Method for preparing perovskite light-emitting device based on electromagnetic heating annealing method

Abstract

A method for preparing a perovskite light-emitting device based on an electromagnetic heating annealing method belongs to the technical field of perovskite device preparation, and the specific scheme comprises the following steps: step 1, evaporating a layer of soft magnetic material film on a substrate; 2, coating the soft magnetic material film with a hole transport layer precursor solution, and carrying out electromagnetic heating annealing to obtain a hole transport layer; 3, coating the hole transport layer with a perovskite precursor solution, and carrying out electromagnetic heating annealing to obtain a light-emitting layer; and 4, sequentially evaporating an electron transport layer, an electron injection layer and an electrode on the light-emitting layer from bottom to top to obtain the perovskite light-emitting device. According to the invention, by adjusting the frequency and intensity of the magnetic field, the heating process can be accurately controlled, the whole object can be uniformly heated, local overheating is avoided, the crystallization quality of the film is improved, and the luminous efficiency of the perovskite LED device is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite device preparation, and particularly relates to a method for preparing perovskite light-emitting devices based on electromagnetic heating annealing method. Background Art

[0002] Perovskite materials have attracted much attention in the field of novel optoelectronic devices due to their excellent optoelectronic properties. Such materials not only have characteristics such as tunable bandgap, high carrier mobility, and long carrier diffusion length, but also show great commercial potential in fields such as solar cells, LED lighting, laser devices, and photodetectors due to their solution processability, low-temperature preparation process, and low-cost advantages. Since the first room-temperature-operating perovskite LED came out in 2014, the performance parameters of related devices have achieved leapfrog improvements.

[0003] In the thin-film preparation process, annealing treatment is a key link in regulating the microstructure of materials. The time-space distribution of the annealing temperature field directly affects the grain growth kinetics, grain boundary formation mechanism, and defect state distribution. Optimizing the annealing process can effectively improve the crystallization quality of the thin film, increase the grain size, and reduce the defect density, which has a decisive effect on the optoelectronic conversion efficiency and operating stability of the device.

[0004] The currently commonly used overall heating method of the substrate has significant physical limitations. When the substrate coated with the thin film is placed on the hot stage as a whole, a vertical temperature gradient from bottom to top will be formed in the system. This non-uniform thermal field causes two-way crystallization competition in the thickness direction of the thin film: nucleation occurs preferentially at the substrate interface due to contact with the heat source, while the surface layer undergoes secondary crystallization due to air convection cooling. This non-equilibrium crystallization process is likely to cause uneven grain size distribution, forming high-density grain boundaries and point defects. More notably, the mismatch in the thermal expansion coefficients of the perovskite layer and the substrate material will generate cumulative tensile stress in the interface region. This mechanical stress not only reduces the carrier transport efficiency but also becomes an inducement for structural failure during the long-term operation of the device. Summary of the Invention

[0005] To solve the problems existing in the background art, the present invention provides a method for preparing perovskite light-emitting devices based on electromagnetic heating annealing method.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing perovskite light-emitting devices based on electromagnetic heating annealing method, comprising the following steps:

[0008] Step 1: Evaporate a soft magnetic material thin film on a substrate;

[0009] Step 2: Coat a hole transport layer precursor solution on the soft magnetic material thin film, and perform electromagnetic heating annealing to obtain a hole transport layer;

[0010] Step 3: Coating a perovskite precursor solution on the hole transport layer, and performing electromagnetic heating annealing to obtain a light-emitting layer;

[0011] Step 4: Using a vacuum coating device to sequentially evaporate an electron transport layer, an electron injection layer, and an electrode on the light-emitting layer from bottom to top to finally obtain a perovskite light-emitting device.

[0012] The electromagnetic heating annealing table used for the electromagnetic heating annealing includes a magnetic field emitter and a heating table panel. The heating table panel is arranged in the space of the magnetic field emitted by the magnetic field emitter. When electromagnetic heating annealing is required, the component is placed on the heating table panel. Preferably, there are two magnetic field emitters, which are symmetrically arranged up and down, and the heating table panel is arranged between the two magnetic field emitters. The material of the electromagnetic coil inside the magnetic field emitter is iron or copper, and the material of the heating table panel is a microcrystalline panel or a mica porcelain plate.

