Light-emitting device and preparation method of light-emitting device

Abstract

The invention discloses a light-emitting device and a preparation method of the light-emitting device. The preparation method of the light-emitting device comprises the steps of forming a hole injection layer; performing plasma treatment on the surface of the hole injection layer; the quantum dot light-emitting layer is formed on the plasma-treated side of the hole injection layer, the quantum dot light-emitting layer comprises at least one of Cd-containing quantum dots, InP quantum dots and ZnSe quantum dots, plasma treatment is performed on the surface of the hole injection layer, the hole injection capacity of the surface of the hole injection layer is enhanced, the quantum dot light-emitting layer is promoted to generate more excitons, and the light-emitting efficiency is improved. And carrier balance is promoted.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a light-emitting device and a method for preparing the light-emitting device. Background Art

[0002] Quantum Dot (QD) is a new type of luminescent material with the advantages of high light color purity, high light quantum efficiency, adjustable light color, and long service life. It has become a research hotspot for new LED luminescent materials. Therefore, quantum dot light emitting diodes (QLED) with quantum dot materials as the light-emitting layer have become the main research direction of new display devices.

[0003] However, the current quantum dot light-emitting diodes suffer from unbalanced carrier injection, which results in low device efficiency. Summary of the invention

[0004] The light-emitting device and the method for preparing the light-emitting device provided by the present invention are used to promote carrier balance.

[0005] In order to solve the above technical problems, the first technical solution provided by the present invention is: providing a method for preparing a light-emitting device, comprising forming a hole injection layer; performing plasma treatment on the surface of the hole injection layer; forming a quantum dot light-emitting layer on the side of the hole injection layer treated with the plasma, wherein the quantum dot light-emitting layer includes at least one of Cd quantum dots, InP quantum dots, and ZnSe quantum dots.

[0006] In one embodiment, the step of performing plasma treatment on the surface of the hole injection layer comprises: performing plasma treatment on the surface of the hole injection layer at 1 Pa-100 Pa for 0.1 min-10 min.

[0007] In one embodiment, the plasma treatment includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment.

[0008] In one embodiment, the material of the hole injection layer includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid.

[0009] In one embodiment, the step of forming a quantum dot light-emitting layer on the plasma-treated side of the hole injection layer comprises: forming a hole transport layer on the plasma-treated side of the hole injection layer; forming the quantum dot light-emitting layer on the side of the hole transport layer away from the hole injection layer; preferably, the material of the hole transport layer comprises poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine], poly(N-vinylcarbazole), polybis(4-phenyl)(4-butylphenyl)amine, 4,4',4"-tri(carbazole-9-yl)triphenylamine, 4,4-N,N-dicarbazole-biphenyl, perfluorocyclobutane, poly[ At least one of bis(4-phenyl)(2,4,6-trimethylphenyl)amine, N-([1,1′-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]-thiophene-2-yl)phenyl)dibenzo[b,d]thiophene-2-amine; preferably, the step of forming a hole transport layer on the plasma-treated side of the hole injection layer comprises: forming a hole transport layer on the plasma-treated surface of the hole injection layer; and / or, the step of forming the quantum dot light-emitting layer on the side of the hole transport layer away from the hole injection layer comprises: forming the quantum dot light-emitting layer on the surface of the hole transport layer away from the hole injection layer.

[0010] In one embodiment, the step of forming a hole injection layer includes: forming an anode layer; plasma treating the surface of the anode layer; preferably, the step of forming a hole injection layer includes: forming the hole injection layer on the plasma-treated side of the anode layer; preferably, the step of forming the hole injection layer on the plasma-treated side of the anode layer includes: forming the hole injection layer on the plasma-treated surface of the anode layer.

[0011] In one embodiment, after the step of forming a quantum dot light-emitting layer on the plasma-treated side of the hole injection layer, the step includes: sequentially forming an electron transport layer and a cathode layer on the side of the quantum dot light-emitting layer away from the hole injection layer; preferably, the material of the electron transport layer includes at least one of ZnO and ZnMgO.

