CN113120947A - Composite material, preparation method thereof and quantum dot light-emitting diode - Google Patents
Composite material, preparation method thereof and quantum dot light-emitting diode Download PDFInfo
- Publication number
- CN113120947A CN113120947A CN201911390336.2A CN201911390336A CN113120947A CN 113120947 A CN113120947 A CN 113120947A CN 201911390336 A CN201911390336 A CN 201911390336A CN 113120947 A CN113120947 A CN 113120947A
- Authority
- CN
- China
- Prior art keywords
- samarium
- composite material
- zinc
- salt
- zinc oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G9/00—Compounds of zinc
- C01G9/02—Oxides; Hydroxides
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/14—Carrier transporting layers
- H10K50/16—Electron transporting layers
- H10K50/165—Electron transporting layers comprising dopants
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
- H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Luminescent Compositions (AREA)
Abstract
The invention belongs to the technical field of nano materials, and particularly relates to a composite material, a preparation method thereof and a quantum dot light-emitting diode. The preparation method of the composite material comprises the following steps: providing zinc salt and samarium salt, dissolving the zinc salt and the samarium salt in an organic solvent to form a cation solution, wherein the molar ratio of zinc element in the zinc salt to samarium element in the samarium salt is 1 (0.05-0.18); adding alkali liquor into the cation solution for reaction to obtain a precursor solution; and separating the precursor solution to prepare the composite material. In the replication material obtained by the preparation method, doped samarium can improve the conduction band energy level position of zinc oxide nanoparticles, and the composite material can be used for an electron transport layer of a quantum dot light-emitting diode to increase the potential barrier between an electrode and the electron transport layer of the device and limit electron injection, so that the carrier injection balance of the device is realized, and the brightness and the efficiency of the device are improved.
Description
Technical Field
The invention belongs to the technical field of nano materials, and particularly relates to a composite material, a preparation method thereof and a quantum dot light-emitting diode.
Background
The semiconductor Quantum Dots (QD) have Quantum size effect, people realize the Light emission with required specific wavelength by regulating the size of the Quantum dots, and Quantum Dot devices such as Quantum Dot Light Emitting Diodes (QLEDs) have a series of advantages of high color saturation, adjustable Light Emitting color, low energy consumption and the like, and have become powerful competitors of next generation display devices. Currently, organic-inorganic hybrid quantum dot light emitting diodes have better device performance than light emitting devices with organic transport layer structures, and this performance improvement benefits from the application of zinc oxide nanoparticles with high electron mobility. However, the excessively high electron mobility of zinc oxide tends to cause excessive electron injection, which leads to the phenomenon of electron accumulation in the quantum dot light emitting layer, and especially in the case of low hole mobility of the organic hole transport layer, insufficient hole injection further aggravates the carrier imbalance.
The injected carriers are balanced by adjusting the carrier mobility of the transmission layer, and the quantum dot device can be efficiently and stably realized. On one hand, organic small molecules or conductive polymers with high mobility can be selected, and on the other hand, the electron injection of the zinc oxide electron transport layer is limited through an interface method. However, both of the above methods have disadvantages, for example, the use of conductive polymers with high mobility is generally expensive, which is not favorable for commercial promotion, and the interface method has difficulty in limiting the control of the electron injection process and is not easy to implement. Thus, there is a need for improvements and enhancements in the art.
Disclosure of Invention
The invention aims to provide a composite material, a preparation method thereof and a quantum dot light-emitting diode, and aims to solve the technical problems that the electron migration rate of zinc oxide is too high and the carrier injection balance is difficult to realize.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a preparation method of a composite material, which comprises the following steps:
providing zinc salt and samarium salt, dissolving the zinc salt and the samarium salt in an organic solvent to form a cation solution, wherein the molar ratio of zinc element in the zinc salt to samarium element in the samarium salt is 1 (0.05-0.18);
adding alkali liquor into the cation solution for reaction to obtain a precursor solution;
and separating the precursor solution to prepare the composite material.
The preparation method of the composite material provided by the invention comprises the steps of dissolving zinc salt and samarium salt in an organic solvent, mixing with alkali liquor for reaction, preparing a precursor solution capable of generating samarium-doped zinc oxide nanoparticles under an alkaline condition, and separating the precursor solution to obtain the composite material (comprising the zinc oxide nanoparticles and samarium element doped in the zinc oxide nanoparticles); in the replication material obtained by the preparation method, doped samarium can improve the conduction band energy level position of zinc oxide nanoparticles, and the composite material can be used for an electron transport layer of a quantum dot light-emitting diode to increase the potential barrier between an electrode and the electron transport layer of the device and limit electron injection, so that the carrier injection balance of the device is realized, and the brightness and the efficiency of the device are improved.
The invention also provides a composite material, which comprises zinc oxide nano-particles and samarium doped in the zinc oxide nano-particles, wherein the molar ratio of zinc element to samarium element in the zinc oxide nano-particles is 1 (0.05-0.18).
In the composite material provided by the invention, zinc oxide has a hexagonal wurtzite structure, samarium atoms are doped to easily enter a zinc oxide crystal without changing the crystal structure of the zinc oxide crystal, and rare earth samarium atoms have larger radius and easily lose 2 s electrons on the outermost layer and one electron on the 5d orbit or the 4f layer on the secondary outer layer to form trivalent rare earth ions, so that multi-electron configuration is generated, and the electron transmission effect of the zinc oxide can be effectively inhibited; the doped samarium element can improve the position of a conduction band energy level of the zinc oxide nano-particles, and the composite material can be used for an electron transmission layer of a quantum dot light-emitting diode to increase a potential barrier between an electrode and the electron transmission layer of a device and limit electron injection, so that the carrier injection balance of the device is realized, and the brightness and the efficiency of the device are improved.
