WO2020134248A1

WO2020134248A1 - Quantum dot light emitting diode and manufacturing method therefor

Info

Publication number: WO2020134248A1
Application number: PCT/CN2019/108097
Authority: WO
Inventors: 雷卉; 曹蔚然
Original assignee: Tcl科技集团股份有限公司
Priority date: 2018-12-29
Filing date: 2019-09-26
Publication date: 2020-07-02
Also published as: CN111384287B; CN111384287A

Abstract

A quantum dot light emitting diode and a manufacturing method therefor. The quantum dot light emitting diode comprises a bottom electrode, a top electrode, and a quantum dot light emitting layer disposed between the bottom electrode and the top electrode; the quantum dot light emitting diode is a bottom-emitting quantum dot light emitting diode; the surface of the bottom electrode close to the quantum dot light emitting layer is provided with a nanopillar array consisting of multiple nanopillars; in the nanopillar array, the diameter of the nanopillar is λ/(4×n1), and the distance between any two adjacent nanopillars is λ/(4×n2), wherein λ is the center wavelength of output light of the quantum dot light emitting diode, n1 is the refractive index of the material of the nanopillars, n2 is the refractive index of the material between the nanopillars, and n1≠n2.

Description

Quantum dot light emitting diode and preparation method thereof

[0001] This application is required to be filed at the China Patent Office on December 29, 2018, and the application number is 2018116459788

The priority of the Chinese patent application with the invention titled "Quantum Dot Light Emitting Diode and its Preparation Method", the entire content of which is incorporated by reference in this application.

Technical field

[0002] The present application relates to the field of display technology, in particular to a quantum dot light emitting diode and a method of manufacturing the same.

Background technique

[0003] In recent years, QLED (Quantum Dot Light Emitting

Diode (Quantum Dot Light Emitting Diode) and OLED (Organic Light Emitting Diode) have gained more and more attention due to their advantages of high brightness, low power consumption, wide color gamut, etc. Technology, and form a chamber of resistance. QLED has shown great application potential due to its advantages such as low start-up voltage, narrow emission peak and adjustable emission wavelength.

[0004] In terms of the performance of the QLED device, the low light extraction efficiency of the device has always been one of the focuses of researchers. The methods commonly used to improve the light-emitting efficiency of the device include controlling the thickness of the device based on the microcavity effect and using photonic crystals. However, such methods usually have complicated procedures and high control difficulty, which is not conducive to implementation.

[0005] Therefore, related technologies need to be improved.

Summary of the invention

technical problem

[0006] One of the purposes of the embodiments of the present application is to provide a quantum dot light emitting diode and a method for manufacturing the same, aiming to solve the technical problem of low light extraction efficiency of existing QLED devices.

Solution to the problem

Technical solution

[0007] To solve the above technical problems, the technical solutions adopted in the embodiments of the present application are:

[0008] In a first aspect, a quantum dot light emitting diode is provided, including a bottom electrode, a top electrode, and a quantum dot light emitting layer disposed between the bottom electrode and the top electrode, the quantum dot light emitting diode It is a bottom-emission type quantum dot light-emitting diode, and the bottom electrode is provided near the surface of the quantum dot light-emitting layer with Nanopillar array composed of dry nanopillars;

[0009] In the nanopillar array, the diameter of the nanopillar is X/(4X11,), and the spacing between any two adjacent nanopillars is X/(4xn ₂ ); where k is The center wavelength of the output light of the quantum dot light emitting diode, ni is the refractive index of the nanopillar, n ₂ is the refractive index of the filling material between the nanopillars, and ni^n 2

[0010] In an embodiment, a backfill layer is provided on the surface of the nanopillar array, the material of the backfill layer is the filling material filled between two adjacent nanopillars, the refractive index of the nanopillars and the The refractive indexes of the backfill layers are not equal.

