WO2022267432A1

WO2022267432A1 - Quantum dot light-emitting diode and preparation method therefor, and display screen

Info

Publication number: WO2022267432A1
Application number: PCT/CN2021/143637
Authority: WO
Inventors: 周娟
Original assignee: Tcl科技集团股份有限公司
Priority date: 2021-06-24
Filing date: 2021-12-31
Publication date: 2022-12-29
Also published as: CN115528183A

Abstract

Disclosed in the present application are a quantum dot light-emitting diode and a preparation method therefor, and a display screen. The quantum dot light-emitting diode comprises an electrode layer, an electron transport layer and a quantum dot layer that are arranged in sequence. The quantum dot light-emitting diode further comprises a first functional layer, which is arranged between the electrode layer and the electron transport layer; and/or a second functional layer, which is arranged between the electron transport layer and the quantum dot layer, wherein the first functional layer and/or the second functional layer are/is at least made of an MXene material having the general formula of Mn+1XnTx.

Description

A quantum dot light-emitting diode and its preparation method and display screen

technical field

The present application relates to the field of display technology, in particular to a quantum dot light-emitting diode, a preparation method thereof, and a display screen.

Background technique

Quantum dot light emitting diodes (Quantum Dot Light Emitting Diodes, QLED) have a narrow half-peak width (full width at half maxima, FWHM), color tunable, and solution-based preparation make it a candidate for next-generation display technology. Therefore, different researchers study QLEDs from different angles, including research on quantum dot layer, hole transport layer, electron transport layer and electrodes; as well as research on the structure, performance and stability of the device, making the device's Performance is gradually improving.

At present, the electron transport layer of QLED prepared by the full solution method mainly uses ZnO nanomaterials as the electron transport layer. ZnO has high carrier mobility and a deep valence band position. The study found that because the rate of exciton recombination in the quantum dot layer in the device is much higher than the rate of exciton generation in electroluminescence, it can be clarified that the excited state lifetime of quantum dots is only nanoseconds, which is much shorter than that of carrier injection in electroluminescence. The time required, the supply of electrons and holes in the device operation are far from meeting the requirements of high-quality QLEDs. Therefore, in order to further improve the performance of the device, it is necessary to properly enhance the carrier injection capability. For this reason, it is necessary to perform some interface treatment between the quantum dot layer, the electron transport layer and the electrodes.

technical problem

The application provides a quantum dot light-emitting diode, its preparation method and a display screen, which can speed up the injection of electrons in the quantum dot light-emitting diode and improve the external quantum efficiency of the quantum dot light-emitting diode.

technical solution

The application provides a quantum dot light-emitting diode. The quantum dot light-emitting diode includes an electrode layer, an electron transport layer, and a quantum dot layer arranged in sequence. The quantum dot light-emitting diode also includes: a first functional layer disposed between the electrode layer and the electron transport layer. and/or, the second functional layer is located between the electron transport layer and the quantum dot layer; the first functional layer and/or the second functional layer are at least made of MXene material with general formula M _n+1 X _n T _x Form, wherein, M is a transition metal element, X is at least one of C or N, T is a terminal functional group, T is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x 1 or 2; MXene material is a two-dimensional transition metal carbide and nitride material with high conductivity and optical transparency.

Optionally, in some embodiments of the present application, one surface of the first functional layer is in contact with the electrode layer, and the other surface is in contact with the electron transport layer; one surface of the second functional layer is in contact with the electron transport layer, and Its other surface is in contact with the quantum dot layer.

Optionally, in some embodiments of the present application, the transition metal element is at least one of Ti, Sc, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, W; and/or, the terminal function The group is at least one of -OH, =O, -F.

Optionally, in some embodiments of the present application, the MXene material is Ti ₂ CT, Ti ₂ CT ₂ , Ti ₃ C ₂ T, Ti ₃ C ₂ T ₂ , Ti ₃ CNT, Ti ₃ CNT ₂ , V ₂ CT , V ₂ CT ₂ , TiNbCT or TiNbCT ₂ at least one.

In some embodiments of the present application, the MXene material is Ti ₂ CT, Ti ₂ CT ₂ , Ti ₃ C ₂ T, Ti ₃ C ₂ T ₂ , Ti ₃ CNT, Ti ₃ CNT ₂ , V ₂ CT, V ₂ CT _2. The electrical conductivity of the prepared film is above 1000 S cm ^-1 , which greatly accelerates the injection of electrons and ensures the supply of electron transport terminals.