[0013] Further, in Step 1, before using the substrate, pre-treatment and cleaning treatment are performed on it: The substrate is etched according to the pattern design by using a laser etching process to obtain a first preform, and then the first preform is sequentially cleaned with deionized water, absolute ethanol, acetone, isopropyl alcohol, and absolute ethanol, and the first preform is dried with nitrogen to obtain a second preform. The second preform is subjected to plasma irradiation for 10 - 15 minutes to obtain a third preform, that is, the pre-treated substrate, which is transferred to a glove box filled with nitrogen. The third preform is placed in a mask for evaporating a soft magnetic material thin film with a specific shape. The third preform and the mask are transferred into a thermal evaporation chamber for evaporating the soft magnetic material. The thickness of the soft magnetic material thin film is 10 - 30 nm. The soft magnetic material includes silicon steel, iron-nickel alloy, iron-cobalt alloy, neodymium iron boron, ferrite, or aluminum nickel cobalt alloy; the substrate is a rigid ITO glass or a flexible ITO-PET substrate.

[0014] In Step 2, the preparation method of the hole transport layer is as follows: Ultrasonically oscillate PEDOT:PSS in an ultrasonic cleaner for 5 - 15 s, filter it with a 220 nm PTFE filter head to obtain the PEDOT:PSS filtrate. Use a pipette to take 40 - 80 μL of the filtrate and drop it on the soft magnetic material film, and spin-coat it evenly with a spin coater at a rotation speed of 3000 - 5000 rpm for 25 - 45 s. Transfer the spin-coated PEDOT:PSS wet film to an electromagnetic heating annealing platform for electromagnetic heating annealing at an annealing temperature of 100 - 160 °C for 10 - 20 min to prepare a PEDOT:PSS film. Dissolve POLY-tpd in chlorobenzene to prepare a POLY-tpd solution with a concentration of 0.5 - 2 mg / ml, filter it with a 220 nm PTFE filter head to obtain the POLY-tpd filtrate. Use a pipette to take 40 - 80 μL of the POLY-tpd filtrate and drop it on the surface of the PEDOT:PSS film and spin-coat it evenly with a spin coater at a rotation speed of 3000 - 5000 rpm for 25 - 45 s. Transfer the spin-coated POLY-tpd wet film to an electromagnetic heating annealing platform for electromagnetic heating annealing at an annealing temperature of 120 - 180 °C for 15 - 25 min to prepare a POLY-tpd film. The PEDOT:PSS film and the POLY-tpd film together form the hole transport layer.

[0015] In Step 3, the preparation method of the light-emitting layer is as follows: Dissolve 44.7 mg of CsBr, 27.8 mg of PbCl2, 36.7 mg of PbBr2, and 28.3 mg of PEABr in 1 mL of DMSO to prepare a perovskite precursor solution. Filter it with a 220 nm nylon filter head to obtain the perovskite precursor filtrate. Plasma irradiate the surface of the hole transport layer for 8 - 12 s. Use a pipette to take 40 - 80 μL of the perovskite precursor solution and drop it on the surface of the hole transport layer, and spin-coat it evenly with a spin coater at a rotation speed of 3000 - 5000 rpm for 25 - 45 s. Transfer the spin-coated perovskite wet film to an electromagnetic heating annealing platform for electromagnetic heating annealing at an annealing temperature of 50 - 100 °C for 8 - 12 min to prepare a perovskite film, that is, the light-emitting layer.

[0016] In Step 4, place the prepared light-emitting layer in a customized mask template for evaporating TPBi and LiF with specific shapes as the electron transport layer and the electron injection layer respectively. Place the prepared electron transport layer and the electron injection layer in a customized mask template for evaporating the electrode. The material of the electrode is silver. The thickness of the electron transport layer is 30 - 50 nm, the thickness of the electron injection layer is 1 - 2 nm, and the thickness of the electrode is 80 - 100 nm.