[0011] In one embodiment, the bottom electrode is an anode, the top electrode is a cathode, and a hole function layer is provided between the backfill layer and the quantum dot light-emitting layer.

[0012] In one embodiment, the bottom electrode is an anode, the top electrode is a cathode, and an electronic functional layer is provided between the top electrode and the quantum dot light-emitting layer.

[0013] In one embodiment, the bottom electrode is a cathode, the top electrode is an anode, and an electronic functional layer is provided between the backfill layer and the quantum dot light-emitting layer

[0014] In one embodiment, the bottom electrode is a cathode, the top electrode is an anode, and a hole function layer is provided between the top electrode and the quantum dot light-emitting layer.

[0015] In one embodiment, the bottom electrode is a cathode, the top electrode is an anode, an electronic functional layer is provided on the surface of the nanopillar array, and the material of the electronic functional layer is the filler material filled in the phase Between two adjacent nanopillars, the refractive index of the electronic functional layer is not equal to the refractive index of the nanopillars.

[0016] In one embodiment, the electronic functional layer is an electron injection layer.

[0017] In one embodiment, a hole function layer is provided between the top electrode and the quantum dot light emitting layer.

[0018] In one embodiment, the bottom electrode is an anode, the top electrode is a cathode, a hole functional layer is provided on the surface of the nanopillar array, and the material of the hole functional layer is filled with the filling material Between two adjacent nano-pillars, the refractive index of the hole functional layer is not equal to the refractive index of the nano-pillars.

[0019] In one embodiment, the hole functional layer is a hole injection layer.

[0020] In one embodiment, an electronic functional layer is provided between the top electrode and the quantum dot light emitting layer.

[0021] The second aspect provides a method for manufacturing a quantum dot light emitting diode, including the following steps:

[0022] providing a bottom electrode; [0023] preparing a nanopillar array on the surface of the bottom electrode;

[0024] In the nanopillar array, the diameter of the nanopillar is X/ (4x _ni ), and the distance between any two adjacent nanopillars is X/ (4xn ₂ ); where k is The center wavelength of the output light of the quantum dot light emitting diode, ni is the refractive index of the material of the nano-pillars, 11 ₂ is the refractive index of the filling material between the nano-pillars, Kn _! ^n _2°

[0025] In one embodiment, the step of preparing a nano-pillar array on the surface of the bottom electrode includes:

[0026] depositing a PS nanosphere solution on the surface of the bottom electrode to obtain a single-layer PS nanosphere film; the PS nanospheres in the PS nanosphere solution have the same diameter;

[0027] etching the single-layer PS nanosphere thin film to reduce the size of the diameter of the PS nanosphere to obtain a single-layer PS nanosphere thin film with reduced PS nanosphere diameter;

[0028] Using the single-layer PS nanosphere thin film with the reduced diameter of the PS nanosphere as a mask, etching the bottom electrode, then removing the PS nanosphere, and forming the same nanopillar on the surface of the bottom electrode Nanopillar array.

[0029] In one embodiment, the diameter of the PS nanospheres in the PS nanosphere solution is 50-2000 nm.

[0030] In one embodiment, the mass percentage of PS nanospheres in the PS nanosphere solution is 0.1-10%.

[0031] In one embodiment, the single-layer PS nanosphere thin film with a reduced diameter of the PS nanosphere is used as a mask, and an etching solution is used to etch the bottom electrode; wherein, the etching solution At least one selected from hydrofluoric acid solution, nitric acid solution, phosphoric acid solution, sulfuric acid solution, hydrochloric acid solution and acetic acid solution.

[0032] In one embodiment, an etching solution is used to etch the bottom electrode at a temperature of 20-100°C.

[0033] In one embodiment, the etching liquid is used to etch the bottom electrode for ls-5h.

[0034] In one embodiment, the etching solution contains at least one of ferric chloride, ferrous chloride and acetone.

