CN115249774A - Quantum dot film and preparation method thereof, and quantum dot light-emitting diode and preparation method thereof - Google Patents

Abstract

The present application relates to the technical field of quantum dot film-forming technology, and in particular, to a quantum dot film and a preparation method thereof, and a quantum dot light-emitting diode and a preparation method thereof. The preparation method of the quantum dot film includes the following steps: providing an initial quantum dot film; and treating the initial quantum dot film with a proton reagent to obtain the quantum dot film. The preparation method can passivate the surface defects of the quantum dots, reduce the quenching of excitons due to defect states, and finally can improve the luminous efficiency and service life of the quantum dot thin film.

Description

Quantum dot film and preparation method thereof, and quantum dot light-emitting diode and preparation method thereof

technical field

The application belongs to the technical field of quantum dot film-forming technology, and in particular relates to a quantum dot film and a preparation method thereof, and a quantum dot light-emitting diode and a preparation method thereof.

Background technique

Quantum Dot (QD) is a nanomaterial with unique luminescent properties, its luminescence wavelength can be adjusted with the size of quantum dots, and it has a wide color gamut, high luminous efficiency, high optical and thermal stability, and solution processing. and other advantages, it has been widely used in the device research of light-emitting diodes in recent years. In recent years, the optoelectronic properties of quantum dot light-emitting diode (Quantum Dot Light Emitting Diode, QLED) devices have been greatly improved, and the device structure has changed to an organic-inorganic hybrid structure. In the process of optimizing the QLED device structure, the brightness and lifetime of the device have been greatly improved. At the same time, in order to meet the needs of commercial applications, more and more attention has been paid to the research on device stability.

The quantum dot materials obtained by conventional synthesis methods are generally connected with surface ligands through coordination bonds. On the one hand, the surface ligands ensure that the quantum dots can be stably dispersed in the solvent without agglomeration and sedimentation, and on the other hand, they can effectively passivate the surface of the quantum dots. Space and dangling keys. However, when quantum dots are used in the quantum dot light-emitting layer of quantum dot light-emitting diode devices, the surface ligands act as insulating organics, which will increase the interface barrier between the light-emitting layer and the adjacent functional layer, which leads to the difficulty of carrier injection, which leads to quantum The operating voltage of the point light-emitting diode device increases, and at the same time, the photoelectric conversion efficiency of the device is low. Therefore, under the premise of ensuring the dispersibility of the quantum dots in the solvent, controlling the lower content of the surface ligands of the quantum dots is an important factor to ensure the performance of the quantum dot light-emitting diode devices. However, with the reduction of the surface ligands, due to the high ratio Due to the characteristics of the surface area, the atoms on the surface of the quantum dot that are not protected by ligands will exist in defect states, and these defect states will trap electrons and holes in the delocalized state of the quantum dot, resulting in quenching of excitons and rapid degradation of device performance. .

Whether it is the ink preparation of the quantum dot light-emitting layer or the preparation of the quantum dot light-emitting diode device, the external environment is a key factor affecting the efficiency and stability of the electroluminescent device. In the process of synthesis, purification, ink preparation, and solution processing of quantum dot materials into the light-emitting layer of quantum dot light-emitting diodes, a certain number of defects will inevitably occur on the surface of quantum dots. At the same time, the high specific surface area characteristics of quantum dots, Atoms not protected by ligands will exist in defect states; these defects have the ability to trap electrons and holes in the delocalized state of the quantum dot, which will introduce some fast non-radiative channels for the exciton recombination of the quantum dot, Moreover, the recombination rate of non-radiative channels brought about by most of the defects is much greater than that of the radiation channels, which will cause a sharp decrease in the luminous efficiency of quantum dots. The presence quenches excitons and increases non-radiative recombination, reducing fluorescence efficiency and optoelectronic properties. The thus prepared quantum dot light-emitting diode devices have obvious brightness and external quantum efficiency roll-off effects, resulting in that the optoelectronic properties cannot meet the needs of commercial applications.

SUMMARY OF THE INVENTION

The purpose of this application is to provide a quantum dot film and its preparation method, and a quantum dot light-emitting diode and its preparation method, aiming to solve the technical problem of how to reduce the surface defects of the quantum dot film.

