WO2022227660A1 - 墨水、量子点薄膜的制备方法和发光二极管的制备方法 - Google Patents

墨水、量子点薄膜的制备方法和发光二极管的制备方法 Download PDF

Info

Publication number
WO2022227660A1
WO2022227660A1 PCT/CN2021/141737 CN2021141737W WO2022227660A1 WO 2022227660 A1 WO2022227660 A1 WO 2022227660A1 CN 2021141737 W CN2021141737 W CN 2021141737W WO 2022227660 A1 WO2022227660 A1 WO 2022227660A1
Authority
WO
WIPO (PCT)
Prior art keywords
ink
solvent
quantum dot
light
quantum dots
Prior art date
Application number
PCT/CN2021/141737
Other languages
English (en)
French (fr)
Inventor
侯文军
Original Assignee
Tcl科技集团股份有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tcl科技集团股份有限公司 filed Critical Tcl科技集团股份有限公司
Publication of WO2022227660A1 publication Critical patent/WO2022227660A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/50—Sympathetic, colour changing or similar inks
    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/12—Deposition of organic active material using liquid deposition, e.g. spin coating
    • H10K71/13—Deposition of organic active material using liquid deposition, e.g. spin coating using printing techniques, e.g. ink-jet printing or screen printing
    • H10K71/135—Deposition of organic active material using liquid deposition, e.g. spin coating using printing techniques, e.g. ink-jet printing or screen printing using ink-jet printing

