WO2022110031A1

WO2022110031A1 - Method for patterning quantum dots

Info

Publication number: WO2022110031A1
Application number: PCT/CN2020/132302
Authority: WO
Inventors: 孙小卫; 方凡; 张志宽; 王恺
Original assignee: 深圳扑浪创新科技有限公司
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2022-06-02

Abstract

A method for patterning quantum dots, comprising the following steps: (1) dissolving a quantum dot precursor in a non-polar solvent, and printing the resulting precursor solution on a substrate to form a precursor pattern; and (2) subjecting the precursor pattern in step (1) to a reaction to form a quantum dot pattern.

Description

A patterning method of quantum dots

technical field

The present application belongs to the technical field of quantum dots, and relates to a method for patterning quantum dots.

Background technique

Inorganic perovskite quantum dots have attracted the attention of many fields, especially in the field of display lighting, due to their simple synthesis method, tunable emission spectrum, narrow half-peak width, covering the entire visible light range, and high luminous efficiency. Compared with organic light-emitting diodes (OLEDs), electroluminescent diodes (PeLEDs) using inorganic perovskite quantum dots as light-emitting layers have the advantages of high color purity, adjustable wavelength, high efficiency, good stability, and full solution processing. , so PeLED has great potential in the fields of future display and solid-state lighting.

Micro LED is a new generation of display technology that has higher brightness and better luminous efficiency than existing OLED technology, but consumes less power. In May 2017, Apple has begun the development of a new generation of display technology. In February 2018, Samsung introduced Micro LED TVs at CES 2018. With the development and research of inorganic perovskite quantum dots, PeLED technology has achieved gratifying achievements in terms of preparation process and device efficiency, and its ultimate application target is high-resolution dynamic full-color display. Therefore, certain treatment needs to be performed on the light-emitting layer, that is, the light-emitting layer must contain three color light-emitting points of red (R), green (G), and blue (B) arranged neatly side by side, so that pixels can be formed. Therefore, higher requirements are placed on the precision (generally micron level), accurate positioning and large area of the light-emitting layer. However, traditional patterning methods such as template method, transfer printing method, photolithography method, etc. cannot meet this requirement at the same time. As a low-consumption, high-precision (can reach micron level), and unmasked patterning technology, inkjet printing technology can print high-precision pixels. OLED (Reference: Makoto Mizukami, Seung-Il Cho, Kaori Watanabe, Miho Abiko, Yoshiyuki Suzuri, Shizuo Tokito, and Junji Kido, IEEE ELECTRON DEVICE LETTERS 2018.) and QLED (Reference: Kim, B.H. Onses, M.S.; Lim, J.B.; Nam, S.; Oh, N.; Kim, H.; Yu, K.J.; Lee, J.W.; Kim, J.H.; Kang, S.K.; Lee, C.H.; Lee, J.; Shin , J.H.; Kim, N.H.; Leal, C.; Shim, M.; Rogers, J.A, Nano letters 2015, 15(2), 969-73.) It has long been commonplace, and laboratory-made PeLEDs are all made by spin coating or light methods such as engraving (References: Liu, P.; Chen, W.; Wang, W.; Xu, B.; Wu, D.; Hao, J.; Cao, W.; Fang, F.; Li, Y. .; Zeng, Y.; Pan, R.; Chen, S.; Cao, W.; Sun, X.W.; Wang, K., Chemistry of Materials 2017, 29(12), 5168-5173), cannot meet the above requirements .

CN109321036A discloses a perovskite quantum dot ink for inkjet printing and a preparation method thereof. The preparation method of the scheme includes: S1, mixing a first precursor of a perovskite raw material with a first ink to obtain a first dispersion; S2, mixing the second precursor of the perovskite raw material with the second ink to obtain a second dispersion; S3, at 140-200° C., mixing the first dispersion and the second dispersion, and reacting to obtain a spray Perovskite quantum dot ink for ink printing. This scheme directly performs inkjet printing on perovskite quantum dots. Due to the growth of perovskite quantum dot crystal particles, it is easy to block the nozzle of the inkjet printer, and it is easy to interrupt production in mass production.

CN108192593A discloses an optical thin film based on the eutectic structure of inorganic perovskite quantum dots and conjugated organic small molecules. In this scheme, the optical thin film is composed of inorganic perovskite quantum dots and conjugated organic small molecules dispersed in an organic solvent together, A composite dispersion is formed; the composite dispersion is formed into a film by dipping and pulling, inkjet printing or spin coating, that is, an optical film based on the eutectic structure of inorganic perovskite quantum dots and conjugated organic small molecules is obtained. This scheme has the problem that the direct inkjet printing of perovskite quantum dots is easy to block the nozzle of the inkjet printer, and other methods cannot prepare high-precision, large-area dot arrays.

CN109321038A discloses a quantum dot ink based on inkjet printing. The quantum dot ink in the scheme includes quantum dots and an organic solvent. The quantum dot materials include core-shell quantum dot systems such as CdS, or inorganic perovskite quantum dots; the organic solvent is a single solvent or a mixed solvent, all of which are low-polarity or non-polarity solvents. This solution also has the problem of direct inkjet printing of perovskite quantum dots. Due to the growth of perovskite quantum dot crystal particles, it is easy to block the nozzle of the inkjet printer, and it is easy to interrupt the production in mass production.

SUMMARY OF THE INVENTION

The purpose of this application is to provide a method for patterning quantum dots. The quantum dot patterning method provided by the present application has high precision and does not block the nozzle of the printer, and is suitable for large-area patterning.

