Preparation method and application of perovskite LaCoO3 visible light conductive film

Abstract

The application discloses a preparation method and application of a perovskite type LaCoO3 visible light conductive thin film, and comprises the following steps: uniformly dispersing a cobalt source and La(NO3)3.6H2O in a proper amount of deionized water, then adding ethylenediaminetetraacetic acid and polyethyleneimine in sequence, uniformly stirring a mixed solution obtained after the above steps, and placing the mixed solution in an oil bath pot to heat and stir until the mixed solution has a certain viscosity, so as to obtain an ink solution; injecting the ink solution into an ink box of an inkjet printing device, placing a cleaned substrate, setting printing parameters, and printing to obtain a thin film; and performing high-temperature sintering on the printed thin film to obtain the perovskite type LaCoO3 visible light conductive thin film. The perovskite type LaCoO3 thin film is prepared by using the inkjet printing technology, and compared with traditional preparation technologies, the production cost is greatly reduced, and the production efficiency is improved; the thin film shows stable visible light conductive response, rapidly reacts to generate obvious photocurrent under irradiation of 32mW / cm 2 ~160mW / cm 2 light intensity, and has great application prospect in the field of photoelectric materials.

Description

Technical Field

[0001] This invention relates to the field of photoconductive thin film preparation technology, specifically to a method for preparing and applying a perovskite-type LaCoO3 visible photoconductive thin film. Background Technology

[0002] Countries worldwide are accelerating the development and utilization of clean energy, with solar energy, as a highly efficient and clean energy source, considered one of the most promising alternative energy sources. The use of renewable solar energy to achieve sustainable development has attracted significant attention in many fields, including photothermal effects, optoelectronics, photochemistry, and energy storage technologies. Among these, visible light photoconductors play a crucial role in optoelectronics, fully utilizing abundant visible light (which accounts for approximately 43% of the solar spectrum, with a bandgap of 1.6-3.1 eV) for optical information storage and signal transmission. Therefore, to meet the growing technological demands of the optoelectronic field, many semiconductor materials have been developed, such as CdS, CdSe, ZnO, Ga2O3, CsPbBr3, and LaCoO3. Perovskite structures, as a novel type of optoelectronic semiconductor, exhibit significant application prospects in optoelectronic devices such as solar cells, photodetectors, and light-emitting diodes due to their intrinsic properties, including high light absorption coefficients, high defect tolerance, long carrier lifetimes, and diffusion lengths.

[0003] As a representative of p-type semiconductors and perovskite-type composite oxides, LaCoO3 has attracted widespread attention due to its unique crystal structure, attractive photoelectric properties, non-toxicity, and low cost. Patent CN201810973502.0 provides a LaCoO3-δ / CNTs bifunctional composite catalyst, its preparation method, and its applications. This method utilizes ball milling to prepare LaCoO3-δ / CNTs with a more uniform crystal structure and a larger specific surface area, exhibiting excellent ORR catalytic activity. It can be used as a bifunctional catalyst in fuel cells and metal-air batteries. Patent CN201810973497.3 provides a phosphorus-doped LaCoO3 bifunctional catalyst, its preparation method, and its applications. This method uses high-energy ball milling and utilizes phosphorus doping to replace the oxygen element in LaCoO3. The prepared phosphorus-doped LaCoO3 bifunctional catalyst has a uniform phosphorus distribution, fine grains, and a large specific surface area, resulting in significantly enhanced catalytic activity in alkaline solutions and excellent ORR and... With its excellent OER catalytic performance and high stability, LaCoO3 has great potential as a bifunctional catalyst in the field of electrocatalysis. Authorized patent CN201811512578.X provides a method for preparing gas-sensitive LaCoO3 epitaxial films. This method uses polymer-assisted deposition to prepare LaCoO3 epitaxial films on PMN-PT single-crystal substrates. These LaCoO3 epitaxial films exhibit high sensitivity to carbon monoxide gas. Furthermore, the gas sensitivity of the LaCoO3 epitaxial films to carbon monoxide gas can be further improved by preparing polymer solutions. It is evident that perovskite-structured LaCoO3 has been applied in many fields such as electrocatalysts, gas-sensitive materials, and photocatalysts. If LaCoO3 films can be used as optoelectronic materials, it can not only solve the problems of poor stability and toxicity of traditional metal sulfide and selenide optoelectronic materials, but also, by utilizing the inducing and restricting effects of different substrates on the growth of epitaxial films, adjust the stress and structural distortion of the epitaxial films, thereby achieving the control of the optoelectronic properties of the epitaxial films. Meanwhile, the quality of the thin film directly affects its various physicochemical properties, so it is also crucial to develop a better method for preparing thin films.