Definitions

  • the present application relates to the technical field of quantum dots, in particular to a method for preparing ink, quantum dot film and a method for preparing light emitting diodes.
  • Quantum dots have unique optoelectronic properties, such as the emission wavelength is continuously adjustable with size and composition, the emission spectrum is narrow, the fluorescence efficiency is high, and the stability is good.
  • Dot Light Emitting Diode, QLED has received extensive attention and research in the display field.
  • QLED display also has the advantages of large viewing angle, high contrast ratio, fast response speed, and flexibility, so it is expected to become the next-generation display technology.
  • the QLED device needs to inject electrons and holes when it works.
  • the simplest QLED device includes a cathode, an electron transport layer, a quantum dot light-emitting layer, a hole transport layer, and an anode.
  • the quantum dot light-emitting layer film is sandwiched between the charge transport layer.
  • a forward bias is applied to both ends of the QLED device, electrons and holes enter the quantum dot light-emitting layer through the electron transport layer and the hole transport layer, respectively. And composite light in the quantum dot light-emitting layer.
  • Inkjet printing is an important solution processing technology for realizing red, green and blue (RGB) three primary color pixels. It is the most potential color film-forming technology for making QLED displays.
  • the phase transition process of the solution to form a solid thin film on a substrate is very complex, so the process of preparing organic thin films by inkjet printing requires continuous research and exploration.
  • the film formation uniformity of quantum dot materials in pixel pits ie, pixel banks
  • the purpose of the embodiments of the present application is to provide an ink, a method for preparing a quantum dot film, and a method for preparing a light-emitting diode.
  • a first aspect provides an ink comprising a solvent and quantum dots and an ionic compound dispersed in the solvent; wherein at least part of the anions and/or at least part of the cations in the ionic compound are bound to the quantum dots point surface;
  • At least some of the at least some of the anions contain photoactive groups, and at least some of the at least some of the cations contain photoactive groups.
  • a method for preparing a quantum dot film comprising the steps of:
  • the liquid film is subjected to ultraviolet irradiation treatment to obtain the quantum dot film.
  • a method for preparing a light-emitting diode comprising the following steps:
  • the surface of the substrate is provided with pixel pits
  • the liquid film is subjected to ultraviolet irradiation treatment to obtain a light-emitting layer.
  • the beneficial effect of the ink provided by the embodiments of the present application is that ionic compounds are dispersed in the ink, and at least part of the anions and/or at least part of the cations in the ionic compounds are bound to the surface of the quantum dots.
  • the lower photoactive groups can chemically react on the surface of the quantum dots, so that the chemical structure of the ligands on the surface of the quantum dots changes, so that the solubility of the quantum dots is reduced or difficult to dissolve; such inks form a liquid film on the substrate and then undergo Ultraviolet light can cause the quantum dots to settle, so as to obtain a quantum dot film with a uniform film layer.
  • the beneficial effect of the method for preparing the quantum dot thin film provided by the embodiment of the present application is that the film is prepared by using the unique ink of the present application.
  • the active groups can undergo chemical reactions, which change the chemical structure of the ligands on the surface of the quantum dots, so that the solubility of the quantum dots is reduced or it is difficult to dissolve and settle, so that a quantum dot film with a uniform film layer can be obtained.
  • the beneficial effect of the preparation method of the light emitting diode provided by the embodiment of the present application is that the unique ink of the present application is used to form a film on the pixel pit substrate to obtain a uniform light emitting layer, so the light emitting performance of the light emitting diode device can be improved.
  • FIG. 1 is a schematic flowchart of a method for preparing a quantum dot film provided in an embodiment of the present application
  • Fig. 2 is the schematic diagram of the preparation process principle of the quantum dot film provided in the embodiment of the present application;
  • FIG. 3 is a schematic flowchart of a method for preparing a light-emitting diode provided by an embodiment of the present application
  • FIG. 4 is a schematic structural diagram of a light emitting diode device provided by an embodiment of the present application.
  • At least one refers to one or more, and “multiple” refers to two or more.
  • At least in part refers to a part or all; “at least one of the following” or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items(s).
  • at least one (one) of a, b, or c or “at least one (one) of a, b, and c” can mean: a, b, c, a-b ( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.
  • Some embodiments of the present application provide an ink, the ink includes a solvent and quantum dots dispersed in the solvent, and the surface of the quantum dots is bound with an anion-cation pair ligand and an ionic compound; wherein, at least part of the anions and/or at least a Part of the cations are bound to the surface of the quantum dots; where,
  • At least some of at least some of the anions contain photoactive groups, and at least some of at least some of the cations contain photoactive groups.
  • the ink provided by the embodiments of the present application has good film formation uniformity.
  • ionic compounds are dispersed in the ink, and at least part of the anions and/or at least part of the cations in the ionic compounds are bound to the surface of the quantum dots, and are bound to the surface of the quantum dots.
  • At least part of the anions and/or at least part of the cations on the surface of the quantum dots contain photoactive groups, and the photoactive groups can undergo chemical reactions on the surface of the quantum dots under ultraviolet light irradiation, so that the chemical structure of the ligands on the surface of the quantum dots changes, thereby The solubility of the quantum dots is reduced or difficult to dissolve; therefore, based on the performance principle of the above-mentioned inks, when the inks of the embodiments of the present application are deposited on the substrate to form a liquid film, ultraviolet light can cause the quantum dots to settle evenly, so that uniform deposition can occur. On the surface of the substrate, a quantum dot film with good film uniformity is obtained.
  • the ink containing quantum dots in the embodiments of the present application at least one ionic compound containing a photoactive group is added, the ionic compound is dispersed in a solvent and dissociated to form anions and cations, and at least part of the anions and/or at least part of the ionic compounds
  • the cations may be bound to the surface of the quantum dots, and at least some of the at least some of the anions bound to the surface of the quantum dots contain photoactive groups, and at least some of the at least some of the cations bound to the surface of the quantum dots contain photoactive groups. That is, the above-mentioned ionic compound dispersed in the ink can be one or more.
  • the quantum dots When it is dispersed in the ink, no matter whether it is at least part of the anions or at least part of the cations of the ionic compound bound to the surface of the quantum dots, it is bound to the quantum dots. At least some of the ions (anions and/or cations) of the ionic compounds on the dot surface contain photoactive groups.
  • the photoactive groups bound to the surface of the quantum dots can undergo a chemical reaction on the surface of the quantum dots under the irradiation of ultraviolet light, so that the chemical structure of the ligands on the surface of the quantum dots is changed, so that the solubility of the quantum dots is reduced or difficult to dissolve.
  • the ink containing quantum dots is dispersed with ionic compounds, and the ionic compounds dissociate into anions and cations, wherein the ionic compounds At least part of the anions are coordinated with the less-electron metal ions on the surface of the quantum dots as multi-electron ligands, and the negative charges generated after the coordination of the ionic compound anions are balanced by the ionic compound cations in the ink solution.
  • the coordinated compound anion contains a photoactive group that is capable of chemical reaction under ultraviolet (UV) light irradiation.
  • the quantum dots with ionic compound anion coordination in the ink can be dissolved in the solvent, and after the chemical reaction occurs, the chemical structure of the ligands on the surface of the quantum dots changes, and the solubility in the original solvent decreases, or there is no Soluble and insoluble, resulting in sedimentation.
  • At least part of the cations in the ionic compound are bound to the surface of the quantum dots in the ink
  • at least part of the photoactive groups contained in the at least part of the cations are selected from Ph 2 I + and Ph 3 S + . at least one.
  • Ph 2 I + and Ph 3 S + can react chemically on the surface of the quantum dots under ultraviolet light irradiation, so that the chemical structure of the ligands on the surface of the quantum dots is changed, so that the solubility of the quantum dots is reduced or difficult to dissolve.
  • the anions in the ionic compound are selected from at least one of PbBr 3 - , ZnCl 4 2- and CdCl 4 2- ; at this time, it is not excluded that Anions in ionic compounds can also have photoactive groups, such as CS 2 N 3 - .
