Light emitting device and method for manufacturing the same

Abstract

A light-emitting device and a method for manufacturing the same. The method for manufacturing the light-emitting device comprises: forming a functional layer, wherein the functional layer has a first surface; performing plasma treatment on the first surface of the functional layer; and forming a perovskite-type light-emitting layer on the first surface after the plasma treatment.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to a light emitting device and a method for manufacturing the same. Background Art

[0002] Perovskite materials usually refer to materials with the molecular formula ABX 3 The material of the composition has excellent optical and optoelectronic properties. The perovskite electroluminescent device made of perovskite material has the characteristics of high external quantum efficiency, continuously adjustable emission spectrum, high color purity, low cost, etc., which makes it widely used in display and lighting fields. However, the perovskite light-emitting diode devices (PeLED) currently prepared based on perovskite materials have the disadvantages of complex structure and low external quantum efficiency. Compared with the organic light-emitting diodes (OLED) that have been widely used, there is still a lot of room for improvement. The formation of high-quality perovskite light-emitting film has strict requirements on the surface flatness and wettability of the substrate located below it, which limits the selection of the lower substrate material, thereby further limiting the design of the structure of the perovskite electroluminescent device. Summary of the invention

[0003] At least one embodiment of the present disclosure provides a method for manufacturing a light-emitting device, the method comprising: forming a functional layer, wherein the functional layer has a first surface; performing plasma treatment on the first surface of the functional layer; and forming a perovskite-type light-emitting layer on the first surface after the plasma treatment.

[0004] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the plasma treatment includes at least one of oxygen plasma treatment, nitrogen plasma treatment and argon plasma treatment.

[0005] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the gas pressure of the gas used for the plasma treatment is 20Pa to 50Pa, and the time of the plasma treatment is 2 to 5 minutes.

[0006] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the functional layer is a hole injection layer, and the material of the functional layer includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinylcarbazole (PVK), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB), and poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD).

[0007] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the functional layer is an electron injection layer, and the material of the functional layer includes zinc oxide (ZnO).

[0008] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the perovskite-type light-emitting layer includes a molecular formula of ABX 3 A is a metal cation or an alkylammonium salt ion, B is a metal cation, and X is a halogen anion.

[0009] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, A includes an organic amine group, an amidine group, a Cs + , K + , Rb + At least one of; B includes Pb 2+ Sn 2+ ,Ge 2+ , Ga 2+ 、In 3+ 、Cd 2+ , Hg 2+ 、Ni 2+ , Mn 2+ 、Bi 3+ , Sb 3+ At least one of; X includes Cl-, Br - , I-At least one of.

[0010] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, forming the perovskite-type light-emitting layer on the first surface after the plasma treatment comprises: n , BX m A precursor solution dissolved as a solute in a first solvent to form a perovskite-type light-emitting layer; and forming the perovskite-type light-emitting layer on the first surface after the plasma treatment using the precursor solution of the perovskite-type light-emitting layer; AX n With BX m The reaction produces ABX 3 , m and n are both positive integers.

[0011] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, forming the perovskite light-emitting layer on the first surface after the plasma treatment using the precursor solution of the perovskite light-emitting layer includes: spin coating the precursor solution of the perovskite light-emitting layer on the first surface after the plasma treatment; adding a second solvent to the precursor solution of the perovskite light-emitting layer during the spin coating process, wherein the second solvent is immiscible with the first solvent; and performing annealing to obtain the perovskite light-emitting layer.

[0012] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the first solvent is at least one of anhydrous N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), and acetonitrile (ACN), and the second solvent includes at least one of toluene, chloroform, chlorobenzene, and acetone.

[0013] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the temperature of the annealing treatment is 70° C. to 80° C., and the time of the annealing treatment is 20 to 40 minutes.

[0014] For example, in the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure, the contact angle between the precursor solution of the perovskite-type light-emitting layer and the first surface after the plasma treatment is less than 16°.

[0015] For example, the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure further includes: using AI, B(I) m As a solute, it is dissolved in the first solvent to form a first precursor solution, and the first precursor solution is used to form a perovskite-type light-emitting layer emitting red light on the first surface after the plasma treatment, wherein AI and B(I) m React Generate ABI 3 .

[0016] For example, the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure further includes: m ABr is dissolved as a solute in the first solvent to form a second precursor solution, and the second precursor solution is used to form a perovskite-type light-emitting layer emitting green light on the first surface after the plasma treatment. ABr and B(Br) m The reaction generates AB(Br) 3 .

[0017] For example, the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure further includes: using ACl, B(Br) m As a solute, ACl and B(Br) are dissolved in the first solvent to form a third precursor solution, and a perovskite-type light-emitting layer emitting blue light is formed on the first surface after the plasma treatment. m The reaction generates AB(Br) 2 Cl.

[0018] For example, the method for manufacturing a light-emitting device provided in at least one embodiment of the present disclosure further includes: before performing the plasma treatment, performing an annealing treatment on the functional layer.

[0019] At least one embodiment of the present disclosure further provides a light-emitting device, comprising: a functional layer and a perovskite-type light-emitting layer. The functional layer has a first surface; the perovskite-type light-emitting layer is in direct contact with the first surface of the functional layer; and a hydrophilic group exists on the first surface of the functional layer.

[0020] For example, in the light emitting device provided in at least one embodiment of the present disclosure, the plasma includes at least one of oxygen plasma, nitrogen plasma and argon plasma.

[0021] For example, in the light-emitting device provided in at least one embodiment of the present disclosure, the surface roughness of the perovskite-type light-emitting layer is less than 2 nm.