In order to realize the above-mentioned application purpose, the technical scheme adopted in this application is as follows:

In a first aspect, the present application provides a method for preparing a quantum dot film, comprising the following steps:

Provide initial quantum dot film;

The initial quantum dot film is treated with a proton reagent to obtain a quantum dot film.

In the preparation method of the quantum dot film provided by the present application, the initial quantum dot film is treated with a proton reagent. During the treatment process, the proton reagent will contact the surface of the initial quantum dot film. Specifically, the proton reagent is protonated. Then, it is connected with dangling bonds on the surface of the quantum dots, thereby passivating the surface defects of the quantum dots, reducing the quenching of excitons due to defect states, and finally improving the luminous efficiency and service life of the quantum dot film.

In a second aspect, the present application provides a quantum dot film prepared by the method for preparing a quantum dot film of the present application.

The quantum dot film provided by the present application is prepared by the unique preparation method of the present application. Because the preparation method uses a proton reagent to treat the initial quantum dot film, the quantum dot film can reduce the surface defect state of the quantum dot and has a good luminous efficiency. and service life.

In a third aspect, the present application provides a quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer located between the anode and the cathode, and the quantum dot light-emitting layer is a quantum dot light-emitting layer prepared by the preparation method of the present application. Point film.

The quantum dot light-emitting layer in the quantum dot light-emitting diode provided by the present application is the quantum dot film obtained by the unique preparation method of the present application, because the quantum dot film can reduce the surface defect state of the quantum dot and reduce the quenching of excitons, Therefore, the device has good luminous efficiency and service life.

In a fourth aspect, the present application provides a method for preparing a quantum dot light-emitting diode, comprising the following steps:

provide the substrate;

An initial quantum dot thin film is prepared on the substrate, and then the initial quantum dot thin film is treated with a proton reagent to obtain a quantum dot light-emitting layer.

The preparation method of the quantum dot film provided by the present application, wherein the quantum dot light-emitting layer is obtained by using a proton reagent to process the initial quantum dot film on the substrate, because the proton reagent will contact the surface of the initial quantum dot film during the treatment process, so that the After the proton reagent is protonated, it is connected with dangling bonds on the surface of the quantum dot, so as to passivate the surface defects of the quantum dot and reduce the quenching of the excitons due to the defect state; therefore, the preparation method of the quantum dot light-emitting diode can finally improve the luminous efficiency and luminous efficiency of the device. service life.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present application. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the schematic flow sheet of the preparation method of quantum dot film provided by the present invention;

2 is a schematic structural diagram of a quantum dot light-emitting diode device provided by the present invention;

3 is a schematic flowchart of a method for preparing a quantum dot film provided by the present invention;

4 is a current efficiency curve diagram of the light-emitting diode devices of Example 1 and Comparative Example 1 provided by the present invention;

FIG. 5 is a graph of the device life test curve of Example 1 and Comparative Example 1 provided by the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

A first aspect of the embodiments of the present application provides a method for preparing a quantum dot film, as shown in FIG. 1 , the preparation method includes the following steps:

S01: Provide initial quantum dot film;

S02: treating the initial quantum dot film with a proton reagent to obtain a quantum dot film.

In the preparation method of the quantum dot film provided by the present application, the initial quantum dot film is treated with a proton reagent. During this process, the proton reagent will contact the surface of the initial quantum dot film. Specifically, after the proton reagent is protonated It is connected with dangling bonds on the surface of the quantum dots, thereby passivating the surface defects of the quantum dots, reducing the quenching of excitons due to defect states, and finally improving the luminous efficiency and service life of the quantum dot thin film.

In the above-mentioned step 01 of the present application; the initial quantum dot film may be a wet film or a dry film; the wet film may be a wet initial quantum dot film formed by depositing a quantum dot solution on a substrate; the dry film may be a The dot solution is deposited on the substrate and subjected to a desolvation process to form a dry solid-state initial quantum dot film. Because some proton reagents may be anti-solvents with the solvent in the quantum dot solution, when the proton reagent treats the wet initial quantum dot film, it may slightly affect the stability of the quantum dots in the initial quantum dot film; therefore, this application is preferably dry. The solid-state initial quantum dot thin film, that is, the initial quantum dot thin film obtained by depositing the quantum dot solution on the substrate and removing the solvent in the present application is preferred.

