Display device and method of manufacturing the same

Abstract

This invention relates to a display device and its fabrication method. The display device includes a substrate, a scattering layer, an anode layer, a light-emitting layer, and a cathode layer. The scattering layer is disposed on the substrate and comprises a porous material or is selected from any one of Fe2O3, ZnO, SiO2, and Si3N4. The anode layer is disposed away from the surface of the substrate from the scattering layer. The light-emitting layer is disposed away from the surface of the scattering layer from the anode layer. The cathode layer is disposed away from the surface of the anode layer from the light-emitting layer. This display device, by disposing of a scattering layer between the substrate and the anode layer, can effectively scatter light emitted downwards through the anode layer in a top-emitting display device, reducing light loss, mitigating the microcavity effect of the top-emitting display device, and eliminating viewing angle problems. This display device can expand the light emission direction of a top-emitting display device, reduce light reflection from the top interface, and improve the light extraction efficiency of the top-emitting display device.

Description

Technical Field

[0001] This invention relates to the field of display device technology, and in particular to a display device and its fabrication method. Background Technology

[0002] OLED (Organic Light-Emitting Diode) is mainly divided into bottom-emitting and top-emitting types according to the light emission method. Currently, commercially available OLEDs mainly adopt the top-emitting light emission method because, compared to bottom-emitting light which passes through a large number of thin film circuit layers and causes a lot of light loss, top-emitting light penetrates fewer film layers and has less light loss.

[0003] Conventional top-emitting, upright OLED devices employ a semi-transparent cathode layer on the emitting side and a reflective layer on the anode side. Light emitted downwards (towards the anode) from the emitting layer is reflected back towards the emitting direction by the reflective layer. However, the reflected light from traditional top-emitting OLED devices is unidirectional. When it encounters the semi-transparent cathode layer with a fixed refractive index, reflection occurs, confining the light within the organic material. This creates a microcavity effect, leading to viewing angle issues and significantly reduced light extraction efficiency. A large amount of light is lost within the OLED emitting layer material and cannot be effectively utilized. Therefore, how to rationally utilize this portion of light, improve light extraction efficiency, and eliminate the microcavity effect has become a research hotspot in this field. Summary of the Invention

[0004] Therefore, it is necessary to provide a display device and its fabrication method to address the problem of low light extraction efficiency in traditional top-emitting display devices.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] In one aspect, the present invention provides a display device comprising:

[0007] Substrate;

[0008] A scattering layer is disposed on the substrate, the scattering layer comprising a material having a porous structure;

[0009] An anode layer is disposed on the surface of the scattering layer away from the substrate.

[0010] A light-emitting layer is disposed on the surface of the anode layer away from the scattering layer; and

[0011] A cathode layer is disposed on the surface of the light-emitting layer away from the anode layer.

[0012] In some embodiments, the porous material is a nanorod, nanotube, nanowire, nanosphere, or nanopolyhedral material.

[0013] In another aspect, the present invention provides a display device comprising:

[0014] Substrate;

[0015] A scattering layer is disposed on the substrate, and the material of the scattering layer is selected from any one of Fe2O3, ZnO, SiO2 and Si3N4;

[0016] An anode layer is disposed on the surface of the scattering layer away from the substrate.

[0017] A light-emitting layer is disposed on the surface of the anode layer away from the scattering layer; and

[0018] A cathode layer is disposed on the surface of the light-emitting layer away from the anode layer.

[0019] In some embodiments, the scattering layer is an α-Fe2O3 nanomaterial layer.

[0020] In some embodiments, the thickness of the scattering layer is 0.1 μm to 1 μm.

[0021] In some embodiments, the anode layer includes:

[0022] A first buffer layer is disposed on the surface of the scattering layer away from the substrate.

[0023] A conductive dielectric layer is disposed on the surface of the first buffer layer away from the scattering layer.

[0024] In some embodiments, the anode layer further includes:

[0025] The second buffer layer is disposed between the first buffer layer and the conductive dielectric layer.

[0026] In some embodiments, the material of the first buffer layer is Si3N4; the material of the second buffer layer is selected from at least one of SiO2, TiO2 or ZnO; and the material of the conductive dielectric layer is selected from at least one of IZO, AZO, ITO, ATO or FTO.

[0027] In some embodiments, the thickness of both the first buffer layer and the second buffer layer is 20nm to 30nm.

[0028] In some embodiments, the thickness of the conductive dielectric layer is 50 nm to 100 nm.

[0029] In some embodiments, the light-emitting layer is an organic light-emitting layer.

[0030] In some embodiments, the material of the cathode layer is selected from at least one of Ag, Al, or Mg / Ag alloy; the thickness of the cathode layer 105 is 18 nm to 20 nm.

[0031] In another aspect, the present invention provides a method for fabricating a display device, comprising the following steps:

[0032] A scattering layer is formed on a substrate, the scattering layer comprising a material having a porous structure;

[0033] An anode layer is formed on the surface of the scattering layer away from the substrate.

[0034] A light-emitting layer is formed on the surface of the anode layer away from the scattering layer; and

[0035] A cathode layer is formed on the surface of the light-emitting layer away from the anode layer.

[0036] In some embodiments, the porous material is a nanorod, nanotube, nanowire, nanosphere, or nanopolyhedral material.