[0022] For example, in the light-emitting device provided in at least one embodiment of the present disclosure, the functional layer is a hole injection layer, and the material of the functional layer includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinylcarbazole (PVK), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB), and poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD).

[0023] For example, in the light-emitting device provided in at least one embodiment of the present disclosure, the material of the functional layer is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), and the surface of the PEDOT:PSS close to the perovskite light-emitting layer has the hydrophilic group and is in direct contact with the perovskite light-emitting layer.

[0024] For example, at least one embodiment of the present disclosure provides a light-emitting device further comprising: an electron injection layer, a modified electrode, a first electrode, and a second electrode. The electron injection layer is located on a side of the perovskite-type light-emitting layer away from the hole injection layer; the modified electrode is located on a side of the electron injection layer away from the perovskite-type light-emitting layer; the hole injection layer, the perovskite-type light-emitting layer, the electron injection layer, and the modified electrode are sandwiched between the first electrode and the second electrode.

[0025] For example, in the light-emitting device provided in at least one embodiment of the present disclosure, the functional layer is an electron injection layer, the material of the functional layer includes zinc oxide (ZnO), and the surface of the ZnO close to the perovskite light-emitting layer has the hydrophilic group and is in direct contact with the perovskite light-emitting layer.

[0026] For example, at least one embodiment of the present disclosure provides a light-emitting device further comprising: a hole injection layer, a modified electrode, a first electrode, and a second electrode. The hole injection layer is located on a side of the perovskite-type light-emitting layer away from the electron injection layer; the modified electrode is located on a side of the electron injection layer away from the perovskite-type light-emitting layer; the hole injection layer, the perovskite-type light-emitting layer, the electron injection layer, and the modified electrode are sandwiched between the first electrode and the second electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure.

[0028] Figures 1A-1F A schematic diagram of a method for manufacturing a light-emitting device provided in one embodiment of the present disclosure;

[0029] Figure 1G-1K A schematic diagram of another method for manufacturing a light-emitting device provided in an embodiment of the present disclosure;

[0030] Figure 2A A flow chart of a method for manufacturing a light-emitting device provided in one embodiment of the present disclosure;

[0031] Figure 2B A flow chart of another method for manufacturing a light emitting device provided in one embodiment of the present disclosure;

[0032] Figure 3A-3B A comparison diagram of contact angle measurement results of the first surface of the functional layer in one embodiment of the present disclosure before and after plasma treatment;

[0033] Figure 4 A transmittance comparison curve of a functional layer before and after plasma treatment in an embodiment of the present disclosure;

[0034] Figure 5 This is a surface SEM image of a perovskite light-emitting layer that emits red light in one embodiment of the present disclosure;

[0035] Figure 6 A surface AFM image of a perovskite light-emitting layer emitting red light in one embodiment of the present disclosure;

[0036] Figure 7 is an absorption and photoluminescence spectrum curve of a red-light-emitting perovskite light-emitting layer in an embodiment of the present disclosure;

[0037] Figure 8 This is a surface SEM image of a perovskite light-emitting layer emitting green light in one embodiment of the present disclosure;

[0038] Fig. 9A surface AFM image of a perovskite light-emitting layer emitting green light in one embodiment of the present disclosure;

[0039] Fig.10 is the absorption and electroluminescence spectrum curve of the perovskite light-emitting layer emitting green light in one embodiment of the present disclosure;

[0040] Fig.11 The current density / brightness-voltage relationship curve of a light-emitting device emitting green light prepared according to a method provided in one embodiment of the present disclosure;

[0041] Fig.12 The external quantum efficiency / current efficiency-current density relationship curve of a light-emitting device emitting green light prepared according to a method provided in one embodiment of the present disclosure;

[0042] Fig.13 An electroluminescence spectrum of a light-emitting device emitting green light provided by an embodiment of the present disclosure;

[0043] Fig.14 A schematic diagram of the structure of a light-emitting device provided in one embodiment of the present disclosure;

[0044] Fig.15 A schematic diagram of the structure of another light-emitting device provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. The embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0046] Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with ordinary skills in the field to which the present invention belongs. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0047] An embodiment of the present disclosure provides a method for manufacturing a light-emitting device, the method comprising: forming a functional layer, wherein the functional layer has a first surface; performing plasma treatment on the first surface of the functional layer; and forming a perovskite-type light-emitting layer on the first surface after the plasma treatment.

[0048] For example, Figures 1A-1F A schematic diagram of a method for manufacturing a light emitting device provided in one embodiment of the present disclosure, Figure 2A A flowchart of a method for manufacturing a light-emitting device provided in an embodiment of the present disclosure. The method for manufacturing a light-emitting device provided in this embodiment includes the following steps.

[0049] like Figure 1A As shown, a substrate substrate 1 is provided. The substrate substrate 1 is cleaned. For example, the substrate substrate 1 is wiped and ultrasonically cleaned with deionized water, acetone solution, ethanol solution, and isopropanol solution in sequence, and is blown dry with nitrogen after cleaning; the cleaned substrate substrate 1 is subjected to plasma pretreatment to enhance the wettability of the surface of the substrate substrate 1. For example, the plasma treatment includes at least one of oxygen plasma treatment, nitrogen plasma treatment, and argon plasma treatment. For example, the material of the substrate substrate 1 can be an inorganic material such as glass, quartz, indium tin oxide (ITO), or an organic material such as polyimide, which is not limited in the embodiments of the present disclosure.

[0050] Then, a first electrode 21 is formed on the base substrate 1. The electrode is, for example, a transparent electrode or an opaque electrode.