The invention also provides a quantum dot light-emitting diode which comprises an anode, a cathode and a quantum dot light-emitting layer positioned between the anode and the cathode, wherein an electron transmission layer is arranged between the cathode and the quantum dot light-emitting layer, and the electron transmission layer is composed of the composite material or the composite material prepared by the preparation method.
The electron transport layer of the quantum dot light-emitting diode provided by the invention is composed of the composite material or the composite material obtained by the preparation method; the composite material can effectively inhibit the electron transmission effect of zinc oxide, and can improve the conduction band energy level position of the zinc oxide, thereby increasing the potential barrier between an electrode and an electron transmission layer of a device, limiting electron injection, finally realizing the carrier injection balance of the device, and improving the brightness and the efficiency of the device.
Drawings
FIG. 1 is a schematic flow chart of a method for preparing a composite material according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a quantum dot light-emitting diode according to an embodiment of the invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In one aspect, an embodiment of the present invention provides a method for preparing a composite material, as shown in fig. 1, the method includes the following steps:
s01: providing zinc salt and samarium salt, dissolving the zinc salt and the samarium salt in an organic solvent to form a cation solution, wherein the molar ratio of zinc element in the zinc salt to samarium element in the samarium salt is 1 (0.05-0.18);
s02: adding alkali liquor into the cation solution for reaction to obtain a precursor solution;
s03: and separating the precursor solution to prepare the composite material.
According to the preparation method of the composite material provided by the embodiment of the invention, zinc salt and samarium salt are dissolved in an organic solvent and then mixed with alkali liquor to react, a precursor solution capable of generating samarium-doped zinc oxide nanoparticles is prepared under an alkaline condition, and the precursor solution is separated to obtain the composite material (comprising the zinc oxide nanoparticles and samarium element doped in the zinc oxide nanoparticles); in the replication material obtained by the preparation method, doped samarium can improve the conduction band energy level position of zinc oxide nanoparticles, and the composite material can be used for an electron transport layer of a quantum dot light-emitting diode to increase the potential barrier between an electrode and the electron transport layer of the device and limit electron injection, so that the carrier injection balance of the device is realized, and the brightness and the efficiency of the device are improved.
In the step S01, the zinc salt is a soluble zinc source, and is specifically selected from at least one of zinc chloride, zinc oleate, zinc nitrate, zinc acetate, and zinc stearate; the samarium salt is a soluble samarium source, and is specifically selected from at least one of samarium acetate, samarium chloride, samarium nitrate hexahydrate and samarium acetylacetonate. Wherein the molar ratio of the zinc element in the zinc salt to the samarium element in the samarium salt is 1: (0.05-0.18), the doping effect in this ratio range is the best. The organic solvent is at least one selected from diethyl formamide, triethanolamine, oleylamine and dimethyl sulfoxide. Dissolving the zinc salt and the samarium salt in an organic solvent to form a cation solution, and then adding alkali liquor to carry out mixing treatment, thereby obtaining a precursor solution.
Under the alkaline condition, the zinc salt and the samarium salt are hydrolyzed in the solution to form zinc hydroxide and samarium hydroxide, and the samarium-doped zinc oxide nano-particles are formed after further removing the solvent. The concentration of hydroxide ion in the added alkali solution is 0.05-0.5mol/L, and the alkali solution is solution of organic base and/or inorganic base such as ammonia water, potassium hydroxide, sodium hydroxide, lithium hydroxide, ethanolamine, ethylene glycol, diethanolamine, triethanolamine, ethylenediamine, etc., but not limited thereto. In the step of adding the alkali liquor for reaction, the total molar amount of the zinc element in the zinc salt and the samarium element in the samarium salt and the molar amount of hydroxide ions in the alkali liquor are 1: (1.5-2.0), adding alkali liquor into the mixed solution to make the solution alkaline, and removing the solvent to obtain the samarium-doped zinc oxide nanoparticles with uniformly dispersed particles. Further, the reaction time is 1-2 h.
In the step S03, the step of separating the precursor solution to prepare the composite material further includes: carrying out solid-liquid separation on the precursor solution; and dissolving the precipitate obtained after the solid-liquid separation and an alcamines stabilizer in a dispersing agent to obtain a solution containing the composite material. Dissolving the precipitate obtained after the solid-liquid separation, namely the samarium-doped zinc oxide nano-particles and an alcamines stabilizer in a dispersing agent to obtain a composite material solution containing the samarium-doped zinc oxide nano-particles; the solid-liquid separation can be a sedimentation treatment (for example, the precursor solution is firstly subjected to a sedimentation treatment to separate out sediments in the solution, and the sediments are collected, washed and dried to obtain the composite material. The zinc oxide nano-particles are easy to agglomerate, and the amine alcohol stabilizer can be combined on the surfaces of the zinc oxide nano-particles, so that the zinc oxide nano-particles are not easy to agglomerate, and a stable composite material solution is obtained. The alkanolamine stabilizer is at least one selected from monoethanolamine, diethanolamine, n-propanolamine, isopropanol amine and dibutanolamine; the dispersant is at least one selected from ethanol, propanol and propylene glycol. Wherein, the molar ratio of the zinc oxide in the zinc oxide nano particles to the alcamines stabilizer is 1: (0.05-0.08), dissolving the precipitate obtained after the solid-liquid separation and the alcohol amine stabilizer in a dispersing agent.