[0037] In another aspect, the present invention provides a method for fabricating a display device, comprising the following steps:

[0038] A scattering layer is formed on a substrate, wherein the material of the scattering layer is selected from any one of Fe2O3, ZnO, SiO2 and Si3N4;

[0039] An anode layer is formed on the surface of the scattering layer away from the substrate.

[0040] A light-emitting layer is formed on the surface of the anode layer away from the scattering layer; and

[0041] A cathode layer is formed on the surface of the light-emitting layer away from the anode layer.

[0042] In some embodiments, the scattering layer is an α-Fe2O3 nanomaterial coating; forming the α-Fe2O3 nanomaterial coating includes the following steps:

[0043] α-Fe2O3 nanomaterials were dispersed in a solvent, and the solution was filtered by pressure to obtain a spin-coating solution;

[0044] The spin-coating solution is dropped onto a substrate for spin coating, and then the solvent is removed by heating to obtain the α-Fe2O3 nanomaterial coating.

[0045] In some embodiments, the preparation of the α-Fe2O3 nanomaterial includes the following steps:

[0046] Soluble ferric salts and bases are dissolved in water, ionic liquids are added and stirred until homogeneous, and then a hydrothermal reaction is carried out.

[0047] After the hydrothermal reaction is completed, the resulting precipitate is washed, dried and heat-treated in sequence to obtain α-Fe2O3 nanomaterials.

[0048] In some embodiments, the soluble ferric salt is ferric chloride hexahydrate; the base is sodium hydroxide; and the ionic liquid is 1-butyl-3-methylimidazolium chloride.

[0049] In some embodiments, forming an anode layer on the surface of the scattering layer away from the substrate includes the following steps:

[0050] A first buffer layer is formed on the surface of the scattering layer away from the substrate.

[0051] A conductive dielectric layer is formed on the surface of the first buffer layer away from the scattering layer.

[0052] In some embodiments, forming an anode layer on the surface of the scattering layer away from the substrate further includes the step of forming a second buffer layer between the first buffer layer and the conductive dielectric layer.

[0053] The display device of the present invention, by providing a scattering layer between the substrate and the anode layer, wherein the scattering layer comprises a porous material to form a porous scattering surface, can effectively scatter light emitted downwards through the anode layer in a top-emitting display device, reducing light loss; and by changing the single light emission direction through scattering, it weakens the microcavity effect of the top-emitting display device and eliminates viewing angle problems. This display device can expand the light emission direction of a top-emitting display device, reduce light reflection from the top interface, and improve the light extraction efficiency of the top-emitting display device. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the display device of the present invention;

[0055] Figure 2 This is a SEM (scanning electron microscope) image of the α-Fe2O3 nanorods prepared in Example 1 of the present invention;

[0056] Figure 3 This is a SEM image of the α-Fe2O3 nanorods prepared in Example 2 of this invention;

[0057] Figure 4 This is a SEM image of the α-Fe2O3 nanorods prepared in Example 3 of this invention;

[0058] Figure 5This is a SEM image of the α-Fe2O3 nanorods prepared in Example 4 of this invention;

[0059] Figure 6 This is a SEM image of the α-Fe2O3 nanopolyhedron prepared in Example 5 of the present invention.

[0060] The above figures include the following reference numerals:

[0061] 101. Substrate; 102. Scattering layer; 103. Anode layer; 103a. Conductive dielectric layer; 103b. First buffer layer; 103c. Second buffer layer; 104. Functional layer; 104a. Hole injection layer; 104b. Hole transport layer; 104c. Light emitting layer; 104d. Electron transport layer; 104e. Electron injection layer; 105. Cathode layer; 106. Encapsulation layer. Detailed Implementation

[0062] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0065] As described in the background section of this invention, traditional top-emitting display devices (such as OLED display devices) suffer from microcavity effects. These microcavity effects can lead to viewing angle problems and significantly reduce light extraction efficiency. A large amount of light is lost within the light-emitting layer material of the top-emitting display device and cannot be used effectively.

[0066] To address the aforementioned problems, one embodiment of the present invention provides a display device.

[0067] Please see Figure 1The structure of the display device includes a substrate 101, a scattering layer 102, an anode layer 103, a light-emitting layer 104c, and a cathode layer 105 stacked sequentially.

[0068] The scattering layer 102 is disposed on the substrate 101 and includes a material with a porous structure. The anode layer 103 is disposed on the side surface of the scattering layer 102 away from the substrate 101. The light-emitting layer 104c is disposed on the side surface of the anode layer 103 away from the scattering layer 102. The cathode layer 105 is disposed on the side surface of the light-emitting layer 104c away from the anode layer 103.

[0069] The aforementioned display device, by providing a scattering layer 102 between the substrate 101 and the anode layer 103, the scattering layer 102 comprising a porous material, can effectively scatter the light emitted downwards from the light-emitting layer 104c of the top-emitting display device that penetrates the anode layer 103, reducing light loss; and by changing the single light emission direction through scattering, it weakens the microcavity effect of the top-emitting display device and eliminates viewing angle problems. This display device can expand the light emission direction of the top-emitting display device, reduce the light reflection effect of the top interface, improve the light extraction efficiency of the top-emitting display device, and effectively solve the problem of low light extraction efficiency in traditional top-emitting display devices.

[0070] In some embodiments, the porous material is a nanorod, nanotube, nanowire, nanosphere, or nanopolyhedral material. Further, the material of the scattering layer 102 is selected from any one of Fe2O3, ZnO, SiO2, and Si3N4.