[0004] Currently, solution spin coating is a common method for preparing perovskite thin films in the laboratory. Although spin coating is simple to operate, has a fast deposition rate, and good repeatability, it also has obvious drawbacks: significant material waste; lack of pattern functionalization; and unsuitability for continuous industrial production. In addition, vacuum thermal evaporation, blade coating, and spray coating have all been explored for thin film preparation. However, vacuum thermal evaporation requires a high vacuum environment, has a slow deposition rate, and requires high-precision masks, resulting in high production costs; blade coating involves direct contact between the blade and the substrate, easily causing cross-contamination; and spray coating cannot achieve precise control over the film pattern. Inkjet printing technology has attracted much attention due to its precise control over droplet distribution, mask-free thin film patterning, high material utilization, low cost, high process efficiency, and ability to fabricate large areas. Its applications include optical thin films (such as films and lenses), life sciences (such as proteomics and DNA sequencing), electronic devices (such as flexible displays), and inkjet-printed electronic products (such as RFID, sensors, batteries, and solar cells). It is considered one of the most promising thin film fabrication technologies. However, there are currently no patents or literature reports on the fabrication of perovskite LaCoO3 thin films using inkjet printing technology for use as visible light photoconductive materials. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0006] To achieve these objectives and other advantages according to the present invention, a method for preparing a perovskite-type LaCoO3 visible photoconductive thin film is provided, characterized by comprising the following steps:

[0007] Step 1: Add the cobalt source and La(NO3)3·6H2O to an appropriate amount of deionized water and stir to obtain a mixture;

[0008] Step 2: Add ethylenediaminetetraacetic acid and polyethyleneimine to the mixture in sequence, and stir continuously until fully dissolved to obtain a mixed solution;

[0009] Step 3: Heat the mixed solution obtained after fully dissolving in Step 2 in an oil bath and stir continuously until the solution mixture has a certain viscosity to obtain the ink solution;

[0010] Step 4: After ultrasonically cleaning the substrate with acetone, ethanol and deionized water for 15 minutes in sequence, dry it in an oven at 50°C; and use a syringe and filter head to inject the ink solution into the ink cartridge.

[0011] Step 5: First, purge nitrogen gas into the inkjet printer until the humidity inside the printer drops to 10%. Then, install the ink cartridge, place the substrate, set the printing parameters, and print the film.

[0012] Step 6: The printed film is sintered at high temperature to obtain a perovskite-type LaCoO3 visible photoconductive film.

[0013] Preferably, the cobalt source is any one of cobalt nitrate, cobalt carbonate, and cobalt oxalate.

[0014] Preferably, in step one, the molar ratio of cobalt source to La(NO3)3·6H2O is 1:1~2, the concentration of cobalt source in the mixture is 0.1~0.2 mol / L, and the concentration of La(NO3)3·6H2O in the mixture is 0.1~0.2 mol / L.

[0015] Preferably, in step two, the molar ratio of ethylenediaminetetraacetic acid to cobalt ions in the cobalt source is 2-4:1; and the molar ratio of polyethyleneimine to cobalt ions in the cobalt source is 8-10:1.

[0016] Preferably, in step two, after adding ethylenediaminetetraacetic acid to the mixture, the mixture is stirred for 20-40 minutes, while polyethyleneimine is dissolved in 10 mL of deionized water and then slowly added dropwise to the mixture.

[0017] Preferably, in step three, the temperature of the mixed solution in the oil bath is 50~100℃.

[0018] Preferably, in step three, the mixed solution is first heated and stirred in an oil bath at 50-60°C for 12 hours, and then the oil bath is heated to 90-100°C and stirred until the solution reaches a suitable viscosity.