[0035] The beneficial effects of the quantum dot light emitting diode provided by the embodiments of the present application are as follows: the bottom electrode in the quantum dot light emitting diode is provided with a nanopillar array composed of several nanopillars near the surface of the quantum dot light emitting layer; The diameter of the nanopillar is X/ (4x _ni ), and the distance between any two adjacent nanopillars is X/ (4xn ₂ ), which can be understood as the distance between the lateral optical thickness of the nanopillar and the nanopillar The filling material has the same lateral optical thickness. In this way, six identical nano-pillars are evenly distributed around each nano-pillar, and extend outward for several cycles, forming a special hexagonal close-packing with two different refractive index materials with high and low refractive index alternately repeated for several cycles in the lateral direction Layer structure, thus forming a ring-like Bragg The effect of the mirror, when the light emitted from the quantum dot light-emitting layer passes through the Bragg reflector during the propagation process, it can partially reflect the light originally emitted from the side of the device to the bottom of the device, thereby reducing the side light, which can be greatly improved The light extraction efficiency of the device.

[0036] The beneficial effects of the manufacturing method of the quantum dot light emitting diode provided by the embodiments of the present application are as follows: The manufacturing method is a high repeatability, low cost, and high light efficiency device manufacturing method. In the manufacturing method, the bottom A nanopillar array composed of the same nanopillars is prepared on the surface of the electrode. In the nanopillar array, the diameter of the nanopillar is X/(4xn _!

) And the spacing between any two adjacent nanopillars is X/ (4xn ₂ ). Such a nanopillar array forms an effect similar to a ring-shaped Bragg reflector, thereby greatly improving the light extraction efficiency of the final device. .

Beneficial effects of invention

Brief description of the drawings

BRIEF DESCRIPTION

[0037] In order to more clearly explain the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings used in the embodiments or exemplary technical descriptions. Obviously, the drawings in the following description are only For some embodiments of the present application, for those of ordinary skill in the art, without paying any creative labor, other drawings may be obtained based on these drawings.

[0038] FIG. 1 is a schematic structural diagram of a QLED device with a ring-like Bragg reflector nanopillar array structure in an embodiment of the present application;

[0039] FIG. 2 is a flowchart of a method for manufacturing a quantum dot light emitting diode according to an embodiment of the present application;

[0040] FIG. 3 is a cross-sectional view of a single-layer PS nanosphere film prepared on the surface of an ITO layer according to an embodiment of the present application;

[0041] FIG. 4 is a top view of a single-layer PS nanosphere film prepared on the surface of an ITO layer according to an example of the present application;

[0042] FIG. 5 is a graph of the results of etching a single-layer PS nanosphere film to adjust the size of PS nanospheres according to an embodiment of the present application;

[0043] FIG. 6 is a structural diagram of an ITO layer covered with a single-layer PS nanosphere thin film using an etching solution according to an embodiment of the present application; [0044] FIG. 7 is a strip obtained after removing PS nanospheres according to an embodiment of the present application A cross-sectional view of the ITO layer of the nano-pillar array structure;

[0045] FIG. 8 is a top view of an ITO layer with a nano-pillar array structure obtained by removing PS nanospheres according to an embodiment of the present application. The ITO layer has a ring-like Bragg reflector structure. Invention Example

Embodiments of the invention

[0046] In order to make the purpose, technical solution and advantages of the present application more clear, the following describes the present application in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application, and are not intended to limit this application.

[0047] Some embodiments of the present application provide a quantum dot light emitting diode, including a bottom electrode, a top electrode, and a quantum dot light emitting layer disposed between the bottom electrode and the top electrode, the quantum dot light emitting diode is a bottom An emission type quantum dot light emitting diode, the bottom electrode is provided with a nanocolumn array composed of several nanopillars near the surface of the quantum dot light emitting layer;

[0048] In the nanopillar array, the diameter of the nanopillar is X/(4X11,), and the spacing between any two adjacent nanopillars is X/(4xn ₂ ); where, k is The center wavelength of the output light of the quantum dot light emitting diode is the refractive index of the nanopillars, n ₂ is the refractive index of the filling material between the nanopillars, and n

1 n ₂ .