[0017] Preferably, the soft magnetic material thin film is not deposited on the substrate corresponding to the light-emitting region.

[0018] Preferably, the deposited soft magnetic material thin film is distributed in a dot array.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The method for preparing a perovskite light-emitting device based on the electromagnetic heating annealing method of the present invention changes the traditional bottom-up annealing process. Compared with the traditional perovskite annealing method, the electromagnetic heating annealing method adopts an inside-out annealing method. By adjusting the frequency and intensity of the magnetic field, the heating process can be precisely controlled, and the whole object can be heated more uniformly, avoiding local overheating, improving the film crystallization quality, and extremely improving the light-emitting efficiency of the perovskite LED device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a schematic diagram of a method for preparing a perovskite light-emitting device based on the electromagnetic heating annealing method;

[0022] Figure 2 In-plane tensile strain diagrams of perovskite light-emitting devices prepared using the traditional annealing method and the electromagnetic heating annealing method in Example 1;

[0023] Figure 3 FIG. is a schematic flow chart of a method for preparing a perovskite light-emitting device based on the electromagnetic heating annealing method in Example 1 of the present invention;

[0024] Figure 4 FIG. is a schematic diagram of the structure of a perovskite device of the present invention;

[0025] Figure 5 For Figure 4 FIG. is a schematic diagram of the structure of the light-emitting region in

[0026] In the figure, 1. Substrate, 2. Soft magnetic material thin film, 3. Hole transport layer, 4. Light-emitting layer, 5. Electron transport layer, 6. Electromagnetic injection layer, 7. Electrode, 8. Magnetic field emitter, 9. Heating table panel, 10. Wet film, 11. Eddy current, 12. Electromagnetic coil, 13. Magnetic field line, 14. Light-emitting region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Example 1:

[0029] This embodiment provides a method for preparing a perovskite light-emitting device based on electromagnetic heating annealing. The flow chart is as shown in Figure 3 and includes the following steps:

[0030] Step 1: Use a rigid ITO glass as the substrate 1 of the perovskite light-emitting device, and perform pretreatment and cleaning on it; deposit a soft magnetic material thin film 2 on the substrate 1, and the deposited soft magnetic material thin film 2 is distributed in a dot array;

[0031] Step 1-1: Etch the substrate using a laser etching process according to the pattern design to obtain a first preform;

[0032] Step 1-2: Ultrasonically clean the first preform successively with deionized water, absolute ethanol, acetone, isopropanol, and absolute ethanol, and blow-dry the first preform with nitrogen to obtain a second preform;

[0033] Step 1-3: Perform plasma irradiation on the second preform for 10-15 minutes to obtain a third preform, and transfer it into a glove box filled with nitrogen;

[0034] Step 1-4: Place the third preform in a mask template for depositing a soft magnetic material thin film 2 with a specific shape;

[0035] Step 1-5: Transfer the third preform and the mask template into a thermal evaporation chamber for evaporating the soft magnetic material. The thickness of the soft magnetic material thin film 2 is 20 nm to obtain a fourth preform. The soft magnetic material is a nickel-iron alloy.

[0036] Step 2: Spin-coat the hole transport layer precursor solution on the substrate 1 deposited with the soft magnetic material thin film 2 and perform electromagnetic heating annealing to obtain a hole transport layer 3;

[0037] Step 2-1: Ultrasonically oscillate PEDOT:PSS in an ultrasonic cleaner for 10 s, and filter it using a 220 nm PTFE filter head to obtain a PEDOT:PSS filtrate;

[0038] Step 2-2: Use a pipette to take 70 μL of the PEDOT:PSS filtrate, drop it on the surface of the substrate deposited with the soft magnetic material thin film, and spin-coat it using a spin coater at a rotation speed of 5000 rpm for 40 s;

[0039] Step 2-3: Transfer the spin-coated PEDOT:PSS wet film to an electromagnetic heating annealing platform for electromagnetic heating annealing. The annealing temperature is 150 °C and the annealing time is 15 minutes to prepare a PEDOT:PSS thin film;

[0040] Step 2-4: Dissolve POLY-tpd in chlorobenzene to prepare a POLY-tpd solution with a concentration of 1 mg / ml. Filter it using a 220 nm PTFE filter head to obtain the POLY-tpd filtrate.