Since the MXene material in the first functional layer has metal-like conductivity and high electron mobility, the injection of electrons in the quantum dot light-emitting diode can be accelerated; by adjusting the terminal functional group T, the band gap of the MXene material can be changed to change its conductivity. Moreover, by adjusting the type and composition of the M metal, the conductivity of the MXene material can also be adjusted; at the same time, since the visible light transmittance of the single-layer MXene material reaches 97%, it can effectively improve the external quantum dot efficiency of the quantum dot light-emitting diode, effectively Improving device performance of quantum dot light-emitting diodes.

The second functional layer, due to the tunability of the work function of the MXene material in the range of 2.14eV to 5.65eV, can reduce the separation of excitons in the quantum dot layer. On the other hand, using the metal-like properties of MXene materials and the characteristics of large electron mobility can accelerate the injection of electrons in quantum dot light-emitting diodes.

Optionally, in some embodiments of the present application, the material of the electron transport layer is ZnO nano material. ZnO has high carrier mobility and deep valence band position.

Optionally, in some embodiments of the present application, the thickness of the electron transport layer may be 30-60 nm, or 40-50 nm, or 45 nm.

Optionally, in some embodiments of the present application, the electrode layer may use common cathode materials in the field, including but not limited to metallic silver or metallic aluminum.

Optionally, in some embodiments of the present application, the thickness of the electrode layer may be 10-100 nm, the thickness of the electrode layer may also be 30-80 nm, and the thickness of the electrode layer may also be 50-60 nm.

Optionally, in some embodiments of the present application, the thickness of the quantum dot layer can be 10-100 nm, the thickness of the quantum dot layer can also be 30-80 nm, and the thickness of the quantum dot layer can also be 50-60 nm.

Optionally, in some embodiments of the present application, the quantum dot light emitting diode further includes a hole transport layer, a hole injection layer and an anode layer (for example, an indium tin oxide layer) arranged in order from top to bottom. Wherein, the hole injection layer is formed on the upper surface of the indium tin oxide layer, and the hole transport layer is formed on the upper surface of the hole injection layer.

Correspondingly, the present application also provides a display screen, which includes the above quantum dot light emitting diode.

In addition, the present application also provides a method for preparing a quantum dot light-emitting diode, including: providing a first functional layer configured to be located between the electrode layer and the electron transport layer; and/or providing a second functional layer , the second functional layer is configured to be located between the quantum dot layer and the electron transport layer; one surface of the first functional layer is in contact with the electrode layer, and the other surface thereof is in contact with the electron transport layer; one surface of the second functional layer is in contact with the electron transport layer. The electron transport layer is in contact, and its other surface is in contact with the quantum dot layer. The first functional layer and/or the second functional layer are at least formed of an MXene material with a general formula of _Mn ₊ _1XnTx , wherein M is a transition metal element, and X is at least one of C or N. T is a terminal functional group, T is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2.

Optionally, in some embodiments of the present application, the method further includes: sequentially forming an anode layer, a hole injection layer, a hole transport layer, the quantum dot layer, the electron transport layer and the electrode layer.

Optionally, in some embodiments of the present application, the method includes the following steps:

1) In a positive bottom emission spin-coating device, a hole injection layer is spin-coated on the anode layer;

2) Spin-coat the hole transport layer on the hole injection layer;

3) Spin-coat the quantum dot layer on the hole transport layer;

4) Spin-coat the electron transport layer on the quantum dot layer;

5) spin coating the first functional layer on the electron transport layer;

6) Evaporate electrodes and complete packaging.

2) Spin-coat the hole transport layer on the hole injection layer;

3) Spin-coat the quantum dot layer on the hole transport layer;

4) spin coating the second functional layer on the quantum dot layer;

5) Spin-coat the electron transport layer on the second functional layer;

6) Evaporate electrodes and complete packaging.

1) In positive bottom emission spin-coated devices, a hole injection layer is spin-coated on the anode layer;

2) Spin-coat the hole transport layer on the hole injection layer;

3) Spin-coat the quantum dot layer on the hole transport layer;

4) spin coating the second functional layer on the quantum dot layer;

5) Spin-coat the electron transport layer on the second functional layer;

6) spin coating the first functional layer on the electron transport layer;

7) Evaporate electrodes and complete the package.

