A nanoporous film material and its preparation method and application

Abstract

A nanoporous thin film material, its preparation method, and its applications are disclosed, relating to the field of functional materials technology. This invention solves the problem that existing nanoporous thin films cannot meet the requirements for high-performance infrared emission. The material's general structural formula is A. x B y O3, wherein A is at least one of Gd, Sm, Eu, Er, Nd, Dy, Lu, La, Tm, Sc, and Y, and B is at least one of Co, Fe, Ni, and Mn; x = 0.95–1.05, y = 0.95–1.05; the pore size of the nanoporous film material is 10 nm–300 nm, and the thickness is 150 nm–450 nm. The infrared thermal emissivity of the nanoporous film material is 60%–90%. This invention utilizes a polymer-assisted deposition method to prepare A. x B y O3 precursor solution; A is deposited on the substrate using spin coating. x B y O3 is used to calcine and obtain a nanoporous thin film material. This invention can be applied in the field of infrared radiation.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a nanoporous thin film material, its preparation method, and its application. Background Technology

[0002] Infrared light, an invisible form of light with wavelengths between 760nm and 1000μm, is an electromagnetic wave with strong thermal effects. In the medical field, electromagnetic waves with wavelengths between 8μm and 15μm are considered to have wavelengths similar to the far-infrared rays emitted by the human body. These wavelengths can resonate effectively with water molecules in cells, thus promoting the growth of plants and animals. For the human body, far-infrared rays can dilate capillaries, promote blood circulation, enhance metabolism, increase tissue regeneration, and improve the body's immunity.

[0003] Nanomaterials, in a narrow sense, refer to materials that have at least one dimension at the nanoscale in three-dimensional space or are composed of nanomaterials as basic elements. Due to their extremely small size, nanomaterials can exhibit many unique properties, showing significant differences from traditional bulk materials in terms of optics, electricity, and mechanics. Nanoporous films, due to their transparency and thinness, offer significant advantages over traditional far-infrared products.

[0004] Currently, there are various methods for preparing nanoporous thin films, such as vapor deposition, magnetron sputtering, and chemical deposition. However, all of these methods have some drawbacks, such as being cumbersome to operate, environmentally unfriendly, having excessively long preparation times, and producing thin films with cracking, inhomogeneity, and low porosity, as well as unsatisfactory infrared emissivity.

[0005] Therefore, most porous films currently available cannot meet the actual requirements for high-performance infrared emission. Summary of the Invention

[0006] To address the problem that existing nanoporous films cannot meet the requirements for high-performance infrared emission, this invention proposes a nanoporous film material, its preparation method, and its application.

[0007] The technical solution of the present invention is as follows:

[0008] A nanoporous thin film material with the general structural formula A x B y O3, wherein A is at least one of Gd, Sm, Eu, Er, Nd, Dy, Lu, La, Tm, Sc, and Y, and B is at least one of Co, Fe, Ni, and Mn, x = 0.95–1.05, y = 0.95–1.05.

[0009] Preferably, the pore size of the nanoporous film material is 10nm to 300nm, and the thickness is 150nm to 450nm.

[0010] Preferably, the infrared thermal emissivity of the nanoporous thin film material is 60% to 90%.

[0011] This invention also provides a method for preparing a nanoporous thin film material, comprising the following steps:

[0012] S1. Preparation of A using polymer-assisted deposition method x B y O3 precursor solution;

[0013] S2. Deposit A ​​on the substrate using spin coating. x B y O3, and calcined, to obtain A x B y O3 nanoporous thin film material.

[0014] Preferably, step S1 specifically includes the following sub-steps:

[0015] S11. In a salt solution containing salts A and B, citric acid is added and stirred until completely dissolved to obtain solution M;

[0016] S12. Polyethyleneimine (PEI) is added to deionized water and stirred until completely dissolved to obtain solution N;

[0017] S13. Add solution N to solution M, and then continue chelation to obtain solution O;

[0018] S14. Concentrate solution O to obtain the precursor solution.

[0019] Preferably, both salt A and salt B are selected from nitrates or acetates; the molar ratio of salt A to salt B is (0.8–1):(0.8–1); the molar ratio of the salt, citric acid monohydrate, and polyethyleneimine is 1:(1.5–2.5):(5 × 10⁻⁶). -6 ~1×10 -4 ).

[0020] Preferably, the chelation time in step S13 is 6h to 14h; the concentration temperature in step S14 is 50℃ to 90℃; and the concentration of the concentrated solution is 0.01mol / L to 0.2mol / L.

[0021] Preferably, step S2 specifically includes the following sub-steps:

[0022] S21. Pre-treat the substrate and then preheat it;

[0023] S22. Coat the precursor solution onto the preheated substrate and homogenize it.

[0024] S23. Place the coated film on a constant temperature heating table to fix the film thickness;

[0025] S24. Repeat steps S22 to S23 until the target thickness is reached to obtain the film;

[0026] S25. After calcining the film, it is cooled to obtain a nanoporous film material.