[0019] Preferably, in step four, the substrate is any one of high-temperature resistant quartz glass, polycrystalline ceramic, corundum, or single-crystal LaAlO3 or SrTiO3, and the filter head has a diameter of 0.2 μm.

[0020] Preferably, in step five, the peak voltage of the printing parameters is 20~30 V, the pulse width is 10~20 μs generated by a single pulse, and the jetting frequency is set to 5 kHz; the ink solution is kept at 30°C during printing, and the perovskite structure material layer is printed on a substrate at 23°C.

[0021] Preferably, in step six, the temperature program is to start from room temperature and increase to 700°C at a rate of 1°C / min, then increase from 700°C to 900°C at a rate of 10°C / min, hold at that temperature for 2 hours, and then decrease to room temperature at a rate of 1°C / min to obtain a visible photoconductive thin film of perovskite-type LaCoO3.

[0022] The present invention also provides a perovskite-type LaCoO3 visible photoconductive thin film, which is obtained by the above preparation method.

[0023] This invention also provides an application of a perovskite-type LaCoO3 visible photoconductive thin film in visible photoconductive materials, wherein the LaCoO3 visible photoconductive thin film exhibits a conductivity of 32 mW / cm². 2 ~160 mW / cm 2 Under light intensity irradiation, it exhibits a stable visible photoconductive response, rapidly generating a significant photocurrent. Furthermore, within this light intensity range, the photocurrent of the LaCoO3 visible photoconductive film gradually increases with increasing light intensity.

[0024] The present invention has at least the following beneficial effects:

[0025] Firstly, the perovskite-type LaCoO3 visible photoconductive thin film prepared by this invention exhibits a stable visible photoconductive response, rapidly generating a significant photocurrent when the light intensity increases from 32 mW / cm². 2 Increased sequentially to 160 mW / cm 2 When the light intensity increases, the photocurrent gradually increases, which has great application prospects in the field of optoelectronic materials;

[0026] Secondly, the method for preparing perovskite-type LaCoO3 visible photoconductive thin films of this invention, compared with traditional preparation techniques, can greatly reduce production costs and improve production efficiency through inkjet printing technology; it can also control the crystal structure of perovskite-type LaCoO3 thin films by using different substrates and changing the thickness of the film, thereby achieving the purpose of studying its visible photoconductive behavior.

[0027] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0028] Figure 1 The XPS spectrum of the LaCoO3 thin film prepared in Example 1 of this invention;

[0029] Figure 2 The X-ray diffraction pattern of the LaCoO3 thin film prepared in Example 1 of this invention;

[0030] Figure 3 The visible photoconductivity spectrum of the LaCoO3 thin film prepared in Example 1 of this invention is shown. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0032] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0033] Example 1

[0034] A perovskite-type LaCoO3 visible photoconductive thin film based on inkjet printing, the specific preparation method includes the following steps:

[0035] Step 1: According to the chemical formula of LaCoO3, Co 3+ Ni 3+ The molar ratio is 1:1. Weigh 3.67g of Co(NO3)2·6H2O and 2.91g of La(NO3)3·6H2O respectively, place them in a 250mL round-bottom flask, add 40mL of deionized water, place the flask on a magnetic stirrer, and stir at room temperature until completely dissolved to obtain a mixed solution.

[0036] Step 2: Weigh 0.03 mol of ethylenediaminetetraacetic acid and add it to a mixed solution of Co(NO3)2·6H2O and La(NO3)3·6H2O, and stir at room temperature for 30 min.

[0037] Step 3: Weigh 0.09 mol of polyethyleneimine and add it to a beaker containing 10 mL of deionized water. Dissolve it completely and then transfer it to a round-bottom flask. Heat and stir in an oil bath at 50°C for 12 hours. Then raise the temperature of the oil bath to 100°C and stir until the solution has a certain viscosity to obtain the ink solution.

[0038] Step 4: Select a corundum sheet as the substrate for spray printing. After ultrasonically cleaning the corundum sheet substrate with acetone, ethanol and deionized water at 40 kHz for 15 min, place it in an oven at 50℃ to dry for later use. At the same time, use a syringe and a filter head with a diameter of 0.2μm to inject the ink solution into the ink cartridge.

