In addition, the charge accumulated at the interface generates a strong local electric field and may produce Joule heating through non-radiative recombination and other mechanisms. These effects accelerate the chemical degradation and aging of luminescent molecules or surrounding functional materials, significantly deteriorating the device's operational lifespan.

[0043] Therefore, how to fundamentally improve the interface characteristics between the functional layers of OLED and reduce the energy barrier, thereby solving the problems related to efficiency, lifespan, power consumption and capacitance, has become a key technical challenge that urgently needs to be solved in this field.

[0044] To address the aforementioned problems, this disclosure provides a light-emitting device.

[0045] like Figure 1 and Figure 2 As shown, the light-emitting device provided in this embodiment includes:

[0046] The anode 100, the light-emitting layer 200, and the cathode 300 are stacked sequentially; and

[0047] A functional stacked film layer is disposed between the anode 100 and the light-emitting layer 200, and between the cathode 300 and the light-emitting layer 200. The functional stacked film layer includes at least two functional film layers selected from a hole injection layer 410, a hole transport layer 420, an electron blocking layer 430, an electron injection layer 440, an electron transport layer 450, and a hole blocking layer 460.

[0048] In the functional stacked film layers, except between the hole blocking layer 460 and the light-emitting layer 200, and between the electron blocking layer 430 and the light-emitting layer 200, at least one first interface transition layer 500 is provided between at least two functionally different and adjacent functional film layers. The material composition of the first interface transition layer 500 includes material A and material B, where material A and material B are the material compositions of two functional film layers adjacent to the first interface transition layer 500, respectively.

[0049] In the above scheme, a first interface transition layer 500 is provided between adjacent functional layers with different functions in the aforementioned functional stacked layers. The material composition of the first interface transition layer 500 includes the material composition of the two adjacent functional layers, that is, the material composition of the first interface transition layer 500 includes material A and material B. In this way, the first interface transition layer 500 can play a core role in energy level buffering and charge bridging, thereby systematically optimizing the overall performance of the device.

[0050] Specifically, in traditional light-emitting devices, there is typically a significant energy level abrupt change, or energy level step, between two adjacent functional film layers due to abrupt changes in material composition. For example... Figure 3 As shown in (a), the electron clouds between two adjacent functional layers overlap with a low probability. Charge carriers need to rely on this low-probability overlap of electron clouds between the two functional layers to jump across them. In other words, charge carriers need to be transported at the interface through a probabilistic jumping mechanism. This low-probability overlap of electron clouds can lead to problems such as charge accumulation between layers and increased trans-voltage.

[0051] In this embodiment of the disclosure, by introducing the first interface transition layer 500, a transition region with continuously changing composition and energy levels is constructed between adjacent functional film layers on both sides where there was originally a sudden change in energy level. Figure 3 As shown in (b), the increased overlap area of ​​electron clouds between adjacent molecular orbitals allows charge carriers to pass through the interface in a more efficient manner, such as through direct transport. The presence of the first interface transition layer 500 enables charge carriers (electrons and holes) to transport in a state of complete electron cloud overlap, significantly reducing or even eliminating the energy barrier that charge carriers must overcome when crossing the interface. Reduced resistance to charge carrier injection and transport directly translates to a decrease in device driving voltage, thus optimizing power consumption. This not only reduces energy loss but also promotes a more balanced injection of electrons and holes into the luminescent layer 200, thereby improving exciton formation efficiency and device luminescence efficiency.

[0052] Furthermore, the reduction of the interface energy barrier and the improvement of transport efficiency fundamentally reduce the hindrance and accumulation of charge carriers at the interface. Accumulated charge is the main cause of enhanced local electric fields, Joule heating effects, and accelerated chemical degradation of organic materials. See also... Figure 4 As shown in (a), in related technologies, the energy level difference between adjacent functional layers causes inefficient charge transfer, leading to charge accumulation at the interface. Please refer to [link to relevant documentation]. Figure 4 As shown in (b), in the light-emitting device of this disclosure, by introducing the first interface transition layer 500, charge accumulation can be minimized, thereby significantly improving the device's lifespan and reliability. Charge accumulation at the interface is an important component of the device's parasitic capacitance. In the light-emitting device of this disclosure, reducing this charge accumulation directly leads to a decrease in the overall capacitance of the device. Lower capacitance allows pixels to charge and discharge faster during signal switching, thereby effectively improving the first-frame ratio of the display panel in dynamic scenes and eliminating ghosting (image retention). At the same time, the improvement in capacitance characteristics also helps to solve color shift problems such as RA greening caused by inconsistent responses of different color sub-pixels.