And further removing the dispersing agent from the samarium-doped zinc oxide nanoparticle solution. The obtained composite material comprises samarium-doped zinc oxide nano-particles and ethanolamine stabilizer combined on the surfaces of the zinc oxide nano-particles. Finally, the method for removing the dispersing agent comprises a sedimentation treatment or an annealing treatment. For the sedimentation treatment, the composite material solution is firstly subjected to sedimentation treatment to precipitate sediment in the solution, and the sediment is collected, cleaned and dried to obtain the composite material. The settling treatment is achieved by adding a precipitating agent such as ethyl acetate. For the annealing treatment, the solution of the composite material can be directly annealed at the temperature of 60-100 ℃ to obtain the powder composite material. In a specific embodiment, in order to obtain the composite material film, the solution of the composite material is deposited on a substrate and is annealed, so that the composite material film, namely the electron transport layer film is obtained; specifically, the temperature of the annealing treatment is 60-100 ℃; the time of the annealing treatment is 20-30 min. The annealing condition can better remove the solvent and form a compact and dense composite material film with uniformly distributed particles.
On the other hand, the embodiment of the invention also provides a composite material, which comprises zinc oxide nanoparticles and samarium doped in the zinc oxide nanoparticles, wherein the molar ratio of zinc element to samarium element in the zinc oxide nanoparticles is 1 (0.05-0.18).
In the composite material provided by the embodiment of the invention, zinc oxide has a hexagonal wurtzite structure, samarium atoms are doped to easily enter a zinc oxide crystal without changing the crystal structure of the zinc oxide crystal, and rare earth samarium atoms have a large radius and easily lose 2 s electrons on the outermost layer and one electron on the 5d orbit or the 4f layer on the secondary outer layer to form trivalent rare earth ions, so that multi-electron configuration is generated, and the electron transmission effect of the zinc oxide can be effectively inhibited; the doped samarium element can improve the position of a conduction band energy level of the zinc oxide nano-particles, and the composite material can be used for an electron transmission layer of a quantum dot light-emitting diode to increase a potential barrier between an electrode and the electron transmission layer of a device and limit electron injection, so that the carrier injection balance of the device is realized, and the brightness and the efficiency of the device are improved.
In one embodiment, the composite material is obtained by the above-described preparation method of the embodiment of the present invention.
In one embodiment, the molar ratio of zinc element to samarium element in the zinc oxide nanoparticles in the composite material is 1: 0.05-0.18. The bottom energy level position of the samarium-doped zinc oxide nanoparticle conduction band is gradually improved along with the increase of the samarium doping amount, but the electron transmission performance is further influenced by too high doping amount, so the effect is optimal within the range of the doping amount.
Furthermore, ethanolamine stabilizers are bonded to the surfaces of the zinc oxide nanoparticles in the composite material. Thus, the dispersibility of the composite material can be improved, and the composite material is more stable in a solution so as to form a film better. Specifically, the alkanolamine stabilizer is at least one selected from monoethanolamine, diethanolamine, n-propanolamine, isopropanolamine and dibutanolamine; the molar ratio of the zinc oxide in the zinc oxide nano particles to the alcamines stabilizer is 1: (0.05-0.08). Within the above ratio range, the stability of the composite material is better.
According to the embodiment of the invention, samarium is doped, so that the electron transfer rate of zinc oxide can be effectively reduced, and the energy level position of the conduction band of the zinc oxide nanoparticles is improved, thus the potential barrier between the electrode and the electron transport layer of the device is increased to limit electron injection, the high-efficiency quantum dot light-emitting diode can be realized, and the active promotion significance is provided for the research and development of the high-brightness and high-efficiency quantum dot light-emitting device. Therefore, the embodiment of the invention provides an application of the composite material or the composite material obtained by the preparation method as an electron transport material; specifically, the composite material or the composite material obtained by the preparation method can be used as an electron transport material for preparing an electron transport layer of a quantum dot light-emitting diode.
Finally, an embodiment of the present invention provides a quantum dot light emitting diode, including an anode, a cathode, and a quantum dot light emitting layer located between the anode and the cathode, where an electron transport layer is disposed between the cathode and the quantum dot light emitting layer, and the electron transport layer is composed of the composite material described above in the embodiment of the present invention or the composite material obtained by the preparation method described above in the embodiment of the present invention.
The electron transport layer in the quantum dot light-emitting diode provided by the embodiment of the invention is composed of the special composite material provided by the embodiment of the invention, the composite material can effectively inhibit the electron transport effect of zinc oxide, and can improve the conduction band energy level position of the zinc oxide, so that the potential barrier between an electrode and an electron transport layer of a device is increased, the electron injection is limited, the carrier injection balance of the device is finally realized, and the brightness and the efficiency of the device are improved.
In one embodiment, the thickness of the electron transport layer is 60-120 nm.
In one embodiment, an electron injection layer is further disposed between the electron transport layer and the cathode. In another embodiment, a hole function layer, such as a hole transport layer, or a stacked hole injection layer and hole transport layer, is disposed between the quantum dot light emitting layer and the anode, wherein the hole injection layer is adjacent to the anode. The electron transport layer based on samarium-doped zinc oxide nanoparticles can adapt to the mobility of a hole transport layer formed by a plurality of organic hole transport materials, so that the carrier injection of the device is balanced.
In one embodiment, a method for manufacturing a QLED device includes the steps of:
a: firstly, growing a hole injection layer on an ITO substrate;
b: then growing a hole transport layer on the hole injection layer;
c: then depositing a quantum dot light-emitting layer on the hole transport layer;
d: and finally, depositing an electron transmission layer on the quantum dot light-emitting layer, and evaporating a cathode on the electron transmission layer to obtain the quantum dot light-emitting diode.