For this purpose, the application adopts the following technical solutions:

The present application provides a method for patterning quantum dots, the method comprising the following steps:

(1) Dissolving the quantum dot precursor in a non-polar solvent, and printing the obtained precursor solution on a substrate to form a precursor pattern;

(2) reacting with the precursor pattern described in step (1) to form a quantum dot pattern.

In the quantum dot patterning method provided in the present application, the precursor of the quantum dot is printed first, and then the patterned precursor is converted into the quantum dot. This method can avoid the problem of nozzle clogging caused by direct printing of quantum dots because the precursor does not produce ionization agglomeration in a non-polar solvent.

And when using the method provided in this application for patterning of quantum dots, the precursor of quantum dots is first dissolved in a non-polar solution for printing, and the precursor of quantum dots will not react in the non-polar solvent to become quantum dots, and After printing the pattern, the vapor of the polar solvent is used to make the precursor undergo a series of changes such as ionization and crystallization, and the reaction generates quantum dots. This patterning method based on in-situ growth makes the final patterned quantum dots blurred. Very low level and high precision.

In this application, the advantage of using the vapor of the polar solvent instead of other phases is that the vapor of the polar solvent will not damage the printed pattern while ensuring the reaction.

The following are optional technical solutions of the present application, but are not intended to limit the technical solutions provided by the present application. Through the following optional technical solutions, the technical purposes and beneficial effects of the present application can be better achieved and realized.

As an optional technical solution of the present application, the method comprises the following steps:

(1) Dissolving the perovskite quantum dot precursor in a non-polar solvent, and printing the obtained precursor solution on a substrate to form a precursor pattern;

(2) The precursor pattern described in step (1) is placed in the vapor of a polar solvent to react to form a perovskite quantum dot pattern.

In the perovskite quantum dot patterning method provided in this application, instead of directly printing perovskite quantum dots, the precursor of perovskite quantum dots is first printed, and then the patterned precursor is converted into perovskite quantum dots. This method can avoid the problem of nozzle clogging caused by direct printing of perovskite quantum dots because the perovskite precursor does not produce ionization agglomeration in non-polar solvents.

And when using the method provided in this application to pattern perovskite quantum dots, the perovskite quantum dot precursor is first dissolved in a non-polar solution for printing, and the perovskite quantum dot precursor is not in the non-polar solvent. The reaction will occur to become quantum dots, and after printing the pattern, the vapor of the polar solvent is used to make the precursor undergo a series of changes such as ionization and crystallization, and the reaction generates perovskite quantum dots. This pattern based on in-situ growth The resulting patterned perovskite quantum dots have a very low degree of fuzziness and high precision.

The perovskite quantum dot patterning method provided in this application can be used to prepare a perovskite quantum dot light-emitting layer.

As an optional technical solution of the present application, the perovskite quantum dots are inorganic perovskite quantum dots.

Optionally, the perovskite quantum dots consist of cation A, cation B and anion X. Here, the cation A is the A-site cation of the perovskite, the cation B is the B-site cation of the perovskite, and the anion X is the X-anion of the perovskite. Cation A, cation B, and anion X form an ABX ₃ -type perovskite structure.

Optionally, the cation A includes Cs ⁺ and/or Rb ⁺ .

Optionally, the cation B includes Pb ²⁺ .

Optionally, the anion X includes any one or a combination of at least two of Br ^- , I- or Cl-, a typical but non-limiting combination is a combination of Cl ^- and Br ^- , Br ^- and I ^- The combination of Cl ^- and I ^- and so on.

Optionally, the perovskite quantum dot precursor in step (1) includes a cation A precursor, a cation B precursor and an optional anion X precursor. When the anion X is included in the cation A precursor or the cation B precursor, the anion X precursor may not be used.

Optionally, the cation A precursor includes any one of Cs ₂ CO ₃ , CsAc (cesium acetate), CsCl, CsBr, CsI, Rb ₂ CO ₃ , RbAc (rubidium acetate), RbCl, RbBr or RbI or A combination of at least two.

Optionally, the cation B precursor includes any one or a combination of at least two of PbCl ₂ , PbBr ₂ , PbI ₂ , PbO or Pb(Ac) ₂ (lead acetate).

Optionally, the anion X precursor comprises any one or a combination of at least two of _NH4Cl , _NH4Br , _NH4I , CsCl, CsBr, CsI, RbCl, RbBr or RbI;

Optionally, in the perovskite quantum dot precursor described in step (1), the molar ratio of cation A, cation B and anion X is (0.9-1.1):(0.9-1.1):3, for example 0.9:1: 3. 0.95:1:3, 1:1:3, 1.1:0.9:3, 1:1.1:3, etc., but not limited to the listed values, other unlisted values within the range are also applicable, optional 1:1:3.

As an optional technical solution of the present application, the quantum dot precursors in step (1) include indium phosphide quantum dot precursors and/or cadmium selenide quantum dot precursors.

Because indium phosphide quantum dots and cadmium selenide quantum dots have similar structures compared to perovskite quantum dots, the method provided in this application is applicable to both perovskite quantum dots and indium phosphide quantum dots and Cadmium Selenide Quantum Dots.

Optionally, the method for reacting with the precursor pattern in step (1) in step (2) is a heating reaction. In the present application, for indium phosphide quantum dots and cadmium selenide quantum dots, it is simpler and more effective to use the method of heating and reacting the precursor pattern.

Optionally, the indium phosphide quantum dot precursor includes a phosphine source and an indium source.