  • At least part of the anions in the ionic compound are bound to the surface of the quantum dots in the ink
  • at least part of the photoactive groups contained in the at least part of the anions are selected from CS 2 N 3 ⁇ .
  • the cation in the ionic compound is selected from at least one of K + and NH 4 + ; at this time, it is not excluded that the cation in the ionic compound can also be There are photoactive groups, such as Ph 2 I + , Ph 3 S + .
  • At least part of the anions in the at least part of the anions contain photoactive groups selected from CS 2 N 3 ⁇
  • at least part of the cations At least a part of the photoactive groups contained are selected from at least one of Ph 2 I + and Ph 3 S + .
  • the boiling point of the solvent in the ink is greater than 150° C.; the boiling point of the solvent makes the ink more suitable for inkjet printing.
  • the solvent in the ink is selected from polar solvents or non-polar solvents.
  • the polar solvent includes at least one of N,N-dimethylformamide, N-methylformamide, dimethyl sulfoxide, and methyl benzoate ;
  • the non-polar solvents include at least one of xylene and phenyl hexane.
  • the solvent of the ink is selected from polar solvents, and the quantum dots with anionic and cationic pair ligands have better solubility in polar solvents.
  • the concentration of quantum dots in the ink is 1wt%-20wt% (weight percentage), and the ink within the above concentration range has good dispersibility and can be used for inkjet printing.
  • the quantum dot material in the ink can be a Cd-containing quantum dot material, such as CdSe/CdS, CdZnSe/CdS, CdSe/CdS/ZnS, etc., or a non-Cd quantum dot material, such as InP/ZnS, ZnSe/ZnS etc.
  • the inks of the embodiments of the present application can use inkjet printing technology to prepare quantum dot films.
  • Some embodiments of the present application also provide a method for preparing a quantum dot film, as shown in FIG. 1 , the preparation method includes the following steps:
  • the method for preparing the quantum dot thin film provided by the embodiments of the present application is prepared by using the unique ink of the present application. Specifically, after the ink is deposited on a substrate to obtain a liquid film, ultraviolet light is applied, and the surface of the quantum dots in the liquid film is irradiated with ultraviolet light.
  • the photoactive groups can chemically react on the surface of the quantum dots, so that the chemical structure of the ligands on the surface of the quantum dots changes, so that the solubility of the quantum dots is reduced or difficult to dissolve, resulting in sedimentation, which can be uniformly deposited on the substrate. surface to obtain a quantum dot thin film with a uniform film layer.
  • the preparation method of the quantum dot film provided by the embodiment of the present application is prepared by using the ink unique to the embodiment of the present application, and the options of the ink mentioned above can all be used in the preparation method of the quantum dot film. Therefore, the above-mentioned preparation method of the quantum dot film has all the advantages of the foregoing ink alternatives, which will not be repeated here.
  • pixel pits are provided on the surface of the substrate
  • the step of depositing ink on the substrate includes: using inkjet printing to print the ink in the pixel pits Bank on the substrate.
  • the inkjet printing material has a high utilization rate, and can realize patterning without using a mask, and using such an ink, the quantum dot material can have good film formation uniformity in the pixel pit.
  • a drying process is performed so that the thickness of the liquid film in the pixel pit Bank ⁇ the depth of the pixel pit Bank.
  • the above drying treatment can be decompression drying at normal temperature (25-27°C), through decompression drying, the ink surface in the pixel pit Bank is flat, and the liquid film thickness is the same as the depth of the pixel pit Bank or lower than the depth of the pixel pit Bank. , which can better ensure that the sub-pixels deposit the same ink, and the formed liquid film layer with multiple sub-pixels has a uniform thickness; then UV irradiation, the quantum dots can form a uniform film layer after chemical reaction and sedimentation under UV irradiation. Subpixel patterned quantum dot films.
  • drying treatment is performed before ultraviolet irradiation, so that the thickness of the ink in the liquid film in the sub-pixels is less than or equal to the depth of the pixel pit Bank.
  • the solvent can be removed by drying first.
  • annealing treatment is performed again; specifically, after ultraviolet irradiation, further drying treatment (such as drying under reduced pressure at room temperature) may be performed to remove the solvent in the sub-pixels, so as to better perform annealing treatment later.
  • a is the inkjet printing quantum dot ink
  • b is the first drying VCD (vacuum chamber drying, that is, reduced pressure drying), so that the pixels The thickness of the quantum dot ink in the pit is flush with the Bank
  • c is UV irradiation, which causes the photoactive groups in the ligands on the surface of the quantum dots to chemically react, and the quantum dot material settles in the solvent
  • d is the second drying VCD The solvent is removed and then thermal annealing is performed to form a solid quantum dot film.
  • annealing treatment is further included.
  • the irradiation time of the ultraviolet light is 1 ⁇ 100s, for example, 20 ⁇ 80s, or 40 ⁇ 60s.
  • the temperature of annealing treatment is 80 ⁇ 150°C; the time of annealing treatment is 1 ⁇ 30min.
  • the quantum dot film (the ink used includes a solvent) And the quantum dots dispersed in the solvent, the above-mentioned ionic compounds of the present application are not dispersed in the ink, the uniformity of the quantum dot film obtained after film formation with such an ink is generally: about 80% in the short axis direction @ ⁇ 10nm (that is, short).
  • the uniformity of the quantum dot film prepared by using this unique ink >95%@ ⁇ 10nm in the short axis direction (that is, about Therefore, the preparation method of the embodiment of the present application significantly improves the uniformity of the quantum dot film; the above quantum dot film can be measured by a step tester.
  • Some embodiments of the present application also provide a method for preparing a light emitting diode, as shown in FIG. 3 , including the following steps:
  • E01 Provide a substrate, and the surface of the substrate is provided with pixel pits;
  • E02 depositing the ink of the present application on a substrate to obtain a liquid film
  • E03 The liquid film is subjected to ultraviolet irradiation treatment to obtain a light-emitting layer.
  • the ink unique to the embodiment of the present application is used to form a film on the pixel pit substrate to obtain a light emitting layer with a uniform film layer. Therefore, the preparation method can improve the light emitting performance of the light emitting diode device. .
  • the ink of the embodiment of the present application is used to prepare the light-emitting layer, and the ink of the embodiment of the present application is deposited on the substrate to obtain a liquid film, and then the liquid film is subjected to ultraviolet
  • the light-emitting layer is obtained by light treatment, and such a process is essentially the process of the preparation method of the quantum dot film of the embodiment of the present application.
  • the method for preparing a light-emitting diode uses the ink unique to the embodiment of the present application to prepare the light-emitting layer, the options of the ink mentioned above can all be used in the method for preparing the light-emitting diode; and the present application implements
  • the preparation method of the light-emitting diode provided in the example uses the preparation method of the quantum dot film of the embodiment of the present application to prepare the light-emitting layer, and the optional solution of the preparation method of the quantum dot film mentioned above can also be used in the preparation method of the light-emitting diode. Therefore, the preparation method of the light emitting diode has all the advantages of the alternative solutions of the aforementioned ink and the aforementioned preparation method of the quantum dot film, and will not be repeated here.
  • the prepared light-emitting diode is a quantum dot light-emitting diode, comprising an anode, a cathode, and a quantum dot light-emitting layer disposed between the anode and the cathode; a hole transport layer may be disposed between the anode and the quantum dot light-emitting layer, Specifically, a hole injection layer may be provided between the hole transport layer and the anode; or an electron transport layer may be provided between the cathode and the quantum dot light-emitting layer, specifically, an electron injection layer may be provided between the electron transport layer and the cathode.
  • the quantum dot light-emitting diode can be an upright device or an inverted device.
  • the preparation method of the light emitting diode includes: preparing an anode on a substrate; preparing a hole injection layer on the anode; preparing a hole transport layer on the hole injection layer; and then using the quantum dot film of the present application Preparation method
  • the quantum dot thin film is prepared on the surface of the hole transport layer on the substrate, that is, the quantum dot light-emitting layer is obtained; the electron transport layer is prepared on the quantum dot light-emitting layer; and the cathode is prepared on the electron transport layer.