[0049] In the quantum dot light emitting diode provided by the embodiment of the present application, a nanopillar array composed of several nanopillars is provided on the surface of the bottom electrode close to the quantum dot light emitting layer; in the nanopillar array, the diameter of the nanopillars M/ (4X11 ,), and the distance between any two adjacent nano-pillars is X/ (4xn ₂ ), it can be understood that the lateral optical thickness of the nano-pillar is the same as the lateral optical thickness of the filling material between the nano-pillars . In this way, six identical nano-pillars are evenly distributed around each nano-pillar, and extend outward for several cycles, forming a special hexagonal close-packing with two different refractive index materials with high and low refractive index alternately repeated for several cycles in the lateral direction Layer structure, thus forming an effect similar to a ring-shaped Bragg reflector; as shown in Figure 8, each nano-pillar is equally spaced (b is the spacing between adjacent nano-pillars, b=X/ (4xn ₂ )) Six identical nanopillars, and the pitch is the same as the diameter of the nanopillars (a is the diameter of the nanopillars, a=X/ (4x _ni ) ). When the light emitted from the quantum dot luminous layer is propagating, it passes through the shape-like ring Bragg When the reflector is used, part of the light originally emitted from the side of the device can be reflected to the bottom of the device to exit, thereby reducing the side light emission and greatly improving the light extraction efficiency of the device.

[0050] It should be noted that, in the specific implementation of this solution, the center wavelength of the output light of the light emitting diode is mainly determined by the light emitting wavelength of the quantum dot light emitting material, for example, when designing a blue quantum dot light emitting diode, due to the wavelength of blue light The range is usually 400~480nm, and the center wavelength is 440nm, but due to luminescence During the use of the diode, due to various factors, such as material aging, device aging, and other factors, the center wavelength will change during the use process (such as the entire life cycle). The center wavelength in this solution needs to take into account these Therefore, the center wavelength in the embodiment of the present application is a floating value centered on a certain monochromatic standard center wavelength, that is, the center wavelength X=standard center wavelength k _Q ±AX, the specific value of AX, those skilled in the art It can be selected according to its specific implementation experience. For example, for blue light, AX can be 2 Onm. Therefore, because the center wavelength of the light-emitting diode is a range value, when applying this solution, when designing the diameter of the nano-pillar, you can According to the range of X/ (4xn ,), choose an appropriate specific diameter.

[0051] For quantum dot light-emitting diodes of other colors, the embodiments of the present application are similar to blue light, and the embodiments of the present application will not be repeated here.

[0052] In an embodiment, in the quantum dot light emitting diode, according to the need of the center wavelength of the light, the diameter, period, height, etc. of the nanopillars in the nanopillar array can be adjusted to match the optimal ring-shaped Bragg reflector Nanopillar array.

[0053] In an embodiment, in the quantum dot light emitting diode, a backfill layer is provided on the surface of the nanopillar array, and the material of the backfill layer is that the filling material is filled between two adjacent nanopillars, the The refractive index of the nano-pillar is not equal to the refractive index of the backfill layer. In an embodiment, a functional layer may also be provided between the backfill layer and the quantum dot light-emitting layer; if the bottom electrode is an anode, a hole functional layer may also be provided between the backfill layer and the quantum dot light-emitting layer, specifically It may be a hole injection layer and a hole transport layer, and an electronic functional layer may also be provided between the top electrode and the quantum dot light-emitting layer. If the bottom electrode is a cathode, an electron functional layer may be provided between the backfill layer and the quantum dot light-emitting layer, such as an electron injection layer and an electron transport layer, and holes may also be provided between the top electrode and the quantum dot light-emitting layer Function layer.