In the quantum dot solution used to prepare the initial quantum dot film, the solvent can be at least one of saturated or unsaturated alkanes, saturated or unsaturated aromatic hydrocarbons, such as dichloromethane, chloroform, toluene, n-hexane, cyclohexane One or more of alkane, n-heptane, n-octane, cycloheptane and dioxane. The quantum dot materials obtained by conventional synthesis methods are generally connected with surface ligands through coordination bonds. In the above-mentioned initial quantum dot film of the present application, the surface of the quantum dots is also bound with surface ligands, and the surface ligands can be long-chain ligands. , such as one or more of oleylamine OLAM, oleic acid OA, tri-n-octylphosphine TOP, tri-n-octylphosphine oxide TOPO, tributylphosphine TBP, etc.; in the initial quantum dot film, the surface of the quantum dots will A certain number of cationic dangling bonds that are not protected by ligands are formed, that is, defect states on the surface of the quantum dots. In this application, the proton reagent is mixed with the initial quantum dot film. The proton reagent is protonated and dehydrogenated at the defect site on the surface of the quantum dot and forms a coordination bond with the cation to passivate the dangling bond. At the same time, there will be some original The site-attached surface ligand will be replaced by the protonated proton reagent. Finally, the quenching of excitons due to defect states is reduced by the treatment of proton reagents, thereby improving the luminous efficiency and lifetime of quantum dot films.

It should be noted that if the proton reagent is directly added to the quantum dot solution, mixed and modified to form a film, because some proton reagents may be anti-solvents with the solvent in the quantum dot solution, so the proton reagent added to the quantum dot solution affects the solution system. The stability of the quantum dots will reduce the dispersibility of the quantum dots in the solvent, and even precipitate and precipitate from the dispersing solvent, and the surface tension and viscosity of the solvent after mixing will change, so the proton reagent is added to the quantum dot solution. However, if the quantum dot solution is first formed into a film to form the initial quantum dot film, even if it is a wet film containing a part of the solvent, such as the proton reagent and the solvent are anti-solvents to each other, because the quantum dots The dot solution has become a very thin film layer, which can passivate the surface defects of the quantum dots in the thin film state and reduce the quenching effect of the excitons due to the defect state, but the effect of the dry solid initial quantum dot film is better. Therefore, in the present application, the proton reagent is used to treat the initial quantum dot film formed into the film, so that the proton reagent is in surface contact with the initial quantum dot film to modify the initial film, instead of using the proton reagent to dope the quantum dot solution. It is further preferred to treat the dried solid initial quantum dot film with a proton reagent. The present application can passivate the defect state traps on the surface of quantum dots and reduce the quenching of excitons by defect states through the preparation method of such a quantum dot film. The quantum dot film prepared by such a process is used for quantum dot light-emitting diodes as light-emitting layers The luminous performance and working life of the device can be improved.

In the initial quantum dot film provided in this application, the quantum dots include II-VI, III-V, IV-VI, VI-VI, VIII-VI, I-III-VI, II -At least one of group IV-VI, group II-IV-V single or composite structure quantum dots. The composite structure quantum dots include core-shell structure quantum dots, and the cores constituting the core-shell structure quantum dots include CdSe, CdS, CdTe, CdSeTe, CdZnS, PbSe, ZnTe, CdSeS, PbS, PbTe, HgS, HgSe, HgTe, at least one of GaN, GaP, GaAs, InP, InAs, InZnP, InGaP and InGaN; the shell constituting the core-shell structure quantum dot contains at least one of ZnSe, ZnS and ZnSeS.