The material of the electron transport layer is the composite material provided by the embodiment of the invention.
In order to obtain a high-quality electron transport layer, the ITO substrate needs to be subjected to a pretreatment process. The specific processing steps of the substrate include: cleaning the whole piece of ITO conductive glass with a cleaning agent, preliminarily removing stains on the surface, then sequentially carrying out ultrasonic cleaning in deionized water, acetone, absolute ethyl alcohol and deionized water for 20min respectively to remove impurities on the surface, and finally blowing dry with high-purity nitrogen to obtain the ITO positive electrode substrate.
The hole injection layer is selected from organic materials having hole injection capability. The hole injection material for preparing the hole injection layer includes, but is not limited to, one or more of poly (3, 4-ethylenedioxythiophene) -polystyrenesulfonic acid (PEDOT: PSS), 2,3,5, 6-tetrafluoro-7, 7',8,8' -tetracyanoquinodimethane (F4-TCNQ), 2,3,6,7,10, 11-hexacyano-1, 4,5,8,9, 12-Hexaazatriphenylene (HATCN), and the like.
The hole transport layer may be made of a hole transport material conventional in the art, including but not limited to TFB, PVK, Poly-TPD, TCTA, PEDOT: PSS, CBP, NiO, MoO3、WoO3Or a mixture of any combination thereof, and can also be other high-performance hole transport materials. The preparation of the hole transport layer comprises: an ITO basePlacing the plate on a spin coater, and spin-coating the prepared solution of the hole transport material to form a film; the film thickness is controlled by adjusting the concentration of the solution, the spin-coating speed and the spin-coating time, and then a thermal annealing process is performed at an appropriate temperature.
The quantum dots in the quantum dot light-emitting layer are oil-soluble quantum dots and comprise binary phase, ternary phase and quaternary phase quantum dots; wherein the binary phase quantum dots include CdS, CdSe, CdTe, InP, AgS, PbS, PbSe, HgS, etc., but are not limited thereto, and the ternary phase quantum dots include ZnXCd1-XS、CuXIn1-XS、ZnXCd1-XSe、ZnXSe1-XS、ZnXCd1-XTe、PbSeXS1-XEtc. are not limited thereto, and the quaternary phase quantum dots include, ZnXCd1-XS/ZnSe、CuXIn1-XS/ZnS、ZnXCd1-XSe/ZnS、CuInSeS、ZnXCd1-XTe/ZnS、PbSeXS1-Xthe/ZnS and the like are not limited thereto. Then the quantum dots can be any one of the three common red, green and blue quantum dots or other yellow light, and the quantum dots can be cadmium-containing or cadmium-free. The quantum dot light emitting layer of the material has the characteristics of wide and continuous excitation spectrum distribution, high emission spectrum stability and the like. Preparing a quantum dot light-emitting layer: spin-coating the prepared luminescent material solution with a certain concentration on a spin coater of a substrate with a spin-coated hole transport layer to form a film, controlling the thickness of the luminescent layer to be about 20-60nm by adjusting the concentration of the solution, the spin-coating speed and the spin-coating time, and drying at a proper temperature.
The electron transport layer is a composite material of the embodiment of the invention: the substrate which is coated with the quantum dot light emitting layer by the spin coating is placed on a spin coater, a composite material solution (such as 20mg/mL) with a certain concentration is prepared to form a film by the spin coating, the thickness of the electron transmission layer is controlled by adjusting the concentration of the solution, the spin coating speed (preferably, the rotating speed is between 2000 and 6000 rpm) and the spin coating time, the thickness is about 60-120nm, and then the film is formed by annealing at the temperature of 60-100 ℃. The step can be annealing in air or in nitrogen atmosphere, and the annealing atmosphere is selected according to actual needs.
Then, the deposition is finishedThe substrate of the functional layer is placed in an evaporation chamber, and a layer of 15-30nm metal Al, Ag and MoO is thermally evaporated through a mask plate3Au or Cu is used as a cathode, or a nano Ag wire or a Cu wire is used, so that the carrier can be injected smoothly due to smaller resistance.
Further, the obtained QLED is subjected to a packaging process, and the packaging process may be performed by a common machine or by a manual method. Preferably, the oxygen content and the water content in the packaging treatment environment are both lower than 0.1ppm so as to ensure the stability of the device.
The invention is described in further detail with reference to a part of the test results, which are described in detail below with reference to specific examples.
Example 1
The synthesis of samarium-doped zinc oxide nanoparticles comprises the following steps:
(1) adding 0.95mmol zinc chloride and 0.05mmol samarium acetate into 10mL diethyl formamide solvent, stirring to dissolve, and preparing cation solution (cation includes Zn)2+And Sm3+) The cation molar concentration of the cation solution is 0.1mol/L, wherein the molar percentage of doping amount samarium/(samarium + zinc) is 5 percent;
(2) adding 0.5mmol of potassium hydroxide into 5mL of absolute ethanol, and stirring to obtain anion solution (anion is OH)-) The anion molar concentration of the anion solution is 0.1 mol/L;
(3) slowly adding the anion solution prepared in the step (2) into the cation solution prepared in the step (1), and fully stirring for reaction for 1 hour;
(4) adding 100mL of ethyl acetate into the reacted solution for particle coagulation, performing centrifugal treatment, and then adding 5mL of isopropanol for dispersion under the ultrasonic condition;
(5) and (5) repeating the treatment in the step (4) for 2-3 times, and adding 80 mu L of ethanolamine serving as a stabilizer to obtain the samarium-doped zinc oxide nanoparticle solution.