[0054] In an embodiment, in the quantum dot light emitting diode, the bottom electrode is a cathode, the top electrode is an anode, an electronic functional layer is provided on the surface of the nanopillar array, and the material of the electronic functional layer is The filling material is filled between two adjacent nano-pillars, and the refractive index of the electronic functional layer is not equal to the refractive index of the nano-pillars; if the electronic functional layer is an electron transport layer, the electron transport layer material is filled in the phase Between two adjacent nano-pillars, if the electron functional layer is an electron injection layer, the material of the electron injection layer is filled between the two adjacent nano-pillars; a hole functional layer is provided between the top electrode and the quantum dot light-emitting layer, The hole functional layer may be a hole transport layer, or a layered hole transport layer and hole injection layer, the hole injection layer and the top electrode Very adjacent.

[0055] In an embodiment, in the quantum dot light-emitting diode, the bottom electrode is an anode, the top electrode is a cathode, the surface of the nano-pillar array is provided with a hole function layer, the hole function layer The material is that the filling material is filled between two adjacent nano-pillars, the refractive index of the hole functional layer and the refractive index of the nano-pillars are not equal; if the hole functional layer is a hole transport layer, the holes The work transport material is filled in the gap between the nanopillars. For example, the hole functional layer is a hole injection layer, and the hole injection layer material fills the gap between the nanopillars. In the embodiment of the present application, the hole functional layer is A hole injection layer; an electron functional layer is provided between the top electrode and the quantum dot light-emitting layer, the electron functional layer may be an electron transport layer, or a stacked electron transport layer and an electron injection layer, the electron injection layer and the top The electrodes are adjacent.

[0056] On the other hand, an embodiment of the present application also provides a method for manufacturing a quantum dot light emitting diode, as shown in FIG. 2, including the following steps:

[0057] S01: providing a bottom electrode;

[0058] S02: preparing a nano-pillar array on the surface of the bottom electrode;

[0059] In the nanopillar array, the diameter of the nanopillar is X/(4X11,), and the spacing between any two adjacent nanopillars is X/(4xn ₂ ); where, k is the center wavelength of the output light of said quantum dot light emitting diode, the refractive index of the material of the nano-pillars, the filler material ₁₁₂ is between the refractive index of the nano-pillars, _Kn! ^ n _{2 °}

[0060] The preparation method of the quantum dot light-emitting diode provided by the embodiments of the present application is a high repeatability, low cost and high light efficiency device preparation method. In this preparation method, the same nanopillars are prepared on the surface of the bottom electrode A nanopillar array composed of, in the nanopillar array, the diameter of the nanopillar is X/(4xn J, and the spacing between any two adjacent nanopillars is X/(4xn ₂ ), such a nanometer The column array forms an effect similar to the ring-shaped Bragg reflector, thereby greatly improving the light extraction efficiency of the finally fabricated device.

[0061] In an embodiment, the step of preparing a nano-pillar array on the surface of the bottom electrode includes:

[0062] depositing a PS nanosphere solution on the surface of the bottom electrode to obtain a single-layer PS nanosphere thin film; the PS nanospheres in the PS nanosphere solution have the same diameter;

[0063] etching the single-layer PS nanosphere film to halve the size of the diameter of the PS nanosphere to obtain a single-layer PS nanosphere film with a reduced diameter of the PS nanosphere; [0064] Using the single-layer PS nanosphere thin film with the reduced diameter of the PS nanospheres as a mask, the bottom electrode is etched, and then the PS nanospheres are removed, and the same nanopillars are formed on the surface of the bottom electrode Nanopillar array.

[0065] Specifically, the PS (Polystyrene, polystyrene) nanospheres in the PS nanosphere solution have a diameter of 50-2000 nm, and thus the spacing between two adjacent nanopillars prepared on the bottom electrode is 25- 1000nm. In one embodiment, the mass percentage of PS nanospheres in the PS nanosphere solution is 0.1-10%. The prepared PS nanosphere solution can be prepared with deionized water/ethanol mixture.