[0041] Step 2-5: Use a pipette to take 70 μL of the POLY-tpd filtrate and drop it onto the surface of the PEDOT:PSS film. Then spin-coat it using a spin coater at a speed of 3000 rpm for 40 s.

[0042] Step 2-6: Transfer the spin-coated POLY-tpd wet film to an electromagnetic heating annealing stage for electromagnetic heating annealing. The annealing temperature is 140 °C and the annealing time is 20 min to prepare the POLY-tpd film. The PEDOT:PSS film and the POLY-tpd film together form the hole transport layer 3.

[0043] Step 3: Spin-coat the perovskite precursor solution on the hole transport layer 3 and perform electromagnetic heating annealing treatment to obtain the light-emitting layer 4.

[0044] Step 3-1: Dissolve 44.7 mg of CsBr, 27.8 mg of PbCl2, 36.7 mg of PbBr2, and 28.3 mg of PEABr in 1 mL of DMSO to prepare the perovskite precursor solution.

[0045] Step 3-2: Filter it using a 220 nm nylon filter head to obtain the perovskite precursor filtrate. Irradiate the surface of the hole transport layer 3 with plasma for 10 s.

[0046] Step 3-3: Use a pipette to take 70 μL of the perovskite precursor solution and drop it onto the surface of the hole transport layer 3. Then spin-coat it using a spin coater at a speed of 5000 rpm for 40 s.

[0047] Step 3-4: Transfer the spin-coated perovskite wet film to an electromagnetic heating annealing stage for electromagnetic heating annealing. The annealing temperature is 70 °C and the annealing time is 10 min to prepare the perovskite film, which is the light-emitting layer 4.

[0048] Step 4: Use a vacuum coating device to sequentially evaporate the electron transport layer 5, the electron injection layer 6, and the electrode 7 from bottom to top on the light-emitting layer to obtain the blue perovskite light-emitting diode.

[0049] Step 4-1: Place the prepared light-emitting layer 4 in Step 3 in a custom-made mask for evaporating specific-shaped TPBi and LiF as the electron transport layer 5 and the electron injection layer 6 respectively. The thickness of TPBi is 40 nm and the thickness of LiF is 1 nm.

[0050] Step 4-2: Place the prepared electron transport layer 5 and electron injection layer 6 in a customized mask for evaporating the electrode 7. Preferably, the material of the electrode 7 is silver and the thickness is 100 nm.

[0051] No soft magnetic material thin film 2 is evaporated on the substrate 1 corresponding to the light-emitting region 14, as Figure 4 shown.

[0052] Figure 4 The schematic structural diagram corresponding to the light-emitting region in Figure 5 is shown as

[0053] The electromagnetic heating annealing table includes two symmetrically arranged magnetic field emitters 8 and a heating table panel 9 up and down. The heating table panel 9 is arranged between the two magnetic field emitters 8, and the heating table panel 9 is arranged in the space of the magnetic field emitted by the magnetic field emitter 8. When electromagnetic heating annealing is required, place the sample on the heating table panel 9. The schematic structural diagram is as Figure 1 shown, where 13 is the magnetic line of force. The material of the electromagnetic coil 12 inside the magnetic field emitter 8 is iron, and the material of the heating table panel 9 is a microcrystalline panel.

[0054] The annealing principle of the present invention is as follows: Evaporate a layer of soft magnetic material thin film 2 on the substrate 1. After spin-coating the required wet film 10, place the substrate 1 on the electromagnetic heating annealing table. Under the action of a high-frequency alternating magnetic field, eddy currents 11 are generated in the soft magnetic material thin film 2, thereby quickly generating heat to anneal the wet film 10.