[0051] like Figure 1B As shown, a functional layer 3 is formed on a side of the first electrode 21 away from the substrate 1, and the functional layer 3 has a first surface 31. For example, in one embodiment, the functional layer 3 is a hole injection layer, and the material of the functional layer 3 includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinyl carbazole (PVK), and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB).

[0052] like Figure 1B As shown, the first surface 31 of the functional layer 3 is subjected to plasma treatment. For example, the plasma treatment includes at least one of oxygen plasma treatment, nitrogen plasma treatment and argon plasma treatment. In this embodiment, the material of the functional layer 3 is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), and the first surface 31 of the functional layer 3 is subjected to oxygen plasma treatment as an example to introduce the manufacturing method and technical effect of the light-emitting device.

[0053] For example, the device with the functional layer 3 prepared is moved to the cavity of the plasma cleaning machine, and after multiple vacuuming / oxygen passing operations, the cavity is ensured to be an oxygen environment. Then, the treatment effect is adjusted by adjusting parameters such as the power of the oxygen plasma treatment, the gas pressure in the cavity, and the oxygen plasma treatment time. For example, the gas pressure of the gas used for plasma treatment is 20Pa~50Pa to obtain a suitable plasma concentration; the plasma treatment time is 2~5 minutes; the plasma treatment power is 30W~40W. For example, the power refers to the power of the plasma treatment equipment. The time and power of the plasma treatment will affect the amount of protrusions on the first surface 31 and thus affect the specific surface area, and will also affect the amount of hydrophilic groups such as nitrogen-containing or oxygen-containing groups contained in the first surface 31, thereby affecting the performance of the perovskite-type light-emitting layer formed on the first surface 31 after plasma treatment and the effect of combining with the first surface 31. The above conditions enable the first surface 31 of the functional layer 3 to have a suitable specific surface area and hydrophilic groups such as nitrogen or oxygen, so that the first surface 31 of the functional layer 3 is well modified, which is beneficial to improving the performance of the perovskite-type light-emitting layer subsequently formed on the first surface 31 of the functional layer 3.

[0054] like Figure 1C As shown, a perovskite light-emitting layer 4 is formed on the first surface 31 after plasma treatment. For example, a precursor solution of the perovskite light-emitting layer is first prepared, and then the precursor solution of the perovskite light-emitting layer is used to form the perovskite light-emitting layer 4 on the first surface 31 after plasma treatment. Since the first surface 31 of the functional layer 3 is plasma treated, the wettability of the precursor solution of the perovskite light-emitting layer to the first surface 31 is improved, and the contact angle becomes smaller, so that the formed perovskite light-emitting layer 4 is smoother, for example, the surface roughness of the perovskite light-emitting layer is less than 2nm, so that the light-emitting performance is improved, for example, the external quantum efficiency of the light-emitting device is improved. In addition, the light transmittance of the functional layer 3 after plasma treatment is improved, which is conducive to improving the light utilization rate of the light-emitting device.

[0055] It should be noted that the perovskite type light emitting layer 4 in the present disclosure is different from the organic light emitting diode (OLED) light emitting layer. For example, the perovskite type light emitting layer 4 includes a molecular formula of ABX 3 A is a metal cation or an alkylammonium salt ion, B is a metal cation, and X is a halogen anion. For example, A includes an organic amine group (such as an alkylamine group RNH 4 + , R is an alkyl group, for example, an alkylamine group is CH 3 NH 4 + ), amidine groups (e.g., formamidine groups NH 2 CH=NH 2 +etc.), Cs + , K + , Rb + At least one of; B includes Pb 2+ Sn 2+ ,Ge 2+ , Ga 2+ 、In 3+ 、Cd 2+ , Hg 2+ 、Ni 2+ , Mn 2+ 、Bi 3+ , Sb 3+ , at least one of; X includes Cl-, Br - , I-At least one of.

[0056] For example, forming the perovskite type light emitting layer 4 on the first surface 31 after the plasma treatment includes: n , BX m A precursor solution of a perovskite-type light-emitting layer is dissolved as a solute in a first solvent to form a precursor solution of the perovskite-type light-emitting layer; and a perovskite-type light-emitting layer is formed on the first surface 31 after the plasma treatment using the precursor solution of the perovskite-type light-emitting layer. n With BX m The reaction produces ABX 3 , m and n are both positive integers. For example, when A is a monovalent ion and B is a divalent ion, n=1, m=2; or, when A is a monovalent ion and B is a trivalent ion, n=1, m=3.

[0057] For example, forming a titanite-type light-emitting layer 3 on a first surface 31 treated with plasma using a precursor solution of a titanite-type light-emitting layer includes: spin coating the precursor solution of a perovskite-type light-emitting layer on the first surface 31 treated with plasma; adding a second solvent to the precursor solution of the perovskite-type light-emitting layer during the spin coating process, wherein the second solvent is immiscible with the first solvent; and performing an annealing treatment to obtain a perovskite-type light-emitting layer 4.

[0058] For example, the first solvent is at least one of anhydrous N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), and acetonitrile (ACN), and the second solvent includes at least one of toluene, chloroform, chlorobenzene, and acetone. Of course, the first solvent and the second solvent are not limited to the above, and can be determined according to the titanium ore material formed.

[0059] For example, the method for manufacturing a light-emitting device provided in an embodiment of the present disclosure further includes: adding a halogenated amine ligand material to a precursor solution for forming a perovskite light-emitting layer; and spin-coating the precursor solution of the perovskite light-emitting layer to which the halogenated amine ligand material is added onto the plasma-treated first surface 31. For example, the halogenated amine ligand material is a brominated ammonium ligand material, and of course, a chlorinated ammonium ligand material or an iodinated amine ligand material may also be used.