The protic reagent refers to a reagent with -OH bond or -NH bond that can be used as a hydrogen bond donor in the molecule, and is also called a protic solvent. The protic reagent includes at least one of a hydroxyl-containing protic reagent and an amino-containing protic reagent. The hydroxyl-containing proton reagent includes at least one of water, methanol, ethanol, propanol such as isopropanol, butanol such as n-butanol, pentanol such as n-pentanol, formic acid, acetic acid, propionic acid and butyric acid; The amino group-containing proton reagent includes at least one of methylamine, ethylamine and propylamine. When the above-mentioned proton reagent is mixed with the initial quantum dot film, it can be dehydrogenated and protonated at the defect state site on the surface of the quantum dot and then combined with the unsaturated cations on the surface of the quantum dot. At the same time, a small amount of long-chain ligands on the surface of the quantum dot Also replaced by protonation reagents.

In the above step S02, there are two ways to mix the proton reagent and the initial quantum dot film. One is to deposit the liquid proton reagent on the surface of the initial quantum dot film for protonation exchange, and cover the initial quantum dot film. , and then annealed to obtain the final modified quantum dot film. One is to contact the gaseous proton reagent with the initial quantum dot film for protonation exchange, and then anneal to obtain the final modified quantum dot film; wherein, the gaseous proton reagent can be heated, sonicated, It is obtained by atomization by spraying and other methods.

Specifically, in one embodiment, the proton reagent is a liquid proton reagent, and the mixing step includes: depositing the liquid proton reagent on the surface of the initial quantum dot film, and then annealing. Wherein, the liquid proton reagent is deposited on the surface of the initial quantum dot film, and then the steps of annealing treatment include: spin-coating the liquid proton reagent in an amount of 3-20 μl/cm ² for 2-5 times each time, that is, Taking the initial quantum dot film as a reference, spin-coat 2-20 μl of liquid proton reagent per unit area of 1 cm ² , and spin-coat 2-5 times.

Specifically, the liquid protic solvent can be dripped multiple times on the initial quantum dot film by using a glue dispenser in a rotating state; wherein, the rotation speed is 1000-3000 rpm, and the volume of the protic solvent added each time is 3-20 μl/cm ² , the number of dripping is 2-5 times. Since the proton reagent is in direct contact with the initial quantum dot film, the proton reagent is easy to volatilize. In order to avoid the difference in the contact time between the covered proton reagent and the initial quantum dot film, the proton reagent is rapidly dripped on the surface of the quantum dot in a rotating state. Because the contact time of the proton solvent added at one time and the surface of the quantum dot film is short under the rotating state of the glue homogenizer, the method of repeated dripping is adopted for many times, so that the protonation can be fully carried out and the quantum dot film can be passivated more effectively. For point surface defects, specifically, the proton reagent was spin-coated 2-5 times in an amount of 3-20/cm ² each time. When the preparation method is used to prepare a quantum dot light-emitting layer in a quantum dot light-emitting diode, the number of times of dropping is in the range of 2-5 times, and the underlying organic hole transport material will not be damaged.

Further, a liquid proton reagent is deposited on the surface of the initial quantum dot film, and then the temperature of the annealing treatment is 60-100° C. and the time is 5-20 min.

In another embodiment, the proton reagent is a gaseous proton reagent, and the mixing treatment step includes: placing the initial quantum dot film in the gaseous proton reagent for standing treatment, and then annealing treatment. Wherein, the standing treatment time is 30s-5min; if the standing time is less than 30s, the protonation reaction at the surface defects of the quantum dots is not sufficient, and the effect of passivating the defects is low; if the standing time is longer than 5min, the Prolonged proton reagent treatment may generate new defect states that become new luminescence quenching centers. When the preparation method is used to prepare the quantum dot light-emitting layer in the quantum dot light-emitting diode, for the structure of the positive device, the above-mentioned static treatment time range will not affect the underlying organic hole transport material, and will not make it degradation.

Further, the initial quantum dot film is placed in the gaseous proton reagent for standing treatment, and then the temperature of the annealing treatment is 60-100° C. and the time is 5-20 min.

A second aspect of the embodiments of the present application is a quantum dot film, wherein the quantum dot film is prepared by the above-mentioned preparation method of the quantum dot film of the present application.