[0053] Furthermore, in order to ensure that the excitons formed by electrons and holes recombine within the light-emitting layer 200 (EML) and prevent the excitons from being transported to other film layers, some light-emitting devices are provided with a hole blocking layer 460 and / or an electron blocking layer 430. Since the hole blocking layer 460 and / or the electron blocking layer 430 need to maintain a certain energy level difference with the light-emitting layer 200, the first interface transition layer 500 is not provided between the electron blocking layer 430 and the light-emitting layer 200, or between the hole blocking layer 460 and the light-emitting layer 200.

[0054] In some exemplary embodiments, such as Figure 1 As shown, at least one of the first interface transition layers 500 is a hybrid layer 510, the material composition of which includes a mixture of material A and material B. That is, at least one of the first interface transition layers 500 is formed by mixing material A and material B in a fixed ratio. For example, in the hybrid layer 510, the mixing ratio of material A and material B is 1:9 to 9:1.

[0055] In the above embodiments, the first interface transition layer 500 contains a mixture of A and B in a fixed proportion to form a composition gradient, which splits a single high energy barrier into two or more lower energy barriers, thereby reducing the energy level step.

[0056] In the manufacturing process, the first interface transition layer 500 can be formed by vapor deposition. Specifically, when vapor-depositing the first interface transition layer 500, as follows: Figure 7As shown, evaporation sources S1 and S2 of A and B can be turned on simultaneously, and the evaporation rate can be fixed by precisely controlling the temperature of the two evaporation sources S1 and S2, thereby obtaining a mixed layer 510 with a fixed ratio. Specifically, the material ratio of material A to material B in co-evaporation can be controlled by adjusting the heating temperature of the evaporation sources S1 and S2 of the two functional films adjacent to the first interface transition layer 500.

[0057] Throughout the evaporation process, the mixing ratio and deposition rate remain constant, meaning the film thickness and ratio of the first interface transition layer 500 are stable, which is beneficial for process control and batch stability in large-scale production. Furthermore, the energy levels and electrical properties of the fixed-ratio mixing layer 510 are constant, making device performance more predictable and designable.

[0058] In some other exemplary embodiments of this disclosure, at least one of the first interface transition layers 500 is a gradient layer 520, whose material composition changes continuously from the side closer to the preceding film layer to the side closer to the following film layer, wherein the preceding film layer and the following film layer are two functional film layers adjacent to the first interface transition layer 500, respectively. For example, when the material composition of the preceding film layer is A and the material composition of the following film layer is B, the proportion of material A in the material composition of the first interface transition layer 500 continuously decreases and the proportion of material B continuously increases from the side closer to the preceding film layer to the side closer to the following film layer.

[0059] Using the above scheme, the first interface transition layer 500 can also be a gradient layer 520. The gradient layer 520 achieves a continuous and seamless transition of material composition from 100% A to 100% B, and the effective energy levels can also present as smoother straight lines or curves, eliminating any tiny energy level steps that may exist in the mixed layer 510. The resistance experienced by charge carriers when traversing the entire interface region is uniform and minimal. Theoretically, lower driving voltage and power consumption optimization can be achieved, making it suitable for display devices that pursue ultra-low power consumption. Furthermore, the smooth transition of energy levels creates a more ideal zero-resistance tunneling environment for charge carriers. Charges do not encounter any local, abrupt potential barriers during transmission, resulting in a smoother transmission process and contributing to higher injection efficiency and better carrier balance. Moreover, the root cause of charge accumulation is the obstacle points on the transmission path, and the gradient layer 520 almost completely smooths out the interface from a physical structure perspective, fundamentally reducing this charge accumulation.