[0012] In order to solve the above technical problems, the second technical solution provided by the present invention is: to provide a light-emitting device, comprising a hole injection layer and a quantum dot light-emitting layer stacked in sequence; wherein the quantum dot light-emitting layer comprises at least one of Cd quantum dots, InP quantum dots, and ZnSe quantum dots; the injection barrier of the hole injection layer into the quantum dot light-emitting layer is less than or equal to 0.3eV.

[0013] In one embodiment, the light-emitting device further comprises a hole transport layer, and the hole transport layer is disposed between the hole injection layer and the quantum dot light-emitting layer; preferably, the injection barrier of the hole injection layer to the quantum dot light-emitting layer is less than or equal to 0.25 eV; preferably, the contact angle between the quantum dot light-emitting layer and the hole injection layer is less than or equal to 35°; preferably, the contact angle between the quantum dot light-emitting layer and the hole injection layer is less than or equal to 30° and greater than or equal to 25; preferably, the material of the hole transport layer comprises poly[9,9-dioctylfluorene-co- At least one of N-[4-(3-methylpropyl)]-diphenylamine], poly(N-vinylcarbazole), polybis(4-phenyl)(4-butylphenyl)amine, 4,4',4"-tri(carbazole-9-yl)triphenylamine, 4,4-N,N-dicarbazole-biphenyl, perfluorocyclobutane, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, N-([1,1'-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]-thiophen-2-yl)phenyl)dibenzo[b,d]thiophen-2-amine.

[0014] In one embodiment, the light-emitting device further comprises an anode layer, wherein the anode layer is located on a side of the hole injection layer away from the quantum dot light-emitting layer; preferably, the surface of the anode layer close to the hole injection layer is plasma treated; preferably, the light-emitting device further comprises an electron transport layer and a cathode layer, wherein the electron transport layer is located on a side of the quantum dot light-emitting layer away from the hole injection layer, and the cathode layer is located on a side of the electron transport layer away from the hole injection layer; preferably, the material of the electron transport layer comprises at least one of ZnO and ZnMgO.

[0015] Beneficial effects of the present invention: Different from the prior art, the present invention discloses a light-emitting device and a method for preparing the light-emitting device; the method for preparing the light-emitting device comprises: forming a hole injection layer; performing plasma treatment on the surface of the hole injection layer; forming a quantum dot light-emitting layer on the plasma-treated side of the hole injection layer, wherein the quantum dot light-emitting layer comprises at least one of Cd quantum dots, InP quantum dots and ZnSe quantum dots, and by performing plasma treatment on the surface of the hole injection layer, the hole injection ability of the surface of the hole injection layer is enhanced, the quantum dot light-emitting layer is promoted to generate more excitons, and the carrier balance is promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1is a schematic structural diagram of a light emitting device provided by an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 The schematic diagram of the light emitting device shown;

[0019] Figure 3 It is a schematic flow chart of a first embodiment of a method for preparing a light-emitting device provided by the present invention;

[0020] Figure 4 It is a schematic flow chart of a second embodiment of a method for preparing a light-emitting device provided by the present invention;

[0021] Figure 5 It is a schematic flow chart of the third embodiment of the method for preparing a light-emitting device provided by the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the following description, for the purpose of explanation rather than limitation, specific details such as particular system structures, interfaces, and technologies are provided to provide a thorough understanding of the present invention.

[0024] The terms "first", "second" and "third" in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. The terms "including" and "having" in the embodiments of the present invention and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or components inherent to these processes, methods, products or devices.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0027] See also Figure 1 and Figure 2 , Figure 1 is a schematic structural diagram of a light emitting device provided in an embodiment of the present invention, Figure 2 yes Figure 1 Schematic diagram of the principle of the light-emitting device shown.

[0028] The light-emitting device 1 provided in the embodiment of the present invention comprises an anode layer 11, a hole injection layer 12, a hole transport layer 13, a quantum dot light-emitting layer 14, an electron transport layer 15 and a cathode layer 16 which are stacked in sequence. That is, in the light-emitting device 1, the hole injection layer 12 and the quantum dot light-emitting layer 14 are stacked, the hole transport layer 13 is arranged between the hole injection layer 12 and the quantum dot light-emitting layer, the anode layer 11 is located on the side of the hole injection layer 12 away from the quantum dot light-emitting layer 14, the electron transport layer 15 is located on the side of the quantum dot light-emitting layer 14 away from the hole injection layer, and the cathode layer 16 is located on the side of the electron transport layer 15 away from the hole injection layer 12.