[0055] Compared with the traditional annealing method, the electromagnetic heating annealing method of the present invention helps to improve the interfacial tensile stress of the thin film, thereby improving the film-forming quality and crystallization effect of the thin film. The comparison diagram is as Figure 2 shown.

[0056] In addition, it should be understood that although this specification is described according to the embodiments, not each embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a perovskite light-emitting device based on electromagnetic heating annealing, characterized in that: The following steps are involved: Step 1: vapor depositing a layer of soft magnetic material film on the substrate; Step 2: coating a hole transport layer precursor solution on the soft magnetic material film, and performing electromagnetic heating annealing to obtain a hole transport layer; Step 3: coating the hole transport layer with a perovskite precursor solution and performing electromagnetic heating annealing to obtain a light-emitting layer; Step 4: Vapor-deposit an electron transport layer, an electron injection layer and an electrode on the light-emitting layer from bottom to top to finally obtain a perovskite light-emitting device.

2. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: The electromagnetic heating annealing table used for the electromagnetic heating annealing comprises a magnetic field transmitter and a heating table plate. The heating table plate is arranged in the space where the magnetic field is emitted by the magnetic field transmitter. When electromagnetic heating annealing is required, the component is placed on the heating table plate.

3. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 2, characterized in that: There are two magnetic field transmitters, which are symmetrically arranged up and down, and the heating table panel is arranged between the two magnetic field transmitters.

4. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: In step one, before use, the substrate is etched using a laser etching process according to the pattern design, and then the substrate is cleaned in sequence using deionized water, anhydrous ethanol, acetone, isopropanol, and anhydrous ethanol, and blown dry using nitrogen, and then irradiated with plasma to obtain a pre-treated substrate.

5. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: In step 1, the thickness of the soft magnetic material film is 10-30 nm, the soft magnetic material includes silicon steel, iron-nickel alloy, iron-cobalt alloy, neodymium iron boron, ferrite or aluminum-nickel-cobalt alloy, and the substrate is rigid ITO glass or flexible ITO-PET substrate.

6. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: In step 2, the preparation method of the hole transport layer is as follows: ultrasonically oscillate and filter PEDOT:PSS, take the filtrate and drop it on the soft magnetic material film, spin coat it evenly, and perform electromagnetic heating annealing on it, the annealing temperature is 100-160°C, the annealing time is 10-20min, and a PEDOT:PSS film is prepared; POLY-tpd is dissolved in chlorobenzene to prepare a 0.5-2mg / ml concentration of POLY-tpd solution, and after filtering, the filtrate is dropped on the surface of the PEDOT:PSS film and spin coat it evenly, and it is subjected to electromagnetic heating annealing, the annealing temperature is 120-180°C, and the annealing time is 15-25min to prepare a POLY-tpd film, and the PEDOT:PSS film and the POLY-tpd film together constitute a hole transport layer.

7. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: Step 3. The preparation method of the light-emitting layer is as follows: 44.7 mg CsBr, 27.8 mg PbCl2, 36.7 mg PbBr2 and 28.3 mg PEABr are dissolved in every 1 mL DMSO to prepare a perovskite precursor solution, which is filtered and dropped onto the surface of the hole transport layer, spin-coated evenly, and subjected to electromagnetic heating annealing at a temperature of 50-100°C for 8-12 min to obtain a light-emitting layer.

8. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: In step three, the hole transport layer is subjected to plasma irradiation treatment before coating the perovskite precursor solution.

9. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: In step 4, the material of the electron transport layer is TPBi, the material of the electron injection layer is LiF, the material of the electrode is silver, the thickness of the electron transport layer is 30-50nm, the thickness of the electron injection layer is 1-2nm, and the thickness of the electrode is 80-100nm.

10. The method for preparing a perovskite light-emitting device based on electromagnetic heating annealing according to claim 1, characterized in that: The soft magnetic material film is not evaporated at the substrate position corresponding to the light-emitting area.

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