Example 2
The synthesis of samarium-doped zinc oxide nanoparticles comprises the following steps:
(1) adding 4.5mmol zinc oleate and 0.5mmol samarium chloride into 100mL triethanolamine solvent in sequence, stirring to dissolve, and preparing cation solution (cation includes Zn)2+And Sm3+) The cation molar concentration of the cation solution is 0.05mol/L, wherein the molar percentage of doping amount samarium/(samarium + zinc) is 10 percent;
(2) adding 2mmol ammonia water into 40mL absolute ethyl alcohol, and stirring uniformly to obtain anion solution (anion is OH)-) The anion molar concentration of the anion solution is 0.05 mol/L;
(3) slowly adding the anion solution prepared in the step (2) into the cation solution prepared in the step (1), and fully stirring for reaction for 2 hours;
(4) adding 60mL of ethyl acetate into the reacted solution for particle coagulation, performing centrifugal treatment, and then adding 5mL of absolute ethyl alcohol for dispersion under the ultrasonic condition;
(5) and (5) repeating the treatment in the step (4) for 2-3 times, and adding 100 mu L of diethanolamine serving as a stabilizer to obtain the samarium-doped zinc oxide nanoparticle solution.
Example 3
The synthesis of samarium-doped zinc oxide nanoparticles comprises the following steps:
(1) adding 1.7mmol of zinc acetate and 0.3mmol of samarium nitrate hexahydrate into 10mL of oleylamine solvent in sequence, stirring for dissolving to obtain cation solution (the cation includes Zn)2+And Sm3+) The cation molar concentration of the cation solution is 0.5mol/L, wherein the molar percentage of doping amount samarium/(samarium + zinc) is 15 percent;
(2) adding 10mmol sodium hydroxide into 20mL absolute ethyl alcohol, and stirring to obtain anion solution (anion is OH)-) The anion molar concentration of the anion solution is 0.5 mol/L;
(3) slowly adding the anion solution prepared in the step (2) into the cation solution prepared in the step (1), and fully stirring for reaction for 1 hour;
(4) adding 100mL of ethyl acetate into the reacted solution for particle coagulation, performing centrifugal treatment, and then adding 10mL of propylene glycol for dispersion under the ultrasonic condition;
(5) and (5) repeating the treatment in the step (4) for 2-3 times, and adding 150 mu L of dibutanolamine as a stabilizer to obtain the samarium-doped zinc oxide nanoparticle solution.
Example 4
A QLED device is structurally shown in figure 2, and comprises a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a quantum dot light-emitting layer 5, an electron transport layer 6 and a cathode 7 which are sequentially stacked from bottom to top. The substrate 1 is made of glass sheets, the anode 2 is made of ITO (indium tin oxide), the hole injection layer 3 is made of PEDOT (PolyEthylene glycol) PSS (PolyEthylene glycol), the hole transport layer 4 is made of TFB (thin film transistor), the quantum dot light-emitting layer 5 is made of quantum dots, the electron transport layer 6 is made of samarium-doped zinc oxide nanoparticles of the embodiment 1, and the cathode 7 is made of Al.
The preparation method of the QLED device comprises the following steps:
1) firstly, placing a patterned ITO substrate in acetone, washing liquor, deionized water and isopropanol in sequence for ultrasonic cleaning, wherein each step of ultrasonic cleaning lasts for about 15 minutes. After the ultrasonic treatment is finished, the ITO substrate is placed in a clean oven to be dried for later use;
2) after the ITO substrate is dried, treating the surface of the ITO substrate for 5 minutes by using ultraviolet-ozone treatment so as to further remove organic matters attached to the surface of the ITO substrate and improve the work function of the ITO;
3) PSS with the thickness of 30nm is deposited on the surface of the processed ITO substrate, and the ITO substrate is placed on a heating table at 150 ℃ to be heated for 30 minutes to remove moisture, and the step needs to be finished in the air;
4) next, the dried ITO substrate coated with the hole injection layer was placed in a nitrogen atmosphere, a hole transport layer TFB was deposited, the thickness of which was 30nm, and it was heated on a heating stage at 150 ℃ for 30 minutes to remove the solvent;
5) and after the wafer processed in the previous step is cooled, depositing a quantum dot light-emitting layer on the surface of the TFB layer, wherein the thickness of the quantum dot light-emitting layer is 20 nm. After the deposition in this step, the wafer was heated on a heating table at 80 ℃ for 10 minutes to remove the residual solvent;
6) spin-coating the samarium-doped zinc oxide nanoparticle solution prepared in the embodiment 1 on a quantum dot light emitting layer to prepare a samarium-doped zinc oxide nanoparticle electron transport layer; wherein the mass concentration of the samarium-doped zinc oxide nanoparticle solution is 20mg/mL, the spin-coating time is 1 minute, the spin-coating speed is 3000rpm, and the spin-coated samarium-doped zinc oxide nanoparticle film is subjected to heat treatment at 80 ℃ for 30 minutes to obtain an electron transport layer, wherein the thickness of the electron transport layer is 80 nm;
7) and finally, placing the sheets with the deposited functional layers in an evaporation bin, and thermally evaporating a layer of 80nm aluminum as a cathode through a mask plate, so that the preparation of the QLED device is completed.