[0027] Preferably, the preheating temperature in step S21 is 250℃~450℃, and the preheating time is 3min~10min; the rotation speed of the homogenizing agent in step S22 is 1500r / min~10000r / min; the heating temperature of the film placed on the constant temperature heating table in step S23 is 250℃~450℃, and the heating time is 3min~10min; the target thickness in step S24 is 150nm~450nm; the calcination in step S25 specifically involves heating to 600℃~1200℃ at a rate of 1℃ / min~5℃ / min and calcining for 4h~10h.

[0028] Preferably, during the spin coating process, the substrate is adsorbed onto the substrate holder by a vacuum filter or clipped / bonded onto the substrate holder.

[0029] The present invention also provides an application of the nanoporous thin film material described above as an infrared emitting film.

[0030] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0031] 1. The nanoporous film product provided by the present invention has a moderate pore size and thickness, which will not cause obvious cracking of the film due to excessively large pore size or thickness, making it difficult to adhere to the substrate; it also avoids the adverse effects of excessively small pore size or thickness on thermal infrared emissivity.

[0032] 2. The nanoporous thin film material provided by this invention has a complete and continuous structure and excellent performance with high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing as the temperature rises.

[0033] 3. The method for preparing nanoporous thin film materials provided by the present invention can adjust the size of nanopores by adjusting the concentration of precursor solution and sintering temperature, and has a large spin-coating area, resulting in a thin and light product at the nanoscale.

[0034] The nanoporous thin film provided by this invention has broad application prospects in infrared thermal radiation. Attached Figure Description

[0035] Figure 1 To prepare A x By Flow diagram of O3 precursor solution;

[0036] Figure 2 For use A x B y A schematic diagram of the process for preparing nanoporous films from O3 precursor solution;

[0037] Figure 3 The precursor solution GdCoO3 prepared in Example 1;

[0038] Figure 4 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 1.

[0039] Figure 5 The image shows the EDS energy spectrum of the GdCoO3 thin film prepared in Example 1.

[0040] Figure 6 The precursor solution GdFeO3 prepared in Example 2;

[0041] Figure 7 The images shown are SEM surface and cross-sectional images of the GdFeO3 thin film prepared in Example 2.

[0042] Figure 8 The images shown are SEM surface and cross-sectional images of the SmCoO3 thin film prepared in Example 3.

[0043] Figure 9 The images shown are SEM surface and cross-sectional images of the SmFeO3 thin film prepared in Example 4.

[0044] Figure 10 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 5.

[0045] Figure 11 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 6.

[0046] Figure 12 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 7.

[0047] Figure 13 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 8.

[0048] Figure 14 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 9.

[0049] Figure 15 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 10.

[0050] Figure 16 The images shown are SEM surface and cross-sectional images of the GdCoO3 thin film prepared in Example 11.

[0051] Figure 17 The results show the average emissivity of GdFeO3 nanoporous films in the mid-infrared band.

[0052] Figure 18 The average emissivity of SmCoO3 nanoporous films in the mid-infrared band is measured.

[0053] Figure 19 The results show the average emissivity of SmFeO3 nanoporous films in the mid-infrared band.

[0054] Figure 20 GdCo 1-x Fe x Average emissivity test results of O3 (0≤x≤0.5) nanoporous films in the mid-infrared band at 300℃;

[0055] Figure 21 GdCo 1-x Fe x Average emissivity test results of O3 (0≤x≤0.5) nanoporous films in the mid-infrared band at 400℃;

[0056] Figure 22 GdCo 1-x Fe x Test results of the average emissivity of O3 (0≤x≤0.5) nanoporous films in the mid-infrared band at 500℃;

[0057] Figure 23 The average emissivity of GdCoO3 nanoporous films of different thicknesses in the mid-infrared band at 400℃ is measured.

[0058] Figure 24 The results show the average emissivity of GdCoO3 nanoporous films at 300℃ under different calcination temperatures in the mid-infrared band.

[0059] Figure 25 The results show the average emissivity of GdMnO3 nanoporous films in the mid-infrared band at different test temperatures. Detailed Implementation

[0060] The preparation method provided by this invention obtains nanoporous thin film material A through two steps. x B y O3: First, A is prepared using polymer-assisted deposition. x B y O3 precursor solution, the specific procedure is as follows: Figure 1 As shown, by controlling key factors such as precursor solution concentration, heating stage temperature, spin coating rate, and spin coating time, nanoporous films with different pore sizes can be prepared on the substrate; then, A is deposited on the substrate using spin coating. x B y O3 was calcined in a muffle furnace to obtain A. x B y O3 nanoporous thin film material, see details below. Figure 2 .

[0061] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0062] Example 1.

[0063] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0064] (2) After stirring for 8 minutes, add 2.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0065] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0066] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0067] (5) Solution C was heated and concentrated in an oil bath at 60°C for 1.5 h to obtain a 0.05 mol / L precursor solution GdCoO3. (See image for the precursor solution.) Figure 3 As shown;

[0068] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0069] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0070] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0071] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0072] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0073] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0074] Figure 4 The SEM images show the surface and cross-sectional views of a 300 nm thick GdCoO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the GdCoO3 polymer-assisted deposition film can be seen, with surface pore sizes ranging from 20 nm to 300 nm.