1) Evaporate electrodes on the substrate in an inverted bottom-emitting spin-coating device;

2) Spin coating the first functional layer on the electrode layer;

3) spin-coating the electron transport layer on the first functional layer;

4) Spin-coat the quantum dot layer on the electron transport layer;

5) Spin-coat the hole transport layer on the quantum dot layer;

6) Spin-coat the hole injection layer on the hole transport layer;

7) An anode layer is formed on the hole injection layer.

2) Spin-coat the electron transport layer on the electrode layer;

3) spin coating the second functional layer on the electron transport layer;

4) spin coating the quantum dot layer on the second functional layer;

5) Spin-coat the hole transport layer on the quantum dot layer;

6) Spin-coat the hole injection layer on the hole transport layer;

7) An anode layer is formed on the hole injection layer.

2) Spin coating the first functional layer on the electrode layer;

3) spin-coating the electron transport layer on the first functional layer;

4) spin coating the second functional layer on the electron transport layer;

5) spin coating the quantum dot layer on the second functional layer;

6) Spin-coat the hole transport layer on the quantum dot layer;

7) Spin-coat the hole injection layer on the hole transport layer;

8) An anode layer is formed on the hole injection layer.

Optionally, in some embodiments of the present application, the first functional layer and/or the second functional layer are at least formed of MXene material, and the concentration of MXene material can be 5~15 mg/mL, or 7~13 mg/mL It can also be 10 mg/mL.

Beneficial effect

This application adopts quantum dot light-emitting diodes based on MXene materials, and inserts the first functional layer and/or the second functional layer between the quantum dot layer, the electron transport layer and the electrode, which has the following beneficial effects:

(1) Effectively improve electron injection ability: Since MXene materials have hydroxyl groups or terminal oxygen on the surface, they have metal-like conductivity, and the conductivity of MXene can be changed by adjusting the type and composition of M metals.

(2) The transmittance of the single-layer MXene material to visible light reaches 97%, which can effectively improve the external quantum dot efficiency of quantum dot light-emitting diodes and effectively improve the device performance of quantum dot light-emitting diodes.

(3) Avoiding the influence of exciton separation between the electron transport layer and the underlying quantum dot layer: At present, the electron transport layer of the quantum dot light-emitting diode prepared by the full solution method mainly uses ZnO nanomaterials as the electron transport layer, and ZnO has a high current-carrying layer. submobility, and deeper valence band positions. ZnO is the same as other metal oxides. Due to the lower conduction band position of ZnO, the excitons in the quantum dots will be separated at the interface between ZnO and the quantum dot layer, resulting in fluorescence quenching, resulting in a decrease in the working efficiency of quantum dot light-emitting diodes. question. Since the work function of the MXene material is adjustable in the range of 2.14 eV to 5.65 eV, MXene with a more suitable work function can be prepared by adjusting the metal type and composition of the MXene material, and it is spin-coated between the quantum dots and the electron transport layer After forming a thin film, the separation of excitons in the quantum dot layer can be reduced, thereby improving the working efficiency of the quantum dot light-emitting diode.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the structure diagram of the quantum dot light-emitting diode prepared by embodiment one;

Fig. 2 is the structural diagram of the quantum dot light-emitting diode prepared in embodiment two;

Fig. 3 is the structural diagram of the quantum dot light-emitting diode prepared in embodiment three;

Fig. 4 is the flow chart of the preparation method of the quantum dot light-emitting diode of embodiment one;

Fig. 5 is the flow chart of the preparation method of the quantum dot light-emitting diode of embodiment two;

Fig. 6 is a flowchart of the preparation method of the quantum dot light-emitting diode of the third embodiment.

Embodiments of the present invention

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of this application.

The application provides a quantum dot light-emitting diode, a preparation method thereof, and a display screen. Each will be described in detail below. It should be noted that the description sequence of the following embodiments is not intended to limit the preferred sequence of the embodiments.

Embodiment one,

As shown in Figure 4, the method for preparing a quantum dot light-emitting diode in this embodiment includes the following steps, and the prepared quantum dot light-emitting diode is shown in Figure 1:

(1) In a positive bottom-emitting spin-coated device, a hole injection layer 2 is spin-coated on the anode layer (indium tin oxide layer) 1;

(2) spin coating the hole transport layer 3 on the hole injection layer 2;

(3) spin coating the quantum dot layer 4 on the hole transport layer 3;

(4) spin coating the electron transport layer 5 on the quantum dot layer 4;

(5) Spin-coat the first functional layer 6 on the electron transport layer 5; the first functional layer 6 is formed of MXene material. The MXene material in this example is Ti ₃ C ₂ T ₂ , and the concentration of the MXene material is 10 mg/mL. The speed is 5000rpm, and the time is 30s;

(6) Metal Ag cathode layer 7 is vapor-deposited, and finally the packaging is completed.

