WO2022121802A1 - Composite nanoparticle, quantum dot light-emitting diode, and preparation method - Google Patents

Abstract

The present disclosure relates to a composite nanoparticle, a quantum dot light-emitting diode, and a preparation method. The composite nanoparticle comprises an oxide nanoparticle containing hydroxyl groups on the surface and a phosphorus-oxygen double bond-contained passivator, and the hydroxyl group on the surface of the oxide nanoparticle forms a hydrogen bond with the phosphorus-oxygen double bond in the passivator.

Description

Composite nanoparticle, quantum dot light-emitting diode and preparation method

priority

The present disclosure claims the priority of a Chinese patent application with an application date of December 8, 2020, an application number of "202011423461.1", and an application title of "Composite Nanoparticles, Quantum Dot Light Emitting Diodes, and Preparation Methods", the entire contents of which are incorporated by reference in this disclosure.

technical field

The present disclosure relates to the field of quantum dots, and in particular, to composite nanoparticles, quantum dot light-emitting diodes and preparation methods.

Background technique

Because quantum dots have the advantages of high light color purity, high luminescence quantum efficiency, tunable luminescence color, and high quantum yield, and can be prepared by printing process, quantum dot-based light emitting diodes (QLEDs) have received widespread attention. Its device performance indicators are also developing rapidly. In QLED devices, N-type oxide nanoparticles are widely used as electron transport layer materials for electroluminescent devices because of their advantages of high transmittance, high electron mobility, low cost, environmental compatibility and simple preparation process. The efficiency of the device is greatly improved, but the problem of the short service life of the device still cannot be solved. Because there are a large number of hydroxyl groups on the surface of most N-type oxide nanoparticles, these hydroxyl groups are easily oxidized under the influence of long-term electrification conditions and the surrounding environment to generate highly oxidative OH radicals, active OH radicals Many organic compounds can be oxidized, resulting in the shedding of ligands on the surface of quantum dots, the increase in surface defects of oxide nanoparticles, and the increase in carrier transport barrier, which seriously reduces the service life of QLED devices.

Therefore, the traditional technology still needs to be improved and developed.

public content

In view of the deficiencies of the above-mentioned conventional technologies, the purpose of the present disclosure is to provide a composite nanoparticle, a quantum dot light-emitting diode and a preparation method thereof, aiming at solving the problem of surface defects of oxide nanoparticles.

The technical solutions of the present disclosure are as follows:

A composite nanoparticle, comprising oxide nanoparticles containing hydroxyl groups on the surface and a passivator containing phosphorus-oxygen double bonds, the hydroxyl groups on the surface of the oxide nanoparticles and the phosphorus-oxygen double bonds in the passivator form hydrogen bonds.

In the composite nanoparticle, the passivating agent is triphenylphosphine oxide.

The composite nanoparticles, wherein the passivating agent is a triphenylphosphine oxide derivative, and the triphenylphosphine oxide derivative is

One of them, wherein R ₁ , R ₂ and R ₃ are delocalized and delocalized π-bonded groups; the delocalized and delocalized π-bonded groups are directly connected to the triphenylphosphine oxide, or the A delocalized pi-bond group is attached to the triphenylphosphine oxide through a pi-bond containing group.

The composite nanoparticle, wherein, the delocalized delocalized π bond group is one of a benzene ring or a butylene group; and/or, the group containing a π bond is a vinyl group or One of the acetylene groups.

In the composite nanoparticles, the oxide nanoparticles are one or more of ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZnMgO, ZnAlO and SnInO.

The composite nanoparticles, wherein the composite nanoparticles are ZnO containing hydroxyl groups on the surface and triphenylphosphine oxide forming hydrogen bonds with the hydroxyl groups.

A quantum dot light-emitting diode, comprising an electron transport layer, and the material of the electron transport layer is the composite nanoparticles described in this disclosure.

The quantum dot light-emitting diode further comprises a cathode, an anode and a quantum dot light-emitting layer arranged between the cathode and the anode, and the electron transport layer is arranged between the cathode and the quantum dot light-emitting layer .

The quantum dot light-emitting diode further comprises a hole function layer disposed between the anode and the quantum dot light-emitting layer, wherein the hole function layer is an electron blocking layer, a hole injection layer and a hole one or more of the transport layers.

The quantum dot light-emitting diode, wherein the quantum dot light-emitting layer material is one or more of red light quantum dots, green light quantum dots and blue light quantum dots, the red light quantum dots, green light quantum dots and blue light quantum dots Independently selected from CdS, CdSe, CdTe, InP, AgS, PbS, HgS, ZnCdS, CuInS, ZnCdSe, ZnSeS, ZnCdTe, PbSeS, ZnCdS/ZnSe, CuInS/ZnS, ZnCdSe/ZnS, CuInSeS, ZnCdTe/ZnS, PbSeS/ZnS one or more of.

In the quantum dot light-emitting diode, the anode is ITO, FTO or ZTO.

In the quantum dot light-emitting diode, the cathode is one or more of Au, Ag, Al, Cu, and Mo.

A preparation method of a quantum dot light-emitting diode, comprising the steps of:

provide the substrate;

An electron transport layer is prepared by depositing a composite nanoparticle solution on the substrate, the composite nanoparticle solution including an organic alcohol, and composite nanoparticles as described in the present disclosure dispersed in the organic alcohol.