[0060] In terms of manufacturing process, the gradient layer 520 can be fabricated using a vapor deposition process. Specifically, during the vapor deposition of the previous film layer material, the evaporation source for the subsequent film layer material is turned on, and the evaporation rates of the two evaporation sources are gradually adjusted to gradually increase the component proportion of the subsequent film layer material and gradually decrease the component proportion of the previous film layer material until a complete transition to the subsequent film layer is achieved, thus performing gradient vapor deposition to form the first interface transition layer 500. Specifically, the material ratio of material A to material B in the gradient vapor deposition can be controlled by adjusting the heating temperature of the evaporation sources of the two functional film layers adjacent to the first interface transition layer 500.

[0061] It should be noted that to achieve precise compositional gradient in the gradient layer 520, precise dynamic control of evaporation sources A and B is required during the vapor deposition process. For example, a control strategy can be preset to control the timing of activating the material composition of the subsequent film layer, as well as the temperature changes of evaporation sources A and B, so that the evaporation rate changes according to a preset curve.

[0062] It should also be noted that, because the entire manufacturing process of the gradient layer 520 involves multiple dynamic variables, it places high demands on the control system of the equipment hardware. Therefore, the manufacturing of the gradient layer 520 may require high-cost equipment and is suitable for high-end products that pursue ultimate performance.

[0063] Furthermore, in some exemplary embodiments, the at least two functionally distinct and adjacent functional layers are selected from at least one pair of the following combinations: between the hole injection layer (HIL) 410 and the hole transport layer (HTL) 420, between the hole transport layer (HTL) 420 and the electron blocking layer (EBL) 430, between the hole blocking layer (HBL) 460 and the electron transport layer (ETL) 450, and between the electron transport layer (ETL) 450 and the electron injection layer (EIL) 440.

[0064] In the above scheme, the first interface transition layer 500 can be disposed on the main interface of the hole and electron transmission link between the anode 100 and the cathode 300 of the light-emitting device.

[0065] For example, on the hole injection side, the first interface transition layer 500 may be disposed between the hole injection layer 410 and the hole transport layer 420; on the hole transport side, the first interface transition layer 500 may be disposed between the hole transport layer 420 and the electron blocking layer 430; on the electron injection side, the first interface transition layer 500 may be disposed between the electron transport layer 450 and the electron injection layer 440; on the electron transport side, the first interface transition layer 500 may be disposed between the hole blocking layer 460 and the electron transport layer 450.

[0066] In some embodiments, such as Figure 1 and Figure 2 As shown, the functional stacked film layer may further include a Prime layer 470 disposed between the light-emitting layer and the hole transport layer (HTL) 420, with the device exciton recombination center mainly concentrated at the interface between the Prime layer 470 and the light-emitting layer. At least one first interface transition layer 500 may also be disposed between the Prime layer 470 and the light-emitting layer, and between the Prime layer 470 and the hole transport layer 420.

[0067] For example, such as Figure 1 and Figure 2 As shown, the light-emitting device may include an anode 100, a cathode 300, and a hole injection layer (HIL) 410, a hole transport layer (HTL) 420, a prime layer 470, a light-emitting layer 200, a hole blocking layer (HBL) 460, an electron transport layer (ETL) 450, and an electron injection layer (EIL) 440 stacked sequentially from the anode to the cathode. A first interface transition layer 500 may be provided between the hole injection layer 410 and the hole transport layer 420, and / or between the hole transport layer 420 and the prime layer 470, and / or between the prime layer 470 and the light-emitting layer 200, and / or between the hole blocking layer 460 and the electron transport layer 450, and / or between the electron transport layer 450 and the electron injection layer 440.

[0068] It should be noted that the first interface transition layer 500 may be provided in only one pair of combinations of functionally different and adjacent functional film layers, or in at least two pairs of combinations of at least two functionally different and adjacent functional film layers. Furthermore, at a single interface, the first interface transition layer 500 may be a single hybrid layer 510 or a gradient layer 520, or it may be configured as multiple layers. When the first interface transition layer 500 is configured as multiple layers, two or more layers of the first interface transition layer 500 with different compositions, proportions, or functions may be continuously provided at a single interface.

[0069] For example, at an interface, a first transition layer can be first set, followed by a second transition layer, wherein the proportion of material A in the first transition layer is higher than that in the second transition layer, and the proportion of material B in the second transition layer is higher than that in the first transition layer. In this way, compared to a single first interface transition layer 500, setting the first interface transition layer 500 as multiple layers decomposes the originally large energy barrier into two smaller energy barriers. This step-down effect is more carrier-friendly and may result in higher transport efficiency, especially when the initial energy barrier is very high.