[0071] An embodiment of the present invention also provides a display device, the structure of which includes a substrate 101, a scattering layer 102, an anode layer 103, a light-emitting layer 104c, and a cathode layer 105 stacked sequentially. The scattering layer 102 is disposed on the substrate 101, and the material of the scattering layer 102 is selected from any one of Fe2O3, ZnO, SiO2, and Si3N4. The anode layer 103 is disposed on the surface of the scattering layer 102 away from the substrate 101, the light-emitting layer 104c is disposed on the surface of the anode layer 103 away from the scattering layer 102, and the cathode layer 105 is disposed on the surface of the light-emitting layer 104c away from the anode layer 103.

[0072] It is understood that in some embodiments, the above-described display device further includes an encapsulation layer 106 disposed on the cathode layer 105 for encapsulating the light-emitting layer 104c.

[0073] Understandably, in some examples, the display device may also include a hole functional layer and / or an electronic functional layer, with the hole functional layer disposed between the anode structure and the light-emitting layer 104c. The electronic functional layer is disposed between the light-emitting layer 104c and the cathode layer 105.

[0074] Furthermore, the hole functional layer includes a hole injection layer 104a and a hole transport layer 104b. The hole injection layer 104a is disposed on the side surface of the anode layer 103 away from the scattering layer 102, and the hole transport layer 104b is disposed on the side surface of the hole injection layer 104a away from the anode layer 103.

[0075] Furthermore, the electronic functional layer includes an electron transport layer 104d and an electron injection layer 104e. The electron transport layer 104d is disposed on the side surface of the light-emitting layer 104c away from the hole transport layer 104b, and the electron injection layer 104e is disposed on the side surface of the electron transport layer 104d away from the light-emitting layer 104c.

[0076] In this specific example, the hole injection layer 104a, hole transport layer 104b, light-emitting layer 104c, electron transport layer 104d, and electron injection layer 104e together constitute the functional layer of the display device. It is understood that the structure of the functional layer is not limited to this and may also include hole blocking layers, electron blocking layers, etc.

[0077] In some embodiments, the scattering layer 102 is an α-Fe2O3 nanomaterial coating; further, the scattering layer 102 is an α-Fe2O3 nanorod material layer or an α-Fe2O3 nanopolyhedral material layer, more preferably an α-Fe2O3 nanorod.

[0078] The α-Fe2O3 nanomaterial coating has a high specific surface area and a porous scattering surface, which can fully scatter the light emitted by the light-emitting layer 104c that penetrates the anode layer 103 downwards, reduce light loss, and improve the light extraction efficiency of the top-emitting display device; moreover, the α-Fe2O3 nanomaterial is easy to prepare and its morphology can be controlled.

[0079] Compared to α-Fe₂O₃ nanopolyhedra, using α-Fe₂O₃ nanorods allows for a better formation of a high specific surface area and porous scattering surface on the surface of the scattering layer 102, resulting in superior light scattering performance. When the scattering layer 102 uses α-Fe₂O₃ nanorods, its specific surface area can reach 42 m². 2 / g or more; when the scattering layer 102 is made of α-Fe2O3 nanopolyhedral material, its specific surface area can reach 33m². 2 / g or more.

[0080] Furthermore, the thickness of the scattering layer 102 is 0.1 μm to 1 μm.

[0081] In some embodiments, α-Fe2O3 nanomaterials are prepared by hydrothermal reaction in an alkaline solution system using soluble trivalent iron salts as the iron source and ionic liquids as surfactants, followed by heat treatment.

[0082] In some embodiments, the anode layer 103 specifically includes a conductive dielectric layer 103a and a first buffer layer 103b. The first buffer layer 103b is disposed on the surface of the scattering layer 102 away from the substrate 101; the conductive dielectric layer 103a is disposed on the surface of the first buffer layer 103b away from the scattering layer 102. This arrangement forms the first buffer layer 103b between the conductive dielectric layer 103a and the scattering layer 102 of the anode layer 103. The first buffer layer 103b has a smooth, flat surface that allows it to contact the scattering layer 102 and provide a buffering effect. The conductive dielectric layer 103a contacts the functional layer 104, enabling interface energy level matching between the anode layer 103 and the functional layer 104.

[0083] Furthermore, in some embodiments, a second buffer layer 103c is also provided on the surface of the first buffer layer 103b away from the scattering layer 102, and a conductive dielectric layer 103a is disposed on the surface of the second buffer layer 103c away from the first buffer layer 103b. The second buffer layer 103c has a smooth and flat surface, which can contact the conductive dielectric layer 103a to provide a buffering effect.

[0084] In some embodiments, the first buffer layer 103b and the second buffer layer 103c are made of different materials. Specifically, in this embodiment, the first buffer layer 103b is made of Si3N4. The second buffer layer 103c is made of at least one material selected from SiO2, TiO2, or ZnO.

[0085] The material of the conductive dielectric layer 103a is selected from at least one of IZO, AZO, ITO, ATO, or FTO. The first buffer layer 103b, the second buffer layer 103c, and the conductive dielectric layer 103a together form a three-layer anode layer 103. For example, when the second buffer layer 103c is SiO2 and the conductive dielectric layer 103a is IZO, a Si3N4 / SiO2 / IZO three-layer anode layer 103 is formed; when the second buffer layer 103c is SiO2 and the conductive dielectric layer 103a is an AZO layer, a Si3N4 / SiO2 / AZO three-layer anode layer 103 is formed.