Example 5
A QLED device is structurally shown in figure 2, and comprises a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a quantum dot light-emitting layer 5, an electron transport layer 6 and a cathode 7 which are sequentially stacked from bottom to top. The substrate 1 is made of glass sheets, the anode 2 is made of ITO (indium tin oxide), the hole injection layer 3 is made of PEDOT (PolyEthylene glycol Ether), the hole transport layer 4 is made of TFB (thin film transistor), the quantum dot light emitting layer 5 is made of quantum dots, the electron transport layer 6 is made of samarium-doped zinc oxide nanoparticles of the embodiment 2, and the cathode 7 is made of Ag.
The preparation method of the QLED device comprises the following steps:
1) firstly, placing a patterned ITO substrate in acetone, washing liquor, deionized water and isopropanol in sequence for ultrasonic cleaning, wherein each step of ultrasonic cleaning lasts for about 15 minutes. After the ultrasonic treatment is finished, the ITO substrate is placed in a clean oven to be dried for later use;
2) after the ITO substrate is dried, treating the surface of the ITO substrate for 5 minutes by using ultraviolet-ozone treatment so as to further remove organic matters attached to the surface of the ITO substrate and improve the work function of the ITO;
3) PSS with the thickness of 30nm is deposited on the surface of the processed ITO substrate, and the ITO substrate is placed on a heating table at 150 ℃ to be heated for 30 minutes to remove moisture, and the step needs to be finished in the air;
4) next, the dried ITO substrate coated with the hole injection layer was placed in a nitrogen atmosphere, a hole transport layer PVK was deposited, the thickness of this layer was 30nm, and it was heated on a heating stage at 150 ℃ for 30 minutes to remove the solvent;
5) and after the wafer processed in the previous step is cooled, depositing the quantum dot light emitting layer on the surface of the PVK layer, wherein the thickness of the quantum dot light emitting layer is 20 nm. After the deposition in this step, the wafer was heated on a heating table at 80 ℃ for 10 minutes to remove the residual solvent;
6) spin-coating the samarium-doped zinc oxide nanoparticle solution prepared in the embodiment 2 on the quantum dot light emitting layer to prepare a samarium-doped zinc oxide nanoparticle electron transport layer; wherein the mass concentration of the samarium-doped zinc oxide nanoparticle solution is 20mg/mL, the spin-coating time is 1 minute, the spin-coating speed is 2500rpm, and the spin-coated samarium-doped zinc oxide nanoparticle film is subjected to heat treatment at 100 ℃ for 30 minutes to obtain an electron transport layer, wherein the thickness of the electron transport layer is 60 nm;
7) and finally, placing the sheets with the deposited functional layers in an evaporation bin, and thermally evaporating a layer of 50nm silver as a cathode through a mask plate, so that the preparation of the QLED device is completed.
Example 6
A QLED device is structurally shown in figure 2, and comprises a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, a quantum dot light-emitting layer 5, an electron transport layer 6 and a cathode 7 which are sequentially stacked from bottom to top. The substrate 1 is made of glass sheets, the anode 2 is made of ITO (indium tin oxide), the hole injection layer 3 is made of PEDOT (PolyEthylene glycol Ether), the hole transport layer 4 is made of TFB (thin film transistor), the quantum dot light emitting layer 5 is made of quantum dots, the electron transport layer 6 is made of samarium-doped zinc oxide nanoparticles of the embodiment 3, and the cathode 7 is made of Ag.
The preparation method of the QLED device comprises the following steps:
1) firstly, placing a patterned ITO substrate in acetone, washing liquor, deionized water and isopropanol in sequence for ultrasonic cleaning, wherein each step of ultrasonic cleaning lasts for about 15 minutes. After the ultrasonic treatment is finished, the ITO substrate is placed in a clean oven to be dried for later use;
2) after the ITO substrate is dried, treating the surface of the ITO substrate for 5 minutes by using ultraviolet-ozone treatment so as to further remove organic matters attached to the surface of the ITO substrate and improve the work function of the ITO;
3) PSS with the thickness of 30nm is deposited on the surface of the processed ITO substrate, and the ITO substrate is placed on a heating table at 150 ℃ to be heated for 30 minutes to remove moisture, and the step needs to be finished in the air;
4) next, the dried ITO substrate coated with the hole injection layer was placed in a nitrogen atmosphere, a hole transport layer TFB was deposited, the thickness of which was 30nm, and it was heated on a heating stage at 150 ℃ for 30 minutes to remove the solvent;
5) and after the wafer processed in the previous step is cooled, depositing the quantum dot light emitting layer on the surface of the TFB layer, wherein the thickness of the TFB layer is 20 nm. After the deposition in this step, the wafer was heated on a heating table at 80 ℃ for 10 minutes to remove the residual solvent;
6) spin-coating the samarium-doped zinc oxide nanoparticle solution prepared in example 3 on a quantum dot light emitting layer to prepare a samarium-doped zinc oxide nanoparticle electron transport layer; wherein the mass concentration of the samarium-doped zinc oxide nanoparticle solution is 20mg/mL, the spin-coating time is 1 minute, the spin-coating speed is 4000rpm, and the spin-coated samarium-doped zinc oxide nanoparticle film is subjected to heat treatment at 60 ℃ for 2 hours to obtain an electron transport layer, wherein the thickness of the electron transport layer is 120 nm;
7) and finally, placing the sheets with the deposited functional layers in an evaporation bin, and thermally evaporating a layer of 50nm aluminum as a cathode through a mask plate, so that the preparation of the QLED device is completed.
Comparative example 1
A quantum dot light emitting diode, which is the same as example 4 except that the material of the electron transport layer is commercial ZnO nanomaterial.