[0039] Step 5: Purge nitrogen gas into the inkjet printer until the humidity inside the equipment drops to 10%. Then install the ink cartridge, place the substrate, and set the printing parameters. The thickness of the film is changed by altering the spacing between adjacent ink droplets. In this embodiment, the spacing between adjacent droplets is 45 μm to obtain the desired sample. The printing parameters are: peak voltage of 22 V, pulse width of 15 μs generated by a single pulse, and jet frequency of 5 kHz. During printing, the ink solution is maintained at 30°C, and the perovskite structure material layer is printed on a substrate at 23°C.

[0040] Step 6: Place the inkjet-printed film in a muffle furnace for sintering. The temperature program is as follows: start from room temperature, increase to 700℃ at 1℃ / min, then increase from 700℃ to 900℃ at 10℃ / min, hold for 2 hours, and then decrease to room temperature at a rate of 1℃ / min to obtain a perovskite-type LaCoO3 visible photoconductive film sample.

[0041] Figure 1 The image shows the XPS spectrum of the LaCoO3 thin film prepared in Example 1 of this invention; the results confirm that the film is mainly composed of La, Co and O elements.

[0042] Figure 2 The X-ray diffraction pattern of the LaCoO3 thin film prepared in Example 1 is shown. The XRD pattern shows that LaCoO3 (PDF#48-0546) diffraction peaks appear at positions such as 2θ=23.2°, 32.8°, 33.2°, 41.3°, 47.4° and 58.9°. This is consistent with the X-ray diffraction pattern of perovskite LaCoO3. The crystal plane indices corresponding to the diffraction peaks are (012), (110), (104), (006), (024) and (214), respectively, which proves that the LaCoO3 prepared in the experiment is well crystallized.

[0043] Figure 3 The image shows the response curves of the LaCoO3 thin film prepared in Example 1 under visible light irradiation of different intensities. The LaCoO3 thin film exhibits a stable visible photoconductive response, rapidly generating a significant photocurrent after being irradiated with visible light, and the response increases as the light intensity increases from 32 mW / cm². 2 Increased sequentially to 160 mW / cm 2 At that time, the photocurrent gradually increases with the increase of light intensity.

[0044] Example 2

[0045] A method for preparing perovskite-type LaCoO3 visible photoconductive thin films based on inkjet printing includes the following steps:

[0046] Step 1: According to the chemical formula of LaCoO3, Co 3+ Ni 3+ To determine the molar ratio, weigh 3.67 g of Co(NO3)2·6H2O and 2.91 g of La(NO3)3·6H2O, place them in a 250 mL round-bottom flask, add 40 mL of deionized water, place the flask on a magnetic stirrer, and stir at room temperature until completely dissolved to obtain a mixed solution.

[0047] Step 2: Weigh 0.03 mol of ethylenediaminetetraacetic acid and add it to a mixed solution of Co(NO3)2·6H2O and La(NO3)3·6H2O, and stir at room temperature for 30 min.

[0048] Step 3: Weigh 0.09 mol of polyethyleneimine and add it to a beaker containing 10 mL of deionized water. Dissolve it completely and then transfer it to a round-bottom flask. Heat and stir in an oil bath at 50°C for 12 hours. Then raise the temperature of the oil bath to 100°C and stir until the solution has a certain viscosity to obtain the ink solution.

[0049] Step 4: Select a polycrystalline ceramic sheet as the substrate for spray printing. After ultrasonically cleaning the polycrystalline ceramic sheet substrate with acetone, ethanol and deionized water at 40kHz for 15 minutes, place it in an oven at 50℃ to dry for later use. At the same time, use a syringe and a filter head with a diameter of 0.2μm to inject the ink solution into the ink cartridge.

[0050] Step 5: Purge nitrogen gas into the inkjet printer until the humidity inside the printer drops to 10%. Then install the ink cartridge, place the substrate, set the printing parameters, and change the film thickness by altering the spacing between adjacent ink droplets. In this embodiment, the spacing between adjacent droplets is 60 μm to obtain the desired sample. The printing parameters are generated by a single pulse with a peak voltage of 22 V and a pulse width of 15 μs, and the jetting frequency is set to 5 kHz. During printing, the ink solution is maintained at 30°C, and the perovskite structure material layer is printed on a substrate at 23°C.