Optionally, the phosphine source comprises tris(trimethylsilyl) phosphine, tris(dimethylamino) phosphine, tris(diethylamino) phosphine, tris(dimethyl-tert-butylsilyl) phosphine or tris(dimethyl-tert-butylsilyl) phosphine Any one or a combination of at least two of (triphenylsilyl)phosphine.

Optionally, the indium source includes any one or a combination of at least two of indium acetate, indium iodide, indium bromide or indium chloride.

Optionally, the cadmium selenide quantum dot precursor includes a cadmium source and a selenium source.

Optionally, the selenium source comprises any one or a combination of at least two of selenium powder, selenium-oleylamine solution, selenium-tributylphosphine solution, or selenium-trioctylphosphine solution.

Optionally, the cadmium source includes any one or a combination of at least two of cadmium oxide, cadmium acetate, methyl cadmium or cadmium oleate.

Optionally, the cadmium selenide quantum dot precursor further includes a zinc source and a sulfur source.

Optionally, the zinc source includes one or a mixture of at least two of zinc oxide, zinc acetate, zinc stearate or zinc oleate.

Optionally, the sulfur source comprises sulfur powder, sulfur in oleylamine solution, sulfur in tributylphosphine solution, sulfur in trioctylphosphine solution, one or a mixture of at least two of dodecanethiol or octanethiol.

As an optional technical solution of the present application, the non-polar solvent in step (1) includes any one or a combination of at least two of octadecene, liquid paraffin, dodecane, octane or hexane.

Optionally, in the precursor solution, the concentration of the precursor is 0.05-5 mol/L, such as 0.05 mol/L, 0.1 mol/L, 0.5 mol/L, 1 mol/L, 2 mol/L, 3 mol/L, 4mol/L or 5mol/L, etc., but not limited to the listed values, and other unrecited values within the numerical range are also applicable. In the present application, if the concentration of the precursor is too high, the precursor reaction will be incomplete; if the concentration of the precursor is too low, less quantum dots will be produced by the reaction. In this application, the concentration of the precursors refers to the total concentration of all the precursors.

As an optional technical solution of the present application, the substrate in step (1) includes a host material.

Optionally, the main body material includes any one of ITO glass, polyethylene film, polypropylene film, polyethylene phthalate film or methyl methacrylate film.

Optionally, the main body material is a cleaned main body material.

Optionally, the cleaning method includes: performing primary cleaning, ultrasonic and secondary cleaning on the main body material.

Optionally, the one-time cleaning method includes: cleaning with a surfactant for 5-10 minutes. The purpose of a wash is to remove large particles. One-wash surfactants can use dish soap.

Optionally, the ultrasonic cleaning method includes: ultrasonically succeding in surfactant, acetone and isopropanol for 20-40 minutes in sequence. The surfactant here can use ITO cleaning solution.

Optionally, the method for secondary cleaning includes: cleaning with an ultraviolet ozone cleaning machine (UV-O ₃ cleaning machine).

As an optional technical solution of the present application, one side of the main body material is provided with a film. Forming a film on the host material helps to improve the patterning accuracy of quantum dots on the one hand, and also helps the subsequent use of the patterned product. Pre-steps.

Optionally, the membrane is a membrane of non-polar material. Because the precursor solution in step (1) uses a non-polar solvent, a non-polar material film is used here, which can form better infiltration with the printed precursor solution, reduce the contact angle, avoid droplets, and improve patterning precision.

Optionally, the film comprises any one of polyvinylcarbazole (PVK) film, poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture (PEDOT:PSS) film or zinc oxide film Or a combination of at least two, optionally a combination of a polyvinylcarbazole (PVK) film and a poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture (PEDOT:PSS) film.

Optionally, when the film is a combination of a polyvinylcarbazole film and a poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film, the poly3,4-ethylenedioxythiophene-polyethylene A styrene sulfonate mixture film is on the host material and the polyvinylcarbazole film is on a poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film.

Optionally, the method for preparing a film on one side of the host material includes: dropping a film raw material solution on one side of the host material, spin-coating the host material, and then annealing.

If a multilayer film is produced, the above method can be repeated.

Optionally, the dropwise addition amount is 60-120 microliters, such as 60 microliters, 70 microliters, 80 microliters, 90 microliters, 100 microliters, 110 microliters or 120 microliters, etc., but Not limited to the recited values, other non-recited values within the range of values apply equally.

Optionally, the spin coating is performed with a spin coater.

Optionally, the rotational speed of the spin coating is 2000-4000 rpm, such as 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm or 4000 rpm, etc., but not limited to Recited values apply equally well to other non-recited values within that range.

Optionally, the spin coating time is 30 to 60 seconds, such as 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, or 60 seconds, etc., but is not limited to the listed values. The same applies to other non-recited values in the range.

Optionally, the annealing is performed on a hot stage.

Optionally, the temperature of the annealing is 100-140°C, such as 100°C, 110°C, 120°C, 130°C, or 140°C, etc., but not limited to the listed values, and other values not listed within this range of values The same applies.

Optionally, the annealing time is 15 to 20 minutes, such as 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, etc., but not limited to the listed values, and other values within the range are not limited. The values listed also apply.

As an optional technical solution of the present application, the printing in step (1) is inkjet printing.

Compared with other patterning methods (such as template method, transfer printing method, photolithography method, etc.), inkjet printing is more conducive to the preparation of high-precision, large-area lattice groups.

Optionally, the inkjet printing is performed with an inkjet printer.

Optionally, the inkjet printer is a non-contact inkjet printer.