[0029] The anode layer 11 and the hole injection layer 12 may be bonded together, or other film structures may be provided. The hole injection layer 12 and the hole transport layer 13 may be bonded together, or other film structures may be provided. The hole transport layer 13 and the quantum dot light-emitting layer 14 may be bonded together, or other film structures may be provided. The quantum dot light-emitting layer 14 and the electron transport layer 15 may be bonded together, or other film structures may be provided. The electron transport layer 15 and the cathode layer 16 may be bonded together, or other film structures may be provided.

[0030] In one embodiment, the surface of the hole injection layer 12 near the quantum dot light-emitting layer 14 is treated with plasma. The hydrophilicity of the surface of the hole injection layer 12 near the quantum dot light-emitting layer 14 is increased after the plasma treatment, and the contact angle between the quantum dot light-emitting layer 14 and the hole injection layer 12 is reduced, and the injection barrier of the hole injection layer 12 to the quantum dot light-emitting layer 14 is also reduced. Optionally, the injection barrier of the hole injection layer 12 to the quantum dot light-emitting layer 14 is less than or equal to 0.3eV. Optionally, the injection barrier of the hole injection layer 12 to the quantum dot light-emitting layer 14 is less than or equal to 0.25eV. Optionally, the contact angle between the quantum dot light-emitting layer 14 and the hole injection layer 12 is less than or equal to 35°. Optionally, the contact angle between the quantum dot light-emitting layer 14 and the hole injection layer 12 is less than or equal to 30° and greater than or equal to 25°.

[0031] In one embodiment, the surface of the anode layer 11 near the hole injection layer 12 is plasma treated. Plasma treatment of the surface of the anode layer 11 near the hole injection layer 12 can achieve similar effects as plasma treatment of the surface of the hole injection layer 12.

[0032] In one embodiment, the hole injection layer 12 is disposed on the surface of the anode layer 11, the hole transport layer 13 is disposed on the surface of the hole injection layer 12 away from the anode layer 11, the quantum dot light-emitting layer 14 is disposed on the surface of the hole transport layer 13 away from the hole injection layer 12, the electron transport layer 15 is disposed on the surface of the quantum dot light-emitting layer 14 away from the hole transport layer 13, and the cathode layer 16 is disposed on the surface of the electron transport layer 15 away from the quantum dot light-emitting layer 14.

[0033] In one embodiment, the anode layer 11 and the hole injection layer 12 are formed in the atmosphere. Since the anode layer 11 and the hole injection layer 12 are not sensitive to water and oxygen during their formation, the anode layer 11 and the hole injection layer 12 can be formed in the atmosphere, which helps to reduce the cost of the device.

[0034] In one embodiment, the hole transport layer 13, the quantum dot light emitting layer 14 and the electron transport layer 15 are formed under N2 or an inert gas atmosphere. Since the hole transport layer 13, the quantum dot light emitting layer 14 and the electron transport layer 15 are sensitive to water and oxygen during their formation, it is necessary to form the hole transport layer 13, the quantum dot light emitting layer 14 and the electron transport layer 15 under the protection of N2 or an inert gas. Optionally, the hole transport layer 13, the quantum dot light emitting layer 14 and the electron transport layer 15 are formed under the protection of N2, and N2 has a lower cost than an inert gas, which is conducive to reducing the cost of the device.

[0035] In one embodiment, the hole injection layer 12 , the hole transport layer 13 , the quantum dot light emitting layer 14 and the electron transport layer 15 are formed by spin coating and baking processes.

[0036] In one embodiment, the cathode layer 16 is formed by an evaporation process.

[0037] In one embodiment, the anode layer 11 is a transparent electrode or an opaque electrode.

[0038] In one embodiment, the material of the hole injection layer 12 (HIL) includes PEDOT:PSS. PEDOT:PSS is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid.