[0066] In one embodiment, the single-layer PS nanosphere thin film is etched by reactive ion etching (RIE, Reactive Ion Etching) method; wherein, the etching atmosphere is selected in the reactive ion etching method From at least one of oxygen and carbon tetrafluoride, the flow rate may be l~200sccm; and/or, the etching power is 0.1-100W; and/or, the etching time is l-500s.

[0067] In an embodiment, the single-layer PS nanosphere thin film with a reduced diameter of the PS nanosphere is used as a mask, and the bottom electrode is etched using an etching solution. Wherein, the etching solution is selected from at least one of hydrofluoric acid solution, nitric acid solution, phosphoric acid solution, sulfuric acid solution, hydrochloric acid solution and acetic acid solution, the bottom electrode is an ITO electrode, these etching solutions react with ITO but are not No corrosion or weak corrosion effect of the nanospheres; the temperature for etching the bottom electrode with an etching solution is 20-100°C; the time for etching the bottom electrode with an etching solution is ls-5h ; The etching solution contains at least one of ferric chloride, ferrous chloride and acetone.

[0068] In an embodiment of the present application, a method for manufacturing a high-efficiency QLED device includes the following steps:

[0069] S1: preparing an ITO electrode on a transparent substrate.

[0070] S2: On the ITO electrode, the PS nanospheres are used as a mask, the nanospheres are further etched by RIE, and then the nanopillar array is prepared by a solution method, thereby obtaining an ITO layer with the nanopillar array. The diameter of the prepared ITO nanopillar is X/ (4x _ni ),

Is the refractive index of the nanopillar, k is the center wavelength of the output light, that is, the lateral optical thickness of the nanopillar is 1/4 of the center wavelength of the output light.

[0071] S3: a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer are sequentially prepared on the ITO layer

, Metal electrodes and other functional layers. The hole injection layer can be adjacent to the ITO layer. The distance between two adjacent nanopillars is X/ (4xn ₂ ). The refractive index of the n ₂ hole injection layer material, that is, the hole injection layer is filled into the nanopillar The lateral optical thickness of the gap between them is 1/4 of the center wavelength of the output light. [0072] The above preparation method, by introducing a ring-like Bragg reflector nanopillar array, thereby improving the light extraction efficiency of the device. By comprehensively adjusting the conditions of the PS nanosphere size, RIE etching parameters, acid solution composition, ITO etching parameters and other conditions, the period, diameter, height, etc. of the prepared nanopillar array can be fine-tuned and adjusted according to the output light center For wavelength requirements, QLED devices with different composition materials, different functional layer thicknesses, and different structures are optimally adapted to obtain higher light extraction efficiency.

[0073] The present application has been tested multiple times in succession, and a part of the test results will now be used as a reference to further describe the present application in detail, which will be described in detail below in conjunction with specific embodiments.

Example 1

[0075] A QLED device with high light extraction efficiency, whose structure is shown in FIG. 1, includes an anode, a hole injection layer, a hole transport layer, a quantum dot light emitting layer, an electron transport layer, and a cathode from bottom to top. A nanopillar array composed of several nanopillars is provided on the surface of the anode near the hole injection layer, and the hole injection layer material is filled in the gap between the nanopillars; in the nanopillar array, the diameter of the nanopillar is X / (4x _ni ), and the distance between any two adjacent nano-pillars is X/ (4xn ₂ ); where, X is the center wavelength of the output light of the quantum dot light-emitting diode, and is the refraction of the nano-pillars Ratio, n ₂ is the refractive index of the hole injection layer material, and n #n ₂ .

[0076] The manufacturing method of the device includes the following steps:

[0077] S11: preparing an ITO electrode (ie, an anode) on a transparent substrate, which may be a rigid or flexible substrate. The preparation method of the ITO electrode can be prepared by traditional sputtering, evaporation and other methods.