Optionally, the diameter of the nozzle of the printer is 5-100 microns, such as 5 microns, 10 microns, 20 microns, 30 microns, 35 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns or 100 microns, etc., but not limited to the listed values, and other unlisted values within the numerical range are also applicable.

As an optional technical solution of the present application, the printing temperature in step (1) is 15-35°C, such as 15°C, 20°C, 25°C, 30°C or 35°C, etc., but not limited to the listed values, The same applies to other non-recited values within this numerical range.

As an optional technical solution of the present application, the polar solvent in step (2) includes any one or a combination of at least two of water, ethanol, isopropanol or isobutanol.

As an optional technical solution of the present application, the flow rate of the vapor of the polar solvent in step (2) is 1 to 100L/min, such as 1L/min, 10L/min, 25L/min, 50L/min, 75L/min or 100L/min, etc., but not limited to the listed numerical values, and other unlisted numerical values within the numerical range are also applicable. Here, if the flow rate of the polar solvent vapor is too large, the polar solvent vapor will condense into droplets and destroy the printed pattern; if the flow rate of the polar solvent vapor is too small, the precursor reaction will be incomplete.

Optionally, the temperature of the reaction in step (2) is 0 to 100°C, such as 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100° C., etc., but not limited to the listed numerical values, and other unlisted numerical values within the numerical range are also applicable. Here, if the reaction temperature is too high, the formed quantum dots will decompose; if the reaction temperature is too low, the growth rate of the quantum dots will be slow.

Optionally, the reaction time of step (2) is 15-120s, such as 15s, 30s, 50s, 70s, 90s, 100s, 110s or 120s, etc., but not limited to the listed values, other values within the range of The same applies to non-recited values.

As a further optional technical solution of the method described in this application, the method comprises the following steps:

(1) Clean the ITO glass with a surfactant for 5-10 minutes, then ultrasonically in the surfactant, acetone and isopropanol for 20-40 minutes, and finally clean it with an ultraviolet ozone cleaning machine to obtain the cleaned ITO glass ;

(2) 60-120 microliters of poly-3,4-ethylenedioxythiophene-polystyrene sulfonate mixture solution was added dropwise to one side of the cleaned ITO glass in step (1). Spin coating at 4000 rpm for 30 to 60 seconds, anneal on a hot stage at 100 to 140°C for 15 to 20 minutes, and then apply the resulting poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film to the film. Add 60-120 microliters of polyvinylcarbazole solution dropwise, spin-coat at 2000-4000 r/min for 30-60 seconds with a glue spinner, and anneal at 100-140°C for 15-20 minutes on a hot stage to form a polymer solution. Vinylcarbazole film to obtain ITO glass with film as a substrate;

(3) Dissolving the cation A precursor, the cation B precursor and the optional anion X precursor in a non-polar solvent to obtain a precursor solution with a precursor concentration of 0.05-5M, in which A, B The element ratio with X is 1:1:3, A is Cs ⁺ , B is Pb ²⁺ , X is any one of Br-, I- or Cl- or a combination of at least two, the precursor is The solution forms a precursor pattern on the substrate in step (2) by inkjet printing with a nozzle diameter of 5-100 microns at 15-35°C;

(4) placing the precursor pattern in step (3) in the vapor of a polar solvent with a flow rate of 1-100 L/min, and reacting at a temperature of 0-100° C. for 15-120 s to form a perovskite quantum dot pattern ;

Wherein, the poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film with film ITO glass in step (2) is located on one side of the ITO glass, and the polyvinylcarbazole film is located on the poly3,4- ethylenedioxythiophene-polystyrene sulfonate mixture film.

Compared with the prior art, the present application has the following beneficial effects:

(1) The patterning method of quantum dots provided in this application realizes patterning based on printing, and the printed precursor pattern reacts in situ to become a quantum dot pattern, with high precision, suitable for large-area quantum dot patterning, and can be used for The preparation of the quantum dot light-emitting layer has a good application prospect in the fields of optoelectronic display and lighting.

(2) The patterning method of quantum dots provided by the present application is not to print quantum dots directly, but to print the precursors of quantum dots first, and then convert the patterned precursors into quantum dots. This can well avoid the problem of nozzle clogging caused by direct printing of quantum dots, and at the same time, the yield of the obtained quantum dots is over 57%.

Description of drawings

FIG. 1 is a fluorescence microscope photograph of the patterned perovskite quantum dots provided in Example 1 of the present application.

FIG. 2 is a fluorescence spectrum of the patterned perovskite quantum dots provided in Example 1 of the present application.

FIG. 3 is the fluorescence spectrum of the patterned cadmium selenide quantum dots provided in Example 5 of the present application.

FIG. 4 is a fluorescence spectrum of the patterned indium phosphide quantum dots provided in Example 6 of the present application.

Detailed ways

In order to better illustrate the present application and facilitate the understanding of the technical solutions of the present application, the present application will be described in further detail below. However, the following embodiments are only simple examples of the present application, and do not represent or limit the protection scope of the present application. The protection scope of the present application is subject to the claims.

The following are typical but non-limiting examples of the application:

Example 1

In this embodiment, the patterning of perovskite quantum dots is carried out according to the following method:

(1) Clean the ITO glass sheet with surfactant (detergent) for 5 minutes to remove large particles; then put the ITO glass sheet cleaned with detergent into surfactant (ITO cleaning solution), acetone, isopropyl alcohol Ultrasonic in turn for 30 minutes; finally, the ultrasonicated ITO glass sheet is dried and placed in a UVO ₃ cleaning machine for secondary cleaning to obtain cleaned ITO glass.