  • the preparation method of the light-emitting diode includes: preparing a cathode on a substrate; preparing an electron transport layer on the cathode; then preparing a quantum dot thin film on the surface of the electron transport layer on the substrate by using the preparation method of the quantum dot thin film of the present application to obtain A quantum dot light-emitting layer; a hole injection layer is prepared on the quantum dot light-emitting layer; a hole transport layer is prepared on the hole injection layer; an anode is prepared on the hole transport layer.
  • a quantum dot light emitting diode device 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.
  • the preparation process of the quantum dot light-emitting layer is as follows: 1) Inkjet printing of quantum dot ink (the unique ink of this application) into the pixel area; 2) Decompression drying, so that the ink in the sub-pixel is the same height as the Bank; 3) UV Irradiation ( ⁇ 405nm), the irradiation time is 1 ⁇ 100s; 4) Drying under reduced pressure to remove the solvent in the sub-pixels; 5) Heat treatment, 80 ⁇ 150°C, 1 ⁇ 30min.
  • the structure of the quantum dot light-emitting diode device is shown in FIG. 4 , from bottom to top: anode (Anode), hole injection layer (HIL), hole transport layer (HTL), quantum dot light-emitting layer (EML-QD), electron transport layer (ETL), cathode (Cathode).
  • Anode Anode
  • HIL hole injection layer
  • HTL hole transport layer
  • EML-QD quantum dot light-emitting layer
  • ETL electron transport layer
  • Cathode cathode
  • the QLED device structure can be inkjet printed, and the specific methods include:
  • the hole injection material includes conductive polymer materials such as polythiophene and polyaniline and their derivatives; after drying under reduced pressure and heat treatment, an organic thin film is prepared with a thickness ranging from It is 10 ⁇ 60nm.
  • a hole transport layer is prepared on the hole injection layer.
  • the material of the hole transport layer is TFB, Poly-TPD, PVK, etc. After drying under reduced pressure and heat treatment, an organic thin film is prepared with a thickness ranging from 10 to 50 nm.
  • a quantum dot light-emitting layer is prepared on the hole transport layer, and the material of the light-emitting layer is a quantum dot material.
  • the preparation process is as follows: 1) Inkjet printing the above-mentioned unique ink of this application into the pixel area; 2) Decompression drying, is The height of the ink in the sub-pixel is the same as that of the Bank; 3) UV irradiation ( ⁇ 405nm), the irradiation time can be 1 ⁇ 100s, and the surface ligands of the quantum dots undergo chemical changes, thereby changing the solubility characteristics of the quantum dots in the solvent, The quantum dots settled; 4) Drying under reduced pressure to remove the solvent in the sub-pixels; 5) Heat treatment at 80°C for 10 min.
  • the red and green quantum dot materials are CdSe-based or InP-based quantum dot materials
  • the wavelength of the red quantum dot light-emitting material is 610 ⁇ 625nm
  • the wavelength of green quantum dots is 525 ⁇ 550nm
  • the blue quantum dot material is CdSe-based or ZnSe-based quantum dots Point material
  • wavelength is 455 ⁇ 480nm
  • thickness is 5 ⁇ 30nm
  • the electron transport material is a metal oxide, mainly including ZnO, Zn x Mg y O, Zn x A ly O, Zn x Mg y Li z O, etc.
  • inorganic nanoparticle films are prepared with a thickness of 10-100 nm.
  • the cathode is prepared by evaporation or sputtering process.
  • the metal electrode can be Al, Ag, Mg: Ag, etc. If it is a top generator device, the electrode thickness is 5 ⁇ 40nm; if it is a bottom emission device, the electrode thickness is 80 ⁇ 150nm.
  • a quantum dot light-emitting diode from bottom to top: a substrate, 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 steps of the device include:
  • TFB Spin coat a layer of TFB on the hole injection layer as a hole transport layer.
  • TFB is dissolved in chlorobenzene at a concentration of 8 mg/ml. annealed for 20 min, and the whole step was carried out in a glove box.
  • the red ink 1 includes a solvent, red quantum dots and ionic compounds dispersed in the solvent, and cations in the ionic compound are bound on the surface of the red quantum dots, wherein the red quantum dot material is CdZnSe/CdS, and the cations of the ionic compound are is Ph 2 I + , the corresponding anion is ZnCl 4 2- , the concentration of red quantum dots is 5wt%, and the solvent is N,N-dimethylformamide and methyl benzoate (volume ratio 2:1).
  • the red ink was ink-jet printed on the hole transport layer in the pixel area; dried under reduced pressure, so that the ink in the sub-pixel was the same height as the Bank; UV irradiation ( ⁇ ⁇ 405 nm), the irradiation time was 50 s; reduced again Press drying to remove the solvent in the sub-pixels; heat treatment at 80° C. for 10 min to obtain a quantum dot light-emitting layer.
  • a quantum dot light-emitting diode from bottom to top: a substrate, 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 steps of the device include:
  • TFB Spin coat a layer of TFB on the hole injection layer as a hole transport layer.
  • TFB is dissolved in chlorobenzene at a concentration of 8 mg/ml. Annealed for 20 min, the whole step was carried out in a glove box.
  • the green ink 2 includes a solvent, green quantum dots and ionic compounds dispersed in the solvent, and anions in the ionic compounds are bound on the surface of the green quantum dots.
  • the green quantum dot material is CdZnSe/ZnS
  • the anion in the ionic compound is CS 2 N 3 -
  • the corresponding cation is K +
  • the concentration of the green quantum dot is 10wt%
  • the solvent is N,N-dimethylformamide and phenylhexane (3:1 by volume).
  • the green ink was ink-jet printed on the hole transport layer in the pixel area; dried under reduced pressure, so that the ink in the sub-pixel was the same height as the Bank; UV irradiation ( ⁇ ⁇ 405 nm), the irradiation time was 50 s; reduced again Press drying to remove the solvent in the sub-pixels; heat treatment at 80° C. for 10 min to obtain a quantum dot light-emitting layer.
  • a quantum dot light-emitting diode from bottom to top: a substrate, 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 steps of the device include:
  • TFB Spin coat a layer of TFB on the hole injection layer as a hole transport layer.
  • TFB is dissolved in chlorobenzene at a concentration of 8 mg/ml. Annealed for 20 min, the whole step was carried out in a glove box.
  • the red ink 1 includes a solvent, red quantum dots and ionic compounds dispersed in the solvent, and cations in the ionic compounds are bound to the surface of the red quantum dots.
  • the green ink 2 includes a solvent, green quantum dots and ionic compounds dispersed in the solvent, and anions in the ionic compounds are bound on the surface of the green quantum dots.
  • the blue ink 3 includes a solvent, blue quantum dots and an ionic compound dispersed in the solvent, and anions in the ionic compound are bound on the surface of the blue quantum dots.
  • red ink 1 the red quantum dot material is CdZnSe/CdS, the cation of the ionic compound is Ph 2 I + , the corresponding anion is ZnCl 4 2- , the concentration of the red quantum dot is 5wt%, and the solvent is N,N- Dimethylformamide and methyl benzoate (2:1 by volume).
  • the green quantum dot material is CdZnSe/ZnS
  • the anion in the ionic compound is CS 2 N 3 -
  • the corresponding cation is K +
  • the concentration of the green quantum dot is 10wt%
  • the solvent is N,N-dimethyl Formamide and phenylhexane (3:1 by volume).
  • blue ink 3 the blue quantum dot material is CdZnSe/ZnS, the anion in the ionic compound is CS 2 N 3 - , the corresponding cation is NH 4 + , the concentration of the blue quantum dot is 3wt%, the solvent is N, N-dimethylformamide and phenylhexane (5:1 by volume).
  • the red ink 1, green ink 2 and blue ink 3 are respectively inkjet printed on the hole transport layer in the corresponding pixel area; dried under reduced pressure, so that the ink in the sub-pixel is the same height as the Bank; UV irradiation ( ⁇ ⁇ 405 nm), the irradiation time was 50 s; dried under reduced pressure again to remove the solvent in the sub-pixels; heat treatment, 80 °C, 10 min, to obtain the quantum dot light-emitting layer.
  • a quantum dot light-emitting diode from bottom to top: a substrate, an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a cathode.
  • the materials and preparation methods of each layer of the device are the same as those in Example 1. same.
  • a quantum dot light-emitting diode from bottom to top: a substrate, an anode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a cathode.
  • the materials and preparation methods of each layer of the device are the same as those in Example 2. same.
  • a quantum dot light-emitting diode from bottom to top: a substrate, 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 directly composed of red ink without ionic compounds dispersed, green ink without ionic compounds dispersed, and blue ink without ionic compounds dispersed (that is, red quantum dots, green quantum dots and blue quantum dots therein
  • the surface of the device is not combined with ionic compound photoactive groups) obtained by inkjet printing respectively.
  • the materials and preparation methods of each layer of the device are the same as those in Example 3.
  • Example 1 The uniformity of the film thickness of the quantum dot light-emitting layer of the devices in Example 1-3 and Comparative Example 1-3 was tested; the quantum dot light-emitting layer film of the device pixel (length 200 microns, width 50 microns) was measured by a white light interferometer , the results are shown in Table 1: Taking Example 1 as an example, 95%@ ⁇ 10nm means that the size of the 95% area on the short axis is within 10nm of the upper and lower difference.
  • Example 1 95%@ ⁇ 10nm
  • Example 2 96%@ ⁇ 10nm
  • Example 3 98%@ ⁇ 10nm Comparative Example 1 80%@ ⁇ 10nm Comparative Example 2 82%@ ⁇ 10nm Comparative Example 3 85%@ ⁇ 10nm
  • the quantum dot light emitting layer has better film uniformity.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