The quantum dot film provided by the present application is prepared by the unique preparation method of the present application. Because the preparation method uses a proton reagent to treat the initial quantum dot film, the quantum dot film can reduce the surface defect state of the quantum dot and has a good luminous efficiency. and service life.

A third aspect of the embodiments of the present application provides a quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer located between the anode and the cathode, and the quantum dot light-emitting layer is prepared by the preparation method of the present application Quantum dot films.

The quantum dot light-emitting layer in the quantum dot light-emitting diode provided by the present application is the quantum dot film obtained by the unique preparation method of the present application, because the quantum dot film can passivate the surface defect state of the quantum dot, and the surface of the quantum dot after passivation is passivated. The defect states are significantly reduced, the ability to capture electrons and holes in the delocalized state is reduced, and the non-radiative recombination channels for exciton quenching are reduced, so the device has good luminous efficiency and lifetime.

Specifically, the external quantum efficiency (EQE) of quantum dot light-emitting diode devices is improved by nearly 30%.

In one embodiment, a hole transport layer may be arranged between the anode and the quantum dot light-emitting layer, and further, a hole injection layer may be arranged between the hole transport layer and the anode; or, the cathode and the An electron transport layer may be arranged between the quantum dot light-emitting layers, and further, an electron injection layer may be arranged between the electron transport layer and the cathode. The quantum dot light-emitting diode can be an upright device or an inverted device.

Further, as shown in FIG. 2 , the quantum dot light-emitting diode device of the present application includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode. The quantum dot light-emitting layer is the quantum dot thin film prepared by the preparation method of the present application.

In a preferred embodiment, the red quantum dot material CdZnSe/ZnSe/ZnS is used as the light-emitting layer of the device, the electroluminescence wavelength of the quantum dot material is 622 nm, the half-peak width is 22 nm, and the connected surface ligand is oleic acid; The methanol solvent is atomized into steam to treat the light-emitting layer film for 1 min. The maximum current efficiency of the quantum dot light-emitting diode device prepared by this method can reach 30cd/A, and there is no obvious roll-off with the increase of brightness. The measured life T ₉₅ @1000nit=3170h (the time it takes for the brightness to decay from 1000nit to 95%), and there is no obvious brightness lifting process in the initial stage of the life test, indicating that the surface defects of the quantum dots have been passivated; The maximum current efficiency of the reagent-treated device is 20cd/A, and the efficiency drops significantly at high brightness. T ₉₅ @1000nit=1000h, there is a brightness increase process of about 5h in the initial stage of the life test, indicating that the surface defects of quantum dot materials are The increase in brightness caused by continuous passivation; the main reason for the difference is that the unpassivated defect states on the surface of the quantum dots have a continuous quenching effect on the electro-generated excitons, resulting in the rolling of the luminous efficiency with the increase of the current. drop.

In another preferred embodiment, a glue dispenser is used to cover the water on the green quantum dot light-emitting layer by spin coating, using a rotation speed of 2000 rpm, dripping 50 ul each time, and repeating three times; the quantum dot selection structure is CdZnSeS/ ZnS, the electroluminescence wavelength is 535nm, the half-peak width is 25nm, and the surface ligand is oleylamine; the maximum current efficiency of the device prepared by this method can reach 80cd/A, and there is no obvious roll-off with the increase of brightness. The lifetime T ₉₅ @1000nit=6400h is obtained; the maximum current efficiency of the untreated device can reach 55cd/A, and there is no obvious roll-off with the increase of brightness, and the measured lifetime T ₉₅ @1000nit=2600h.

In one embodiment, the anode is selected from one or more of indium tin oxide, fluorine-doped tin oxide, indium zinc oxide, graphene, and carbon nanotubes; the material of the hole injection layer is PEDOT: PSS, oxide One or more of nickel, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, copper oxide; hole transport layer material is one or more of PVK, Poly-TPD, CBP, TCTA and TFB The quantum dot light-emitting layer includes red light quantum dot light-emitting layer, green light quantum dot light-emitting layer and blue light quantum dot light-emitting layer; quantum dot materials include II-VI semiconductor nanocrystals, III-V semiconductor nanocrystals, II-V group semiconductors At least one of compound, III-VI compound, IV-VI group compound, I-III-VI group compound, II-IV-VI group compound, and group IV element, the quantum dot light-emitting layer is composed of the above quantum dot film of the present application The material of the electron transport layer is one or more of n-type ZnO, TiO ₂ , SnO, Ta ₂ O ₃ , AlZnO, ZnSnO, InSnO and Alq ₃ ; the cathode is selected from Al, Ca, Ba , one or more of Ag.