[0060] Specifically, the brominated ammonium ligand material includes: any one or more of brominated 3,3-diphenylpropylamine, ethylamine bromide, butylamine bromide, octylamine bromide, phenylethylamine bromide, and amphetamine bromide. Taking the brominated ammonium ligand material as brominated 3,3-diphenylpropylamine (DPPA-Br) as an example, the preparation of this ligand material is described. A certain amount of 3,3, diphenylpropylamine (DPPA) is mixed with ethanol in a volume ratio of 1:1, cooled to below 10°C in an ice water bath, and then a slightly excess of HBr aqueous solution is added dropwise for two hours. After drying by rotary evaporation, recrystallization is performed with ethanol, and finally suction filtration is performed and washed with anhydrous ether 3 times, and finally vacuum dried at 50°C for 12 hours. Obtain the brominated ammonium ligand material.

[0061] For example, a certain amount of the second solvent is added to the precursor solution of the perovskite type light-emitting layer during the spin coating process to crystallize the perovskite material, and the halogenated amine ligand material is grafted onto the crystallized perovskite material to form a perovskite film. For example, after starting the spin coating, the second solvent is added dropwise at the 6th second, for example, the second solvent is added dropwise within 1 minute, so as to obtain a better crystallization effect of the perovskite material.

[0062] For example, the annealing temperature is 70° C. to 80° C., and the annealing time is 20 to 40 minutes, which has achieved the ideal effect.

[0063] For example, the contact angle between the precursor solution of the perovskite-type light-emitting layer and the first surface after the plasma treatment is less than 16°. Figure 3A-3B This is a comparison chart of contact angle measurement results before and after plasma treatment of the first surface of the functional layer in one embodiment of the present disclosure. Figure 3A The angle α shown is the contact angle when the precursor solution of the perovskite-type light-emitting layer is spin-coated on the first surface of the functional layer that has not been plasma treated, and α=16°. Figure 3BThe angle β shown is the contact angle when the precursor solution of the perovskite-type light-emitting layer is spin-coated on the first surface 31 of the plasma-treated functional layer, and α=12.5°. It can be seen that plasma treatment of the first surface 31 of the functional layer 3 can improve the wettability of the precursor solution of the perovskite-type light-emitting layer to the first surface 31, and reduce the contact angle when the precursor solution is formed on the first surface 31 of the plasma-treated functional layer 3, so that the perovskite-type light-emitting layer 4 obtained after annealing is smoother and the light-emitting performance is improved, for example, the external quantum efficiency of the light-emitting device is improved. Therefore, when the functional layer 3 is the above-mentioned hole injection layer, it also has the function of the hole transport layer, and there is no need to set a hole transport layer separately, which simplifies the manufacturing process and structure of the light-emitting device.

[0064] in addition, Figure 4 : is a transmittance comparison curve of the functional layer before and after plasma treatment in one embodiment of the present disclosure. The light transmittance of the functional layer 3 after plasma treatment is higher than the light transmittance before plasma treatment. For example, the light transmittance of the functional layer 3 after plasma treatment can reach more than 96%. It can be proved that plasma treatment of the first surface 31 of the functional layer 3 can improve the light transmittance of the functional layer 3, thereby improving the light utilization rate of the light-emitting device.

[0065] For example, the method for manufacturing a light-emitting device includes: forming a perovskite light-emitting layer emitting red light, a perovskite light-emitting layer emitting green light, and a perovskite light-emitting layer emitting blue light on the first surface 31 after plasma treatment to achieve color lighting or color display.

[0066] For example, AI, B(I) m As a solute, it is dissolved in a first solvent to form a first precursor solution, and the first precursor solution is used to form a perovskite-type light-emitting layer emitting red light on the first surface after plasma treatment, wherein AI and B(I) m React Generate ABI 3 In this embodiment, AI is used as NH 2 CH=NH 2 I, B(I) m PbI 2 , take the first solvent as anhydrous DMF as an example.

[0067] For example, NH 2 CH=NH 2 I, PbI 2 , amine halide is dissolved in a first solvent in a certain proportion to obtain a first precursor solution. 2 CH=NH 2 I, PbI 2, amine halides are dissolved in anhydrous DMF at a molar ratio of 1:1:0.5 to form a first precursor solution with a concentration of 0.2M. After passing through a 0.22um nylon filter head for use, the first precursor solution is spin-coated onto the first surface 31 treated with oxygen plasma. When the spin coating speed reaches 4000rpm, for example, in the 6th second after the start, the second solvent (anti-solvent) is quickly added, and the second solvent is added within 1 second to quickly form a perovskite film and control the formation of perovskite grains in the perovskite film. For example, after annealing at 80°C, a perovskite light-emitting layer emitting red light is obtained. The surface morphology of the perovskite light-emitting layer emitting red light is as shown in Figure 5 and Figure 6 As shown, the prepared red-light-emitting perovskite light-emitting layer is very dense, has no obvious defects, has a very smooth and uniform surface, and has a low average surface roughness of only 0.57 nm. Figure 7 The absorption and electroluminescence spectrum curves of the red-emitting perovskite light-emitting layer. Figure 7 It can be seen that the emission peak is located at 675nm and the half-width is only 50nm. The perovskite light-emitting layer that emits red light can be used to obtain a higher color gamut.

[0068] For example, ABr, B(Br) m ABr is dissolved as a solute in the first solvent to form a second precursor solution, and the second precursor solution is used to form a perovskite-type light-emitting layer emitting green light on the first surface after plasma treatment. ABr and B(Br) m The reaction generates AB(Br) 3 In this example, ABr is used as NH 2 CH=NH 2 Br, B(Br) m PbBr 2 , take the first solvent as anhydrous DMF as an example.