In step (5), MXene materials can be prepared by the following methods:

(1) Add 4.8g LiF to 60mL 9mol/L HCl solution to obtain an etching solution;

(2) Weigh 3g of Ti ₃ AlC ₂ Max phase powder, add it to the above etching solution at 35°C for 24 hours, and centrifuge at 3500rpm for 5min to obtain the acidic product dispersion;

(3) Thoroughly wash the acidic product dispersion obtained in step 2) with deionized water, after washing, the pH>5, and finally dissolve the flaky Ti ₃ C ₂ T ₂ in ethanol.

The final product Ti ₃ C ₂ T ₂ has terminal functional groups (Terminal, T) including -F and -OH.

In the quantum dot light-emitting diode prepared in this embodiment, a first functional layer is inserted between the electrode layer and the electron transport layer. By changing the metal type and composition in MXene, the conductivity of the first functional layer can be easily adjusted. In addition, By adjusting the terminal functional group T, the band gap of the MXene material can be changed to change its conductivity. For example, the band gap widths of Ti ₃ C ₂ with -OH and -F as terminal groups are 0.05eV and 0.1eV respectively, so Has metal-like properties. At the same time, since the transmittance of single-layer MXene to visible light reaches 97%, it can effectively improve the external quantum dot efficiency of quantum dot light-emitting diodes, and effectively improve the device performance of quantum dot light-emitting diodes.

The structure of the quantum dot light-emitting diode prepared in this embodiment is shown in Figure 1, which includes an anode layer 1, a hole injection layer 2, a hole transport layer 3, a quantum dot layer 4, an electron transport layer 5, and a first functional layer from bottom to top. Layer 6, cathode layer 7.

Embodiment two,

As shown in Figure 5, the method for preparing a quantum dot light-emitting diode in this embodiment includes the following steps, and the prepared quantum dot light-emitting diode is shown in Figure 2:

(2) spin coating the hole transport layer 3 on the hole injection layer 2;

(3) spin coating the quantum dot layer 4 on the hole transport layer 3;

(4) The second functional layer 8 is spin-coated on the quantum dot layer 4; the second functional layer 8 is formed of MXene material, and V ₂ CT ₂ is selected as the MXene material in this embodiment. The concentration of MXene material is 10mg/mL, the spin coating speed is 5000rpm, and the time is 30s;

(5) The electron transport layer 5 is spin-coated on the second functional layer 8; the electron transport layer is made of ZnO nanometer material.

In step (4), MXene materials can be prepared by the following methods:

(1) Add 4.8g LiF to 60mL 9mol/L HCl solution to obtain an etching solution;

(2) Weigh 3g of V ₂ AlC Max phase powder, add it to the above etching solution at 35°C for 24 hours, and centrifuge at 3500rpm for 5min to obtain the acidic product dispersion;

(3) Thoroughly wash the acidic product dispersion obtained in step 2) with deionized water, after washing, the pH>5, and finally dissolve the flaky V ₂ CT ₂ in ethanol.

The final product V ₂ CT ₂ has terminal functional groups (Terminal, T) including -F and -OH.

Using ZnO nanomaterials as the electron transport layer, ZnO has high carrier mobility and deep valence band position. ZnO is the same as other metal oxides. Due to the lower conduction band position of ZnO, the excitons in the quantum dots will be separated at the interface between ZnO and the quantum dot layer, resulting in fluorescence quenching, resulting in a decrease in the working efficiency of quantum dot light-emitting diodes. question.

In the quantum dot light-emitting diode prepared in this example, the second functional layer is inserted between the electron transport layer and the quantum dot layer. The separation of excitons in the quantum dot layer; on the other hand, the use of MXene metals, which have a large electron mobility, can speed up the injection of electrons in quantum dot light-emitting diodes.

The structure of the quantum dot light-emitting diode prepared in this embodiment is shown in Figure 2, which includes an anode layer 1, a hole injection layer 2, a hole transport layer 3, a quantum dot layer 4, a second functional layer 8, an electron transport layer from bottom to top. Layer 5, cathode layer 7.