[0070] For example, at an interface, a mixed layer 510 with a fixed ratio can be deposited first, followed by a gradient layer 520. The mixed layer 510 can first achieve a preliminary and stable energy level matching. The gradient layer 520 then achieves a seamless transition from the mixed phase to material B. This combination balances the process stability of the mixed layer 510 with the superior performance of the gradient layer 520.

[0071] For example, at an interface, two transition layers with different functional focuses can be set. The first interface transition layer 500 prioritizes electron injection, while the second interface transition layer 500 incorporates a small amount of other functional materials to quench defect states at the interface or adjust the dipole. In this way, not only is transport improved, but stability issues are also solved simultaneously.

[0072] Furthermore, in some embodiments, such as Figure 9 As shown, the light-emitting device can be a stacked light-emitting device, which can include at least two light-emitting units 10 connected by at least one charge-generating layer (CGL) 20. A second interface transition layer 600 is provided between the charge-generating layer 20 and the functional film layer of the adjacent light-emitting unit 10. The material composition of the second interface transition layer 600 includes material C and material D, where material C and material D are the material compositions of the charge-generating layer 20 and the adjacent functional film layer, respectively.

[0073] For example, the stacked structure of the stacked light-emitting device includes an anode 100, a first light-emitting unit, a charge-generating layer 20, a second light-emitting unit, and a cathode 300 stacked sequentially. A second interface transition layer 600 may be provided between the charge-generating layer 20 and the electron transport layer 450 of the first light-emitting unit, and / or between the charge-generating layer 20 and the hole transport layer 420 of the second light-emitting unit.

[0074] Using the above scheme, a significant energy barrier typically exists between the charge generation layer 20 and adjacent film layers, posing an additional source of voltage loss in the stacked device. The second interface transition layer 600 smooths the energy level difference between the charge generation layer 20 and the light-emitting unit 10, greatly reducing the difficulty of injecting charge from the charge generation layer 20 into the light-emitting unit 10. Furthermore, the smooth interface allows electrons and holes generated by the charge generation layer 20 to be received by their respective adjacent units with zero resistance, avoiding carrier accumulation and recombination at the interface of the charge generation layer 20. This ensures that all light-emitting units 10 receive a balanced and sufficient number of carriers, thereby achieving the theoretically high efficiency gain of the stacked device. In addition, the interface of the charge generation layer 20 is one of the most vulnerable and easily aged regions in the stacked device; charge accumulation there generates enormous heat and a local electric field, accelerating material degradation. The second interface transition layer 600, by eliminating charge accumulation, directly protects the core component, the charge generation layer 20, greatly extending the overall lifespan of the stacked device.

[0075] Furthermore, in related technologies, in order to match the energy levels of the charge generation layer 20 and the light-emitting units 10 on both sides, the material of the charge generation layer 20 needs to undergo rigorous screening. Introducing the second interface transition layer 600 relaxes the stringent requirements on the energy levels of the charge generation layer 20 material itself, increases the range of selectable materials for the charge generation layer 20, and reduces the design and material costs of the stacked device.

[0076] The second interface transition layer 600 can also be a hybrid layer 510 or a gradient layer 520. Its manufacturing process is the same as that of the first interface transition layer 500, and will not be described in detail here.

[0077] Furthermore, this disclosure provides a display device that includes the light-emitting device described in the embodiments of this disclosure. The display device provided in the embodiments of this disclosure obviously also possesses the beneficial effects brought about by the light-emitting device provided in the embodiments of this disclosure, and will not be elaborated further here.

[0078] The display devices provided in this disclosure may include, but are not limited to: smartphones, tablets, televisions, smartwatches, in-vehicle displays, VR / AR devices, laptops, foldable display devices, etc.

[0079] Furthermore, this disclosure provides a method for fabricating a light-emitting device, used to fabricate the light-emitting device in the embodiments of this disclosure. The method includes the following steps: forming the anode 100, the light-emitting layer 200, the cathode 300, and the functional stacked film layer, wherein the first interface transition layer 500 is formed by vapor deposition. The method for fabricating the light-emitting device provided in the embodiments of this disclosure obviously also has the beneficial effects brought by the light-emitting device provided in the embodiments of this disclosure, and will not be elaborated further here.