本申请公开一种墨水、量子点薄膜的制备方法和发光二极管的制备方法。该墨水包括溶剂和分散在溶剂中的量子点和离子化合物；其中，离子化合物中的至少部分阴离子和/或至少部分阳离子结合在量子点表面；其中，至少部分阴离子中的至少部分含有光活性基团，至少部分阳离子中的至少部分含有光活性基团。该离子化合物中的光活性基团在紫外光照射下在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而溶解性降低；这样的墨水可以得到膜层均匀的量子点薄膜。

Description

墨水、量子点薄膜的制备方法和发光二极管的制备方法
本申请要求于2021年04月25日在中国专利局提交的、申请号为202110447977.8、申请名称为“墨水和量子点薄膜的制备方法及发光二极管的制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及量子点技术领域，具体涉及一种墨水、量子点薄膜的制备方法和发光二极管的制备方法。
 背景技术
量子点（Quantum Dot，QD）具有独特的光电性质，如发光波长随尺寸和成分连续可调、发光光谱窄、荧光效率高、稳定性好等，因此，基于量子点的量子点发光二极管（Quantum Dot Light Emitting Diode，QLED）在显示领域得到广泛的关注和研究。此外，QLED显示还具有可视角大、对比度高、响应速度快、可柔性等优点，因而有望成为下一代的显示技术。
QLED器件工作时需要注入电子和空穴，最简单的QLED器件包括阴极、电子传输层、量子点发光层、空穴传输层和阳极。在QLED器件中，量子点发光层薄膜夹在电荷传输层中间，当正向偏压加到QLED器件两端时，电子和空穴分别通过电子传输层和空穴传输层进入量子点发光层，并在量子点发光层复合发光。
喷墨打印（inkjet printing）是一种重要的实现红绿蓝（RGB）三原色像素的溶液加工技术，其材料利用率高，且无需使用掩膜板可实现图案化，同时具有工艺简单、成本低廉的特点，是制作QLED显示屏最具潜力的彩色化成膜技术。溶液在基板上形成固态薄膜的相转变过程十分复杂，所以采用喷墨打印制备有机薄膜的工艺需要不断的研究和探索。针对调控喷墨打印制备的薄膜形貌的研究有很多，但因为墨水干燥过程的复杂性，量子点材料在像素坑（即像素Bank）内的成膜均匀性严重影响着量子点器件的性能。
 技术问题
本申请实施例的目的在于提供一种墨水、量子点薄膜的制备方法及发光二极管的制备方法。
 技术解决方案
本申请实施例采用的技术方案是：
第一方面，提供一种墨水，所述墨水包括溶剂和分散在所述溶剂中的量子点和离子化合物；其中，所述离子化合物中的至少部分阴离子和/或至少部分阳离子结合在所述量子点表面；其中，
所述至少部分阴离子中的至少部分含有光活性基团，所述至少部分阳离子中的至少部分含有光活性基团。
第二方面，提供一种量子点薄膜的制备方法，包括如下步骤：
提供基板；
将本申请所述的墨水沉积在所述基板上，得到液膜；
将所述液膜进行紫外光照处理，得到所述量子点薄膜。
第三方面，提供一种发光二极管的制备方法，包括如下步骤：
提供基板，所述基板表面设置有像素坑；
将本申请所述的墨水沉积在所述基板上，得到液膜；
将所述液膜进行紫外光照处理，得到发光层。
 有益效果
本申请实施例提供的墨水的有益效果在于墨水中分散有离子化合物，该离子化合物中的至少部分阴离子和/或至少部分阳离子结合在量子点表面，因其含有光活性基团，在紫外光照射下光活性基团能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解性；这样的墨水在基板上呈液膜后经紫外光照可以使量子点发生沉降，从而得到膜层均匀的量子点薄膜。
本申请实施例提供的量子点薄膜的制备方法有益效果在于采用本申请特有的墨水制备成膜，该墨水沉积在基板上得到液膜后，紫外光照条件下液膜中结合在量子点表面的光活性基团能够发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解性而发生沉降，这样可以得到膜层均匀的量子点薄膜。
本申请实施例提供的发光二极管的制备方法有益效果在于采用本申请特有的墨水在像素坑基板上成膜，得到膜层均匀的发光层，因此，能提高发光二极管器件的发光性能。
 附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例或示范性技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图。
图1是本申请实施例提供的量子点薄膜的制备方法流程示意图；
图2是本申请实施例提供的量子点薄膜的制备过程原理示意图；
图3是本申请实施例提供的发光二极管的制备方法流程示意图；
图4是本申请实施例提供的发光二极管器件的结构示意图。
 本发明的实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。
本申请中，术语“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况。其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。
本申请中，“至少一种”是指一种或者多种，“多种”是指两种或两种以上。“至少部分”是指一部分或者全部；“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项（个）或复数项（个）的任意组合。例如，“a,b,或c中的至少一项（个）”，或，“a,b,和c中的至少一项（个）”，均可以表示：a, b, c, a-b（即a和b）, a-c, b-c, 或a-b-c，其中a,b,c分别可以是单个，也可以是多个。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，部分或全部步骤可以并行执行或先后执行，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
在本申请实施例中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请实施例和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
为了说明本申请所提供的技术方案，以下结合具体附图及实施例进行详细说明。
本申请一些实施例提供一种墨水，该墨水包括溶剂和分散在溶剂中的量子点，量子点表面结合有阴阳离子对配体和离子化合物；其中，离子化合物中的至少部分阴离子和/或至少部分阳离子结合在量子点表面；其中，
至少部分阴离子中的至少部分含有光活性基团，至少部分阳离子中的至少部分含有光活性基团。
本申请实施例提供的墨水具有很好的成膜均匀性，具体地，该墨水中分散有离子化合物，该离子化合物中的至少部分阴离子和/或至少部分阳离子结合在量子点表面，而且结合在量子点表面的至少部分阴离子和/或至少部分阳离子含有光活性基团，在紫外光照射下光活性基团能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解；因此，基于上述墨水的性能原理，将本申请实施例的墨水沉积在基板上呈液膜时紫外光照，可以使量子点发生均匀沉降，这样能均匀沉积在基板表面，从而得到具有膜层均匀性好的量子点薄膜。
本申请实施例含有量子点的墨水中，加入至少一种含有光活性基团的离子化合物，该离子化合物分散在溶剂中解离形成阴离子和阳离子，该离子化合物中至少部分阴离子和/或至少部分阳离子可以结合在量子点表面，而该结合在量子点表面的至少部分阴离子中的至少部分含有光活性基团，结合在量子点表面的至少部分阳离子中的至少部分含有光活性基团。即上述分散在墨水中的离子化合物可以是一种也可以是多种，当其分散在墨水中时，不管结合在量子点表面的是离子化合物的至少部分阴离子还是至少部分阳离子，其结合在量子点表面的离子化合物中的至少部分离子（阴离子和/或阳离子）含光活性基团。结合在量子点表面的光活性基团在紫外光照射下能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解。
以离子化合物中的至少部分阴离子中至少部分含有光活性基团结合在墨水中的量子点表面为例：含量子点的墨水分散有离子化合物，离子化合物解离成阴离子和阳离子，其中离子化合物的至少部分阴离子作为多电子配体与量子点中表面的少电子金属离子配位，离子化合物阴离子配位后产生的负电荷通过墨水溶液中的离子化合物阳离子平衡。该配位的化合物阴离子含有一种光活性基团，可以在紫外光（UV）照射下能够发生化学反应。发生化学反应前，墨水中具有离子化合物阴离子配位的量子点能够在溶剂中溶解，而发生化学反应后，量子点表面配体的化学结构发生变化，在原有溶剂中的溶解性降低，或者没有溶解性而不能溶解，从而发生沉降。