[0086] In some embodiments, the thickness of the first buffer layer 103b and the second buffer layer 103c is both 20nm to 30nm, and the thickness of the conductive dielectric layer 103a is 50nm to 100nm. Specifically, the thicknesses of the first buffer layer 103b, the second buffer layer 103c, and the conductive dielectric layer 103a can be set within the above ranges according to actual needs. In one specific example, the thickness of the first buffer layer 103b and the second buffer layer 103c is both 15nm, while the thickness of the conductive dielectric layer 103a is 75nm.

[0087] In some embodiments, the material of the cathode layer 105 is selected from at least one of Al, Ag or Mg / Ag alloy, and the thickness of the cathode layer 105 is 18 nm to 20 nm.

[0088] In some embodiments of the present invention, a method for fabricating a display device is also provided, the method comprising the following steps S100 to S400:

[0089] Step S100: A scattering layer 102 is formed on a substrate 101, the scattering layer 102 comprising a material having a porous structure;

[0090] Step S200: An anode layer 103 is formed on the surface of the scattering layer 102 away from the substrate 101;

[0091] Step S300: Form a light-emitting layer 104c on the surface of the anode layer 103 away from the scattering layer 102; and

[0092] Step S400: A cathode layer 105 is formed on the surface of the light-emitting layer 104c away from the anode layer 103.

[0093] Specifically, materials with porous structures can be nanorods, nanotubes, nanowires, nanospheres, or nanopolyhedra, such as nanoFe2O3, nanoZnO, nanoSiO2, and nanoSi3N4.

[0094] In some embodiments of the present invention, another method for fabricating a display device is also provided, the method comprising the following steps S100 to S400:

[0095] Step S100: A scattering layer 102 is formed on the substrate 101. The material of the scattering layer 102 is selected from any one of Fe2O3, ZnO, SiO2 and Si3N4.

[0096] Step S200: An anode layer 103 is formed on the surface of the scattering layer 102 away from the substrate 101;

[0097] Step S300: Form a light-emitting layer 104c on the surface of the anode layer 103 away from the scattering layer 102; and

[0098] Step S400: A cathode layer 105 is formed on the surface of the light-emitting layer 104c away from the anode layer 103.

[0099] The above-described fabrication method involves setting a scattering layer 102 between the substrate 101 and the anode layer 103. This scattering layer 102 can fully scatter the light emitted by the light-emitting layer 104c that penetrates the anode layer 103 downwards, reducing light loss. By scattering, the single light emission direction is changed, the microcavity effect is weakened, the viewing angle problem is eliminated, and the light extraction efficiency of the top-emitting display device is improved.

[0100] In some embodiments, the scattering layer 102 is an α-Fe2O3 nanomaterial coating. The α-Fe2O3 nanomaterial coating has a high specific surface area and a porous scattering surface, which can fully scatter the light emitted downward from the light-emitting layer 104c that penetrates the anode layer 103, reduce light loss, and improve the light extraction efficiency of the top-emitting display device.

[0101] Further, forming the scattering layer 102 includes the following steps:

[0102] α-Fe2O3 nanomaterials were dispersed in a solvent, and the solution was filtered by pressure to obtain a spin-coating solution. The spin-coating solution was dropped onto a substrate 101 for spin coating, and then the solvent was removed by heating to obtain a scattering layer.

[0103] Furthermore, the preparation of α-Fe2O3 nanomaterials includes the following steps:

[0104] Soluble ferric salts and alkalis are dissolved in water, and ionic liquids are added and stirred until homogeneous. Then, a hydrothermal reaction is carried out. After the hydrothermal reaction is completed, the resulting precipitate is washed, dried, and heat-treated in sequence to obtain α-Fe2O3 nanomaterials.

[0105] Specifically, soluble ferric salts and alkalis are first dissolved in water, and ionic liquids are added and stirred until homogeneous. The solution is then transferred to a hydrothermal reactor for hydrothermal reaction. After the hydrothermal reaction is completed, the resulting precipitate is washed and dried. The precipitate is then placed in a muffle furnace for heat treatment and ground into powder to obtain α-Fe2O3 nanomaterials with good dispersibility, small diameter, and large specific surface area.

[0106] This invention utilizes soluble ferric salts as raw materials to prepare α-Fe₂O₃ nanomaterials in an alkaline solution system using an ionic liquid-assisted hydrothermal method. This preparation method is simple to operate, yields α-Fe₂O₃ nanomaterials with high specific surface area, and allows for convenient control of the morphology of the α-Fe₂O₃ nanomaterials by adjusting the amounts of alkali and ionic liquid.

[0107] In some embodiments, the soluble ferric salt is ferric chloride hexahydrate (FeCl3·6H2O); the base is sodium hydroxide; and the ionic liquid is 1-butyl-3-methylimidazolium chloride ([Bmim]Cl).

[0108] The method for fabricating the display device of the present invention generally adopts the method of "dispersion-pressure filtration-spin coating-post baking" to prepare a scattering layer 102 on a substrate 101. The preparation method is simple and easy to operate. The prepared scattering layer 102 has a high specific surface area and a porous scattering surface, which can fully scatter the light emitted by the light-emitting layer 104c downward and penetrate the anode layer 103, reduce light loss, change the single light emission direction by scattering, weaken the microcavity effect, eliminate the viewing angle problem, and improve the light extraction efficiency of the top-emitting display device.