The preparation method of the quantum dot light-emitting diode, wherein, the step of providing the substrate comprises:

Provide anode substrate;

preparing a hole injection layer on the surface of the anode substrate;

preparing a hole transport layer on the surface of the hole injection layer;

preparing a quantum dot light-emitting layer on the surface of the hole transport layer to form the substrate;

After the step of depositing a composite nanoparticle solution on the substrate to prepare an electron transport layer, the method further includes: preparing a cathode on the surface of the electron transport layer.

The method for preparing a quantum dot light-emitting diode, wherein the step of providing a substrate comprises: providing a cathode substrate to form the substrate;

After the step of depositing a composite nanoparticle solution on the substrate to prepare an electron transport layer, the method further includes:

preparing a quantum dot light-emitting layer on the surface of the electron transport layer;

preparing a hole transport layer on the surface of the quantum dot light-emitting layer;

preparing a hole injection layer on the surface of the hole transport layer;

An anode is prepared on the surface of the hole injection layer.

In the preparation method of the quantum dot light-emitting diode, the mass fraction of the composite nanoparticle solution is 0.1-10%.

In the preparation method of the quantum dot light-emitting diode, the organic alcohol is one of ethanol, propanol or butanol.

In the preparation method of the quantum dot light-emitting diode, the thickness of the electron transport layer is 10-60 nm.

Beneficial effect: In the composite nanoparticles provided by the present disclosure, the phosphorus-oxygen double bond in the passivation agent can easily interact with the hydroxyl groups on the surface of the oxide nanoparticles to form hydrogen bonds, thereby playing a passivation effect on the oxide nanoparticles , reduce its surface defects.

Description of drawings

FIG. 1 is a schematic structural diagram of a preferred embodiment of a positive structure quantum dot light emitting diode disclosed.

FIG. 2 is a schematic structural diagram of a preferred embodiment of an inversion structure quantum dot light emitting diode disclosed.

FIG. 3 is a flow chart of a preferred embodiment of a method for fabricating a quantum dot light-emitting diode with a positive structure disclosed.

FIG. 4 is a flow chart of a preferred embodiment of a method for fabricating a quantum dot light-emitting diode with an inversion structure disclosed.

Detailed ways

The present disclosure provides a composite nanoparticle, a quantum dot light-emitting diode and a preparation method. In order to make the purpose, technical solution and effect of the present disclosure clearer and clearer, the present disclosure will be further described below in detail. It should be understood that the embodiments described herein are only used to explain the present disclosure, but not to limit the present disclosure.

There are a large number of -OH (hydroxyl) on the surface of oxide nanoparticles. These -OH are easily oxidized under the influence of long-term electrification conditions and the surrounding environment to generate highly oxidative OH radicals and active OH radicals. Many organic substances can be oxidized, leading to the shedding of ligands on the surface of quantum dots, the increase of surface defects of oxide nanoparticles, and the increase of carrier transport barrier, which seriously reduces the luminous efficiency and service life of QLED devices.

Based on the problems existing in the prior art, embodiments of the present disclosure provide a nanocomposite particle, which includes oxide nanoparticles containing hydroxyl groups on the surface and a passivator containing phosphorus-oxygen double bonds. The hydroxyl groups form hydrogen bonds with the phosphorus-oxygen double bonds in the passivator.

In this embodiment, the oxygen atom in the phosphorus-oxygen double bond of the passivating agent can interact with the hydroxyl group on the surface of the oxide nanoparticle to form a hydrogen bond, so as to passivate the surface of the oxide nanoparticle and reduce its Surface defects.

In some embodiments, the passivating agent is triphenylphosphine oxide, and its chemical structural formula is

The oxygen atoms in the phosphorus-oxygen double bond of the triphenylphosphine oxide interact with the hydroxyl groups on the surface of the oxide nanoparticles to form hydrogen bonds, so as to passivate the oxide nanoparticles, and the triphenylphosphine oxide The superstructure or the formation of periodic closely-packed interconnected structures can be achieved through π-π conjugated self-assembly, thereby improving the passivation stability of the surface of the oxide nanoparticles, and the oxide nanoparticles can be stably passivated surface, thereby reducing its surface defects more effectively.

In some embodiments, the passivating agent is a triphenylphosphine oxide derivative, and the triphenylphosphine oxide derivative is

One of them, wherein R ₁ , R ₂ and R ₃ are delocalized and delocalized π-bonded groups; the delocalized and delocalized π-bonded groups are directly connected to the triphenylphosphine oxide, or the A delocalized pi-bond group is attached to the triphenylphosphine oxide through a pi-bond containing group.

In this embodiment, the oxygen atom in the phosphorus-oxygen double bond of the triphenylphosphine oxide derivative can interact with the hydroxyl group on the surface of the oxide nanoparticles to form hydrogen bonds, so as to passivate the oxide nanoparticles , and triphenylphosphine oxide derivatives can achieve superstructures or form periodic closely-packed interconnected structures through π–π conjugated self-assembly, thereby improving the passivation stability of the oxide nanoparticle surface. , which can stably passivate the surface of oxide nanoparticles and reduce their surface defects more effectively. When the R ₁ , R ₂ and R ₃ are delocalized π-bonded groups directly connected to the triphenylphosphine oxide, the delocalized π-bonded delocalized π-bonded groups are directly connected to triphenyl On the one hand, phosphine oxide can avoid increasing the steric hindrance effect, so as to avoid weakening the interaction between the phosphorus-oxygen double bond and the hydroxyl group. The π bond forms conjugation, thereby achieving a wider range of conjugation, expanding the conjugation area of triphenylphosphine oxide derivatives, facilitating the formation of periodic closely-packed interconnected structures, thereby improving its passivation N-type oxidation stability of nanoparticles.