A fourth aspect of the present application provides a method for preparing a quantum dot light-emitting diode, as shown in FIG. 3 , the preparation method includes the following steps:

E01: Provide substrate;

E02: preparing an initial quantum dot thin film on the substrate, and then treating the initial quantum dot thin film with a proton reagent to obtain a quantum dot light-emitting layer.

The preparation method of the quantum dot film provided by the present application, wherein the quantum dot light-emitting layer is obtained by using a proton reagent to process the initial quantum dot film on the substrate, because the proton reagent will contact the surface of the initial quantum dot film during the treatment process, so that the After the proton reagent is protonated, it is connected with dangling bonds on the surface of the quantum dot, so as to passivate the surface defects of the quantum dot and reduce the quenching of the excitons due to the defect state; therefore, the preparation method of the quantum dot light-emitting diode can finally improve the luminous efficiency and luminous efficiency of the device. service life.

Specifically, an initial quantum dot thin film is formed on the provided substrate, and then the initial quantum dot thin film is treated with a proton reagent to obtain a quantum dot light-emitting layer. Wherein, the initial quantum dot film may be a wet film or a dry film; in this application, a dry solid-state initial quantum dot film is preferred, that is, in this application, the quantum dot solution is preferably deposited on a substrate and treated with solvent removal to obtain an initial quantum dot film.

Further, the proton reagent is a liquid proton reagent, and the step of treating the initial quantum dot film with the proton reagent includes: depositing a liquid proton reagent on the surface of the initial quantum dot film, and then annealing; or, the proton reagent is a gaseous state The proton reagent is used, and the steps of treating the initial quantum dot film with the proton reagent include: placing the initial quantum dot film in a gaseous proton reagent for standing treatment, and then annealing treatment. Wherein, the liquid proton reagent is deposited on the surface of the initial quantum dot film, and then the steps of annealing treatment include: spin-coating the liquid proton reagent in an amount of 3-20 μl/cm ² for 2-5 times each time; the temperature of the subsequent annealing treatment It is 60-100℃, and the time is 5-20min. The initial quantum dot film is placed in a gaseous proton reagent for a standing treatment time of 30s-5min, and the subsequent annealing treatment is performed at a temperature of 60-100° C. and a time of 5-20min. The specific contents of the two cases have been described in detail above.

Further, the protic reagent includes at least one of a hydroxyl-containing protic reagent and an amino-containing protic reagent. The hydroxyl-containing proton reagent includes at least one of water, methanol, ethanol, propanol, butanol, pentanol, formic acid, acetic acid, propionic acid and butyric acid; the amino-containing proton reagent includes methylamine, ethylamine and propylamine at least one of.

In the above-mentioned preparation method of a quantum dot light-emitting diode, the substrate used may be an anode substrate or a cathode substrate.

In one embodiment, the substrate is an anode substrate, and after the quantum dot light-emitting layer is prepared on the anode substrate, a cathode is further prepared on the quantum dot light-emitting layer. Wherein, before preparing the quantum dot light-emitting layer, a hole functional layer (such as a hole transport layer, or a hole injection layer and a hole transport layer stacked in sequence) can be prepared on the anode substrate, and then the hole function layer can be prepared on the anode substrate. Prepare the quantum dot light-emitting layer; after preparing the quantum dot light-emitting layer, an electronic functional layer (such as an electron transport layer, or an electron transport layer and an electron injection layer stacked in sequence) can be prepared on the quantum dot light-emitting layer first, and then the electronic functional layer can be prepared on the quantum dot light-emitting layer. Prepare the cathode.