[0069] For example, NH 2 CH=NH 2 Br, PbBr 2 , amine halide is dissolved in a first solvent in a certain proportion to obtain a second precursor solution. 2 CH=NH 2 Br, PbBr 2, amine halides are dissolved in anhydrous DMF at a molar ratio of 1:1:0.35 to prepare a second precursor solution with a concentration of 0.2M. After passing through a 0.22um nylon filter head for use, the second precursor solution is spin-coated onto the first surface 31 treated with oxygen plasma. When the spin coating speed reaches 4000rpm, for example, in the 6th second after the start, the second solvent (anti-solvent) is quickly added, and the second solvent is added within 1 second to quickly form a perovskite film and control the formation of perovskite grains in the perovskite film. For example, after annealing at 80°C, a perovskite light-emitting layer emitting green light is obtained. The surface morphology of the perovskite light-emitting layer emitting green light is as shown in Figure 8 and Fig. 9 As shown, the prepared green-light-emitting perovskite layer is very dense, has no obvious defects, has a very smooth and uniform surface, and has a low average surface roughness of only 1.7 nm. Fig.10 The absorption and electroluminescence spectrum curves of the perovskite light-emitting layer emitting green light. Fig.10 It can be seen that the emission peak is located at 526nm and the half-width is only 22nm. The perovskite light-emitting layer that emits green light can be used to obtain a higher color gamut.

[0070] For example, ACl, B(Br) m As a solute, it is dissolved in the first solvent to form a third precursor solution, and a perovskite-type light-emitting layer emitting blue light is formed on the first surface after plasma treatment. ACl and B(Br) m The reaction generates AB(Br) 2 In this embodiment, ABr is used as NH 2 CH=NH 2 Cl, B(Br) m PbBr 2 , the first solvent is anhydrous DMF as an example. 2 CH=NH 2 Cl, PbBr 2 , amine halide is dissolved in anhydrous DMF at a molar ratio of 1:1:0.8 to prepare a third precursor solution with a concentration of 0.2M. After passing through a 0.22um nylon filter head, the third precursor solution is spin-coated on the first surface 31 treated with oxygen plasma. When the spin-coating speed reaches 4000rpm, for example, in the 6th second after the start, the second solvent (anti-solvent) is quickly added, and the second solvent is added within 1 second to quickly form a perovskite film and control the formation of perovskite grains in the perovskite film. For example, after annealing at 80°C, a perovskite light-emitting layer emitting blue light is obtained. The perovskite light-emitting layer emitting blue light is very dense, has no obvious defects, has a very flat and uniform surface, and has a low average surface roughness. The emission peak of the blue light emitted by it is located at 460nm~480nm.

[0071] Fig.11 and Fig.12 The performance parameter curve of the green light perovskite electroluminescent device prepared by the method provided in the above embodiment of the present disclosure is shown in Figure 1. The turn-on voltage of the light emitting device is 2.9V, and the maximum brightness reaches more than 8000cd / m at 4.6V. 2 At the same time, the external quantum efficiency of the light-emitting device can reach more than 16%, and the current efficiency exceeds 60cd / A. Fig.13 is the curve of the electroluminescence spectrum of the light-emitting device emitting green light as a function of voltage, Fig.13 It can be seen that the peak is always maintained at 526nm, the half-peak width of the spectrum is 23nm, and it has very high color purity, which is consistent with Fig.10 The photoluminescence spectrum shown is consistent. Moreover, the peak position does not change with the increase of the voltage applied to the light-emitting device, and has high spectral stability.

[0072] The perovskite type light-emitting layer is composed of nano-sized perovskite nanocrystals, for example, the size of the crystallized perovskite material is greater than 20nm. Of course, the perovskite type light-emitting layer can be composed of nano-sized perovskite quantum dots, for example, the size of the perovskite quantum dots is less than 20nm. In the preparation method of the perovskite type light-emitting layer of this embodiment, the size of the formed perovskite material after crystallization can be controlled by controlling the amount of the added halogenated ligand material and the amount of the second solvent. Generally, if the amount of the halogenated ligand material is large, it is easy to form perovskite quantum dots, and the perovskite quantum dots have better luminous efficiency; if the amount of the halogenated ligand material is small, it is easy to form perovskite nanocrystals, and the perovskite nanocrystals have better carrier transport ability. Those skilled in the art can design it according to needs.

[0073] like Figure 1D As shown, in the case where the functional layer 3 is a hole injection layer, the method for manufacturing a light-emitting device further includes: forming an electron injection layer 5 located on a side of the perovskite-type light-emitting layer 4 away from the hole injection layer 3, such as Figure 1D As shown; forming a modified electrode 6, such as Figure 1E As shown; and forming a second electrode 22, as Figure 1F As shown. The hole injection layer 3, the perovskite type light emitting layer 4 and the electron injection layer 5 are sandwiched between the first electrode 21 and the second electrode 22. The modified electrode 6 is located on the side of the electron injection layer 5 away from the perovskite type light emitting layer 4. The material of the modified electrode 6 is LiF or CsCO 3 , to adjust the rate of electron injection, for example, to slow down the rate of electron injection, so as to balance the rate of hole injection and the rate of electron injection, and achieve better luminous effect and energy efficiency. For example, the second electrode 22 may include a plurality of spaced portions, such as Figure 1F As shown, the second electrode 22 may also be a full-surface electrode.