(2) The ITO glass after the cleaning described in step (1) is placed on a spin coating machine to make a film, and the materials of the film are PEDOTS:PSS and PVK, which are used as substrates; the specific operation steps are to make the ITO glass sheet Place it on the glue homogenizer and turn on the adsorption button of the glue homogenizer, and put the coated side of the ITO glass sheet up; then drop 100 microliters of PEDOT:PSS solution on the ITO glass sheet; Spin coating conditions were 3000 rpm, spin coating time of 45 seconds, and finally annealed at 130°C for 20 minutes on a hot stage. Continue to put the annealed ITO glass sheet on the glue spinner again, turn on the adsorption button, and turn the coated side of the glass sheet up; drop 100 microliters of PVK solution on the glass sheet; turn on the spin coating button of the glue spinner, and spin the film to make a film. The coating conditions were 3000 rev/min of rotation speed and 45 seconds of time; annealed at 130° C. for 20 minutes on a hot stage to obtain ITO glass with film, which was used as a substrate.

(3) Mix the cation A precursor CsBr and the cation B precursor PbBr ₂ according to the ratio of Cs ⁺ :Pb ²⁺ :Br ^- =1:1:3 to form a precursor solution in dodecane (precursor concentration 2.5M). The precursor solution is loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by the American microfab company, the diameter of the nozzle of the printer is 60 microns, and the precursor solution is printed at 25 ° C to the step (3). A precursor pattern is formed on the PVK film of the substrate.

(4) placing the precursor pattern in step (3) in water vapor with a flow rate of 10 L/min, and reacting at a temperature of 25° C. for 60 s to form a perovskite quantum dot pattern.

The test results of printing patterned perovskite quantum dots CsPbBr ₃ in this example are shown in Table 1.

FIG. 1 is a fluorescence microscope photo of the patterned perovskite quantum dots provided in this embodiment. From this figure, it can be seen that high-quality perovskite quantum dots can be accurately printed by using this patent.

FIG. 2 shows the fluorescence spectrum of the patterned perovskite quantum dots provided in this embodiment. From this figure, it can be seen that the perovskite quantum dots patterned by the above method have a narrow half-peak width and good optical quality.

Example 2

(1) Clean the ITO glass sheet with surfactant (detergent) for 10 minutes to remove large particles; then put the ITO glass sheet cleaned with detergent into surfactant (ITO cleaning solution), acetone, isopropanol Ultrasonic in turn for 40 minutes; finally, the ultrasonicated ITO glass sheet is dried and placed in a UVO ₃ cleaning machine for secondary cleaning to obtain cleaned ITO glass.

(2) The ITO glass after the cleaning described in step (1) is placed on a spin coating machine to make a film, and the materials of the film are PEDOTS:PSS and PVK, which are used as substrates; the specific operation steps are to make the ITO glass sheet Place it on the glue dispenser and turn on the adsorption button of the glue dispenser, turn the coated side of the ITO glass sheet up; then drop 120 microliters of PEDOT:PSS solution on the ITO glass sheet; then turn on the spin coating button of the glue dispenser to spin the film, The spin coating conditions were 4000 rpm, 60 seconds spin coating time, and finally annealed at 140°C for 17 minutes on a hot stage. Continue to put the annealed ITO glass sheet on the glue spinner again, turn on the adsorption button, and turn the coated side of the glass sheet up; drop 100 microliters of PVK solution on the glass sheet; turn on the spin coating button of the glue spinner, and spin the film to make a film. The coating conditions were 4000 rev/min of rotation speed and 60 seconds of time; annealed at 140° C. for 17 minutes on a hot stage to obtain ITO glass with film, which was used as a substrate.

(3) The cation A precursor cesium carbonate, the cation B precursor lead oxide and the anion X precursor ammonium bromide are dissolved in octane according to the ratio of Cs ⁺ :Pb ²⁺ :Br ^- =0.9:0.9:3. Precursor solution (precursor concentration 0.05M). The precursor solution is loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by the American microfab company, the diameter of the nozzle of the printer is 100 microns, and the precursor solution is printed at 35 ° C to the step (3). A precursor pattern is formed on the PVK film of the substrate.

(4) placing the precursor pattern in step (3) in ethanol vapor with a flow rate of 1 L/min, and reacting at a temperature of 0° C. for 15 s to form a perovskite quantum dot pattern.

Example 3

(1) Clean the ITO glass sheet with surfactant (detergent) for 8 minutes to remove large particles; then put the ITO glass sheet cleaned with detergent into surfactant (ITO cleaning solution), acetone, isopropyl alcohol Ultrasonic in turn for 20 minutes; finally, the ultrasonicated ITO glass sheet is dried and placed in a UVO ₃ cleaning machine for secondary cleaning to obtain cleaned ITO glass.

(2) The ITO glass after the cleaning described in step (1) is placed on a glue leveler and spin-coated to form a film, and the material of the film is PVK, which is used as a substrate; the specific operation steps are to place the ITO glass sheet on the glue leveler. On the machine and open the adsorption button of the glue dispenser, put the coated side of the ITO glass sheet upward; then drop 60 μl of PVK solution on the ITO glass sheet; then turn on the spin coating button of the glue dispenser to rotate the film, and the spin coating condition is 2000 rpm. rev/min, spin coating time of 30 seconds; finally, annealed at 100° C. for 15 minutes on a hot stage to obtain ITO glass with film, which was used as a substrate.