[0039] In one embodiment, the material of the hole transport layer 13 (HTL) includes at least one of TFB, PVK, poly-TPD, TCTA, CBP, PFCB, PTAA, and DBTA. TFB is poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine], PVK is poly(N-vinylcarbazole), poly-TPD is polybis(4-phenyl)(4-butylphenyl)amine, TCTA is 4,4',4"-tri(carbazole-9-yl)triphenylamine, CBP is 4,4-N,N-dicarbazole-biphenyl, PFCB is perfluorocyclobutane, PTAA is poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, DBTA is N-([1,1′-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]-thiophen-2-yl)phenyl)dibenzo[b,d]thiophen-2-amine.

[0040] In one embodiment, the material of the quantum dot light-emitting layer 14 (QD) includes at least one of Cd quantum dots, InP quantum dots, and ZnSe quantum dots.

[0041] In one embodiment, the material of the electron transport layer 15 (ETL) includes at least one of ZnO and ZnMgO.

[0042] Due to the material properties of the quantum dot light-emitting layer 14, the material properties of the electron transport layer 15, and the material properties of the hole injection layer 12 and the hole transport layer 13, the mobility of the electron transport layer 15 material is high, resulting in the electron (e - ) injection and transport capabilities are much greater than holes (h + ) injection and transport capabilities, there is a carrier injection imbalance, resulting in low device efficiency; among them, since the electron injection and transport capabilities are much greater than the hole injection and transport capabilities, it is not necessary to set an electron injection layer to avoid further accelerating the electron transport capacity, thereby avoiding further aggravation of the carrier injection imbalance.

[0043] For the above-mentioned problem of unbalanced carrier injection, the embodiment of the present invention sets a hole transport layer 13 between the hole injection layer 12 and the quantum dot light-emitting layer 14 to reduce the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14, which is beneficial to the injection and transmission of holes. By plasma-treating the surface of the hole injection layer 12 close to the quantum dot light-emitting layer 14, the energy level of the hole injection layer 12 is improved, and the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14 is reduced, which is beneficial to hole injection, and the hole injection ability on the surface of the hole injection layer 12 is enhanced. The hole injection ability at the interface between the hole injection layer 12 and the hole transport layer 13 is enhanced, and the quantum dot light-emitting layer 14 is promoted to generate more excitons, promote carrier balance, and improve the efficiency of the device. Optionally, the surface plasma treatment of the hole injection layer 12 is performed for 0.1min-10min at 1Pa-100Pa. Optionally, the plasma treatment of the hole injection layer 12 includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment; that is, the atmosphere of the plasma treatment includes at least one of ammonia, oxygen, carbon monoxide, argon, nitrogen, and hydrogen. The surface of the hole injection layer 12 is plasma treated with the above-mentioned pressure, atmosphere, and time, and the surface of the hole injection layer 12 is well modified, thereby improving the hole injection ability of the interface between the hole injection layer 12 and the hole transport layer 13.

[0044] The embodiment of the present invention also performs plasma treatment on the surface of the anode layer 11 near the hole injection layer 12. By performing plasma treatment on the surface of the anode layer 11, the work function of the anode layer 11 is increased, hole injection is promoted, and the quantum dot light-emitting layer 14 is further promoted to generate more excitons, promote carrier balance, and improve the efficiency of the device. Optionally, at 1Pa-100Pa, the surface of the anode layer 11 is plasma treated for 0.1min-10min. Optionally, the plasma treatment of the anode layer 11 includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment; that is, the atmosphere of the plasma treatment includes at least one of ammonia, oxygen, carbon monoxide, argon, nitrogen, and hydrogen. The surface of the anode layer 11 is plasma treated with the above-mentioned pressure, atmosphere, and time, and the surface of the anode layer 11 is well modified to promote hole injection. It should be noted that the conditions for plasma treatment of the anode layer 11 and the conditions for plasma treatment of the hole injection layer 12 may be the same or different, and are specifically designed according to needs.

[0045] See also Figure 3 , Figure 3 It is a schematic flow chart of the first embodiment of the method for preparing a light-emitting device provided by the present invention.

[0046] A first embodiment of the present invention provides a method for preparing a light emitting device, which specifically includes:

[0047] Step S01: forming a hole injection layer 12 .

[0048] In one embodiment, the hole injection layer 12 is formed in an atmospheric environment. Since the hole injection layer 12 is not sensitive to water and oxygen during its formation, the anode layer 11 can be formed in an atmospheric environment, which is beneficial to reducing the cost of the device compared to other atmospheric conditions.