[0109] In some embodiments, an anode layer 103 is formed on the surface of the scattering layer 102 away from the substrate 101, including the following steps:

[0110] A first buffer layer 103b is formed on the surface of the scattering layer 102 away from the substrate 101;

[0111] A conductive dielectric layer 103a is formed on the surface of the first buffer layer 103b away from the scattering layer 102.

[0112] Furthermore, forming an anode layer 103 on the surface of the scattering layer 102 away from the substrate 101 further includes the following step: forming a second buffer layer 103c between the first buffer layer 103b and the conductive dielectric layer 103a.

[0113] Specifically, a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a can be prepared on the surface of the scattering layer 102 away from the substrate 101 using magnetron sputtering, thereby forming the integral anode layer 103. Alternatively, other existing methods can be used to form the anode layer 103.

[0114] The present invention will be further described below with reference to specific embodiments and comparative examples, but these should not be construed as limiting the scope of protection of the present invention.

[0115] Example 1:

[0116] A method for fabricating a display device according to an embodiment of the present invention includes the following steps:

[0117] 1) Preparation of α-Fe2O3 nanorod materials

[0118] Accurately weigh 1.082 g FeCl3·6H2O and 3.2 g NaOH, and completely dissolve them in 40 mL deionized water under magnetic stirring for 10 min until completely dissolved. Then, add 1 mol of ionic liquid 1-butyl-3-methylimidazolium chloride as a surfactant, stir vigorously for 20 min, and transfer to a hydrothermal reactor with a polytetrafluoroethylene liner. Heat the reactor at 150 °C for 8 h in a constant-temperature drying oven. After the hydrothermal reaction, allow it to cool naturally to room temperature. Wash the resulting precipitate several times with ultrapure water and ethanol, and vacuum dry it at 80 °C for 3 h. Then, place the sample in a muffle furnace and heat-treat it at 250 °C for 2 h. Grind the precipitate into powder and observe its morphology under an electron microscope. The SEM image of the product is shown below. Figure 2 As shown. The obtained product is an α-Fe2O3 nanorod material with good dispersibility, small diameter, and large specific surface area.

[0119] 2) Preparation of the scattering layer spin-coating solution

[0120] The powdered α-Fe2O3 nanorods prepared in step 1) were dissolved in a propylene glycol methyl ether acetate solution and heated and stirred at 80°C. After the nanomaterials were completely dissolved, the solution was filtered to obtain a spin-coating solution free of impurities.

[0121] 3) Preparation of scattering layer

[0122] The spin coating solution prepared in step 2) is dropped onto the substrate 101 and spin coated. After spin coating is completed, the substrate is placed on a hot stage to evaporate the solvent, thereby obtaining a scattering layer 102 with a high scattering surface and a thickness of 0.2 μm.

[0123] 4) Preparation of the anode layer

[0124] An anode layer 103 was fabricated on the scattering layer 102 using magnetron sputtering. The anode layer 103 consists of a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the scattering layer 102 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0125] 5) Fabrication of functional layers

[0126] A functional layer 104 is fabricated on the anode layer 103. The functional layer 104 consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e, thereby forming a complete functional layer 104.

[0127] 6) Preparation of metal cathode

[0128] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0129] 7) Fabrication of the encapsulation layer

[0130] A 70 nm encapsulation layer (CPL) 106 is deposited on a semi-transparent cathode layer 105.

[0131] The display device of this embodiment is obtained by means of the above method. The specific surface area of ​​the scattering layer 102 in the display device and the external quantum efficiency (EQE) of the display device are shown in Table 1.

[0132] Example 2:

[0133] A method for fabricating a display device according to an embodiment of the present invention includes the following steps:

[0134] 1) Preparation of α-Fe2O3 nanorod materials

[0135] Accurately weigh 1.082 g FeCl3·6H2O and 3.2 g NaOH, and completely dissolve them in 40 mL deionized water under magnetic stirring for 10 min until completely dissolved. Then transfer the solution to a hydrothermal reactor with a polytetrafluoroethylene liner and heat at 150 °C for 8 h in a constant temperature drying oven. After the hydrothermal reaction, allow it to cool naturally to room temperature. Wash the resulting precipitate several times with ultrapure water and ethanol, and vacuum dry it at 80 °C for 3 h. Then place the sample in a muffle furnace and heat-treat it at 250 °C for 2 h. Grind the precipitate into powder and observe the morphology of the product under an electron microscope. The SEM image is shown below. Figure 3 As shown, the obtained α-Fe2O3 nanomaterials are aggregated and irregularly shaped α-Fe2O3 nanorods.

[0136] 2) Preparation of the scattering layer spin-coating solution

[0137] The prepared powdered α-Fe2O3 nanorods were dissolved in a propylene glycol methyl ether acetate solution, heated and stirred at 80°C, and after complete dissolution, the solution was filtered to obtain a spin-coating solution free of impurities.

[0138] 3) Preparation of scattering layer

[0139] The spin coating solution obtained in the above steps is dropped onto the substrate 101 and spin-coated. After spin coating is completed, the substrate is placed on a hot stage to evaporate the solvent, thereby obtaining a scattering layer 102 with a high scattering surface and a thickness of 0.2 μm.