In one embodiment, the substrate is a cathode substrate, and after the quantum dot light-emitting layer is prepared on the cathode substrate, an anode is further prepared on the quantum dot light-emitting layer. Wherein, before preparing the quantum dot light-emitting layer, an electronic functional layer (such as an electron transport layer, or an electron injection layer and an electron transport layer stacked in sequence) can be prepared on the cathode substrate, and then the quantum dot light-emitting layer can be prepared on the electronic functional layer. ; After preparing the quantum dot light-emitting layer, a hole functional layer (such as a hole transport layer, or a hole transport layer and a hole injection layer stacked in sequence) can be prepared on the quantum dot light-emitting layer first, and then the hole function layer can be prepared on the quantum dot light-emitting layer. Prepare the cathode.

The following description will be given in conjunction with specific embodiments.

Example 1

A quantum dot light-emitting diode, as shown in Figure 2, includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode.

The preparation method of the device includes:

PEDOT:PSS material was spin-coated on the anode layer ITO, and then annealed at 100 °C for 15 min to obtain a hole injection layer; then spin-coated TFB material on the hole injection layer, annealed at 100 °C for 15 min to form a hole transport layer; A CdZnSe/ZnSe/ZnS red quantum dot layer was formed on the hole transport layer at the part of the device, and then the device was placed in an ultrasonic atomized methanol atmosphere for 1 min, and then taken out and annealed at 80 °C for 10 min to obtain a quantum dot light-emitting layer; A ZnO electron transport layer is made on the point light-emitting layer; finally, an electroluminescent device is formed by evaporating an Al cathode electrode layer and encapsulating it.

The photoelectric properties and lifetime of the quantum dot light-emitting diode device were tested, and the test results are shown in Table 1 and Figures 3-4.

Example 2

A quantum dot light-emitting diode, as shown in Figure 2, includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode.

The preparation method of the device includes:

PEDOT:PSS material was spin-coated on the anode layer ITO, and then annealed at 100 °C for 15 min to obtain a hole injection layer; then spin-coated TFB material on the hole injection layer, annealed at 100 °C for 15 min to form a hole transport layer; A CdZnSeS/ZnS green quantum dot layer was formed on the hole transport layer in the upper part, and a distilled water film was covered on the green quantum dot layer by spin coating with a glue dispenser. Annealed at 80°C for 10 min on the plate to obtain a quantum dot light-emitting layer; a ZnO electron transport layer was fabricated on the quantum dot light-emitting layer; finally, an electroluminescent device was formed by evaporating the Ag cathode electrode layer and encapsulating it.

The photoelectric properties and lifetime of the quantum dot light-emitting diode device were tested, and the test results are shown in Table 1.

Comparative Example 1

A quantum dot light-emitting diode, as shown in Figure 2, includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode.

The material and preparation method of each layer of the device are the same as those in Example 1, except that the quantum dot light-emitting layer is directly formed on the hole transport layer to form a CdZnSe/ZnSe/ZnS red quantum dot layer.

The photoelectric properties and lifetime of the quantum dot light-emitting diode device were tested, and the test results are shown in Table 1 and Figures 3-4.

Comparative Example 2

A quantum dot light-emitting diode, as shown in Figure 2, includes an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode.

The material and preparation method of each layer of the device are the same as those in Example 2 except that the quantum dot light-emitting layer is directly formed on the hole transport layer to form a CdZnSeS/ZnS green quantum dot layer.

The photoelectric properties and lifetime of the quantum dot light-emitting diode device were tested, and the test results are shown in Table 1.

Test Results

The above embodiments and comparative examples are tested, and the life test of the device adopts a 128-channel life test system customized by Guangzhou New Vision Company. The system architecture is to drive the QLED with a constant voltage and constant current source, and test the change of voltage or current; the photodiode detector and test system, test the change of the brightness (photocurrent) of the QLED; the luminance meter test and calibrate the brightness (photocurrent) of the QLED; the results are as follows Figure 4-5 and Table 1.