In some embodiments, the R ₁ , R ₂ and R ₃ are delocalized π bond delocalized π bond groups, and the delocalized π bond delocalized π bond group is connected to the The triphenylphosphine oxide link. By way of example, a delocalized pi-bonded pi-bonded group is attached to the triphenylphosphine oxide through a vinyl or ethynyl group. The delocalized π-bond delocalized π-bond group in this embodiment can also form conjugation with the π-bond on triphenylphosphine oxide, thereby realizing a wider range of conjugation and expanding triphenylphosphine oxide derivatives The conjugation area is convenient to form periodic close-packed interconnected structures, thereby improving the stability of their passivated N-type oxide nanoparticles.

In some embodiments, the delocalized π-bond delocalized π-bond group is one of a butylene group or a benzene ring, but is not limited thereto. In a molecule composed of multiple atoms, if there are parallel p orbitals, they coherently overlap together to form a whole, and p electrons move between multiple atoms to form a π-type chemical bond. The bond is called delocalized π bond, or conjugated delocalized π bond delocalized π bond, referred to as delocalized π bond delocalized π bond. Delocalized π bond Delocalized π bond is a π bond formed by 3 or more atoms parallel to each other with p orbitals overlapping each other from the side. Taking benzene ring as an example, the molecular structure of benzene ring is that all six carbon atoms are sp2 heterozygous. The p orbitals are combined into a regular hexagon in the same plane, and the remaining p orbitals that are not hybridized on each carbon atom are parallel to the plane formed by the benzene molecule, so all p orbitals can be Overlapping each other; the delocalized π bonds of benzene The delocalized π bonds are evenly distributed on six carbon atoms, so the bond length and bond energy of each carbon-carbon bond in the benzene molecule are equal. Taking 1,3-butadiene as an example, its 4 carbon atoms are adjacent to 3 atoms, so sp hybridization is adopted, and these hybrid orbitals overlap each other to form a molecular σ skeleton, so all atoms are in the same plane; Each carbon atom also has a p orbital that is not involved in hybridization, which is perpendicular to the molecular plane. There is one electron in each p orbital, so there is a p-p delocalized π bond delocalized with "4 orbitals and 4 electrons" in the butadiene molecule. pi key.

In some embodiments, the π bond-containing group is one of a vinyl group or an acetylene group. When the orbital (p orbital) of two atoms approaches from the direction perpendicular to the internuclear connecting line of the bonding atoms, the electron clouds overlap to form a bond, and the covalent bond formed in this way is called a π bond.

In some embodiments, the oxide nanoparticles are N-type oxide nanoparticles. As an example, the N-type oxide nanoparticles are one or more of ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZnMgO, ZnAlO and SnInO, but are not limited thereto.

In some embodiments, the composite nanoparticles are ZnO with hydroxyl groups on the surface and triphenylphosphine oxide hydrogen-bonded with the hydroxyl groups. In this embodiment, the oxygen atoms in the triphenylphosphine oxide interact with the hydroxyl groups on the surface of the N-type oxide nanoparticles to form hydrogen bonds, and the triphenylphosphine oxide molecules are self-assembled through π–π conjugated to achieve ultra-high structure, thereby improving the passivation stability, which can stably passivate the surface of N-type oxide nanoparticles, reduce surface defects, and eliminate the hydroxyl groups suspended on the surface, so as to continuously and effectively exert the electron transport performance of composite nanoparticles.

In some embodiments, a quantum dot light-emitting diode is also provided, which includes an electron transport layer, and the material of the electron transport layer is composite nanoparticles, and the composite nanoparticles include oxide nanoparticles containing hydroxyl groups on the surface and phosphorus oxide nanoparticles A passivating agent for double bonds, the hydroxyl groups on the surface of the oxide nanoparticles form hydrogen bonds with the phosphorus-oxygen double bonds in the passivating agent.

In this embodiment, since the hydroxyl groups on the surface of the oxide nanoparticles in the composite nanoparticles can interact with the oxygen atoms in the phosphorus-oxygen double bond in the passivating agent to form hydrogen bonds, the surface of the oxide nanoparticles can be passivated. It can effectively reduce the surface defects; after the hydroxyl groups on the surface of the oxide nanoparticles participate in the formation of hydrogen bonds, the hanging hydroxyl groups can be prevented from being oxidized under the influence of long-term electrification conditions and the surrounding environment to form highly oxidizing OH radicals, so that the active OH radicals can be prevented from oxidizing organic substances, thereby reducing the shedding of ligands on the surface of quantum dots, and at the same time effectively exerting the electron transport properties of oxide nanoparticles. Therefore, using the composite nanoparticles as the electron transport layer material of the quantum dot light emitting diode can effectively improve the luminous efficiency and service life of the quantum dot light emitting diode.

In some embodiments, a quantum dot light-emitting diode is also provided, which includes an electron transport layer, and the material of the electron transport layer is composite nanoparticles, and the composite nanoparticles include oxide nanoparticles containing hydroxyl groups on the surface and triphenylene For phosphine oxide, the hydroxyl groups on the surface of the oxide nanoparticles form hydrogen bonds with the phosphorus-oxygen double bonds in the triphenylphosphine oxide.