[0140] 4) Preparation of the anode layer

[0141] An anode layer 103 was fabricated on the scattering layer 102 using magnetron sputtering. The anode layer 103 consists of a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the scattering layer 102 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0142] 5) Fabrication of functional layers

[0143] A functional layer 104 is fabricated on the anode layer 103. This functional layer 104 consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e, thereby forming a complete functional layer 104.

[0144] 6) Preparation of metal cathode

[0145] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0146] 7) Fabrication of the encapsulation layer

[0147] A 70nm encapsulation layer 106 is deposited on a semi-transparent cathode layer 105.

[0148] The display device of this embodiment is obtained by means of the above method. The specific surface area of ​​the scattering layer 102 in the display device and the external quantum efficiency (EQE) of the display device are shown in Table 1.

[0149] Example 3:

[0150] A method for fabricating a display device according to an embodiment of the present invention includes the following steps:

[0151] 1) Preparation of α-Fe2O3 nanorod materials

[0152] Accurately weigh 1.082 g FeCl3·6H2O and 3.2 g NaOH, and completely dissolve them in 40 mL deionized water under magnetic stirring for 10 min until completely dissolved. Then, add 3 mol of ionic liquid 1-butyl-3-methylimidazolium chloride as a surfactant, stir vigorously for 20 min, and transfer to a hydrothermal reactor with a polytetrafluoroethylene liner. Perform the hydrothermal reaction at 150 °C for 8 h in a constant temperature drying oven. After the reaction, allow it to cool naturally to room temperature. Wash the resulting precipitate several times with ultrapure water and ethanol, and vacuum dry at 80 °C for 3 h. Then, place the sample in a muffle furnace and heat-treat at 250 °C for 2 h. Grind the precipitate into powder and observe the morphology of the product under an electron microscope. The SEM image is shown below. Figure 4 As shown, this product is an aggregated α-Fe2O3 nanorod material with a non-uniform morphology.

[0153] 2) Preparation of the scattering layer spin-coating solution

[0154] The powdered α-Fe2O3 nanorods obtained above were dissolved in a propylene glycol methyl ether acetate solution and heated and stirred at 80°C. After the nanomaterials were completely dissolved, the solution was filtered to obtain a spin-coating solution free of impurities.

[0155] 3) Preparation of scattering layer

[0156] The spin coating solution prepared above is dropped onto the substrate 101 and spin coated. After spin coating is completed, the substrate is placed on a hot stage to evaporate the solvent, thereby obtaining a scattering layer 102 with a high scattering surface and a thickness of 0.2 μm.

[0157] 4) Preparation of the anode layer

[0158] An anode layer 103 was fabricated on the scattering layer 102 using magnetron sputtering. The anode layer 103 consists of a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the scattering layer 102 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0159] 5) Fabrication of functional layers

[0160] A functional layer 104 is fabricated on the anode layer 103 prepared above. The functional layer 104 consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e.

[0161] 6) Preparation of metal cathode

[0162] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0163] 7) Fabrication of the encapsulation layer

[0164] A 70nm encapsulation layer 106 is deposited on a semi-transparent cathode layer 105.

[0165] The display device of this embodiment is obtained by means of the above method. The specific surface area of ​​the scattering layer 102 in the display device and the external quantum efficiency (EQE) of the display device are shown in Table 1.

[0166] Example 4:

[0167] A method for fabricating a display device according to an embodiment of the present invention includes the following steps:

[0168] 1) Preparation of α-Fe2O3 nanorod materials

[0169] Accurately weigh 1.082 g FeCl3·6H2O and 3.2 g NaOH, and completely dissolve them in 40 mL deionized water under magnetic stirring for 10 min until completely dissolved. Then, add 6 mol of ionic liquid 1-butyl-3-methylimidazolium chloride as a surfactant, stir vigorously for 20 min, and transfer to a hydrothermal reactor with a polytetrafluoroethylene liner. Perform the hydrothermal reaction at 150 °C for 8 h in a constant temperature drying oven. After the reaction, allow it to cool naturally to room temperature. Wash the resulting precipitate several times with ultrapure water and ethanol, and vacuum dry at 80 °C for 3 h. Then, place the sample in a muffle furnace and heat-treat at 250 °C for 2 h. Grind the precipitate into powder and observe the morphology of the product under an electron microscope. The SEM image is shown below. Figure 5 As shown, the obtained nanomaterials are atypical rod-shaped α-Fe2O3 materials with severe aggregation and non-uniform morphology.

[0170] 2) Preparation of the scattering layer spin-coating solution

[0171] The powdered α-Fe2O3 nanorods prepared above were dissolved in a propylene glycol methyl ether acetate solution and heated and stirred at 80°C. After the nanomaterials were completely dissolved, the solution was filtered to obtain a spin-coating solution free of impurities.

[0172] 3) Preparation of scattering layer

[0173] The spin coating solution obtained above is dropped onto the substrate 101 and spin coated. After spin coating is completed, the substrate is placed on a hot stage to evaporate the solvent, thereby obtaining a scattering layer 102 with a high scattering surface and a thickness of 0.2 μm.