[0074] For example, the material of the electron injection layer 5 includes zinc oxide (ZnO). For example, the material of the electron injection layer 5 is ZnO. ZnO has a good electron injection function and an electron transport function, so the electron transport layer can be omitted. Alternatively, the electron injection layer 5 includes a stacked zinc oxide layer and a polyethyleneimine (PEI) layer, and the polyethyleneimine layer is located on the side of the zinc oxide layer away from the perovskite light-emitting layer 4. The PEI layer can adjust the energy level of ZnO and slow down the rate of electron injection, thereby balancing the rate of hole injection and the rate of electron injection, and achieving a better luminous effect and energy efficiency.

[0075] In another embodiment of the present disclosure, for example, referring to Figure 2B and Figure 1B The method for manufacturing the light-emitting device further includes: before the plasma treatment, annealing the functional layer 3 to release the stress of various structures on the functional layer 3 and the substrate 1, and further improve the stability of the perovskite-type light-emitting layer formed on the functional layer 3 later. The other steps of this embodiment are the same as those in the previous embodiment, please refer to the previous description, and will not be repeated here.

[0076] Figure 1G-1K A schematic diagram of another method for manufacturing a light emitting device provided in an embodiment of the present disclosure. Figure 1G-1K In the manufacturing method of the light-emitting device shown, the functional layer 30 is an electron injection layer.

[0077] like Figure 1G As shown, the method for manufacturing a light emitting device includes: sequentially forming a first electrode 210, a modified electrode 60 and a functional layer 30 on a base substrate 10. The functional layer 30 is an electron injection layer, and its material includes zinc oxide (ZnO).

[0078] like Figure 1H As shown, the method for manufacturing the light-emitting device further includes: performing plasma treatment on the first surface 301 of the functional layer 30 (ie, the electron injection layer). The plasma treatment is the same as the plasma treatment performed on the electron injection layer 30 in the previous embodiment. Please refer to the previous description.

[0079] like Fig. 1I As shown, the method for manufacturing the light emitting device further includes: forming a perovskite type light emitting layer 40 on the first surface 301 of the electron injection layer 30 treated by plasma. The specific method for forming the perovskite type light emitting layer 40 is described above.

[0080] The method for manufacturing the light emitting device further includes: forming a hole injection layer 50 located on a side of the perovskite light emitting layer 40 away from the electron injection layer 30, such as Figure 1J As shown; and forming a second electrode 220, as Figure 1KThe hole injection layer 50 , the perovskite type light emitting layer 40 and the electron injection layer 30 are sandwiched between the first electrode 21 and the second electrode 22 .

[0081] For example, in one example, the electron injection layer 30 is a zinc oxide layer, and the first surface 301 of the zinc oxide layer is plasma-treated, and the perovskite light-emitting layer 40 is formed on the first surface 301 of the zinc oxide layer after the plasma treatment; for example, in another example, the electron injection layer 30 includes a stacked zinc oxide layer and a polyethyleneimine (PEI) layer, and the polyethyleneimine layer is located on the side of the zinc oxide layer close to the base substrate 10, and the first surface 301 of the zinc oxide layer is plasma-treated, and the perovskite light-emitting layer 40 is formed on the first surface 301 of the zinc oxide layer after the plasma treatment.

[0082] Figure 1G-1K Other features of the manufacturing method provided by the illustrated embodiment are the same as those described in the previous embodiment, and can achieve the same or similar technical effects as the previous embodiment.

[0083] At least one embodiment of the present disclosure further provides a light-emitting device, which is formed according to any one of the methods for manufacturing a light-emitting device provided in the embodiments of the present disclosure. The light-emitting device comprises: a functional layer and a perovskite-type light-emitting layer. The functional layer has a first surface; the perovskite-type light-emitting layer is in direct contact with the first surface of the functional layer; and a hydrophilic group exists on the first surface of the functional layer.

[0084] Demonstratively, Fig.14 This is a schematic diagram of the structure of a light emitting device provided by an embodiment of the present disclosure. Fig.14As shown, the light-emitting device is formed according to any one of the methods for manufacturing a light-emitting device provided in the embodiments of the present disclosure. The light-emitting device includes: a functional layer 3 and a perovskite-type light-emitting layer 4. The functional layer 3 has a first surface 31; the perovskite-type light-emitting layer 4 is in direct contact with the first surface 31 of the functional layer 3; and a hydrophilic group exists on the first surface 31 of the functional layer 3. For example, the hydrophilic group includes an oxygen-containing hydrophilic group or a nitrogen-containing hydrophilic group. The oxygen-containing hydrophilic group is, for example, a hydroxyl group (OH-), and the nitrogen-containing hydrophilic group is, for example, an amino group. For example, the hydrophilic group is formed by plasma treatment of the first surface 31. For example, the plasma includes at least one of oxygen plasma, nitrogen plasma, and argon plasma. There are hydrophilic groups on the first surface 31 and the perovskite light-emitting layer 4 is in direct contact with the first surface 31 of the functional layer 3, which can make the first surface 31 rougher. Therefore, in the process of forming the perovskite light-emitting layer 4 on the first surface 31, the wettability of the precursor solution used to form the perovskite light-emitting layer 4 to the first surface 31 is improved, so that the perovskite light-emitting layer 4 is smoother. For example, the surface roughness of the perovskite light-emitting layer is less than 2nm, so that its light-emitting performance is improved. For example, the external quantum efficiency of the light-emitting device is improved, and the light-emitting performance remains stable as the voltage applied to the perovskite light-emitting layer changes.

[0085] For example, the functional layer 3 is a hole injection layer, and the material of the functional layer 3 includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinylcarbazole (PVK), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB), and poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD).