In this embodiment, the oxygen atoms in the phosphorus-oxygen double bond of the triphenylphosphine oxide interact with the hydroxyl groups on the surface of the oxide nanoparticles to form hydrogen bonds, so as to passivate the oxide nanoparticles, and the The triphenylphosphine oxide can realize superstructure or form a periodic closely packed interconnected structure through π-π conjugated self-assembly, thereby improving the passivation stability of the surface of the oxide nanoparticles, which can stabilize Passivate the surface of oxide nanoparticles, thereby reducing their surface defects more effectively. After the surface of the oxide nanoparticles is passivated, the suspended hydroxyl groups can be prevented from being oxidized to generate highly oxidative OH radicals under the influence of long-term electrification conditions and the surrounding environment, so that active OH radicals can be avoided. Oxidize organic matter, thereby reducing the shedding of ligands on the surface of quantum dots, and at the same time effectively exerting the electron transport properties of oxide nanoparticles. Therefore, using the composite nanoparticles as the electron transport layer material of the quantum dot light emitting diode can effectively improve the luminous efficiency and service life of the quantum dot light emitting diode.

In some embodiments, a quantum dot light-emitting diode is also provided, which includes an electron transport layer, and the material of the electron transport layer is composite nanoparticles, and the composite nanoparticles include oxide nanoparticles containing hydroxyl groups on the surface and triphenylene A phosphine oxide derivative, the hydroxyl group on the surface of the oxide nanoparticle forms a hydrogen bond with the phosphorus-oxygen double bond in the triphenylphosphine oxide derivative, the passivating agent is a triphenylphosphine oxide derivative, the Triphenylphosphine oxide derivatives are

One of, wherein, R ₁ , R ₂ and R ₃ are delocalized π bond delocalized π bond groups; the delocalized π bond delocalized π bond group is directly connected to the triphenylphosphine oxide, Alternatively, the delocalized pi-bond group is linked to the triphenylphosphine oxide through a pi-bond-containing group.

In this embodiment, the oxygen atom in the phosphorus-oxygen double bond of the triphenylphosphine oxide derivative can interact with the hydroxyl group on the surface of the oxide nanoparticles to form hydrogen bonds, so as to passivate the oxide nanoparticles , and triphenylphosphine oxide derivatives can realize superstructures or form periodic closely-packed interconnected structures through π–π conjugated self-assembly, thereby improving the passivation stability of the oxide nanoparticle surfaces. , which can stably passivate the surface of oxide nanoparticles and reduce their surface defects more effectively. Further, since the R ₁ , R ₂ and R ₃ are delocalized π bond groups directly connected to the triphenylphosphine oxide, on the one hand, it can avoid increasing the steric hindrance effect, thereby avoiding weakening the phosphorus-oxygen double bond. The interaction with the hydroxyl group, on the other hand, the delocalized π-bonded group can also form conjugation with the π-bond on triphenylphosphine oxide, thereby realizing a wider range of conjugation and expanding the derivatization of triphenylphosphine oxide. The conjugated area of the compound facilitates the formation of periodic close-packed interconnected structures, thereby improving the stability of their passivated N-type oxide nanoparticles. After the surface of the oxide nanoparticles is stably passivated, it can more effectively prevent the hanging hydroxyl groups from being oxidized to generate highly oxidative OH radicals under the influence of long-term power-on conditions and the surrounding environment, so as to avoid active The OH radicals oxidize organic matter, thereby reducing the shedding of ligands on the surface of quantum dots, and at the same time effectively exerting the electron transport properties of oxide nanoparticles. Therefore, using the composite nanoparticles as the material of the electron transport layer of the quantum dot light emitting diode can effectively improve the luminous efficiency and service life of the quantum dot light emitting diode.

In some embodiments, the R ₁ , R ₂ and R ₃ are delocalized pi-bonded groups, and the delocalized pi-bonded groups are linked to the triphenylphosphine oxide through a pi-bond-containing group, By way of example, a delocalized pi-bonded group is attached to the triphenylphosphine oxide through a vinyl group. The delocalized π-bond group in this embodiment can also form conjugation with the π-bond on triphenylphosphine oxide, thereby realizing a wider range of conjugation and expanding the conjugation area of triphenylphosphine oxide derivatives , facilitating the formation of periodic closely-packed interconnected structures, thereby enhancing the stability of their passivated N-type oxide nanoparticles.

In some embodiments, a quantum dot light-emitting diode is provided, which includes an electron transport layer, and the material of the electron transport layer is ZnO containing hydroxyl groups on the surface and triphenylphosphine oxide forming hydrogen bonds with the hydroxyl groups. In this embodiment, the oxygen atoms in the triphenylphosphine oxide interact with the hydroxyl groups on the surface of the N-type oxide nanoparticles to form hydrogen bonds, and the triphenylphosphine oxide molecules are self-assembled through π–π conjugated to achieve ultra-high structure, thereby improving the passivation stability, which can stably passivate the surface of N-type oxide nanoparticles, reduce surface defects, and eliminate the hydroxyl groups suspended on the surface, so as to continuously and effectively exert the electron transport performance of the electron transport layer material.