[0174] 4) Preparation of the anode layer

[0175] An anode layer 103 was fabricated on the scattering layer 102 using magnetron sputtering. The anode layer 103 consists of a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the scattering layer 102 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0176] 5) Fabrication of functional layers

[0177] A functional layer 104 is fabricated on the anode layer 103. The functional layer 104 consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e.

[0178] 6) Preparation of metal cathode

[0179] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0180] 7) Fabrication of the encapsulation layer

[0181] A 70nm encapsulation layer 106 is deposited on a semi-transparent cathode layer 105.

[0182] The display device of this embodiment is obtained by means of the above method. The specific surface area of ​​the scattering layer 102 in the display device and the external quantum efficiency (EQE) of the display device are shown in Table 1.

[0183] Example 5:

[0184] A method for fabricating a display device according to an embodiment of the present invention includes the following steps:

[0185] 1) Preparation of α-Fe2O3 nanomaterials

[0186] Accurately weigh 1.082 g FeCl3·6H2O and 0.4 g NaOH, and completely dissolve them in 40 mL deionized water under magnetic stirring for 10 min until completely dissolved. Then, add 6 mol of ionic liquid 1-butyl-3-methylimidazolium chloride as a surfactant, stir vigorously for 20 min, and transfer to a hydrothermal reactor with a polytetrafluoroethylene liner. Perform the hydrothermal reaction at 150 °C for 8 h in a constant temperature drying oven. After the reaction, allow it to cool naturally to room temperature. Wash the resulting precipitate several times with ultrapure water and ethanol, and vacuum dry at 80 °C for 3 h. Then, place the sample in a muffle furnace and heat-treat at 250 °C for 2 h. Grind the precipitate into powder and observe the morphology of the product under an electron microscope. The SEM image is shown below. Figure 6 As shown, this nanomaterial is a highly aggregated, uniformly morphologically homogeneous α-Fe₂O₃ nanocubic polyhedral material.

[0187] 2) Preparation of the scattering layer spin-coating solution

[0188] The powdered α-Fe2O3 nanomaterials prepared above were dissolved in a propylene glycol methyl ether acetate solution, heated and stirred at 80°C, and after the nanomaterials were completely dissolved, the solution was filtered to obtain a spin-coating solution free of impurities.

[0189] 3) Preparation of scattering layer

[0190] The spin coating solution prepared above is dropped onto the substrate 101 and spin-coated. After spin coating is completed, the substrate is placed on a hot stage to evaporate the solvent, thereby obtaining a scattering layer 102 with a high scattering surface and a thickness of 0.2 μm.

[0191] 4) Preparation of the anode layer

[0192] An anode layer 103 was fabricated on the scattering layer 102 using magnetron sputtering. The anode layer 103 consists of a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the scattering layer 102 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0193] 5) Fabrication of functional layers

[0194] A functional layer 104 is fabricated on the anode layer 103. Each layer of the functional layer 104 is made of organic material, hence it is a functional layer. Specifically, it consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e.

[0195] 6) Preparation of metal cathode

[0196] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0197] 7) Fabrication of the encapsulation layer

[0198] A 70nm encapsulation layer 106 is deposited on a semi-transparent cathode layer 105.

[0199] The display device of this embodiment is obtained by means of the above method. The specific surface area of ​​the scattering layer 102 in the display device and the external quantum efficiency (EQE) of the display device are shown in Table 1.

[0200] Comparative Example 1:

[0201] A method for fabricating a display device, the method comprising the following steps:

[0202] 1) Preparation of the anode layer

[0203] An anode layer 103 is fabricated on a substrate 101 using magnetron sputtering. The anode layer 103 comprises a first buffer layer 103b, a second buffer layer 103c, and a conductive dielectric layer 103a, arranged sequentially from the side closest to the substrate 101 as Si3N4 / SiO2 / IZO. The Si3N4 layer (first buffer layer 103b) has a thickness of 15 nm, the SiO2 layer (second buffer layer 103c) has a thickness of 15 nm, and the IZO layer (conductive dielectric layer 103a) has a thickness of 75 nm.

[0204] 2) Preparation of functional layers

[0205] A functional layer 104 is fabricated on the anode layer 103. This functional layer 104 consists of a hole injection layer 104a, a hole transport layer 104b, a light-emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e. Specifically, 36 nm CuPc is spin-coated onto the anode layer 103 as the hole injection layer 104a, 25 nm PEDOT-PSS is spin-coated onto the hole injection layer 104a as the hole transport layer 104b, 30 nm host CBP and guest DCNP are spin-coated onto the hole transport layer 104b as the light-emitting layer 104c, 30 nm Liq is vapor-deposited onto the light-emitting layer 104c as the electron transport layer 104d, and 1 nm Yb is vapor-deposited onto the electron transport layer 104d as the electron injection layer 104e.

[0206] 3) Preparation of metal cathode

[0207] An 18 nm Ag layer was deposited on the electron injection layer 104e as a semi-transparent cathode layer 105.

[0208] 4) Preparation of the encapsulation layer

[0209] A 70nm encapsulation layer 106 is deposited on a semi-transparent cathode layer 105.

[0210] The display device of this comparative example was obtained using the above method. The external quantum efficiency (EQE) of this display device is shown in Table 1.

[0211] Table 1 shows the external quantum efficiency and specific surface area of ​​the scattering layer of the display devices in each embodiment and comparative example.