Table 1

EL(nm) FWHM(nm) EQE(%) CE(cd/A) T₉₅@1000nit(h) Example 1 626 twenty two 19.9 27 3170 Example 2 535 25 18 80 6400 Comparative Example 1 626 twenty two 10 13.5 1260 Comparative Example 2 535 25 11 55 2600

It can be seen from the data in Table 1 that compared with the comparative example not treated with proton reagents, the examples of the present application can passivate the surface defects of quantum dots by treating with proton reagents in the preparation process of the quantum dot light-emitting layer in the quantum dot light-emitting diode. state, thereby improving the luminous efficiency and service life of the device.

The above descriptions are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims (16)

1. a preparation method of quantum dot film, is characterized in that, comprises the steps: Provide initial quantum dot film; The initial quantum dot film is treated with a proton reagent to obtain a quantum dot film. 2 . The preparation method according to claim 1 , wherein the preparation method of the initial quantum dot film comprises: depositing a quantum dot solution on a substrate and removing solvent to obtain the initial quantum dot film. 3 . 3. The preparation method of claim 1, wherein the proton reagent is a liquid proton reagent, and the processing step comprises: depositing the liquid proton reagent on the surface of the initial quantum dot film, and then annealing deal with. 4. The preparation method according to claim 3, wherein the liquid proton reagent is deposited on the surface of the initial quantum dot film, and then the step of annealing treatment comprises: depositing the liquid proton reagent with 3- Spin-coat ^2-5 times in an amount of 20 μl/cm; and/or, The temperature of the annealing treatment is 60-100° C., and the time is 5-20 min. 5 . The preparation method of claim 1 , wherein the proton reagent is a gaseous proton reagent, and the processing step comprises: placing the initial quantum dot film in the gaseous proton reagent. 6 . Standing treatment, then annealing treatment. 6. preparation method as claimed in claim 5 is characterized in that, the time of described standing treatment is 30s-5min; And/or, The temperature of the annealing treatment is 60-100° C., and the time is 5-20 min. 7. The preparation method according to any one of claims 1-6, wherein the protic reagent comprises at least one of a hydroxyl-containing protic reagent and an amino-containing protic reagent. 8. preparation method as claimed in claim 7 is characterized in that, described hydroxyl-containing protic reagent comprises in water, methanol, ethanol, propanol, butanol, amyl alcohol, formic acid, acetic acid, propionic acid and butyric acid at least one; and/or, The amino group-containing proton reagent includes at least one of methylamine, ethylamine and propylamine. 9 . A quantum dot film, characterized in that, the quantum dot film is prepared by the preparation method according to any one of claims 1 to 8 . 10. A quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer between the anode and the cathode, wherein the quantum dot light-emitting layer is the quantum dot film of claim 9 . 11. A method for preparing a quantum dot light-emitting diode, comprising the steps of: A substrate is provided; an initial quantum dot thin film is prepared on the substrate, and then the initial quantum dot thin film is treated with a proton reagent to obtain a quantum dot light-emitting layer. 12 . The preparation method according to claim 11 , wherein the preparation method of the initial quantum dot film comprises: depositing a quantum dot solution on the substrate, and removing the solvent to obtain the initial quantum dot film. 13 . 13. The preparation method according to claim 11, wherein the proton reagent is a liquid proton reagent, and the processing step comprises: depositing the liquid proton reagent on the surface of the initial quantum dot film, and then annealing processing; or, The proton reagent is a gaseous proton reagent, and the processing step includes: placing the initial quantum dot film in the gaseous proton reagent for standing treatment, and then annealing treatment. 14. The preparation method according to claim 13, wherein the step of depositing the liquid proton reagent on the surface of the initial quantum dot film comprises: depositing the liquid proton reagent at a rate of 3-20 μl/cm ² each time amount of spin coating 2-5 times; or, The standing treatment time is 30s-5min. 15. The preparation method according to any one of claims 11-14, wherein the protic reagent comprises at least one of a hydroxyl-containing protic reagent and an amino-containing protic reagent. 16. The preparation method of claim 15, wherein the hydroxyl-containing protic reagent comprises water, methanol, ethanol, propanol, butanol, amyl alcohol, formic acid, acetic acid, propionic acid and butyric acid at least one; and/or, The amino group-containing proton reagent includes at least one of methylamine, ethylamine and propylamine.

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