Comparative example 2
A quantum dot light emitting diode, which is the same as example 5 except that the material of the electron transport layer is commercial ZnO nanomaterial.
Comparative example 3
A quantum dot light emitting diode, which is the same as example 6 except that the material of the electron transport layer is commercial ZnO nanomaterial.
Performance testing
The electron transport layers and quantum dot light emitting diodes of examples 4 to 6 and comparative examples 1 to 3 were subjected to performance tests, and the test indexes and test methods were as follows:
(1) electron mobility: testing the current density (J) -voltage (V) of the electron transport layer film, drawing a curve relation graph, fitting a Space Charge Limited Current (SCLC) region in the relation graph, and then calculating the electron mobility according to a well-known Child's law formula:
J＝(9/8)εrε0μeV2/d3
wherein J represents current density in mAcm-2；εrDenotes the relative dielectric constant,. epsilon0Represents the vacuum dielectric constant; mu.seDenotes the electron mobility in cm2V-1s-1(ii) a V represents the drive voltage, in units of V; d represents the film thickness in m.
(2) Resistivity: and measuring the film resistivity of the electron transport layer by using the same resistivity measuring instrument.
(3) External Quantum Efficiency (EQE): measured using an EQE optical test instrument.
Note: the electron mobility and resistivity were tested as single layer thin film structure devices, namely: cathode/electron transport layer film/anode. The external quantum efficiency test is the QLED device, namely: anode/hole injection layer/hole transport layer/quantum dot light emitting layer/electron transport layer/cathode.
The test results are shown in table 1 below:
TABLE 1
As can be seen from table 1 above, the electron transport layer thin film provided by the embodiment of the present invention has better electron mobility. The external quantum efficiency of the quantum dot light-emitting diode provided by the embodiments 4-6 (the electron transport layer material is the composite material specific to the embodiments) is obviously higher than that of the quantum dot light-emitting diode in which the electron transport layer material is the zinc oxide nano material in the comparative example, which shows that the quantum dot light-emitting diode obtained by the embodiments has better light-emitting efficiency.
It is noted that the embodiments provided by the present invention all use blue light quantum dots CdXZn1-XS/ZnS is used as a material of a luminescent layer, is based on that a blue light luminescent system uses more systems (the blue light quantum dot luminescent diode has more reference value because high efficiency is difficult to achieve), and does not represent that the invention is only used for the blue light luminescent system.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. The preparation method of the composite material is characterized by comprising the following steps:
providing zinc salt and samarium salt, dissolving the zinc salt and the samarium salt in an organic solvent to form a cation solution, wherein the molar ratio of zinc element in the zinc salt to samarium element in the samarium salt is 1 (0.05-0.18);
adding alkali liquor into the cation solution for reaction to obtain a precursor solution;
and separating the precursor solution to prepare the composite material.
2. The method of preparing a composite material according to claim 1,
in the step of adding the alkali liquor into the cation solution for reaction, the total molar amount of the zinc element in the zinc salt and the samarium element in the samarium salt and the molar amount of hydroxide ions in the alkali liquor are 1 (1.5-2.0); and/or the presence of a gas in the gas,
the concentration of hydroxide ions in the alkali liquor is 0.05-0.5 mol/L; and/or the presence of a gas in the gas,
the reaction time is 1-2 h.
3. The method of preparing a composite material according to claim 1, wherein the step of separating the precursor solution to prepare the composite material further comprises:
carrying out solid-liquid separation on the precursor solution;
and dissolving the precipitate obtained after the solid-liquid separation and an alcamines stabilizer in a dispersing agent to obtain a solution containing the composite material.
4. The method of claim 3, wherein the alkanolamine stabilizer is at least one selected from the group consisting of monoethanolamine, diethanolamine, n-propanolamine, isopropanolamine and dibutanolamine; and/or the presence of a gas in the gas,
the dispersant is at least one selected from ethanol, propanol and propylene glycol.
5. The method for preparing a composite material according to any one of claims 1 to 4, wherein the zinc salt is selected from at least one of zinc chloride, zinc oleate, zinc nitrate, zinc acetate and zinc stearate; and/or the presence of a gas in the gas,
the samarium salt is selected from at least one of samarium acetate, samarium chloride, samarium nitrate hexahydrate and samarium acetylacetonate; and/or the presence of a gas in the gas,
the organic solvent is at least one selected from diethyl formamide, triethanolamine, oleylamine and dimethyl sulfoxide.
6. The composite material is characterized by comprising zinc oxide nanoparticles and samarium doped in the zinc oxide nanoparticles, wherein the molar ratio of zinc element to samarium element in the zinc oxide nanoparticles is 1 (0.05-0.18).
7. The composite material of claim 6, wherein ethanolamine-based stabilizers are bound to the surfaces of the zinc oxide nanoparticles.
8. The composite material of claim 7, wherein the alkanolamine stabilizer is selected from at least one of monoethanolamine, diethanolamine, n-propanolamine, isopropanol amine, and dibutanolamine; and/or the presence of a gas in the gas,
the molar ratio of the zinc oxide in the zinc oxide nano-particles to the alcohol amine stabilizer is 1 (0.05-0.08).
9. 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 an electron transport layer is arranged between the cathode and the quantum dot light-emitting layer, and the electron transport layer is composed of a composite material obtained by the preparation method according to any one of claims 1 to 5 or the composite material according to any one of claims 6 to 8.