[0086] For example, the material of the functional layer 3 is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), and the surface of the PEDOT:PSS close to the perovskite light-emitting layer 4 has the plasma and is in direct contact with the perovskite light-emitting layer 4. In this case, the functional layer 3 also has the function of a hole transport layer, and there is no need to separately set a hole transport layer between the first surface 31 and the perovskite light-emitting layer 4, which simplifies the manufacturing process and structure of the light-emitting device.

[0087] For example, Fig.14 As shown, the light emitting device further includes: an electron injection layer 5, a modified electrode 6, a first electrode 21 and a second electrode 22. The electron injection layer 5 is located on the side of the perovskite light emitting layer 4 away from the hole injection layer 3; the modified electrode 6 is located on the side of the electron injection layer 5 away from the perovskite light emitting layer 4; the hole injection layer 3, the perovskite light emitting layer 4, the electron injection layer 5 and the modified electrode 6 are sandwiched between the first electrode 21 and the second electrode 22. The material of the modified electrode 6 is LiF or CsCO3 , to adjust the rate of electron injection, for example, to slow down the rate of electron injection, thereby balancing the rate of hole injection and the rate of electron injection to achieve better luminescence effect and energy efficiency.

[0088] The perovskite type light emitting layer is composed of nano-sized perovskite nanocrystals, for example, the size of the crystallized perovskite material is greater than 20nm. Of course, the perovskite type light emitting layer can be composed of nano-sized perovskite quantum dots, for example, the size of the perovskite quantum dots is less than 20nm. Those skilled in the art can design it as needed.

[0089] For other unmentioned features of the light-emitting device, please refer to the description in the previous embodiment related to the manufacturing method.

[0090] It should be noted that, in the present disclosure, the direct contact between the perovskite light-emitting layer and the first surface of the functional layer means that there is no other layer or structure between the perovskite light-emitting layer and the first surface of the functional layer in a direction perpendicular to the substrate.

[0091] It should be noted that the surface roughness in the present disclosure refers to the unevenness of the surface with small spacing and tiny peaks and valleys, that is, the distance (wavelength) between two peaks or two valleys on the surface in a direction perpendicular to the surface. The smaller the surface roughness, the smoother the surface.

[0092] For example, Fig.15 1 is a schematic diagram of the structure of another light-emitting device provided by an embodiment of the present disclosure. In the light-emitting device, the functional layer 30 is an electron injection layer. The first surface 301 of the electron injection layer 30 has the hydrophilic group and the perovskite light-emitting layer 40 is in direct contact with the first surface 301.

[0093] For example, the material of the electron injection layer 30 (i.e., the electron injection layer) includes zinc oxide (ZnO), and the surface of ZnO close to the perovskite light-emitting layer 40 has the hydrophilic group and is in direct contact with the perovskite light-emitting layer 40. For example, the material of the electron injection layer 5 is ZnO. ZnO has a good electron injection function and an electron transport function, so that the electron transport layer can be omitted. Alternatively, the electron injection layer 5 includes a stacked zinc oxide layer and a polyethyleneimine (PEI) layer, and the polyethyleneimine layer is located on the side of the zinc oxide layer away from the perovskite light-emitting layer 4. The PEI layer can adjust the energy level of ZnO and slow down the rate of electron injection, thereby balancing the rate of hole injection and the rate of electron injection, and achieving a better luminous effect and energy efficiency.

[0094] For example, Fig.15As shown, the light emitting device further includes: a modified electrode 60, a hole injection layer 50, a first electrode 210 and a second electrode 220. The hole injection layer 50 is located on the side of the perovskite light emitting layer 40 away from the electron injection layer 30; the hole injection layer 50, the perovskite light emitting layer 40, the functional layer 30 (i.e., the electron injection layer) and the modified electrode 60 are sandwiched between the first electrode 210 and the second electrode 220. The modified electrode 60 is located on the side of the electron injection layer 30 away from the perovskite light emitting layer 4. The material of the modified electrode 60 is LiF or CsCO 3 , to adjust the rate of electron injection, for example, to slow down the rate of electron injection, thereby balancing the rate of hole injection and the rate of electron injection to achieve better luminescence effect and energy efficiency.

[0095] Fig.15 Other features of the light-emitting device provided in the illustrated embodiment are the same as those described in the previous embodiment, and can achieve the same or similar technical effects as the previous embodiment.

[0096] The above description is merely an exemplary embodiment of the present disclosure and is not intended to limit the protection scope of the present disclosure. The protection scope of the present disclosure is determined according to the scope defined in the claims.

Claims

1. A method for manufacturing a light emitting device, comprising: forming a functional layer, wherein the functional layer has a first surface; performing plasma treatment on the first surface of the functional layer; forming a perovskite-type light-emitting layer on the first surface after the plasma treatment; The perovskite-type light-emitting layer comprises a material with a molecular formula of ABX3, wherein A is a metal cation or an alkylammonium salt ion, B is a metal cation, and X is a halogen anion; Forming the perovskite-type light-emitting layer on the first surface after the plasma treatment comprises: AX n , BX m A precursor solution dissolved as a solute in a first solvent to form a perovskite-type light-emitting layer; and The perovskite-type light-emitting layer is formed on the first surface after the plasma treatment using a precursor solution of the perovskite-type light-emitting layer; wherein AX n With BX m The reaction produces ABX3, where m and n are both positive integers.

2. The method for manufacturing a light emitting device according to claim 1, wherein: The plasma treatment includes at least one of oxygen plasma treatment, nitrogen plasma treatment, and argon plasma treatment.