[0078] S12: preparing a single layer periodic order PS nanosphere mask on the surface of the ITO layer. Based on the PS nanosphere suspension (the solvent can be deionized water or ethanol), a single-layer PS nanosphere thin film was prepared on the ITO surface by self-organizing method, spin coating method, etc. (as shown in Figure 3 and Figure 4).

[0079] Among them, the diameter of the PS nanospheres may be 50 to 2000 nm, and the prepared PS nanosphere deionized water/ethanol mixed liquid has a mass percentage of 0.1 to 10%. Using PS nanospheres of the same size, a single-layer periodic ordered PS nanosphere thin film with hexagonal close-packed structure can be obtained.

[0080] RIE etching to reduce the size of the PS nanospheres and increase the gap between the PS nanospheres (as shown in FIG. 5); wherein, the etching atmosphere may be a single oxygen/carbon tetrafluoride/ Mixed gas flow, the flow rate can be 1~200 seem, the etching power can be 0.1~100W, and the etching time can be l~500s.

[0081] S13: Preparation of nano-pillar array by solution method: selection can react with ITO but no corrosion of PS nanospheres or The ITO etching solution with weak corrosion effect etches the ITO layer covered with the PS nanosphere mask. Due to the blocking effect of the PS nanosphere mask, the ITO etching solution can react and etch the ITO without covering the PS nanospheres. (As shown in Figure 6); After the etching is completed, the residual PS nanospheres are removed by a solution method, a cauterization method, etc., to obtain a nanopillar array with the same period and size as the PS nanosphere mask plate (as shown in Figures 7 and 8) Shown).

[0082] Wherein, the ITO etching solution may be a single/mixed acid solution of hydrofluoric acid, nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, etc., its concentration may be 0.1-20%, and the etching temperature may be 20-100 °C, the etching time can be ls~5 h. In the acid solution, inorganic salts such as ferric chloride and ferrous chloride, and solvents such as acetone can be added to adjust the etching effect.

[0083] S14: On the ITO electrode having the above nanopillar array, a hole injection layer and a hole transport layer are sequentially prepared

, Quantum dot light-emitting layer, electron transport layer, metal electrode (ie cathode), so as to obtain a complete QLED device as shown in Figure 1.

[0084] The above are only optional embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, this application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of this application shall be included in the scope of the claims of this application.

Claims

[Claim 1] A quantum dot light emitting diode, comprising a bottom electrode, a top electrode, and a quantum dot light emitting layer disposed between the bottom electrode and the top electrode, the quantum dot light emitting diode being a bottom emission type quantum dot A light-emitting diode, characterized in that, a surface of the bottom electrode near the quantum dot light-emitting layer is provided with a nano-pillar array composed of several nano-pillars; in the nano-pillar array, the diameter of the nano-pillar is X/ (4x _ni ), and the distance between any two adjacent nanopillars is X/ (4xn ₂ ); where, X is the center wavelength of the output light of the quantum dot light emitting diode, ni is the refractive index of the nanopillar, n ₂ is the refractive index of the filling material between the nanopillars,

[Claim 2] The quantum dot light emitting diode according to claim 1, wherein a backfill layer is provided on the surface of the nanopillar array, and the material of the backfill layer is that the filling material is filled in two adjacent nanopillars Between, the refractive index of the nanopillar and the refractive index of the backfill layer are not equal.

[Claim 3] The quantum dot light emitting diode according to claim 2, wherein the bottom electrode is an anode, the top electrode is a cathode, and the backfill layer and the quantum dot light emitting layer are provided between Hole function layer.

[Claim 4] The quantum dot light emitting diode according to claim 2, wherein the bottom electrode is an anode, the top electrode is a cathode, and a light emitting layer between the top electrode and the quantum dot is provided Electronic functional layer.