在一个实施例中，当离子化合物中的至少部分阳离子结合在墨水中的量子点表面时，该至少部分阳离子中至少部分含有的光活性基团选自Ph 2I +和Ph 3S +中的至少一种。Ph 2I +、Ph 3S +在紫外光照射下能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解。当含有上述光活性基团的阳离子结合在墨水中的量子点表面时，离子化合物中的阴离子选自PbBr 3 -、ZnCl 4 2-、CdCl 4 2-中的至少一种；此时，不排除离子化合物中的阴离子也可以有光活性基团，如CS 2N 3 -。
在另一个实施例中，当离子化合物中的至少部分阴离子结合在墨水中的量子点表面时，该至少部分阴离子中至少部分含有的光活性基团选自CS 2N 3 -。CS 2N 3 -在紫外光照射下能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解。当含有上述光活性基团的阴离子结合在墨水中的量子点表面时，离子化合物中的阳离子选自K +和NH 4 +中的至少一种；此时，不排除离子化合物中的阳离子也可以有光活性基团，如Ph 2I +、Ph 3S +。
在一个实施例中，当离子化合物中的至少部分阴离子和至少部分阳离子结合在量子点表面时，至少部分阴离子中的至少部分含有的光活性基团选自CS 2N 3 -，至少部分阳离子中的至少部分含有的光活性基团选自Ph 2I +和Ph 3S +中的至少一种。这样，在紫外光照射下量子点表面配体的化学结构更容易发生变化，从而使量子点更易沉淀。
在一个实施例中，墨水中的溶剂的沸点大于150℃；该沸点的溶剂，使得该墨水更好地适应于喷墨打印。具体地，墨水中的溶剂选自极性溶剂或非极性溶剂。例如，当墨水中的溶剂选自极性溶剂时，极性溶剂包括N,N-二甲基甲酰胺、N-甲基甲酰胺、二甲基亚砜、苯甲酸甲酯中的至少一种；当墨水中的溶剂选自非极性溶剂时，非极性溶剂包括二甲苯和苯基己烷中的至少一种。在一个可选实施例中，墨水的溶剂选自极性溶剂，具有阴阳离子对配体的量子点在极性溶剂中具有较好的溶解性。
在一个实施例中，墨水中的量子点浓度为1wt%-20wt%（重量百分含量），上述浓度范围内的墨水具有较好的分散性，可以较好地进行喷墨打印。
其中，墨水中的量子点材料可以是含Cd的量子点材料，比如说CdSe/CdS、CdZnSe/CdS、CdSe/CdS/ZnS等等，也可以是非Cd的量子点材料，比如说InP/ZnS、ZnSe/ZnS等。
本申请实施例的墨水可以利用喷墨打印技术制备量子点薄膜。
本申请一些实施例还提供一种量子点薄膜的制备方法，如图1所示，该制备方法包括如下步骤：
S01：提供基板；
S02：将本申请的墨水沉积在基板上，得到液膜；
S03：将液膜进行紫外光照处理，得到量子点薄膜。
本申请实施例提供的量子点薄膜的制备方法采用本申请特有的墨水制备，具体地，将该墨水沉积在基板上得到液膜后，进行紫外光照，在紫外光照射下液膜中量子点表面的光活性基团能够在量子点表面发生化学反应，使量子点表面配体的化学结构发生变化，从而使量子点的溶解性降低或者难以溶解性，从而发生沉降，这样可以均匀地沉积在基板表面，得到具有膜层均匀的量子点薄膜。
需要说明的是，本申请实施例提供的量子点薄膜的制备方法采用本申请实施例特有的墨水制备，前述提到的墨水的可选方案均可以用于该量子点薄膜的制备方法中。因此，上述量子点薄膜的制备方法具有前述墨水的可选方案的所有优势，在此不再赘述。
在一个实施例中，基板表面设有像素坑（即像素Bank），将墨水沉积基板上的步骤包括：采用喷墨打印将墨水打印在基板上的像素坑Bank中。喷墨打印材料利用率高，可以不需使用掩膜板实现图案化，而且使用这样的墨水可以量子点材料在像素坑内具有很好的成膜均匀性。
具体地，将墨水沉积在基板上后，进行干燥处理，使像素坑Bank中的液膜厚度≤像素坑Bank的深度。上述干燥处理可以是常温（25-27℃）减压干燥，通过减压干燥使像素坑Bank内的墨水表面呈平面，且液膜厚度与像素坑Bank的深度相同或低于像素坑Bank的深度，这样可以更好地保证子像素沉积相同的墨水，而且形成的具有多个子像素的液膜层厚度均匀；然后紫外光照，量子点在UV照射下发生化学反应沉降后能够形成膜层均匀的具有子像素图案的量子点薄膜。
具体地，将墨水沉积在基板上后，在紫外光照之前，先进行干燥处理，从而使子像素中的液膜中墨水厚度≤像素坑Bank的深度，紫外光照的步骤之后，可以先干燥去溶剂后，再进行退火处理；具体地，在紫外光照之后还可以进一步干燥处理（如常温减压干燥）去除子像素内溶剂，以便后续更好地进行退火处理。
图2所示，形成均匀的具有子像素图案的量子点薄膜的原理示意图；a为喷墨打印量子点墨水；b为进行第一次干燥VCD（vacuum chamber drying，即减压干燥），使像素坑里面的量子点墨水的厚度与Bank齐平；c为UV照射，使量子点表面的配体中的光活性基团发生化学反应，量子点材料在溶剂中沉降；d为第二次干燥VCD去除溶剂并后续进行热退火处理，形成固态的量子点薄膜。
在一个实施例中，紫外光照的步骤之后，还包括退火处理。紫外光照的照射时间为1~100s，例如可以是20~80s，也可以是40~60s。退火处理的温度为80~150℃；退火处理的时间为1~30min。
本申请实施例通过外部UV照射改变量子点发光材料在溶液中溶解特性，从而使量子点沉降，有利提升量子点薄膜的成膜均匀性；现有常规方案下量子点薄膜（使用的墨水包括溶剂和分散在溶剂中的量子点，墨水中没有分散本申请上述离子化合物，用这样的墨水成膜后得到量子点薄膜）的均匀性一般是：短轴方向上约80%@±10nm（即短轴上约80%区域尺寸上下差10nm）；而本申请实施例中，使用该特有的墨水制备得到的量子点薄膜的均匀性：短轴方向上>95%@±10nm（即短轴上约95%以上区域尺寸上下差10nm）；因此，本申请实施例的制备方法显著提高量子点薄膜均匀性；上述量子点薄膜可以通过台阶测试仪进行测量得到。
本申请一些实施例还提供一种发光二极管的制备方法，如图3所示，包括如下步骤：
E01：提供基板，基板表面设置有像素坑；
E02：将本申请的墨水沉积在基板上，得到液膜；
E03：将液膜进行紫外光照处理，得到发光层。
本申请实施例提供的发光二极管的制备方法中，采用本申请实施例特有的墨水在像素坑基板上成膜，得到膜层均匀的发光层，因此，该制备方法能提高发光二极管器件的发光性能。
需要说明的是，本申请实施例提供的发光二极管的制备方法采用本申请实施例的墨水制备发光层，而将本申请实施例的墨水沉积在基板上，得到液膜，再将液膜进行紫外光照处理得到发光层，这样的过程实质上是本申请实施例的量子点薄膜的制备方法过程。因本申请实施例提供的发光二极管的制备方法因采用本申请实施例特有的墨水制备发光层，前述提到的墨水的可选方案均可以用于该发光二极管的制备方法中；而且本申请实施例提供的发光二极管的制备方法采用本申请实施例的量子点薄膜的制备方法制备发光层，前述提到的量子点薄膜的制备方法的可选方案也可以用于该发光二极管的制备方法中。因此，该发光二极管的制备方法具有前述墨水、以及前述量子点薄膜的制备方法的可选方案的所有优势，在此不再赘述。
在一个实施例中，该制备的发光二极管为量子点发光二极管，包括阳极、阴极以及设置的阳极与阴极之间的量子点发光层；阳极与量子点发光层之间可以设置空穴传输层，具体地，空穴传输层与阳极之间可以设置空穴注入层；或者，阴极与量子点发光层之间可以设置电子传输层，具体地，电子传输层与阴极之间可以设置电子注入层。该量子点发光二极管可以是正置器件也可以是倒置器件。
在一个实施例中，该发光二极管的制备方法包括：在基板上制备阳极；在阳极上制备空穴注入层；在空穴注入层上制备空穴传输层；然后采用本申请的量子点薄膜的制备方法在基板上的空穴传输层表面制备量子点薄膜，即得到量子点发光层；在量子点发光层上制备电子传输层；在电子传输层上制备阴极。
或者，该发光二极管的制备方法包括：在基板上制备阴极；在阴极上制备电子传输层；然后采用本申请的量子点薄膜的制备方法在基板上的电子传输层表面制备量子点薄膜，即得到量子点发光层；在量子点发光层上制备空穴注入层层；在空穴注入层上制备空穴传输层；在空穴传输层上制备阳极。
在一个实施例中，量子点发光二极管器件包括阳极、空穴注入层、空穴传输层、量子点发光层、电子传输层和阴极。该量子点发光层为本申请制备方法制备得到的量子点薄膜。量子点发光层制备工艺如下：1）喷墨打印量子点墨水（本申请上述特有的墨水）到像素区域内；2）减压干燥，使子像素中的墨水与Bank的高度相同；3）UV照射（λ<405nm），照射时间为1~100s；4）减压干燥，去除子像素内溶剂；5）热处理，80~150℃，1~30min。
在一个实施例中，量子点发光二极管器件结构如图4所示，从下到上依次为：阳极（Anode）、空穴注入层（HIL）、空穴传输层（HTL）、量子点发光层（EML-QD）、电子传输层（ETL）、阴极（Cathode）。可以喷墨打印QLED器件结构，具体方法包括：
（1）在子像素的阳极上制备空穴注入层，空穴注入材料包括聚噻吩、聚苯胺等导电高分子材料及其衍生物；经过减压干燥和热处理工艺后制备成有机薄膜，厚度范围是10~60nm。
（2）在空穴注入层上制备空穴传输层，空穴传输层材料为TFB、Poly-TPD、PVK等，经过减压干燥和热处理工艺后制备成有机薄膜，厚度范围是10~50nm。