In some embodiments, a quantum dot light-emitting diode is provided, which includes a cathode, an anode, and a quantum dot light-emitting layer disposed between the cathode and the anode, and an electron transport layer is disposed between the cathode and the quantum dot light-emitting layer , a hole functional layer is arranged between the anode and the quantum dot light-emitting layer, wherein the electron transport layer materials are N-type oxide nanoparticles containing hydroxyl groups on the surface and triphenyl groups that form hydrogen bonds with the hydroxyl groups Phosphine oxide or triphenylphosphine oxide derivatives, the hole functional layer is one or more of an electron blocking layer, a hole injection layer and a hole transport layer, but is not limited thereto.

In some embodiments, a quantum dot light-emitting diode with a positive structure is provided, as shown in FIG. 1 , which includes an anode disposed on the surface of a substrate, a hole injection layer disposed on the surface of the anode, and a hole injection layer disposed on the surface of the anode. A hole transport layer on the surface, a quantum dot light-emitting layer arranged on the surface of the hole transport layer, an electron transport layer arranged on the surface of the quantum dot light-emitting layer, and a cathode arranged on the surface of the electron transport layer, wherein the electron transport layer The materials are N-type oxide nanoparticles containing hydroxyl groups on the surface and triphenylphosphine oxide or triphenylphosphine oxide derivatives that form hydrogen bonds with the hydroxyl groups.

In some embodiments, a quantum dot light-emitting diode with an inversion structure is also provided, as shown in FIG. 2 , which includes a cathode disposed on the surface of the substrate, an electron transport layer disposed on the surface of the cathode, and an electron transport layer disposed on the surface of the electron transport layer. The quantum dot light-emitting layer, the hole transport layer provided on the surface of the quantum dot light-emitting layer, the hole injection layer provided on the surface of the hole transport layer, and the anode provided on the surface of the hole injection layer, wherein the electron transport layer material N-type oxide nanoparticles containing hydroxyl groups on the surface and triphenylphosphine oxide or triphenylphosphine oxide derivatives that form hydrogen bonds with the hydroxyl groups.

In various embodiments of the present disclosure, the materials of each functional layer are common materials in the art, such as:

In some embodiments, the substrate may be a rigid substrate (glass) or a flexible substrate.

In some embodiments, the anode may be ITO, FTO, or ZTO.

In some embodiments, the hole injection layer material may be water-soluble PEDOT:PSS, or may be other materials with good hole injection properties, such as NiO, MoO ₃ , WO ₃ or V ₂ O ₅ .

In some embodiments, the hole injection layer material is PEDOT:PSS, and its thickness is 10-100 nm.

In some embodiments, the hole transport layer material may be commonly used poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine) (TFB), poly(N ,N'bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine)(Poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N -Phenyl-1,4-phenylenediamine) (PFB), 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA), 4,4'-bis(9-carbazole) ) biphenyl (CBP), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), One or more of N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), which can also be Other high-performance hole transport materials, such as MoO ₃ , WoO ₃ , NiO, CuO, V ₂ O ₅ , CuS, etc.

In some embodiments, the hole transport layer has a thickness of 1-100 nm.

In some embodiments, the quantum dot light-emitting layer material may be one or more of common red light quantum dots, green light quantum dots and blue light quantum dots.

In some embodiments, the cathode may be Au, Ag, Al, Cu, Mo, or alloys thereof.

In some embodiments, the cathode has a thickness of 60-120 nm.

In some embodiments, a method for preparing a positive structure quantum dot light-emitting diode is also provided, as shown in FIG. 3 , which includes the steps:

S10, providing an anode substrate, and preparing a hole injection layer on the surface of the anode substrate;

S20, preparing a hole transport layer on the surface of the hole injection layer;

S30, preparing a quantum dot light-emitting layer on the surface of the hole transport layer;

S40, depositing a composite material solution on the surface of the quantum dot light-emitting layer to obtain an electron transport layer, the composite material solution comprising an organic alcohol and N-type oxide nanoparticles containing hydroxyl groups on the surface dispersed in the organic alcohol and The hydroxyl group forms a hydrogen-bonded triphenylphosphine oxide or a triphenylphosphine oxide derivative, and the triphenylphosphine oxide derivative is

One of, wherein, R ₁ , R ₂ and R ₃ are delocalized π bond groups; the delocalized π bond groups are directly connected to the triphenylphosphine oxide, or the delocalized π bond groups The group is connected to the triphenylphosphine oxide through a group containing a π bond;

S50, preparing a cathode on the electron transport layer to prepare the quantum dot light-emitting diode.

In each embodiment of the present disclosure, the preparation method of each layer may be a chemical method or a physical method, wherein the chemical method includes but is not limited to chemical vapor deposition method, continuous ion layer adsorption and reaction method, anodization method, electrolytic deposition method, co-precipitation method One or more of; physical methods include but are not limited to solution methods (such as spin coating, printing, blade coating, dip-pulling, immersion, spraying, roll coating, casting, slot coating method or strip coating method, etc.), evaporation method (such as thermal evaporation method, electron beam evaporation method, magnetron sputtering method or multi-arc ion coating method, etc.), deposition method (such as physical vapor deposition method) , atomic layer deposition, pulsed laser deposition, etc.) one or more.

In some embodiments, the preparation of the composite material solution includes the steps of: adding triphenylphosphine oxide or a triphenylphosphine oxide derivative to the organic alcohol solution of N-type oxide nanoparticles containing hydroxyl groups on the surface, and sonicating Dispersion treatment is performed to obtain the composite material solution. In this embodiment, the organic alcohol is one of ethanol, propanol or butanol, but not limited thereto; the mass fraction of the composite material solution is 0.1-10%.