(3) The cation A precursor cesium acetate, the cation B precursor lead lead bromide and the anion X precursor ammonium bromide are dissolved in oleic acid according to the ratio of Cs ⁺ :Pb ²⁺ :I ^- =1.1:1.1:3 The formed precursor solution (precursor concentration was 5M). The precursor solution is loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by microfab company in the United States, the diameter of the nozzle of the printer is 5 microns, and the precursor solution is printed at 15 ° C. A precursor pattern is formed on the PVK film of the substrate.

(4) placing the precursor pattern in step (3) in isopropanol vapor with a flow rate of 100 L/min, and reacting at a temperature of 100° C. for 120 s to form a perovskite quantum dot pattern.

The test results of printing patterned perovskite quantum dots CsPbI ₃ in this example are shown in Table 1.

Example 4

The perovskite quantum dot patterning method of this implementation refers to Example 1, the difference is that the operation of step (2) is not performed, and the cleaned ITO glass obtained in step (1) is directly used as the substrate to perform the operation of step (3). .

Example 5

In this embodiment, the patterning of cadmium selenide quantum dots is carried out according to the following method:

(2) The ITO glass after the cleaning described in step (1) is placed on a spin coating machine to make a film, and the materials of the film are PEDOTS:PSS and PVK, which are used as substrates; the specific operation steps are to make the ITO glass sheet Place it on the glue homogenizer and turn on the adsorption button of the glue homogenizer, and put the coated side of the ITO glass sheet up; then drop 100 microliters of PEDOT:PSS solution on the ITO glass sheet; Spin coating conditions were 3000 rpm, spin coating time of 45 seconds, and finally annealed at 130°C for 20 minutes on a hot stage. Continue to put the annealed ITO glass sheet on the glue spinner again, turn on the adsorption button, and turn the coated side of the glass sheet up; drop 100 microliters of PVK solution on the glass sheet; turn on the spin coating button of the glue spinner to rotate the film, spin The coating conditions were 3000 rev/min of rotation speed and 45 seconds of time; annealed at 130° C. for 20 minutes on a hot stage to obtain ITO glass with film, which was used as a substrate.

(3) Mix the precursors of cadmium selenide, zinc source, cadmium source, selenium source and sulfur source in a ratio of 20:1:8:4 in a mixed solution of octadecene and oleic acid to form a precursor solution ( The precursor concentration was 0.25M). The precursor solution is loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by the American microfab company, the diameter of the nozzle of the printer is 60 microns, and the precursor solution is printed at 25 ° C to the step (3). A precursor pattern is formed on the PVK film of the substrate.

(4) The precursor pattern in step (3) is heated and reacted at 300° C. for 10 minutes to form a cadmium selenide quantum dot pattern.

Table 1 shows the test results of printing patterned cadmium selenide quantum dots CdSe in this embodiment.

The fluorescence spectrum of the patterned cadmium selenide quantum dots provided in this embodiment is shown in FIG. 3 , and it can be seen from the figure that the cadmium selenide quantum dots with good optical properties can be prepared by the above scheme.

Example 6

In this embodiment, the patterning of indium phosphide quantum dots is performed according to the following method:

(3) Mix the phosphine source of indium phosphide and the indium source according to the ratio of 1:3.5 and the ratio of the precursor according to the ratio of the precursor to form a precursor solution in octadecene (precursor concentration is 0.25M). The precursor solution is loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by the American microfab company, the diameter of the nozzle of the printer is 60 microns, and the precursor solution is printed at 25 ° C to the step (3). A precursor pattern is formed on the PVK film of the substrate.

(4) The precursor pattern in step (3) is placed at 200° C. for 10 minutes to react to form an indium phosphide quantum dot pattern.

Table 1 shows the test results of printing patterned indium phosphide quantum dots InP in this embodiment.

The fluorescence spectrum of the patterned indium phosphide quantum dots provided in this embodiment is shown in Figure 4, and it can be seen from the figure that the indium phosphide quantum dots with good optical properties can be prepared by the above scheme.

Comparative Example 1

The patterning method of perovskite quantum dots in this comparative example is as follows:

The CsPbBr ₃ perovskite quantum dots were mixed with dodecane to obtain a quantum dot dispersion (quantum dot concentration was 0.1 mol/L), and the quantum dot dispersion was loaded into the jetlab2 type non-contact spray produced by the American microfab company. In the ink cartridge of the ink printer, the nozzle diameter of the printer is 60 microns, and the quantum dot dispersion is printed on the PVK film of the substrate described in Example 1 at 25°C to form the same perovskite quantum dot pattern as in Example 1.

The test results of printing patterned perovskite quantum dots CsPbBr ₃ in this comparative example are shown in Table 1.

Comparative Example 2

(1) Mix the cation A precursor CsBr and the cation B precursor PbBr ₂ according to the ratio of Cs ⁺ :Pb ²⁺ :Br ^- =1:1:3 to form a precursor solution in DMF (the precursor concentration is the same as Example 1 is the same). The precursor solution was loaded into the ink cartridge of the jetlab2 type non-contact inkjet printer produced by the American microfab company, the diameter of the nozzle of the printer was 60 microns, and the precursor solution was printed at 25 ° C as described in Example 1. A precursor pattern is formed on the PVK film of the substrate.

(2) drying the precursor pattern described in step (2), the drying temperature is 60° C., and the drying time is 10 minutes, to obtain a perovskite quantum dot pattern.

Comparative Example 3

In this comparative example, except that in step (4), water is applied on the precursor pattern described in step (3), and the reaction is carried out under the temperature and reaction time of Example 1, other operation steps and specific operation conditions and implementation Example 1 is the same.

testing method

The samples were observed with a fluorescence microscope to test the printing accuracy, pattern flatness and pattern ambiguity of the examples and comparative examples. The needle blockage was recorded in the experiment, and the yield of quantum dots was measured by a yield tester. have to.