（3）在空穴传输层上制备量子点发光层，发光层材料为量子点材料，制备工艺如下：1）喷墨打印本申请上述特有的墨水到像素区域内；2）减压干燥，是子像素中的墨水与Bank的高度相同；3）UV照射（λ<405nm），照射时间可以为1~100s，量子点的表面配体发生化学变化，从而改变量子点在溶剂中的溶解特性，量子点发生沉降；4）减压干燥，去除子像素内溶剂；5）热处理，温度为80℃，时间为10min。
其中，红色和绿色量子点材料是CdSe基或者InP基量子点材料，红色量子点发光材料波长为610~625nm，绿色量子点波长为525~550nm，蓝色量子点材料是CdSe基或者ZnSe基量子点材料，波长是455~480nm，厚度是5~30nm；
（4）在量子点发光层上制备电子传输层，电子传输材料为金属氧化物，主要包括ZnO、Zn xMg yO、Zn xAl yO、Zn xMg yLi zO等，经过减压干燥和热处理工艺后制备成无机纳米颗粒薄膜，厚度为10~100nm。
（5）蒸镀或溅射工艺制备阴极，金属电极可以是Al、Ag、Mg：Ag等，如果为顶发生器器件，电极厚度为5~40nm；如果为底发射器件，电极厚度为80~150nm。
下面结合具体实施例进行说明。
实施例1
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
该器件的制备步骤包括：
（1）在基板上蒸镀ITO做阳极，ITO的厚度为40nm，之后UVO（紫外光臭氧）清洗15min，清洗表面的同时改善表面浸润度，并提高ITO的功函数。
（2）在阳极上旋涂一层PEDOT:PSS做空穴注入层，旋涂转速为4000转每分钟，旋涂40s，之后在150℃退火15min，整个步骤在空气中进行。
（3）在空穴注入层上旋涂一层TFB做空穴传输层，TFB溶解在氯苯中，浓度为8mg/ml，旋涂转速为3000转每分钟，旋涂时间30s，之后在150℃下退火20min，整个步骤在手套箱中进行。
（4）在空穴传输层上制备量子点发光层，具体地：
配制红色墨水1：该红色墨水1包括溶剂和分散在溶剂中的红色量子点和离子化合物，红色量子点表面结合有离子化合物中阳离子，其中，红色量子点材料是CdZnSe/CdS，离子化合物的阳离子是Ph 2I +，对应的阴离子是ZnCl 4 2-，红色量子点的浓度是5wt%，溶剂是N,N-二甲基甲酰胺和苯甲酸甲酯（体积比2:1）。将该红色墨水喷墨打印到像素区域内的空穴传输层上；减压干燥，使子像素中的墨水与Bank的高度相同；UV照射（λ < 405 nm），照射时间为50s；再次减压干燥，去除子像素内溶剂；热处理，80℃，10min，得到量子点发光层。
（5）在量子点发光层上旋涂将氧化锌纳米颗粒溶液，旋涂转速为3000转每分钟，旋涂时间30s，之后在80℃下加热20min，该步骤在手套箱中进行。
（6）在氧电子传输层上蒸镀100nm的Al做阴极。
实施例2
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
该器件的制备步骤包括：
（1）在基板上蒸镀ITO做阳极，ITO的厚度为40nm，之后UVO（紫外光臭氧）清洗15min，清洗表面的同时改善表面浸润度，并提高ITO的功函数。
（2）在阳极上旋涂一层PEDOT:PSS做空穴注入层，旋涂转速为4000转每分钟，旋涂40s，之后在150℃退火15min，整个步骤在空气中进行。
（3）在空穴注入层上旋涂一层TFB做空穴传输层，TFB溶解在氯苯中，浓度为8mg/ml，旋涂转速为3000转每分钟，旋涂时间30s，之后在150℃下退火20min，整个步骤在手套箱中进行。
（4）在空穴传输层上制备量子点发光层，具体地：
配制绿色墨水2：该绿色墨水2包括溶剂和分散在溶剂中的绿色量子点和离子化合物，绿色量子点表面结合有离子化合物中的阴离子。其中，绿色量子点材料是CdZnSe/ZnS，离子化合物中阴离子是CS 2N 3 -，所对应的阳离子是K +，绿色量子点的浓度是10wt%，溶剂是N,N-二甲基甲酰胺和苯基己烷（体积比3:1）。
将该绿色墨水喷墨打印到像素区域内的空穴传输层上；减压干燥，使子像素中的墨水与Bank的高度相同；UV照射（λ < 405 nm），照射时间为50s；再次减压干燥，去除子像素内溶剂；热处理，80℃，10min，得到量子点发光层。
（5）在量子点发光层上旋涂将氧化锌纳米颗粒溶液，旋涂转速为3000转每分钟，旋涂时间30s，之后在80℃下加热20min，该步骤在手套箱中进行。
（6）在氧电子传输层上蒸镀100nm的Al做阴极。
实施例3
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
该器件的制备步骤包括：
（1）在基板上蒸镀ITO做阳极，ITO的厚度为40nm，之后UVO（紫外光臭氧）清洗15min，清洗表面的同时改善表面浸润度，并提高ITO的功函数。
（2）在阳极上旋涂一层PEDOT:PSS做空穴注入层，旋涂转速为4000转每分钟，旋涂40s，之后在150℃退火15min，整个步骤在空气中进行。
（3）在空穴注入层上旋涂一层TFB做空穴传输层，TFB溶解在氯苯中，浓度为8mg/ml，旋涂转速为3000转每分钟，旋涂时间30s，之后在150℃下退火20min，整个步骤在手套箱中进行。
（4）在空穴传输层上制备量子点发光层，具体地：
配制红色墨水1：该红色墨水1包括溶剂和分散在溶剂中的红色量子点和离子化合物，红色量子点表面结合有离子化合物中的阳离子。
配制绿色墨水2：该绿色墨水2包括溶剂和分散在溶剂中的绿色量子点和离子化合物，绿色量子点表面结合有离子化合物中的阴离子。
配制蓝色墨水3：该蓝色墨水3包括溶剂和分散在溶剂中的蓝色量子点和离子化合物，蓝色量子点表面结合有离子化合物中的阴离子。
其中，红色墨水1中：红色量子点材料是CdZnSe/CdS，离子化合物的阳离子是Ph 2I +，对应的阴离子是ZnCl 4 2-，红色量子点的浓度是5wt%，溶剂是N,N-二甲基甲酰胺和苯甲酸甲酯（体积比2:1）。
绿色墨水2中：绿色量子点材料是CdZnSe/ZnS，离子化合物中阴离子是CS 2N 3 -，所对应的阳离子是K +，绿色量子点的浓度是10wt%，溶剂是N,N-二甲基甲酰胺和苯基己烷（体积比3:1）。
蓝色墨水3中：蓝色量子点材料是CdZnSe/ZnS，离子化合物中阴离子是CS 2N 3 -，所对应的阳离子是NH 4 +，蓝色量子点的浓度是3wt%，溶剂是N,N-二甲基甲酰胺和苯基己烷（体积比5:1）。
将该红色墨水1、绿色墨水2和蓝色墨水3分别喷墨打印到对应的像素区域内的空穴传输层上；减压干燥，使子像素中的墨水与Bank的高度相同；UV照射（λ < 405 nm），照射时间为50s；再次减压干燥，去除子像素内溶剂；热处理，80℃，10min，得到量子点发光层。
（5）在量子点发光层上旋涂将氧化锌纳米颗粒溶液，旋涂转速为3000转每分钟，旋涂时间30s，之后在80℃下加热20min，该步骤在手套箱中进行。
（6）在氧电子传输层上蒸镀100nm的Al做阴极。
对比例1
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
除了量子点发光层直接由未分散有离子化合物的红色墨水（即其中绿色量子点表面未结合离子化合物光活性基团）喷墨打印得到，该器件的各层的材料和制备方法与实施例1相同。
对比例2
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
除了量子点发光层直接由未分散有离子化合物的红色墨水（即其中绿色量子点表面未结合离子化合物光活性基团）喷墨打印得到，该器件的各层的材料和制备方法与实施例2相同。
对比例3
一种量子点发光二极管，从下到上依次：基板，阳极，空穴注入层，空穴传输层，量子点发光层，电子传输层，阴极。
除了量子点发光层直接由未分散有离子化合物的红色墨水、未分散有离子化合物的绿色墨水和未分散有离子化合物的蓝色墨水（即其中的红色量子点、绿色量子点和蓝色量子点的表面均未结合离子化合物光活性基团）分别喷墨打印得到，该器件的各层的材料和制备方法与实施例3相同。
性能测试
对实施例1-3和对比例1-3中器件的量子点发光层膜层厚度均匀性进行测试；利用白光干涉仪测量器件像素（长200微米，宽50微米）的量子点发光层膜层，结果如表1所示：以实施例1为例，95%@±10nm表示短轴上95%区域尺寸上下差10nm内。
表1
项目组别 量子点发光层均匀性
实施例1 95%@±10nm
实施例2 96%@±10nm
实施例3 98%@±10nm
对比例1 80%@±10nm
对比例2 82%@±10nm
对比例3 85%@±10nm
从表1的数据可知：相对对比例，本申请实施例的量子点发光二极管器件中，量子点发光层具有更好的薄膜均匀性。
以上仅为本申请的可选实施例而已，并不用于限制本申请。对于本领域的技术人员来说，本申请可以有各种更改和变化。凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的权利要求范围之内。