Embodiment three,

As shown in Figure 6, the method for preparing a quantum dot light-emitting diode in this embodiment includes the following steps, and the prepared quantum dot light-emitting diode is shown in Figure 3:

(2) spin coating the hole transport layer 3 on the hole injection layer 2;

(3) spin coating the quantum dot layer 4 on the hole transport layer 3;

(4) The second functional layer 8 is spin-coated on the quantum dot layer 4; the second functional layer 8 is formed of MXene material, and Ti ₂ CT ₂ is selected as the MXene material in this embodiment. The concentration of MXene material is 10mg/mL, the spin coating speed is 5000rpm, and the time is 30s;

(5) Spin-coat the electron transport layer 5 on the second functional layer 8; the electron transport layer 5 uses ZnO nanomaterials;

(6) The first functional layer 6 is spin-coated on the electron transport layer 5; the first functional layer 6 is formed of MXene material, and Ti ₂ CT ₂ is selected as the MXene material in this embodiment. The concentration of MXene material is 10mg/mL, the spin coating speed is 5000rpm, and the time is 30s;

(7) The metallic Ag cathode layer 7 is evaporated, and finally the packaging is completed.

In step (4) and step (6), MXene materials can be prepared by the following methods:

(1) Add 4.8g LiF to 60mL 9mol/L HCl solution to obtain an etching solution;

(2) Weigh 3g of Ti ₂ AlC Max phase powder, add it to the above etching solution at 35°C for 24 hours, and centrifuge at 3500rpm for 5min to obtain the acidic product dispersion;

(3) Thoroughly wash the acidic product dispersion obtained in step 2) with deionized water, after washing, the pH>5, and finally dissolve the flaky Ti ₂ CT ₂ in ethanol.

The final product Ti ₂ CT ₂ has terminal functional groups (Terminal, T) including -F and -OH.

In this embodiment, the first functional layer and the second functional layer are used to prepare a sandwich structure, which can further enhance the injection of electrons, and at the same time ensure that the problem of exciton separation between the quantum dot layer and the electron transport layer is weakened.

The structure of the quantum dot light-emitting diode prepared in this embodiment is shown in Figure 3, which includes an anode layer 1, a hole injection layer 2, a hole transport layer 3, a quantum dot layer 4, a second functional layer 8, an electron transport layer from bottom to top Layer 5, first functional layer 6, cathode layer 7.

Embodiment four,

The method for preparing quantum dot light-emitting diodes in this embodiment includes the following steps:

(1) In an inverted bottom emission spin-coating device, a metal Ag electrode layer is evaporated on the substrate;

(2) The first functional layer is spin-coated on the electrode layer; the first functional layer is formed of MXene material, and the MXene material of this embodiment is Ti ₃ CNT ₂ . The concentration of MXene material is 10mg/ml, the spin coating speed is 5000rpm, and the time is 30s;

(3) Spin-coat an electron transport layer on the first functional layer; the electron transport layer uses ZnO nanomaterials;

(4) The second functional layer is spin-coated on the electron transport layer; the second functional layer is formed of MXene material, and the MXene material of this embodiment is Ti ₃ CNT ₂ . The concentration of MXene material is 10mg/ml, the spin coating speed is 5000rpm, and the time is 30s;

(5) spin coating the quantum dot layer on the second functional layer;

(6) Spin-coat the hole transport layer on the quantum dot layer;

(7) Spin-coat the hole injection layer on the hole transport layer;

(8) Forming an indium tin oxide layer on the hole transport layer.

In step (2) and step (4), MXene materials can be prepared by the following methods:

(1) Add 4.8g LiF to 60mL 9mol/L HCl solution to obtain an etching solution;

(2) Weigh 3g of Ti ₃ AlCN Max phase powder, add it to the above etching solution at 35°C for 24 hours, and centrifuge at 3500rpm for 5min to obtain an acidic product dispersion;

(3) Thoroughly wash the acidic product dispersion obtained in step 2) with deionized water, after washing, the pH>5, and finally dissolve the flaky Ti ₃ CNT ₂ in ethanol.

The final product Ti ₃ CNT ₂ has terminal functional groups (Terminal, T) including -F and -OH.

The quantum dot light-emitting diode structure prepared in this embodiment includes an electrode layer, a first functional layer, an electron transport layer, a second functional layer, a quantum dot layer, a hole transport layer, a hole injection layer, and an indium tin oxide layer from bottom to top. Floor.