10. The quantum dot light-emitting diode of claim 9, wherein the electron transport layer has a thickness of 60-120 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911390336.2A CN113120947A (en) | 2019-12-30 | 2019-12-30 | Composite material, preparation method thereof and quantum dot light-emitting diode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911390336.2A CN113120947A (en) | 2019-12-30 | 2019-12-30 | Composite material, preparation method thereof and quantum dot light-emitting diode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113120947A true CN113120947A (en) | 2021-07-16 |
Family
ID=76767458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911390336.2A Pending CN113120947A (en) | 2019-12-30 | 2019-12-30 | Composite material, preparation method thereof and quantum dot light-emitting diode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113120947A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023088088A1 (en) * | 2021-11-19 | 2023-05-25 | Tcl科技集团股份有限公司 | Nanoparticle, preparation method therefor, and light-emitting diode |
| WO2023124478A1 (en) * | 2021-12-30 | 2023-07-06 | Tcl科技集团股份有限公司 | Basic zinc salt nanoparticles and preparation method therefor, and quantum dot light-emitting diode |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103364446A (en) * | 2013-06-28 | 2013-10-23 | 上海纳米技术及应用国家工程研究中心有限公司 | Preparation method of rare earth doped zinc oxide nanowire for gas sensor |
| CN108183173A (en) * | 2017-12-14 | 2018-06-19 | 中国科学院广州能源研究所 | It is a kind of based on light emitting diode with quantum dots for mixing yttrium zinc oxide electron transfer layer and preparation method thereof |
| CN110416420A (en) * | 2018-04-28 | 2019-11-05 | Tcl集团股份有限公司 | Light emitting diode with quantum dots and preparation method thereof |
-
2019
- 2019-12-30 CN CN201911390336.2A patent/CN113120947A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103364446A (en) * | 2013-06-28 | 2013-10-23 | 上海纳米技术及应用国家工程研究中心有限公司 | Preparation method of rare earth doped zinc oxide nanowire for gas sensor |
| CN108183173A (en) * | 2017-12-14 | 2018-06-19 | 中国科学院广州能源研究所 | It is a kind of based on light emitting diode with quantum dots for mixing yttrium zinc oxide electron transfer layer and preparation method thereof |
| CN110416420A (en) * | 2018-04-28 | 2019-11-05 | Tcl集团股份有限公司 | Light emitting diode with quantum dots and preparation method thereof |
Non-Patent Citations (4)
| Title |
|---|
| HU YAJING: "Luminescence Properties and Controllable Synthesis of Sm3+-doped ZnO Quantum Dots", 《RARE METAL MATERIALS AND ENGINEERING》 * |
| M.A.M. AHMED: "Structural, optical and electrical properties of the fabricated Schottky diodes based on ZnO, Ce and Sm doped ZnO films prepared via wet chemical technique", 《MATERIALS RESEARCH BULLETIN》 * |
| P.HARIKRISHNAN: "Optical properties of samarium doped Zinc Oxide thin film", 《RESEARCHGATE》 * |
| Y. J. ZHU: "Effect of lithium doping on the photoluminescence of Sm:ZnO powders", 《J SOL-GEL SCI TECHNOL》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023088088A1 (en) * | 2021-11-19 | 2023-05-25 | Tcl科技集团股份有限公司 | Nanoparticle, preparation method therefor, and light-emitting diode |
| WO2023124478A1 (en) * | 2021-12-30 | 2023-07-06 | Tcl科技集团股份有限公司 | Basic zinc salt nanoparticles and preparation method therefor, and quantum dot light-emitting diode |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109980106B (en) | Electron transport material, preparation method thereof and QLED device | |
| CN112538163B (en) | Composite material, preparation method thereof and quantum dot light emitting diode | |
| CN109994607B (en) | Hole transport material and preparation method and application thereof | |
| CN113120947A (en) | Composite material, preparation method thereof and quantum dot light-emitting diode | |
| CN110838560B (en) | Core-shell nano material, preparation method thereof and quantum dot light-emitting diode | |
| CN112625674B (en) | Composite material, quantum dot light-emitting diode and preparation method thereof | |
| CN112397659B (en) | Composite material, preparation method thereof and quantum dot light-emitting diode | |
| CN112397656B (en) | Composite material, preparation method thereof and quantum dot light-emitting diode | |
| CN112349850A (en) | Inorganic semiconductor material and preparation method thereof | |
| CN113707777B (en) | Composite material, preparation method thereof and light-emitting device | |
| CN112397670B (en) | Composite material and preparation method thereof and quantum dot light-emitting diode | |
| CN109695028A (en) | Zinc-oxide film and preparation method thereof, luminescent device | |
| CN112397661B (en) | Nano material, preparation method thereof and quantum dot light-emitting diode | |
| CN111384245B (en) | Composite material, preparation method thereof and quantum dot light-emitting diode | |
| CN114388713A (en) | Electron transport material, preparation method thereof and photoelectric device | |
| CN113121382A (en) | Metal compound material and preparation method thereof, quantum dot light-emitting diode and light-emitting device | |
| CN113054118B (en) | Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof | |
| CN112397655B (en) | Composite material and preparation method thereof and quantum dot light-emitting diode | |
| CN113054145B (en) | Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof | |
| CN112397620B (en) | Nano composite particle and preparation method and application thereof | |
| CN113045211B (en) | Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof | |
| CN112349870B (en) | Quantum dot light-emitting diode and preparation method thereof | |
| CN110963535A (en) | Composite material, preparation method thereof and quantum dot light-emitting diode | |
| CN113054062B (en) | Nano material and preparation method thereof, quantum dot light-emitting diode and light-emitting device | |
| CN111725433B (en) | Quantum dot light-emitting diode and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210716 |