Table 1

Combining the above examples and comparative examples, it can be seen that the patterning method of the perovskite quantum dots of Examples 1-3 is based on inkjet printing, and the perovskite quantum dots are not directly printed, but the perovskite quantum dots are printed first. dot precursors, and then convert the patterned precursors into perovskite quantum dots, which well avoids the problem of nozzle clogging, and does not form satellite droplets during the printing process, resulting in the formation of quantum dots in the non-printing area, Therefore, the advantages of inkjet printing can be fully utilized, so that the printing accuracy is high, the pattern is not blurred, and the nozzle is not blocked, and it is suitable for patterning perovskite quantum dots in a large area. Moreover, in Examples 1-3, the precursor solution was printed on a non-polar PVK film, and the solvent of the precursor solution was also a non-polar solvent, so that the contact angle was smaller and the wetting was better, which could further improve the printing pattern. flatness.

In Example 4, no film was formed on ITO glass, the wettability of the precursor solution on the substrate was slightly poor, and the contact angle of the precursor solution after printing on ITO glass was larger than that in Examples 1-3, resulting in the flatness of the printed pattern in Example 4. The test results of this aspect are slightly insufficient compared to Examples 1-3.

Comparative Example 1 Direct inkjet printing of perovskite quantum dots instead of precursors, because the agglomeration of quantum dots caused serious blockage of the nozzle of Comparative Example 1, and it was impossible to pattern perovskite quantum dots in a large area for a long time. At the same time, when the needle was partially blocked It will change the flight angle of the printing droplets and the formation of satellite droplets, which will affect the accuracy of the pattern and the blurring of the pattern.

The solvent in the precursor solution of perovskite quantum dots printed in Comparative Example 2 is a polar solvent. The limitation of the solvent will make it difficult to adjust the viscosity of the solvent, resulting in the appearance of satellite droplets during the printing process, which affects the accuracy of the pattern and the degree of ambiguity of the pattern. At the same time, due to the problem of solvent and substrate contact angle, the flatness of the sample is slightly insufficient.

Comparative Example 3 did not use the vapor of polar solvent for the reaction, but directly coated the polar solvent on the precursor pattern, which would cause the polar solvent to wash out the printed agglomerates, making the image have problems in blurriness and flatness, At the same time, since the amount of polar solvent is too large, the precursor of quantum dots can be dissolved, so that the yield of quantum dots in Comparative Example 3 is not as good as that of Example 3.

The applicant declares that the present application illustrates the detailed method of the present application through the above-mentioned embodiments, but the present application is not limited to the above-mentioned detailed method, which does not mean that the present application must rely on the above-mentioned detailed method for implementation.

Claims

A method for patterning quantum dots, comprising the following steps:

(1) Dissolving the quantum dot precursor in a non-polar solvent, and printing the obtained precursor solution on a substrate to form a precursor pattern;

(2) reacting with the precursor pattern described in step (1) to form a quantum dot pattern.
The method of claim 1, wherein the method comprises the steps of:

(1) Dissolving the perovskite quantum dot precursor in a non-polar solvent, and printing the obtained precursor solution on a substrate to form a precursor pattern;

(2) The precursor pattern described in step (1) is placed in the vapor of a polar solvent to react to form a perovskite quantum dot pattern.
The method according to claim 2, wherein the perovskite quantum dots are inorganic perovskite quantum dots.
The method of claim 2, wherein the perovskite quantum dots consist of cation A, cation B and anion X;

Optionally, the cation A includes Cs + and/or Rb + ;

Optionally, the cation B includes Pb 2+ ;

Optionally, the anion X includes any one or a combination of at least two of Cl - , Br - or I - ;

Optionally, the perovskite quantum dot precursor in step (1) includes a cation A precursor, a cation B precursor and an optional anion X precursor;

Optionally, the cation A precursor includes any one or a combination of at least two of Cs 2 CO 3 , CsAc, CsCl, CsBr, CsI, Rb 2 CO 3 , RbAc, RbCl, RbBr or RbI;

Optionally, the cation B precursor includes any one or a combination of at least two of PbCl 2 , PbBr 2 , PbI 2 , PbO or Pb(Ac) 2 ;

Optionally, the anion X precursor comprises any one or a combination of at least two of NH4Cl , NH4Br , NH4I , CsCl, CsBr, CsI, RbCl, RbBr or RbI;

Optionally, in the perovskite quantum dot precursor described in step (1), the molar ratio of cation A, cation B and anion X is (0.9-1.1):(0.9-1.1):3, optionally 1: 1:3.
The method according to claim 1, wherein the quantum dot precursor in step (1) comprises an indium phosphide quantum dot precursor and/or a cadmium selenide quantum dot precursor;

Optionally, the method for reacting with the precursor pattern described in step (1) in step (2) is a heating reaction;

Optionally, the indium phosphide quantum dot precursor includes a phosphine source and an indium source;

Optionally, the phosphine source comprises tris(trimethylsilyl) phosphine, tris(dimethylamino) phosphine, tris(diethylamino) phosphine, tris(dimethyl-tert-butylsilyl) phosphine or tris(dimethyl-tert-butylsilyl) phosphine (triphenylsilyl)phosphine any one or a combination of at least two;

Optionally, the indium source includes any one or a combination of at least two of indium acetate, indium iodide, indium bromide or indium chloride;

Optionally, the cadmium selenide quantum dot precursor includes a cadmium source and a selenium source;