A quantum dot light-emitting diode provided in the embodiments of the present application and its preparation method and display screen have been introduced in detail above. In this paper, specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only It is used to help understand the method and its core idea of this application; at the same time, for those skilled in the art, according to the idea of this application, there will be changes in the specific implementation and application scope. In summary, this specification The content should not be construed as a limitation of the application.

Claims

A quantum dot light emitting diode, comprising an electrode layer, an electron transport layer and a quantum dot layer arranged in sequence, wherein the quantum dot light emitting diode further comprises:

a first functional layer disposed between the electrode layer and the electron transport layer;

The first functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , and T is a terminal functional group, T is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2.
The quantum dot light emitting diode according to claim 1, wherein one surface of the first functional layer is in contact with the electrode layer, and the other surface of the first functional layer is in contact with the electron transport layer.
The quantum dot light-emitting diode according to claim 1, wherein the transition metal element is at least one of Ti, Sc, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, W.
The quantum dot light-emitting diode according to claim 1, wherein the terminal functional group is at least one of -OH, =O, -F.
The quantum dot light-emitting diode according to claim 3, wherein the MXene material is Ti 2 CT, Ti 2 CT 2 , Ti 3 C 2 T, Ti 3 C 2 T 2 , Ti 3 CNT, Ti 3 CNT 2 , At least one of V 2 CT, V 2 CT 2 , TiNbCT or TiNbCT 2 .
The quantum dot light emitting diode according to claim 1, wherein the material of the electron transport layer is ZnO nano material.
The quantum dot light-emitting diode according to claim 1, wherein the thickness of the electron transport layer is 30-60 nm.
The quantum dot light emitting diode according to claim 1, wherein the electrode layer is a cathode layer.
The quantum dot light-emitting diode according to claim 1, wherein the thickness of the electrode layer is 10-100 nm.
The quantum dot light-emitting diode according to claim 1, wherein the thickness of the quantum dot layer is 10-100 nm.
The quantum dot light-emitting diode according to claim 1, wherein the concentration of the MXene material is 5-15 mg/mL.
The quantum dot light emitting diode according to claim 1, wherein the quantum dot light emitting diode further comprises a hole transport layer, a hole injection layer and an anode layer arranged in sequence.
A quantum dot light emitting diode, comprising an electrode layer, an electron transport layer and a quantum dot layer arranged in sequence, wherein the quantum dot light emitting diode further comprises:

The second functional layer is located between the electron transport layer and the quantum dot layer;

The second functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , and T is a terminal functional group, T is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2.
The quantum dot light emitting diode according to claim 13, wherein the quantum dot light emitting diode further comprises:

a first functional layer disposed between the electrode layer and the electron transport layer;

The first functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , and T is a terminal functional group, T is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2.
The quantum dot light-emitting diode according to claim 13, wherein the concentration of the MXene material is 5-15 mg/mL.
The quantum dot light emitting diode according to claim 13, wherein one surface of the second functional layer is in contact with the electron transport layer, and the other surface of the second functional layer is in contact with the quantum dot layer.
A display screen, wherein the display screen comprises the quantum dot light emitting diode according to claim 1.
A method for preparing a quantum dot light-emitting diode, wherein the method includes:

providing a first functional layer configured to be located between the electrode layer and the electron transport layer;

The first functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , T is a terminal functional group, and T It is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2; the concentration of the MXene material is 5 to 15 mg/mL.
A method for preparing a quantum dot light-emitting diode, wherein the method includes:

providing a second functional layer, the first functional layer configured to be located between the quantum dot layer and the electron transport layer;

The second functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , T is a terminal functional group, and T It is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2; the concentration of the MXene material is 5 to 15 mg/mL.
A method for preparing a quantum dot light-emitting diode, wherein the method includes:

providing a first functional layer configured to be located between the electrode layer and the electron transport layer;

providing a second functional layer configured to be located between the quantum dot layer and the electron transport layer;

The first functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , T is a terminal functional group, and T It is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2;

The second functional layer is at least formed of an MXene material with a general formula of Mn + 1XnTx, wherein M is a transition metal element, X is at least one of C or N , T is a terminal functional group, and T It is connected to M in the form of a covalent bond, n is an integer between 1 and 4, and x is 1 or 2.