In some embodiments, the electron transport layer has a thickness of 10-60 nm.

In some embodiments, a preparation method of an inversion structure quantum dot light-emitting diode is also provided, as shown in FIG. 4 , which includes the steps:

S100, providing a cathode substrate, depositing a composite material solution on the surface of the cathode substrate to obtain an electron transport layer, the composite material solution comprising an organic alcohol and an N-type oxide containing a hydroxyl group on the surface dispersed in the organic alcohol Nanoparticles and triphenylphosphine oxide or triphenylphosphine oxide derivatives that form hydrogen bonds with said hydroxyl groups, said triphenylphosphine oxide derivatives are

One of, wherein, R ₁ , R ₂ and R ₃ are delocalized π bond groups; the delocalized π bond groups are directly connected to the triphenylphosphine oxide, or the delocalized π bond groups The bond group is connected to the triphenylphosphine oxide through a group containing a π bond;

S200, preparing a quantum dot light-emitting layer on the surface of the electron transport layer;

S300, preparing a hole transport layer on the surface of the quantum dot light-emitting layer;

S400, preparing a hole injection layer on the surface of the hole transport layer;

S500, an anode is prepared on the surface of the hole injection layer to prepare the quantum dot light-emitting diode.

The preparation method of a quantum dot light-emitting diode of the present disclosure will be further explained below through examples:

An embodiment of the present disclosure provides a method for fabricating a positive-type quantum dot light-emitting diode, including the following steps:

First, place the patterned ITO substrate in acetone, washing solution, deionized water and isopropanol in order for ultrasonic cleaning. Each step of the above ultrasonics needs to last about 15 minutes; after the ultrasonication is completed, the ITO is placed in a clean oven. Internal drying for use; after the ITO substrate is dried, the surface of the ITO is treated with ultraviolet ozone for 5 minutes to further remove the organic matter attached to the surface of the ITO and improve the work function of the ITO.

Then spin-coat a layer of PEDOT:PSS on the surface of the treated ITO substrate with a thickness of 20nm, and place the substrate on a heating table at 150°C for 30 minutes to remove moisture. This step needs to be done in the air;

Next, place the dried substrate coated with the hole injection layer in a nitrogen atmosphere, spin-coat a layer of hole transport layer material TFB, the thickness of this layer is 20nm, and place the substrate on a heating stage at 150°C. Heating for 30 minutes to remove solvent;

After the wafer treated in the previous step was cooled, the green quantum dot luminescent material was spin-coated on the surface of the hole transport layer with a thickness of 20 nm. residual solvent;

Subsequently, 14 mg of triphenylphosphorus oxide was added to 10 ml of an ethanol solution of ZnO nanoparticles with a concentration of 30 mg/mL, and then deposited on the quantum dot layer as an electron transport layer with a thickness of 30 nm. Place on a heating stage at 80°C for 10 minutes to remove residual solvent.

Finally, the wafers with each functional layer deposited are placed in an evaporation chamber and a layer of aluminum is thermally evaporated as a cathode through a mask plate, with a thickness of 100 nm, the device preparation is completed, and the quantum dot light-emitting diode is obtained.

The efficiency and service life of the quantum dot light-emitting diode prepared in Example 1 were tested. Compared with ZnO nanoparticles as the electron transport layer, the external quantum efficiency did not change much, from 16.8% to 16.9%, and the device life was T95@1000nits From 1100 hours to 2300 hours, the improvement is obvious.

An embodiment of the present disclosure provides a method for fabricating an inversion structure quantum dot light-emitting diode, which includes the following steps:

First, the patterned ITO substrate was placed in acetone, washing solution, deionized water and isopropanol in sequence for ultrasonic cleaning, and each step of the above ultrasonics lasted about 15 minutes. After the ultrasonic is completed, the ITO is placed in a clean oven for drying for use; after the ITO substrate is dried, the surface of the ITO is treated with ultraviolet ozone for 5 minutes to further remove the organic matter attached to the surface of the ITO.

Then 28 mg of triphenylphosphorus oxide was added to 10 mL of an ethanol solution of ZnO nanoparticles with a concentration of 30 mg/mL, mixed uniformly, and then spin-coated on ITO as an electron transport layer with a thickness of 25 nm. Heat on a heating stage at 80°C for 10 minutes to remove residual solvent.

After the sheet was cooled, the red quantum dot luminescent material was spin-coated on the surface of the electron transport layer with a thickness of 20 nm. After this step of deposition is completed, the wafer is placed on a heating table at 80°C for 10 minutes to remove residual solvent;

Next, a layer of hole transport layer material NPB is evaporated, and the thickness of this layer is 10 nm.

Then, another layer of hole injection layer material MoO ₃ is evaporated, and the thickness of this layer is 30 nm.

Finally, the wafers with each functional layer deposited are placed in an evaporation chamber, and a layer of silver is thermally evaporated through a mask as an anode, with a thickness of 80 nm, the device preparation is completed, and the quantum dot light-emitting diode is obtained.

The efficiency and service life of the quantum dot light-emitting diode prepared in Example 2 were tested. Compared with ZnO nanoparticles as the electron transport layer, the external quantum efficiency did not change much, from 18.1% to 19.2%, and the device life was T95@1000nits There are 4400 hours increased to 6500 hours, the improvement is obvious.