Optionally, the selenium source comprises any one or a combination of at least two of selenium powder, oleylamine solution of selenium, tributylphosphine solution of selenium or trioctylphosphine solution of selenium;

Optionally, the cadmium source includes any one or a combination of at least two of cadmium oxide, cadmium acetate, methylcadmium or cadmium oleate;

Optionally, the cadmium selenide quantum dot precursor further includes a zinc source and a sulfur source;

Optionally, the zinc source comprises one or a mixture of at least two of zinc oxide, zinc acetate, zinc stearate or zinc oleate;

Optionally, the sulfur source includes sulfur powder, sulfur in oleylamine solution, sulfur in tributylphosphine solution, sulfur in trioctylphosphine solution, one or a mixture of at least two of dodecanethiol or octanethiol.
The method according to any one of claims 1-5, wherein the non-polar solvent in step (1) comprises any one or at least one of octadecene, liquid paraffin, dodecane, octane or hexane a combination of the two;

Optionally, in the precursor solution, the concentration of the precursor is 0.05-5 mol/L.
The method according to any one of claims 1-6, wherein in step (1) the substrate comprises a host material;

Optionally, the main body material includes any one of ITO glass, polyethylene film, polypropylene film, polyethylene phthalate film or methyl methacrylate film;

Optionally, the main body material is cleaned main body material;

Optionally, the cleaning method includes: performing primary cleaning, ultrasonic and secondary cleaning on the main body material;

Optionally, the one-time cleaning method includes: cleaning with a surfactant for 5-10 minutes;

Optionally, the ultrasonic cleaning method includes: ultrasonically sonicating in surfactant, acetone and isopropanol for 20-40 minutes in sequence;

Optionally, the method for secondary cleaning includes: cleaning with an ultraviolet ozone cleaning machine.
The method of claim 7, wherein one side of the host material has a film;

Optionally, the membrane is a non-polar material membrane;

Optionally, the film includes any one or a combination of at least two of polyvinylcarbazole film, poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film or zinc oxide film, which can be Selected as a combination of polyvinylcarbazole film and poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film;

Optionally, when the film is a combination of a polyvinylcarbazole film and a poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film, the poly3,4-ethylenedioxythiophene-polyethylene The styrene sulfonate mixture film is located on the host material, and the polyvinyl carbazole film is located on the poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film;

Optionally, the method for preparing a film on one side of the host material includes: dropping a film raw material solution on one side of the host material, spin-coating the host material, and then annealing;

Optionally, the dropwise addition amount is 60-120 microliters;

Optionally, the spin coating is performed with a glue spreader;

Optionally, the rotational speed of the spin coating is 2000-4000 rpm;

Optionally, the spin coating time is 30-60 seconds;

Optionally, the annealing is performed on a hot stage;

Optionally, the temperature of the annealing is 100-140°C;

Optionally, the annealing time is 15-20 minutes.
The method according to any one of claims 1-8, wherein the printing in step (1) is inkjet printing;

Optionally, the inkjet printing is performed with an inkjet printer;

Optionally, the inkjet printer is a non-contact inkjet printer;

Optionally, the diameter of the nozzle of the printer is 5-100 microns;

Optionally, the printing temperature in step (1) is 15-35°C.
The method according to any one of claims 1-9, wherein the polar solvent of step (2) comprises any one or a combination of at least two in water, ethanol, isopropanol or isobutanol;

Optionally, wherein, the flow rate of the vapor of the polar solvent in step (2) is 1-100 L/min;

Optionally, the temperature of the reaction in step (2) is 0-100°C;

Optionally, the reaction time of step (2) is 15-120 s.
The method of claim 2, wherein the method comprises the steps of:

(1) Clean the ITO glass with a surfactant for 5-10 minutes, then ultrasonically in the surfactant, acetone and isopropanol for 20-40 minutes in turn, and finally clean it with an ultraviolet ozone cleaning machine to obtain the cleaned ITO glass ;

(2) 60-120 microliters of poly-3,4-ethylenedioxythiophene-polystyrene sulfonate mixture solution was added dropwise to one side of the cleaned ITO glass in step (1). Spin coating at 4000 rpm for 30 to 60 seconds, anneal on a hot stage at 100 to 140°C for 15 to 20 minutes, and then apply the resulting poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film to the film. Add 60-120 microliters of polyvinylcarbazole solution dropwise, spin-coat at 2000-4000 r/min for 30-60 seconds with a glue spinner, and anneal at 100-140°C for 15-20 minutes on a hot stage to form a polymer solution. Vinylcarbazole film to obtain ITO glass with film as a substrate;

(3) Dissolving the cation A precursor, the cation B precursor and the optional anion X precursor in a non-polar solvent to obtain a precursor solution with a precursor concentration of 0.05-5 mol/L, in which A The element ratio of , B and X is 1:1:3, A is Cs + , B is Pb 2+ , X is any one or a combination of at least two in Br-, I- or Cl-, the said The precursor solution is printed on the substrate in step (2) by inkjet printing with a nozzle diameter of 5-100 microns at 15-35° C. to form a precursor pattern;

(4) placing the precursor pattern in step (3) in the vapor of a polar solvent with a flow rate of 1-100 L/min, and reacting at a temperature of 0-100° C. for 15-120 s to form a perovskite quantum dot pattern ;

Wherein, the poly3,4-ethylenedioxythiophene-polystyrene sulfonate mixture film with film ITO glass in step (2) is located on one side of the ITO glass, and the polyvinylcarbazole film is located on the poly3,4- ethylenedioxythiophene-polystyrene sulfonate mixture film.