3. The method for manufacturing a light emitting device according to claim 1, wherein: The gas pressure of the gas used for the plasma treatment is 20Pa to 50Pa, and the time of the plasma treatment is 2 to 5 minutes.

4. The method for manufacturing a light emitting device according to claim 1, wherein: The functional layer is a hole injection layer, and the material of the functional layer includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinylcarbazole (PVK), poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB), and poly[bis(4-phenyl)(4-butylphenyl)amine] (Poly-TPD).

5. The method for manufacturing a light emitting device according to claim 1, wherein: The functional layer is an electron injection layer, and the material of the functional layer includes zinc oxide (ZnO).

6. The method for manufacturing a light emitting device according to claim 1, wherein: A includes organic amine groups, amidine groups, Cs + , K + , Rb + At least one of; B includes Pb 2+ Sn 2+ ,Ge 2+ , Ga 2+ 、In 3+ 、Cd 2+ , Hg 2+ 、Ni 2+ , Mn 2+ 、Bi 3+ , Sb 3+ At least one of; X includes Cl-, Br - , at least one of I-.

7. The method for manufacturing a light emitting device according to claim 1, wherein: Forming the perovskite-type light-emitting layer on the first surface treated by the plasma using a precursor solution of the perovskite-type light-emitting layer comprises: Spin coating a precursor solution of the perovskite-type light-emitting layer onto the first surface after the plasma treatment; adding a second solvent to the precursor solution of the perovskite-type light-emitting layer during the spin coating process, wherein the second solvent is immiscible with the first solvent; and Annealing treatment is performed to obtain the perovskite type light-emitting layer.

8. The method for manufacturing a light emitting device according to claim 7, wherein: The first solvent is at least one of anhydrous N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), and acetonitrile (ACN), and the second solvent includes at least one of toluene, chloroform, chlorobenzene, and acetone.

9. The method for manufacturing a light emitting device according to claim 7, wherein: The temperature of the annealing treatment is 70° C. to 80° C., and the time of the annealing treatment is 20 to 40 minutes.

10. The method for manufacturing a light emitting device according to any one of claims 1 to 9, wherein: The contact angle between the precursor solution of the perovskite-type light-emitting layer and the first surface after the plasma treatment is less than 16°.

11. The method for manufacturing a light emitting device according to any one of claims 1 to 9, further comprising: Take AI, B(I) m As a solute, it is dissolved in the first solvent to form a first precursor solution, and the first precursor solution is used to form a perovskite-type light-emitting layer emitting red light on the first surface after the plasma treatment, wherein AI and B(I) m The reaction produced ABI3.

12. The method for manufacturing a light emitting device according to any one of claims 1 to 9, further comprising: ABr, B(Br) m ABr is dissolved as a solute in the first solvent to form a second precursor solution, and the second precursor solution is used to form a perovskite-type light-emitting layer emitting green light on the first surface after the plasma treatment. ABr and B(Br) m The reaction produces AB(Br)3.

13. The method for manufacturing a light emitting device according to any one of claims 1 to 9, further comprising: With ACl, B(Br) m As a solute, ACl and B(Br) are dissolved in the first solvent to form a third precursor solution, and a perovskite-type light-emitting layer emitting blue light is formed on the first surface after the plasma treatment. m The reaction produces AB(Br)2Cl.

14. The method for manufacturing a light emitting device according to any one of claims 1 to 9, further comprising: Before the plasma treatment, the functional layer is subjected to an annealing treatment.

15. A light-emitting device manufactured by the manufacturing method according to any one of claims 1 to 14, comprising: A functional layer, wherein the functional layer has a first surface; and The perovskite-type light-emitting layer is in direct contact with the first surface of the functional layer; wherein, A hydrophilic group exists on the first surface of the functional layer.

16. The light emitting device according to claim 15, wherein: The plasma includes at least one of oxygen plasma, nitrogen plasma, and argon plasma.

17. The light emitting device according to claim 15, wherein: The surface roughness of the perovskite-type light-emitting layer is less than 2 nm.

18. The light emitting device according to any one of claims 15 to 17, wherein: The functional layer is a hole injection layer, and the material of the functional layer includes at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), polyvinyl carbazole (PVK), and pentafluorobenzyl (PFB).

19. The light emitting device according to claim 18, wherein: The material of the functional layer is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), and the surface of the PEDOT:PSS close to the perovskite type light-emitting layer has the hydrophilic group and is in direct contact with the perovskite type light-emitting layer.

20. The light emitting device according to claim 18, further comprising: An electron injection layer is located on a side of the perovskite-type light-emitting layer away from the hole injection layer; A modified electrode is located on a side of the electron injection layer away from the perovskite-type light-emitting layer; as well as A first electrode and a second electrode; wherein the hole injection layer, the perovskite-type light-emitting layer, the electron injection layer and the modified electrode are sandwiched between the first electrode and the second electrode.

21. The light emitting device according to any one of claims 15 to 17, wherein: The functional layer is an electron injection layer, and the material of the functional layer includes zinc oxide (ZnO). The surface of the ZnO close to the perovskite type light-emitting layer has the hydrophilic group and is in direct contact with the perovskite type light-emitting layer.

22. The light emitting device according to claim 21, further comprising: A hole injection layer, located on a side of the perovskite-type light-emitting layer away from the electron injection layer; A modified electrode is located on a side of the electron injection layer away from the perovskite-type light-emitting layer; as well as A first electrode and a second electrode; wherein the hole injection layer, the perovskite-type light-emitting layer, the electron injection layer and the modified electrode are sandwiched between the first electrode and the second electrode.

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