An embodiment of the present disclosure provides a method for fabricating a positive-type quantum dot light-emitting diode, including the following steps:

First, place the patterned ITO substrate in acetone, washing solution, deionized water and isopropanol in order for ultrasonic cleaning. Each step of the above ultrasonics needs to last about 15 minutes; after the ultrasonication is completed, the ITO is placed in a clean oven. Internal drying for use; after the ITO substrate is dried, the surface of the ITO is treated with ultraviolet ozone for 5 minutes to further remove the organic matter attached to the surface of the ITO and improve the work function of the ITO.

Then spin-coat a layer of PEDOT:PSS on the surface of the treated ITO substrate with a thickness of 20nm, and place the substrate on a heating table at 150°C for 30 minutes to remove moisture. This step needs to be done in the air;

Next, place the dried substrate coated with the hole injection layer in a nitrogen atmosphere, spin-coat a layer of hole transport layer material PFB, the thickness of this layer is 20nm, and place the substrate on a heating stage at 150°C. Heating for 30 minutes to remove solvent;

After the wafer treated in the previous step was cooled, the green quantum dot luminescent material was spin-coated on the surface of the hole transport layer with a thickness of 20 nm. residual solvent;

Subsequently, 18 mg of triphenylphosphine oxide derivative was added to 10 mL of the ethanol solution of ZnO nanoparticles with a concentration of 30 mg/mL.

Among them, R ₁ is a butylene group, which is then deposited on the quantum dot layer as an electron transport layer with a thickness of 30 nm. After the deposition is completed, the film is placed on a heating table at 80 ° C and heated for 10 minutes to remove residues solvent.

Finally, the wafers with each functional layer deposited are placed in an evaporation chamber and a layer of aluminum is thermally evaporated as a cathode through a mask plate, with a thickness of 100 nm, the device preparation is completed, and the quantum dot light-emitting diode is obtained.

The efficiency and service life of the quantum dot light-emitting diode prepared in Example 3 were tested. Compared with ZnO nanoparticles as the electron transport layer, the external quantum efficiency did not change much, from 16.8% to 17.5%, and the device life was T95@1000nits From 1200 hours to 3500 hours, the improvement is obvious.

An embodiment of the present disclosure provides a method for fabricating a positive-type quantum dot light-emitting diode, including the following steps:

First, place the patterned ITO substrate in acetone, washing solution, deionized water and isopropanol in order for ultrasonic cleaning. Each step of the above ultrasonics needs to last about 15 minutes; after the ultrasonication is completed, the ITO is placed in a clean oven. Internal drying for use; after the ITO substrate is dried, the surface of the ITO is treated with ultraviolet ozone for 5 minutes to further remove the organic matter attached to the surface of the ITO and improve the work function of the ITO.

Then spin-coat a layer of PEDOT:PSS on the surface of the treated ITO substrate with a thickness of 20nm, and place the substrate on a heating table at 150°C for 30 minutes to remove moisture. This step needs to be done in the air;

Next, place the dried substrate coated with the hole injection layer in a nitrogen atmosphere, spin-coat a layer of hole transport layer material PFB, the thickness of this layer is 20nm, and place the substrate on a heating stage at 150°C. Heating for 30 minutes to remove solvent;

After the wafer treated in the previous step was cooled, the green quantum dot luminescent material was spin-coated on the surface of the hole transport layer with a thickness of 20 nm. residual solvent;

Subsequently, 18 mg of triphenylphosphine oxide derivative was added to 10 mL of 30 mg/mL ethanol solution of ZnO nanoparticles,

Wherein, R ₂ is a benzene ring, and the benzene ring is connected to the triphenylphosphine oxide through a vinyl group, and then it is deposited on the quantum dot layer as an electron transport layer with a thickness of 30 nm. After the deposition is completed, the The slides were placed on a heating stage at 80°C for 10 minutes to remove residual solvent.

Finally, the wafers with each functional layer deposited are placed in an evaporation chamber and a layer of aluminum is thermally evaporated as a cathode through a mask plate, with a thickness of 100 nm, the device preparation is completed, and the quantum dot light-emitting diode is obtained.

The efficiency and service life of the quantum dot light-emitting diode prepared in Example 4 were tested. Compared with ZnO nanoparticles as the electron transport layer, the external quantum efficiency did not change much, from 16.8% to 17.3%, and the device life was T95@1000nits From 1200 hours to 3300 hours, the improvement is obvious.

To sum up, the quantum dot light-emitting diode provided by the present disclosure includes an electron transport layer, and the material of the electron transport layer is oxide nanoparticles containing hydroxyl groups on the surface and triphenylphosphine oxide or triphenylphosphine oxide that forms hydrogen bonds with the hydroxyl groups. Phenylphosphine oxide derivatives. The oxygen atoms in the phosphorus-oxygen double bond of the triphenylphosphine oxide and its derivatives can easily interact with the hydroxyl groups on the surface of the oxide nanoparticles to form hydrogen bonds, so as to passivate the oxide nanoparticles, and the three Phenylphosphine oxide or its derivatives can achieve superstructures or form periodic closely-packed interconnected structures through π–π conjugated self-assembly, thereby improving passivation stability and stabilizing passivation oxide nanoparticles surface, reduce surface defects, and eliminate the hydroxyl groups hanging on the surface of the oxide nanoparticles, so as to prevent the hanging hydroxyl groups from being oxidized to generate highly oxidizing OH radicals, so as to reduce the shedding of ligands on the surface of quantum dots, and at the same time effectively play the role of The electron transport performance of the electron transport material can greatly improve the luminous efficiency and service life of the quantum dot light-emitting diode.