[0051] Step 6: Place the inkjet-printed film in a muffle furnace for sintering. The temperature program is as follows: start from room temperature, increase to 700℃ at 1℃ / min, then increase from 700℃ to 900℃ at 10℃ / min, hold for 2 hours, and then decrease to room temperature at a rate of 1℃ / min to obtain a perovskite-type LaCoO3 visible photoconductive film sample.

[0052] Example 3

[0053] A method for preparing perovskite-type LaCoO3 visible photoconductive thin films based on inkjet printing includes the following steps:

[0054] Step 1: According to the chemical formula of LaCoO3, Co 3+ Ni 3+ To determine the molar ratio, weigh 3.67 g of Co(NO3)2·6H2O and 2.91 g of La(NO3)3·6H2O, place them in a 250 mL round-bottom flask, add 40 mL of deionized water, place the flask on a magnetic stirrer, and stir at room temperature until completely dissolved to obtain a mixed solution.

[0055] Step 2: Weigh 0.03 mol of ethylenediaminetetraacetic acid and add it to a mixed solution of Co(NO3)2·6H2O and La(NO3)3·6H2O, and stir at room temperature for 30 min.

[0056] Step 3: Weigh 0.09 mol of polyethyleneimine and add it to a beaker containing 10 mL of deionized water. Dissolve it completely and then transfer it to a round-bottom flask. Heat and stir in an oil bath at 50°C for 12 hours. Then raise the temperature of the oil bath to 100°C and stir until the solution has a certain viscosity to obtain the ink solution.

[0057] Step 4: Select a high-temperature resistant quartz glass sheet as the substrate for spray printing. After ultrasonically cleaning the quartz glass substrate with acetone, ethanol and deionized water at 40 kHz for 15 min, place it in an oven at 50℃ to dry for later use. At the same time, use a syringe and a filter head with a diameter of 0.2μm to inject the ink solution into the ink cartridge.

[0058] Step 5: Purge nitrogen gas into the inkjet printer until the humidity inside the equipment drops to 10%. Then install the ink cartridge, place the substrate, and set the printing parameters. The thickness of the film is changed by altering the spacing between adjacent ink droplets. In this embodiment, the spacing between adjacent droplets is 45 μm to obtain the desired sample. The printing parameters are generated by a single pulse with a peak voltage of 22 V and a pulse width of 15 μs, and the jetting frequency is set to 5 kHz. During printing, the ink solution is maintained at 30°C, and the perovskite structure material layer is printed on a substrate at 23°C.

[0059] Step 6: Place the inkjet-printed film in a muffle furnace for sintering. The temperature program is as follows: start from room temperature, increase to 700℃ at 1℃ / min, then increase from 700℃ to 900℃ at 10℃ / min, hold for 2 hours, and then decrease to room temperature at a rate of 1℃ / min to obtain a perovskite-type LaCoO3 visible photoconductive film sample.

[0060] Example 4

[0061] A method for preparing a perovskite-type LaCoO3 visible photoconductive thin film based on inkjet printing includes the following steps:

[0062] Step 1: According to the chemical formula of LaCoO3, Co 3+ Ni 3+ To determine the molar ratio, weigh 3.67 g of Co(NO3)2·6H2O and 2.91 g of La(NO3)3·6H2O, place them in a 250 mL round-bottom flask, add 40 mL of deionized water, place the flask on a magnetic stirrer, and stir at room temperature until completely dissolved to obtain a mixed solution.

[0063] Step 2: Weigh 0.03 mol of ethylenediaminetetraacetic acid and add it to a mixed solution of Co(NO3)2·6H2O and La(NO3)3·6H2O, and stir at room temperature for 30 min.

[0064] Step 3: Weigh 0.09 mol of polyethyleneimine and add it to a beaker containing 10 mL of deionized water. Dissolve it completely and then transfer it to a round-bottom flask. Heat and stir in an oil bath at 50°C for 12 hours. Then raise the temperature of the oil bath to 100°C and stir until the solution has a certain viscosity to obtain the ink solution.