Claims (23)

  1. 一种墨水，其特征在于，所述墨水包括溶剂和分散在所述溶剂中的量子点和离子化合物；其中，所述离子化合物中的至少部分阴离子和/或至少部分阳离子结合在所述量子点表面；其中，
    所述至少部分阴离子中的至少部分含有光活性基团，所述至少部分阳离子中的至少部分含有光活性基团。
  2. 如权利要求1所述的墨水，其特征在于，当所述离子化合物中的至少部分阳离子结合在所述量子点表面时，所述至少部分阳离子中含有的光活性基团选自Ph 2I +和Ph 3S +中的至少一种。
  3. 如权利要求2所述的墨水，其特征在于，所述离子化合物中的阴离子选自PbBr 3 -、ZnCl 4 2-和CdCl 4 2-中的至少一种。
  4. 如权利要求1所述的墨水，其特征在于，当所述离子化合物中的至少部分阴离子结合在所述量子点表面时，所述至少部分阴离子中含有的光活性基团选自CS 2N 3 -。
  5. 如权利要求4所述的墨水，其特征在于，所述离子化合物中的阳离子选自K +和NH 4 +中的至少一种。
  6. 如权利要求1所述的墨水，其特征在于，当所述离子化合物中的至少部分阴离子和至少部分阳离子结合在所述量子点表面时，所述至少部分阴离子中含有的光活性基团选自CS 2N 3 -，所述至少部分阳离子中含有的光活性基团选自Ph 2I +和Ph 3S +中的至少一种。
  7. 如权利要求1-6任一项所述的墨水，其特征在于，所述溶剂的沸点大于150℃。
  8. 如权利要求1-7任一项所述的墨水，其特征在于，所述溶剂选自极性溶剂或非极性溶剂；当所述溶剂选自极性溶剂时，所述极性溶剂包括N,N-二甲基甲酰胺、N-甲基甲酰胺、二甲基亚砜和苯甲酸甲酯中的至少一种；当所述溶剂选自非极性溶剂时，所述非极性溶剂包括二甲苯和苯基己烷中的至少一种。
  9. 如权利要求1-6任一项所述的墨水，其特征在于，所述墨水中量子点浓度为1wt%~20wt%。
  10. 一种量子点薄膜的制备方法，其特征在于，包括如下步骤：
    提供基板；
    将权利要求1-6任一项所述的墨水沉积在所述基板上，得到液膜；
    将所述液膜进行紫外光照处理，得到所述量子点薄膜。
  11. 如权利要求10所述的量子点薄膜的制备方法，其特征在于，所述溶剂的沸点大于150℃。
  12. 如权利要求10或11所述的量子点薄膜的制备方法，其特征在于，所述溶剂选自极性溶剂或非极性溶剂；当所述溶剂选自极性溶剂时，所述极性溶剂包括N,N-二甲基甲酰胺、N-甲基甲酰胺、二甲基亚砜和苯甲酸甲酯中的至少一种；当所述溶剂选自非极性溶剂时，所述非极性溶剂包括二甲苯和苯基己烷中的至少一种。
  13. 如权利要求10所述的量子点薄膜的制备方法，其特征在于，所述墨水中量子点浓度为1wt%~20wt%。
  14. 如权利要求10所述的量子点薄膜的制备方法，其特征在于，所述基板表面设有像素坑，将所述墨水沉积所述基板上的步骤包括：采用喷墨打印将所述墨水打印在所述基板上的像素坑中。
  15. 如权利要求14所述的量子点薄膜的制备方法，其特征在于，将所述墨水沉积在所述基板上后，进行干燥处理，使所述像素坑中的液膜厚度≤所述像素坑的深度。
  16. 如权利要求10所述的量子点薄膜的制备方法，其特征在于，所述紫外光照的照射时间为1~100s；
    和/或所述紫外光照的步骤之后，先干燥去溶剂后，再退火处理；
    和/或所述紫外光照的步骤之后，还包括在80~150℃条件下退火1~30min。
  17. 一种发光二极管的制备方法，其特征在于，包括如下步骤：
    提供基板，所述基板表面设置有像素坑；
    将权利要求1-6任一项所述的墨水沉积在所述基板上，得到液膜；
    将所述液膜进行紫外光照处理，得到发光层。
  18. 如权利要求17所述的发光二极管的制备方法，其特征在于，所述溶剂的沸点大于150℃。
  19. 如权利要求17或18所述的发光二极管的制备方法，其特征在于，所述溶剂选自极性溶剂或非极性溶剂；当所述溶剂选自极性溶剂时，所述极性溶剂包括N,N-二甲基甲酰胺、N-甲基甲酰胺、二甲基亚砜和苯甲酸甲酯中的至少一种；当所述溶剂选自非极性溶剂时，所述非极性溶剂包括二甲苯和苯基己烷中的至少一种。
  20. 如权利要求17所述的发光二极管的制备方法，其特征在于，所述墨水中量子点浓度为1wt%~20wt%。
  21. 如权利要求17所述的发光二极管的制备方法，其特征在于，将所述墨水沉积所述基板上的步骤包括：采用喷墨打印将所述墨水打印在所述基板上的像素坑中。
  22. 如权利要求21所述的发光二极管的制备方法，其特征在于，将所述墨水沉积在所述基板上后，进行干燥处理，使所述像素坑中的液膜厚度≤所述像素坑的深度。
  23. 如权利要求17所述的发光二极管的制备方法，其特征在于，所述紫外光照的照射时间为1~100s；
    和/或所述紫外光照的步骤之后，先干燥去溶剂后，再退火处理；
    和/或所述紫外光照的步骤之后，还包括在80~150℃条件下退火1~30min。
PCT/CN2021/141737 2021-04-25 2021-12-27 墨水、量子点薄膜的制备方法和发光二极管的制备方法 WO2022227660A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202110447977.8A CN115232512A (zh) 2021-04-25 2021-04-25 墨水和量子点薄膜的制备方法及发光二极管的制备方法
CN202110447977.8 2021-04-25

Publications (1)

Publication Number Publication Date
WO2022227660A1 true WO2022227660A1 (zh) 2022-11-03

Family

ID=83665755

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/141737 WO2022227660A1 (zh) 2021-04-25 2021-12-27 墨水、量子点薄膜的制备方法和发光二极管的制备方法

Country Status (2)

Country Link
CN (1) CN115232512A (zh)
WO (1) WO2022227660A1 (zh)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080171188A1 (en) * 2005-08-05 2008-07-17 Fujifilm Manufacturing Europe B.V. Porous membrane and recording medium, as well as process for preparing same
TW201137062A (en) * 2010-02-05 2011-11-01 Cambrios Technologies Corp Photosensitive ink compositions and transparent conductors and method of using the same
CN106009930A (zh) * 2016-04-25 2016-10-12 苏州星烁纳米科技有限公司 量子点墨水
CN106118242A (zh) * 2016-07-28 2016-11-16 Tcl集团股份有限公司 一种喷墨打印用的量子点油墨及其制备方法
CN107026239A (zh) * 2016-09-22 2017-08-08 广东聚华印刷显示技术有限公司 有机电致发光器件及其制备方法和应用
CN111384269A (zh) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 量子点发光二极管及其制备方法
CN111384268A (zh) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 量子点发光二极管的制备方法及量子点墨水
US20200287137A1 (en) * 2019-03-06 2020-09-10 Tandem PV, Inc. Processing of perovskite films using inks with complexing agents

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080171188A1 (en) * 2005-08-05 2008-07-17 Fujifilm Manufacturing Europe B.V. Porous membrane and recording medium, as well as process for preparing same
TW201137062A (en) * 2010-02-05 2011-11-01 Cambrios Technologies Corp Photosensitive ink compositions and transparent conductors and method of using the same
CN106009930A (zh) * 2016-04-25 2016-10-12 苏州星烁纳米科技有限公司 量子点墨水
CN106118242A (zh) * 2016-07-28 2016-11-16 Tcl集团股份有限公司 一种喷墨打印用的量子点油墨及其制备方法
CN107026239A (zh) * 2016-09-22 2017-08-08 广东聚华印刷显示技术有限公司 有机电致发光器件及其制备方法和应用
CN111384269A (zh) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 量子点发光二极管及其制备方法
CN111384268A (zh) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 量子点发光二极管的制备方法及量子点墨水
US20200287137A1 (en) * 2019-03-06 2020-09-10 Tandem PV, Inc. Processing of perovskite films using inks with complexing agents

Also Published As

Publication number Publication date
CN115232512A (zh) 2022-10-25

Similar Documents

Publication Publication Date Title
Chen et al. High performance inkjet-printed QLEDs with 18.3% EQE: improving interfacial contact by novel halogen-free binary solvent system
Xiong et al. Realizing 17.0% external quantum efficiency in red quantum dot light-emitting diodes by pursuing the ideal inkjet-printed film and interface
CN108735906B (zh) 丙烯酸酯共聚物修饰的金属氧化物、qled及制备方法
US6087196A (en) Fabrication of organic semiconductor devices using ink jet printing
CN103283054B (zh) 有机el元件
CN107968108B (zh) 像素界定层及其制备方法和应用
CN105609652B (zh) 一种基于钙钛矿材料的发光二极管的制备方法
DE112011104040T5 (de) Lochinjektionsschichten
Lee et al. Recent advances in patterning strategies for full-color perovskite light-emitting diodes
CN103620805B (zh) 有机发光元件
CN110048024B (zh) 显示基板及其制造方法、显示装置
TW201308711A (zh) 控制應用於有機發光二極體之經溶液處理之過渡金屬氧化物之受體強度之方法
CN107346776A (zh) 印刷显示器件及其制作方法和应用
US10319910B2 (en) Organic electroluminescent diode and method for manufacturing hole transporting layer thereof
CN111525048B (zh) 复合材料及其制备方法与发光二极管
KR100923197B1 (ko) 양면 발광 백색유기발광다이오드 및 그의 제조 방법
Xie Solution-Processed Organic Light-Emitting Devices
WO2022227660A1 (zh) 墨水、量子点薄膜的制备方法和发光二极管的制备方法
Zhang et al. Fabrication of Large‐Area Uniform Nanometer‐Thick Functional Layers and Their Stacks for Flexible Quantum Dot Light‐Emitting Diodes
TWI513079B (zh) 含混合主體之有機發光二極體及其製作方法
KR20170140140A (ko) 계면 조절 첨가제가 도핑된 저분자 발광층에 기반한 자체계량 용액 공정 유기발광소자
CN109860441B (zh) 一种有机电致发光显示面板、其制作方法及显示装置
CN112802984A (zh) 电子器件的制备方法及显示装置
CN114203940B (zh) 薄膜的制备方法和发光二极管
WO2022226878A1 (zh) 导电膜层、有机电致发光器件、显示装置及方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21939119

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21939119

Country of ref document: EP

Kind code of ref document: A1