[0049] In one embodiment, the hole injection layer 12 is formed by a spin coating and baking process.

[0050] In one embodiment, the material of the hole injection layer 12 includes PEDOT:PSS. It can be understood that when the hole injection layer 12 is formed by a spin coating process, the material of the spin-coated slurry includes PEDOT:PSS.

[0051] Step S02 : performing plasma treatment on the surface of the hole injection layer 12 .

[0052] In one embodiment, the surface plasma treatment of the hole injection layer 12 is performed at 1Pa-100Pa for 0.1min-10min, so that the surface of the hole injection layer 12 is well modified, the energy level of the hole injection layer 12 is improved, and the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14 is reduced, which is beneficial to hole injection, enhances the hole injection ability on the surface of the hole injection layer 12, enhances the hole injection ability at the interface between the hole injection layer 12 and the hole transport layer 13, promotes the quantum dot light-emitting layer 14 to generate more excitons, promotes carrier balance, and improves the efficiency of the device.

[0053] In one embodiment, the plasma treatment performed on the surface of the hole injection layer 12 includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment; that is, the atmosphere of the plasma treatment includes at least one of ammonia, oxygen, carbon monoxide, argon, nitrogen, and hydrogen. By using the above atmosphere for plasma treatment, the surface of the hole injection layer 12 is well modified, and the hole injection ability of the hole injection layer 12 is improved.

[0054] Step S03: forming a quantum dot light-emitting layer 14 on the plasma-treated side of the hole injection layer 12, wherein the quantum dot light-emitting layer 14 includes at least one of Cd quantum dots, InP quantum dots, and ZnSe quantum dots.

[0055] In one embodiment, the quantum dot light-emitting layer 14 is formed under N2 or an inert gas atmosphere. Since the quantum dot light-emitting layer 14 is sensitive to water and oxygen during its formation, it is necessary to form the quantum dot light-emitting layer 14 under the protection of N2 or an inert gas. Optionally, the quantum dot light-emitting layer 14 is formed under the protection of N2, which has a lower cost than an inert gas, and is conducive to reducing the cost of the device.

[0056] In one embodiment, the quantum dot light emitting layer 14 is formed by spin coating and baking processes.

[0057] In one embodiment, a hole transport layer 13 is formed on the plasma-treated side of the hole injection layer 12, and a quantum dot light-emitting layer 14 is formed on the side of the hole transport layer 13 away from the hole injection layer 12. By forming the hole transport layer 13 between the hole injection layer 12 and the quantum dot light-emitting layer 14, the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14 is reduced, which is beneficial to the injection and transport of holes.

[0058] Optionally, a quantum dot light-emitting layer 14 is formed on the surface of the hole transport layer 13 away from the hole injection layer 12. Optionally, a hole transport layer 13 is formed on the plasma-treated surface of the hole injection layer 12. Optionally, the hole transport layer 13 is formed under N2 or an inert gas atmosphere; since the hole transport layer 13 is sensitive to water and oxygen during its formation, it is necessary to form the hole transport layer 13 under the protection of N2 or an inert gas. Optionally, the hole transport layer 13 is formed by spin coating and baking processes. Optionally, the hole transport layer 13 (HTL) material includes at least one of TFB, PVK, poly-TPD, TCTA, CBP, PFCB, PTAA, and DBTA.

[0059] The embodiment of the present invention performs plasma treatment on the surface of the hole injection layer 12, thereby improving the energy level of the hole injection layer 12 and reducing the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14, which is beneficial to hole injection, enhances the hole injection ability on the surface of the hole injection layer 12, enhances the hole injection ability at the interface between the hole injection layer 12 and the hole transport layer 13, promotes the quantum dot light-emitting layer 14 to generate more excitons, promotes carrier balance, and improves the efficiency of the device.

[0060] See also Figure 4 , Figure 4 It is a schematic flow chart of the second embodiment of the method for preparing a light-emitting device provided by the present invention.

[0061] The second embodiment of the present invention provides a method for preparing a light-emitting device, which is different from the method for preparing a light-emitting device provided by the first embodiment of the present invention in that: before step S01, it also includes step S00 and step S00'.

[0062] Step S00: forming an anode layer 11 .