[0065] Step 4: Select a single-crystal LaAlO3 wafer as the substrate for spray printing. After ultrasonically cleaning the single-crystal LaAlO3 substrate with acetone, ethanol and deionized water at 40kHz for 15 minutes, place it in an oven at 50℃ to dry for later use. At the same time, use a syringe and a filter head with a diameter of 0.2μm to inject the ink solution into the ink cartridge.

[0066] Step 5: Purge nitrogen gas into the inkjet printer until the humidity inside the printer drops to 10%. Then install the ink cartridge, place the substrate, and set the printing parameters. The thickness of the film is changed by altering the spacing between adjacent ink droplets. In this embodiment, the spacing between adjacent droplets is 35 μm to obtain the desired sample. The printing parameters are generated by a single pulse with a peak voltage of 22 V and a pulse width of 15 μs, and the jetting frequency is set to 5 kHz. During printing, the ink solution is maintained at 30°C, and the perovskite structure material layer is printed on a substrate at 23°C.

[0067] Step 6: Place the inkjet-printed film in a muffle furnace for sintering. The temperature program is as follows: start from room temperature, increase to 700℃ at 1℃ / min, then increase from 700℃ to 900℃ at 10℃ / min, hold for 2 hours, and then decrease to room temperature at a rate of 1℃ / min to obtain a perovskite-type LaCoO3 visible photoconductive film sample.

[0068] Example 5

[0069] A method for preparing perovskite-type LaCoO3 visible photoconductive thin films based on inkjet printing includes the following steps:

[0070] Step 1: According to the chemical formula of LaCoO3, Co 3+ Ni 3+ To determine the molar ratio, weigh 3.67 g of Co(NO3)2·6H2O and 2.91 g of La(NO3)3·6H2O, place them in a 250 mL round-bottom flask, add 40 mL of deionized water, place the flask on a magnetic stirrer, and stir at room temperature until completely dissolved to obtain a mixed solution.

[0071] Step 2: Weigh 0.03 mol of ethylenediaminetetraacetic acid and add it to a mixed solution of Co(NO3)2·6H2O and La(NO3)3·6H2O, and stir at room temperature for 30 min.

[0072] Step 3: Weigh 0.09 mol of polyethyleneimine and add it to a beaker containing 10 mL of deionized water. Dissolve it completely and then transfer it to a round-bottom flask. Heat and stir in an oil bath at 50°C for 12 hours. Then raise the temperature of the oil bath to 100°C and stir until the solution has a certain viscosity to obtain the ink solution.

[0073] Step 4: Select single-crystal SrTiO3 as the substrate for spray printing. After ultrasonically cleaning the single-crystal SrTiO3 substrate with acetone, ethanol and deionized water at 40kHz for 15 minutes, place it in an oven at 50℃ to dry for later use. At the same time, use a syringe and a filter head with a diameter of 0.2μm to inject the ink solution into the ink cartridge.

[0074] Step 5: Pour nitrogen gas into the inkjet printer until the humidity inside the printer drops to 10%. Then install the ink cartridge, place the substrate, and set the printing parameters. The thickness of the film is changed by altering the spacing between adjacent ink droplets. In this embodiment, the spacing between adjacent droplets is 25 μm to obtain the desired sample. The printing parameters are generated by a single pulse with a peak voltage of 22 V and a pulse width of 15 μs, and the jetting frequency is set to 5 kHz. During printing, the ink solution is maintained at 30°C, and the perovskite structure material layer is printed on a substrate at 23°C.

[0075] Step 6: Place the inkjet-printed film in a muffle furnace for sintering. The temperature program is as follows: start from room temperature, increase to 700℃ at 1℃ / min, then increase from 700℃ to 900℃ at 10℃ / min, hold for 2 hours, and then decrease to room temperature at a rate of 1℃ / min to obtain a perovskite-type LaCoO3 visible photoconductive film sample.

[0076] Example 6

[0077] The other conditions are the same as in Example 1, except that in this example, the distance between adjacent ink droplets is 25 μm.

[0078] Example 7

[0079] The other conditions are the same as in Example 1, except that in this example, the distance between adjacent ink droplets is 35 μm.

[0080] Example 8

[0081] The other conditions are the same as in Example 1, except that in this example, the distance between adjacent ink droplets is 60 μm.