It should be understood that the application of the present disclosure is not limited to the above examples, and those of ordinary skill in the art can make improvements or transformations according to the above descriptions, and all these improvements and transformations should fall within the protection scope of the appended claims of the present disclosure.

Claims (19)

1. A composite nanoparticle, comprising oxide nanoparticles containing hydroxyl groups on the surface and a passivator containing phosphorus-oxygen double bonds, the hydroxyl groups on the surface of the oxide nanoparticles and the phosphorus-oxygen double bonds in the passivator form hydrogen bonds.
2. The composite nanoparticle of claim 1, wherein the passivating agent is triphenylphosphine oxide.
3. The composite nanoparticle according to claim 1, wherein the passivating agent is a triphenylphosphine oxide derivative, and the triphenylphosphine oxide derivative is

   

   

   One of them, wherein R ₁ , R ₂ and R ₃ are delocalized π bond groups; the delocalized delocalized π bond groups are directly connected to the triphenylphosphine oxide, or the delocalized delocalized π bond groups are directly connected to the triphenylphosphine oxide. The domain pi bond group is linked to the triphenylphosphine oxide through a pi bond containing group.
4. The composite nanoparticle according to claim 3, wherein the delocalized delocalized π bond group is one of a benzene ring or a butylene group.
5. The composite nanoparticle according to claim 3, wherein the group containing a π bond is one of a vinyl group or an acetylene group.
6. The composite nanoparticle according to claim 1, wherein the oxide nanoparticle is one or more of ZnO, _TiO2 , _SnO2 , _Ta2O3 , ZnMgO, _ZnAlO and SnInO.
7. The composite nanoparticle according to claim 1, wherein the composite nanoparticle is ZnO and triphenylphosphine oxide containing hydroxyl groups on the surface, and the hydroxyl groups contained on the surface of the ZnO and the phosphorus-oxygen bismuth of the triphenylphosphine oxide bonds form hydrogen bonds.
8. A quantum dot light-emitting diode, comprising an electron transport layer, and the material of the electron transport layer is the composite nanoparticle according to any one of claims 1-7.
9. The quantum dot light-emitting diode according to claim 8, further comprising a cathode, an anode, and a quantum dot light-emitting layer disposed between the cathode and the anode, and the electron transport layer is disposed between the cathode and the quantum dots between the light-emitting layers.
10. The quantum dot light-emitting diode according to claim 9, further comprising a hole functional layer disposed between the anode and the quantum dot light-emitting layer, wherein the hole functional layer is an electron blocking layer, a hole injection layer one or more of a layer and a hole transport layer.
11. The quantum dot light-emitting diode according to claim 10, wherein the quantum dot light-emitting layer material is one or more of red light quantum dots, green light quantum dots and blue light quantum dots, the red light quantum dots, green light quantum dots and blue light quantum dots independently selected from CdS, CdSe, CdTe, InP, AgS, PbS, HgS, ZnCdS, CuInS, ZnCdSe, ZnSeS, ZnCdTe, PbSeS, ZnCdS/ZnSe, CuInS/ZnS, ZnCdSe/ZnS, CuInSeS, ZnCdTe/ZnS , one or more of PbSeS/ZnS.
12. The quantum dot light emitting diode of claim 10, wherein the anode is ITO, FTO or ZTO.
13. The quantum dot light-emitting diode according to claim 10, wherein the cathode is selected from one or more of Au, Ag, Al, Cu, and Mo.
14. A preparation method of a quantum dot light-emitting diode, comprising the steps of:

    provide the substrate;

    A composite nanoparticle solution is deposited on the substrate to prepare an electron transport layer, the composite nanoparticle solution includes an organic alcohol, and the composite nanoparticle according to any one of claims 1-7 dispersed in the organic alcohol .
15. The method for manufacturing a quantum dot light-emitting diode according to claim 14, wherein the step of providing the substrate comprises:

    Provide anode substrate;

    preparing a hole injection layer on the surface of the anode substrate;

    preparing a hole transport layer on the surface of the hole injection layer;

    preparing a quantum dot light-emitting layer on the surface of the hole transport layer to form the substrate;

    After the step of depositing a composite nanoparticle solution on the substrate to prepare an electron transport layer, the method further includes: preparing a cathode on the surface of the electron transport layer.
16. The method for manufacturing a quantum dot light-emitting diode according to claim 14, wherein the step of providing a substrate comprises: providing a cathode substrate to form the substrate;

    After the step of depositing a composite nanoparticle solution on the substrate to prepare an electron transport layer, the method further includes:

    preparing a quantum dot light-emitting layer on the surface of the electron transport layer;

    preparing a hole transport layer on the surface of the quantum dot light-emitting layer;

    preparing a hole injection layer on the surface of the hole transport layer;

    An anode is prepared on the surface of the hole injection layer.
17. The method for preparing a quantum dot light-emitting diode according to any one of claims 14-16, wherein the mass fraction of the composite nanoparticle solution is 0.1-10%.
18. The method for preparing a quantum dot light-emitting diode according to any one of claims 14-16, wherein the organic alcohol is one of ethanol, propanol or butanol.
19. The method for manufacturing a quantum dot light-emitting diode according to any one of claims 14-16, wherein the electron transport layer has a thickness of 10-60 nm.

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