[0080] For example, when at least one of the first interface transition layers 500 is a hybrid layer 510, the formation of the first interface transition layer 500 by the vapor deposition process specifically includes: simultaneously activating the evaporation sources for vapor deposition of two functional film layers adjacent to the first interface transition layer 500, and performing co-evaporation to form the first interface transition layer 500. Wherein, the material ratio of material A to material B in the co-evaporation is controlled by adjusting the heating temperature of the evaporation sources for the two functional film layers adjacent to the first interface transition layer 500.

[0081] Specifically, the fabrication process of the above-mentioned hybrid layer 510 can be as follows:

[0082] First, the previous film layer is formed: First, within a vacuum chamber, the anode 100 and the preceding film layer are prepared; then, as... Figure 6 As shown, the above-mentioned previous film layer is deposited by vapor deposition. At this time, only the evaporation source baffle of material A is turned on, while the baffle of material B is in the closed state. Then, when the film layer of material A reaches the target thickness, it is ready to enter the vapor deposition stage of the mixed layer 510.

[0083] Then, a hybrid layer 510 is formed by co-evaporation: while the evaporation source of material A remains on, the baffle of the evaporation source S1 of material B is turned on. At this time, as... Figure 7 As shown, two evaporation sources (S1, S2) simultaneously jet molecular streams onto the substrate. The evaporation rates of materials A and B are adjusted by independently and precisely controlling the heating temperatures of the two evaporation sources (S1, S2). For example, to obtain a 1:1 mixed layer 510, the temperature is adjusted so that the evaporation rates of A and B are equal. To obtain an 8:2 ratio, the temperature is adjusted so that the evaporation rate of A is much higher than that of B. This co-evaporation process is maintained until the deposited mixed layer 510 reaches a predetermined thickness. During this period, the temperatures of each evaporation source (S1, S2) remain stable to ensure a constant mixing ratio.

[0084] Then, the next film layer is formed: such as Figure 8 As shown, after the above-mentioned mixed layer 510 is deposited, the evaporation source baffle of material A is closed. At this time, only the molecular flow of material B remains in the chamber to continue deposition, thus seamlessly transitioning to the pure film deposition of the latter film layer. After the pure film layer of material B reaches the target thickness, its evaporation source baffle is closed, and the preparation of the latter film layer is completed.

[0085] For example, when at least one of the first interface transition layers 500 is a gradient layer 520, the formation of the first interface transition layer 500 by the vapor deposition process specifically includes: during the vapor deposition of the previous film layer material, turning on the evaporation source for the vapor deposition of the next film layer material, and gradually adjusting the evaporation rates of the two evaporation sources so that the component proportion of the next film layer material gradually increases and the component proportion of the previous film layer material gradually decreases until a complete transition to the next film layer is achieved, thereby performing gradient vapor deposition to form the first interface transition layer 500. For example, the material ratio of material A to material B in the gradient vapor deposition is controlled by adjusting the heating temperature of the evaporation sources of the two functional film layers adjacent to the first interface transition layer 500.

[0086] Specifically, the process of creating the gradient layer 520 described above can be as follows:

[0087] First, the previous film layer is formed: First, the anode 100 and the previous film layer are prepared in the vacuum chamber; then, the above-mentioned previous film layer is deposited by evaporation. At this time, only the baffle of the evaporation source S1 of material A is turned on, and the baffle of material B is closed; then, when the film layer of material A reaches the target thickness, it is ready to enter the gradient layer 520 evaporation stage.

[0088] Then, a gradient layer 520 is formed by gradient evaporation: while material A is still being deposited, the baffle of the evaporation source S1 for material B is turned on. In the initial stage, the heating temperature of the evaporation source S2 for material B is set relatively low, resulting in a slow evaporation rate. Then, the heating temperature of the evaporation source S2 for material B is increased linearly or non-linearly. Simultaneously, the heating temperature of the evaporation source S1 for material A is decreased linearly or non-linearly. During this dynamic adjustment process, the composition of the film deposited on the substrate gradually changes. Initially, the deposited film composition is mainly material A, mixed with a small amount of material B (e.g., 90% A: 10% B); during the process, the proportion of material B in the deposited film continuously increases, while the proportion of material A continuously decreases (e.g., gradually changing from 50% A: 50% B to 20% A: 80% B); at the end, the proportion of material A in the deposited film drops to 0, and the proportion of material B reaches 100%. The duration of the entire gradient process is the deposition time of the gradient layer 520.