[0082] Example 9

[0083] The other conditions are the same as in Example 2, except that in this example, the distance between adjacent ink droplets is 45 μm.

[0084] Example 10

[0085] The other conditions are the same as in Example 5, except that in this example, the distance between adjacent ink droplets is 35 μm.

[0086] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing a perovskite type LaCoO3 visible light conducting thin film, characterized in that, The method comprises the following steps: Step one, add cobalt source and La(NO3)3·6H2O into a certain amount of deionized water, and stir to obtain a mixed solution; Step two, add ethylenediaminetetraacetic acid and polyethyleneimine into the mixed solution in sequence, and continuously stir until fully dissolved to obtain a mixed solution; Step three, heat the mixed solution obtained after fully dissolving in step two in an oil bath and continuously stir until the solution has a certain viscosity to obtain an ink solution; Step four, clean the substrate by ultrasonic cleaning with acetone, ethanol and deionized water in sequence, and dry for use; and use a syringe and a filter head to inject the ink solution into an ink cartridge; Step five, first, pass nitrogen into the inkjet printing equipment until the humidity in the equipment decreases to 10%, then install the ink cartridge, put in the substrate, and set the printing parameters to print a film; Step six, sinter the film obtained by printing at high temperature to obtain a perovskite LaCoO3 visible light conductive film; In step two, first, add ethylenediaminetetraacetic acid into the mixed solution, and stir for 20-40 min; then, dissolve polyethyleneimine in a certain amount of deionized water, and slowly drop into the mixed solution; In step three, the heating temperature of the mixed solution in the oil bath is 50-100℃, first, heat and stir the mixed solution in the oil bath at 50-60℃ for 12-24 h, then, increase the temperature of the oil bath to 90-100℃, and stir until the solution reaches a suitable viscosity; In step five, the peak voltage of the printing parameters is 20-30 V, the pulse width is 10-20 μs, which is generated by a single pulse, and the ejection frequency is set to 5 kHz; during printing, the ink solution is kept at 30℃, and the perovskite structure material layer is printed on the substrate at 23℃; In step six, the temperature program is as follows: start from room temperature, increase to 700-750℃ at a rate of 1-3℃ / min, then increase from 700℃ to 900-1000℃ at a rate of 10-15℃ / min, keep the temperature for 2-4 h, and then decrease to room temperature at a rate of 1-3℃ / min to obtain the perovskite LaCoO3 visible light conductive film.

2. The method for preparing the perovskite-type LaCoO3 visible light conducting thin film according to claim 1, characterized in that, The cobalt source is any one of cobalt nitrate, cobalt carbonate and cobalt oxalate.

3. The method for preparing a perovskite-type LaCoO3 visible photoconductive thin film as described in claim 1, characterized in that, In step one, the molar ratio of cobalt source to La(NO3)3·6H2O is 1:1-2, the concentration of cobalt source in the mixed solution is 0.1-0.2 mol / L, the concentration of La(NO3)3·6H2O in the mixed solution is 0.1-0.2 mol / L, in step two, the molar ratio of ethylenediaminetetraacetic acid to cobalt ions in the cobalt source is 2-4:1, and the molar ratio of polyethyleneimine to cobalt ions in the cobalt source is 8-10:

1.

4. The method of claim 1, wherein the perovskite-type LaCoO3 visible light conducting thin film is prepared by the steps of: (a) preparing a solution of a perovskite-type LaCoO3 precursor; (b) coating the solution on a substrate; (c) drying the coated solution; and (d) calcining the dried coated solution. In step four, the substrate is any one of high-temperature-resistant quartz glass sheet, polycrystalline ceramic sheet, corundum sheet, single crystal LaAlO3 or SrTiO3.

5. The application of a perovskite LaCoO3 visible photoconductive thin film prepared by the method described in any one of claims 1 to 4 in visible photoconductive materials, characterized in that, The perovskite LaCoO3 visible light conducting thin film has a light intensity of 32 mW / cm 2 160 mW / cm 2 Under the irradiation of light intensity, the perovskite LaCoO3 visible light conducting thin film has stable visible light conducting response, rapid response and obvious photocurrent, and the photocurrent gradually increases with the increase of light intensity in the light intensity range.

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