[Claim 5] The quantum dot light emitting diode according to claim 2, wherein the bottom electrode is a cathode, the top electrode is an anode, and the backfill layer and the quantum dot light emitting layer are provided between Electronic function layer

[Claim 6] The quantum dot light emitting diode according to claim 2, wherein the bottom electrode is a cathode, the top electrode is an anode, and the top electrode and the quantum dot light emitting layer are provided between Hole function layer.

[Claim 7] The quantum dot light-emitting diode according to claim 1, wherein the bottom electrode is a cathode, the top electrode is an anode, and an electron functional layer is provided on the surface of the nanopillar array, the electrons The material of the functional layer is that the filling material is filled between two adjacent nano-pillars, and the refractive index of the electronic functional layer is not equal to the refractive index of the nano-pillars.

[Claim 8] The quantum dot light-emitting diode according to claim 7, wherein the electron functional layer is an electron injection layer.

[Claim 9] The quantum dot light emitting diode according to claim 7, wherein a hole function layer is provided between the top electrode and the quantum dot light emitting layer.

[Claim 10] The quantum dot light emitting diode according to claim 1, wherein the bottom electrode is an anode, the top electrode is a cathode, and a hole function layer is provided on the surface of the nanopillar array, The material of the hole functional layer is that the filling material is filled between two adjacent nano-pillars, and the refractive index of the hole functional layer is not equal to the refractive index of the nano-pillars.

[Claim 11] The quantum dot light-emitting diode according to claim 10, wherein the hole functional layer is a hole injection layer.

[Claim 12] The quantum dot light emitting diode according to claim 10, wherein an electronic functional layer is provided between the top electrode and the quantum dot light emitting layer.

[Claim 13] A method for preparing a quantum dot light emitting diode, characterized in that it comprises the following steps: providing a bottom electrode;

Preparing a nanopillar array on the surface of the bottom electrode;

In the nanopillar array, the diameter of the nanopillar is X/ (4x _ni ) and the distance between any two adjacent nanopillars is X/ (4xn ₂ ); wherein, X is the quantum dot light emission The center wavelength of the output light of the diode,

Is the refractive index of the material of the nanopillars, n ₂ is the refractive index of the filling material between the nanopillars,

[Claim 14] The preparation method according to Claim 13, wherein the step of preparing a nano-pillar array on the surface of the bottom electrode comprises:

Depositing a PS nanosphere solution on the surface of the bottom electrode to obtain a single-layer PS nanosphere thin film; the diameter of the PS nanospheres in the PS nanosphere solution is the same;

Etching the single-layer PS nanosphere film to reduce the size of the PS nanosphere diameter to obtain a single-layer PS nanosphere film with a reduced diameter of the PS nanosphere; a single-layer PS with the reduced diameter of the PS nanosphere The nanosphere film is a mask plate, the bottom electrode is etched, and then the PS nanospheres are removed, and a nanopillar array composed of the same nanopillars is formed on the surface of the bottom electrode.

[Claim 15] The preparation method according to claim 14, wherein the diameter of the PS nanosphere in the PS nanosphere solution is 50-2000 nm.

[Claim 16] The preparation method according to claim 14, wherein the mass percentage of the PS nanospheres in the PS nanosphere solution is 0.1-10%.

[Claim 17] The preparation method according to claim 14, characterized in that the bottom electrode is etched using an etching solution using a single-layer PS nanosphere thin film with a reduced diameter of the PS nanosphere as a mask plate Etching treatment; wherein, the etching solution is selected from at least one of hydrofluoric acid solution, nitric acid solution, phosphoric acid solution, sulfuric acid solution, hydrochloric acid solution and acetic acid solution.

[Claim 18] The preparation method according to claim 17, wherein the temperature at which the bottom electrode is etched using an etching solution is 20-100°C.

[Claim 19] The preparation method according to claim 17, characterized in that the etching electrode is used to etch the bottom electrode for ls-5h.

[Claim 20] The preparation method according to claim 17, wherein the etching solution contains at least one of ferric chloride, ferrous chloride, and acetone.