[0089] Then, when the composition has completely transitioned to 100% material B, the evaporation source baffle for material A is closed. At this point, only the molecular flow of material B remains in the chamber to continue deposition, thus seamlessly transitioning to the pure film deposition of the latter film layer. Once the pure film layer of material B reaches the target thickness, its evaporation source baffle is closed, and the preparation of the latter film layer is complete.

[0090] The following points need to be explained:

[0091] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0092] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0093] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0094] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure shall be determined by the scope of the claims.

Claims

1. A light-emitting device, characterized in that, include: The anode, light-emitting layer, and cathode are stacked sequentially. and A functional stacked film layer is disposed between the anode and the light-emitting layer, and between the cathode and the light-emitting layer, wherein the functional stacked film layer includes at least two functional film layers selected from the following: a hole injection layer, a hole transport layer, an electron blocking layer, an electron injection layer, an electron transport layer, and a hole blocking layer; wherein, In the functional stacked film layer, apart from the hole blocking layer and the light-emitting layer, and the electron blocking layer and the light-emitting layer, at least one first interface transition layer is provided between at least two functionally different and adjacent functional film layers. The material composition of the first interface transition layer includes material A and material B, where material A and material B are the material compositions of the two functional film layers adjacent to the first interface transition layer, respectively.

2. The light-emitting device according to claim 1, characterized in that, At least one of the first interface transition layers is a hybrid layer, the material composition of which comprises a mixture of material A and material B.

3. The light-emitting device according to claim 2, characterized in that, In the hybrid layer, the mixing ratio of material A and material B is 1:9 to 9:

1.

4. The light-emitting device according to claim 1, characterized in that, At least one of the first interface transition layers is a gradient layer, the material composition of which changes continuously from the side closer to the previous film layer to the side closer to the next film layer, wherein the previous film layer and the next film layer are two functional film layers adjacent to the first interface transition layer.

5. The light-emitting device according to claim 1, characterized in that, The at least two functionally distinct and adjacent functional layers are selected from at least one pair of the following combinations: between the hole injection layer and the hole transport layer, between the hole transport layer and the electron blocking layer, between the hole blocking layer and the electron transport layer, and between the electron transport layer and the electron injection layer.

6. The light-emitting device according to claim 1, characterized in that, The light-emitting device is a stacked light-emitting device, comprising at least two light-emitting units connected by at least one charge-generating layer CGL, wherein a second interface transition layer is provided between the charge-generating layer and the functional film layer of the adjacent light-emitting unit; the material composition of the second interface transition layer includes material C and material D, wherein material C and material D are the material compositions of the charge-generating layer and the adjacent functional film layer, respectively.

7. A display device, characterized in that, Includes the light-emitting device as described in any one of claims 1 to 6.

8. A method for manufacturing a light-emitting device, characterized in that, The method for manufacturing a light-emitting device as described in any one of claims 1 to 6 comprises the following steps: The anode, the light-emitting layer, the cathode, and the functional stacked film layer are formed, wherein the first interface transition layer is formed by vapor deposition.

9. The method for manufacturing a light-emitting device according to claim 8, characterized in that, When at least one of the first interface transition layers is a hybrid layer, the step of forming the first interface transition layer by vapor deposition specifically includes: simultaneously turning on the evaporation sources of two functional films adjacent to the first interface transition layer to perform co-evaporation to form the first interface transition layer. When at least one of the first interface transition layers is a gradient layer, the step of forming the first interface transition layer by vapor deposition specifically includes: during the vapor deposition of the previous film layer material, turning on the evaporation source for vapor deposition of the next film layer material, and gradually adjusting the evaporation rates of the two evaporation sources so that the component proportion of the next film layer material gradually increases and the component proportion of the previous film layer material gradually decreases until the transition to the next film layer is complete, so as to perform gradient vapor deposition and form the first interface transition layer.

10. The method for manufacturing a light-emitting device according to claim 9, characterized in that, By adjusting the heating temperature of the evaporation source of the two functional films adjacent to the first interface transition layer, the material ratio of material A to material B in co-evaporation or gradient evaporation can be controlled.

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