[0212] Serial Number Example <![CDATA[1000cd / m 2 @EQE]]> <![CDATA[Specific surface area of the scattering layer (m 2 / g)]]> 1 Example 1 28.90 60.2 2 Example 2 23.75 42.1 3 Example 3 25.77 51.0 4 Example 4 24.99 48.8 5 Example 5 22.05 33.7 6 Comparative Example 1 21.75 --

[0213] As shown in Table 1, in Examples 1-5 of the present invention, by providing a scattering layer 102 formed of α-Fe2O3 nanomaterial between the substrate 101 and the anode layer 103, the external quantum efficiency of the display device is significantly improved compared to the technical solution in Comparative Example 1 without a scattering layer. This demonstrates that the technical solution of the present invention can significantly improve the light extraction efficiency of the top-emitting display device. Moreover, as the specific surface area of ​​the scattering layer 102 in the top-emitting display device increases, the external quantum efficiency of the display device also increases accordingly.

[0214] As can be seen from the comparison of Examples 1 to 5, in the preparation steps of α-Fe2O3 nanomaterials, the morphology of the prepared α-Fe2O3 nanomaterials can be controlled by adjusting the amount of alkali (sodium hydroxide) and ionic liquid added, thereby preparing a scattering layer 102 with a higher specific surface area.

[0215] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A top-emitting display device, characterized in that, include: Substrate; A scattering layer is disposed on the substrate, the scattering layer comprising a material having a porous structure; An anode layer is disposed on the surface of the scattering layer away from the substrate. A light-emitting layer is disposed on the surface of the anode layer away from the scattering layer; and A cathode layer is disposed on the surface of the light-emitting layer away from the anode layer; The porous material is a nanorod, nanotube, nanowire, nanosphere, or nanopolyhedral material; the scattering layer is made of any one of Fe2O3, ZnO, SiO2, and Si3N4.

2. The top-emitting display device according to claim 1, characterized in that, The scattering layer is an α-Fe2O3 nanomaterial layer.

3. The top-emitting display device according to any one of claims 1 to 2, characterized in that, The thickness of the scattering layer is 0.1 μm to 1 μm.

4. The top-emitting display device according to any one of claims 1 to 2, characterized in that, The anode layer includes: A first buffer layer is disposed on the surface of the scattering layer away from the substrate. A conductive dielectric layer is disposed on the surface of the first buffer layer away from the scattering layer.

5. The top-emitting display device according to claim 4, characterized in that, The anode layer further includes: The second buffer layer is disposed between the first buffer layer and the conductive dielectric layer.

6. The top-emitting display device according to claim 5, characterized in that, The material of the first buffer layer is Si3N4; the material of the second buffer layer is selected from at least one of SiO2, TiO2 or ZnO; the material of the conductive dielectric layer is selected from at least one of IZO, AZO, ITO, ATO or FTO.

7. The top-emitting display device according to claim 5, characterized in that, The thickness of the first buffer layer and the second buffer layer is 20 nm to 30 nm; the thickness of the conductive dielectric layer is 50 nm to 100 nm.

8. The top-emitting display device according to any one of claims 1 to 2, characterized in that, The light-emitting layer is an organic light-emitting layer; the material of the cathode layer is selected from at least one of Ag, Al, or Mg / Ag alloy; the thickness of the cathode layer is 18 nm to 20 nm.

9. A method for fabricating a top-emitting display device, characterized in that, Includes the following steps: A scattering layer is formed on a substrate, the scattering layer comprising a material having a porous structure; An anode layer is formed on the surface of the scattering layer away from the substrate. A light-emitting layer is formed on the surface of the anode layer away from the scattering layer; and A cathode layer is formed on the surface of the light-emitting layer away from the anode layer; The porous material is a nanorod, nanotube, nanowire, nanosphere, or nanopolyhedral material; the scattering layer is made of any one of Fe2O3, ZnO, SiO2, and Si3N4.

10. The method for fabricating a top-emitting display device according to claim 9, characterized in that, The scattering layer is an α-Fe2O3 nanomaterial coating; forming the α-Fe2O3 nanomaterial coating includes the following steps: α-Fe2O3 nanomaterials were dispersed in a solvent, and the solution was filtered by pressure to obtain a spin-coating solution; The spin-coating solution is dropped onto a substrate for spin coating, and then the solvent is removed by heating to obtain the α-Fe2O3 nanomaterial coating.

11. The method for fabricating a top-emitting display device according to claim 10, characterized in that, The preparation of the α-Fe2O3 nanomaterial includes the following steps: Soluble ferric salts and bases are dissolved in water, ionic liquids are added and stirred until homogeneous, and then a hydrothermal reaction is carried out. After the hydrothermal reaction is completed, the resulting precipitate is washed, dried and heat-treated in sequence to obtain α-Fe2O3 nanomaterials.

12. The method for fabricating a top-emitting display device according to any one of claims 9 to 11, characterized in that, The process of forming an anode layer on the surface of the scattering layer away from the substrate includes the following steps: A first buffer layer is formed on the surface of the scattering layer away from the substrate. A conductive dielectric layer is formed on the surface of the first buffer layer away from the scattering layer.

13. The method for fabricating a top-emitting display device according to claim 12, characterized in that, The process of forming an anode layer on the surface of the scattering layer away from the substrate further includes the following steps: A second buffer layer is formed between the first buffer layer and the conductive dielectric layer.

Images