[0063] In one embodiment, the anode layer 11 is cleaned. Optionally, the anode layer 11 is an ITO (indium tin oxide) substrate.

[0064] In one embodiment, the anode layer 11 is formed in an atmospheric environment, which helps to reduce device costs.

[0065] In one embodiment, the anode layer 11 is a transparent electrode or an opaque electrode.

[0066] Step S00 ′: performing plasma treatment on the surface of the anode layer 11 .

[0067] In one embodiment, the surface of the anode layer 11 is plasma treated at 1 Pa to 100 Pa for 0.1 min to 10 min.

[0068] In one embodiment, the plasma treatment of the anode layer 11 includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment; that is, the atmosphere of the plasma treatment includes at least one of ammonia, oxygen, carbon monoxide, argon, nitrogen, and hydrogen.

[0069] It should be noted that the step of forming the hole injection layer 12 is specifically to form the hole injection layer 12 on the plasma-treated side of the anode layer 11. Optionally, the hole injection layer 12 is formed on the plasma-treated surface of the anode layer 11.

[0070] The embodiment of the present invention performs plasma treatment on the surface of the anode layer 11 to increase the work function of the anode layer 11, promote hole injection, further promote the quantum dot light-emitting layer 14 to generate more excitons, promote carrier balance, and improve the efficiency of the device.

[0071] See also Figure 5 , Figure 5 It is a schematic flow chart of the third embodiment of the method for preparing a light-emitting device provided by the present invention.

[0072] The third embodiment of the present invention provides a method for preparing a light-emitting device, which is different from the method for preparing a light-emitting device provided by the first embodiment of the present invention in that: after step S03, step S04 is further included.

[0073] Step S04 : forming an electron transport layer 15 and a cathode layer 16 in sequence on a side of the quantum dot light emitting layer 14 away from the hole injection layer 12 .

[0074] In one embodiment, an electron transport layer 15 is formed on the surface of the quantum dot light emitting layer 14 away from the hole injection layer 12. Optionally, the electron transport layer 15 is formed under N2 or an inert gas atmosphere; since the electron transport layer 15 is sensitive to water and oxygen during its formation, it is necessary to form the electron transport layer 15 under the protection of N2 or an inert gas. Optionally, the electron transport layer 15 is formed by spin coating and baking processes. Optionally, the material of the electron transport layer 15 includes at least one of ZnO and ZnMgO.

[0075] In one embodiment, the cathode layer 16 is formed on the surface of the electron transport layer 15 away from the quantum dot light emitting layer 14. Optionally, the cathode layer 16 is formed by an evaporation process.

[0076] Due to the material properties of the quantum dot light-emitting layer 14, the material properties of the electron transport layer 15, and the material properties of the hole injection layer 12 and the hole transport layer 13, the electron transport layer 15 material has high mobility, and the electron injection and transport capabilities are much greater than the hole injection and transport capabilities. By arranging the hole transport layer 13 between the hole injection layer 12 and the quantum dot light-emitting layer 14, the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14 is reduced, which is beneficial to the injection and transport of holes; by plasma treatment of the surface of the hole injection layer 12, the energy level of the hole injection layer 12 is improved, and the energy level barrier between the hole injection layer 12 and the quantum dot light-emitting layer 14 is reduced, which is beneficial to hole injection, enhances the hole injection capability on the surface of the hole injection layer 12, enhances the hole injection capability at the interface between the hole injection layer 12 and the hole transport layer 13, promotes the quantum dot light-emitting layer 14 to generate more excitons, promotes carrier balance, and improves the efficiency of the device.

[0077] An embodiment of the present invention further provides a light-emitting device, which is prepared by the method for preparing a light-emitting device provided by any of the above embodiments.

[0078] The above are only implementation modes of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a light-emitting device, characterized in that: include: forming a hole injection layer; performing plasma treatment on the surface of the hole injection layer; A quantum dot light-emitting layer is formed on the plasma-treated side of the hole injection layer, and the quantum dot light-emitting layer includes at least one of Cd quantum dots, InP quantum dots, and ZnSe quantum dots.

2. The preparation method according to claim 1, characterized in that: The step of plasma treating the surface of the hole injection layer comprises: The surface of the hole injection layer is subjected to plasma treatment at 1 Pa to 100 Pa for 0.1 min to 10 min.

3. The preparation method according to claim 1, characterized in that: The plasma treatment includes at least one of ammonia plasma treatment, oxygen plasma treatment, carbon monoxide plasma treatment, argon plasma treatment, nitrogen plasma treatment, and hydrogen plasma treatment.

4. The preparation method according to claim 1, characterized in that: The material of the hole injection layer includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The step of forming a quantum dot light-emitting layer on the plasma-treated side of the hole injection layer comprises: forming a hole transport layer on the plasma-treated side of the hole injection layer; Forming the quantum dot light-emitting layer on a side of the hole transport layer away from the hole injection layer; Preferably, the material of the hole transport layer includes at least one of poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine], poly(N-vinylcarbazole), polybis(4-phenyl)(4-butylphenyl)amine, 4,4',4"-tri(carbazole-9-yl)triphenylamine, 4,4-N,N-dicarbazole-biphenyl, perfluorocyclobutane, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, N-([1,1'-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]-thiophene-2-yl)phenyl)dibenzo[b,d]thiophene-2-amine; Preferably, the step of forming a hole transport layer on the plasma-treated side of the hole injection layer comprises: forming a hole transport layer on the plasma-treated surface of the hole injection layer; And / or, the step of forming the quantum dot light-emitting layer on a side of the hole transport layer away from the hole injection layer comprises: The quantum dot light-emitting layer is formed on a surface of the hole transport layer away from the hole injection layer.

6. The preparation method according to claim 1, characterized in that: The step of forming a hole injection layer includes: forming an anode layer; performing plasma treatment on the surface of the anode layer; Preferably, the step of forming a hole injection layer comprises: forming the hole injection layer on the plasma-treated side of the anode layer; Preferably, the step of forming the hole injection layer on the plasma-treated side of the anode layer comprises: The hole injection layer is formed on the plasma-treated surface of the anode layer.

7. The preparation method according to claim 1, characterized in that: After the step of forming a quantum dot light-emitting layer on the plasma-treated side of the hole injection layer, the step includes: An electron transport layer and a cathode layer are sequentially formed on a side of the quantum dot light-emitting layer away from the hole injection layer; Preferably, the material of the electron transport layer includes at least one of ZnO and ZnMgO.

8. A light emitting device, characterized in that: include: A hole injection layer and a quantum dot light-emitting layer are stacked in sequence; The quantum dot light-emitting layer includes at least one of Cd quantum dots, InP quantum dots and ZnSe quantum dots; and the injection barrier of the hole injection layer into the quantum dot light-emitting layer is less than or equal to 0.3 eV.

9. The light emitting device according to claim 8, characterized in that: The light emitting device further comprises a hole transport layer, wherein the hole transport layer is disposed between the hole injection layer and the quantum dot light emitting layer; Preferably, the injection barrier of the hole injection layer to the quantum dot light-emitting layer is less than or equal to 0.25 eV; Preferably, the contact angle between the quantum dot light-emitting layer and the hole injection layer is less than or equal to 35°; Preferably, the contact angle between the quantum dot light-emitting layer and the hole injection layer is less than or equal to 30° and greater than or equal to 25; Preferably, the material of the hole transport layer includes at least one of poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine], poly(N-vinylcarbazole), polybis(4-phenyl)(4-butylphenyl)amine, 4,4',4"-tri(carbazole-9-yl)triphenylamine, 4,4-N,N-dicarbazole-biphenyl, perfluorocyclobutane, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, N-([1,1'-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]-thiophene-2-yl)phenyl)dibenzo[b,d]thiophene-2-amine.

10. The light emitting device according to claim 8, characterized in that: The light emitting device further comprises an anode layer, wherein the anode layer is located on a side of the hole injection layer away from the quantum dot light emitting layer; Preferably, the surface of the anode layer close to the hole injection layer is plasma treated; preferably, the light-emitting device further comprises an electron transport layer and a cathode layer, the electron transport layer is located on a side of the quantum dot light-emitting layer away from the hole injection layer, and the cathode layer is located on a side of the electron transport layer away from the hole injection layer; Preferably, the material of the electron transport layer includes at least one of ZnO and ZnMgO.

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