[0075] The elemental composition ratios in the thin films prepared in this embodiment were characterized, and the EDS spectra are shown below. Figure 5 As shown in Table 1, the proportions of each element in the thin film can be seen, which proves that the thin film with the structural formula GdCoO3 was successfully prepared in this embodiment.

[0076] Table 1

[0077] element Line type Wt% Wt%Sigma At% O K-line system 19.46 0.31 62.52 Co L-line system 20.42 0.46 17.82 Gd M-line system 60.12 0.58 19.66 Total 100.00 100.00

[0078] Example 2.

[0079] (1) Weigh and mix 1 mmol of Gd and Fe nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0080] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0081] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0082] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0083] (5) Solution C was heated and concentrated in an oil bath at 60°C for 1.5 h to obtain a 0.05 mol / L precursor solution GdFeO3. (See image for the precursor solution.) Figure 6 As shown;

[0084] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0085] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0086] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0087] (9) Use a dropper to take a portion of the 0.05 mol / L GdFeO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0088] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0089] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdFeO3 film.

[0090] Figure 7 The images show the surface and cross-sectional views of a 300 nm thick GdFeO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the polymer-assisted deposition film is visible, with surface pore sizes ranging from 10 nm to 150 nm.

[0091] Samples 1-5 of the GdFeO3 thin film prepared in this embodiment were cut and sampled. Their mid-infrared thermal radiation performance was tested at 100℃, 200℃, 300℃, 400℃, and 500℃, respectively. The average emissivity results in the mid-infrared band are shown below. Figure 17 As shown in the figure, the thin film prepared in this application possesses excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing with increasing temperature. Therefore, it has promising applications in high infrared emissivity thin films.

[0092] Example 3.

[0093] (1) Weigh and mix 1 mmol of Sm and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0094] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0095] (3) Weigh 0.7g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0096] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0097] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution SmCoO3.

[0098] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0099] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0100] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0101] (9) Use a dropper to take a portion of the 0.05 mol / L SmCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0102] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0103] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain the SmCoO3 film.

[0104] Figure 8 SEM surface and cross-sectional images of a 300 nm thick SmCoO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L: representing the microstructure of the SmCoO3 polymer-assisted deposition film.

[0105] Samples 1-5 of the SmCoO3 thin film prepared in this embodiment were cut and sampled. Their mid-infrared thermal radiation performance was tested at 100℃, 200℃, 300℃, 400℃, and 500℃, respectively. The average emissivity results in the mid-infrared band are shown below. Figure 18 As shown in the figure, the thin film prepared in this application possesses excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing with increasing temperature. Therefore, it has promising applications in high infrared emissivity thin films.

[0106] Example 4.

[0107] (1) Weigh and mix 1 mmol of Sm and Fe nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0108] (2) After stirring for 8 minutes, add 1.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0109] (3) Weigh 0.65g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0110] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0111] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution SmFeO3.

[0112] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0113] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0114] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0115] (9) Use a dropper to take a portion of the 0.05 mol / L SmFeO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0116] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0117] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain the SmFeO3 film.

[0118] Figure 9 The images show the surface and cross-sectional views of a 300 nm thick SmFeO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the SmFeO3 polymer-assisted deposition film is visible, with surface pore sizes ranging from 20 nm to 200 nm.

[0119] Samples 1-5 of the SmFeO3 thin film prepared in this embodiment were cut and sampled. Their mid-infrared thermal radiation performance was tested at 100℃, 200℃, 300℃, 400℃, and 500℃, respectively. The average emissivity results in the mid-infrared band are shown below. Figure 19 As shown in the figure, the thin film prepared in this application possesses excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing with increasing temperature. Therefore, it has promising applications in high infrared emissivity thin films.

[0120] Example 5.

[0121] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0122] (2) After stirring for 8 minutes, add 1.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0123] (3) Weigh 0.6g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0124] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0125] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution GdCoO3.

[0126] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0127] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0128] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0129] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0130] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 20 layers are spin-coated and the final film thickness is 150nm.

[0131] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0132] Figure 10 The images show the surface and cross-sectional views of a 150 nm thick GdCoO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the GdCoO3 polymer-assisted deposition film is visible, with surface pore sizes ranging from 10 nm to 300 nm.

[0133] Example 6.

[0134] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0135] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0136] (3) Weigh 0.7g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0137] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0138] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution GdCoO3.

[0139] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0140] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0141] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0142] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0143] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 60 layers are spin-coated and the final film thickness is 450nm.

[0144] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0145] Figure 11 The images show the surface and cross-sectional views of a 450 nm thick GdCoO3 film sintered at 750 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the polymer-assisted deposition film of GdCoO3 can be seen, with surface pore sizes ranging from 10 nm to 150 nm.

[0146] Example 7.

[0147] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0148] (2) After stirring for 8 minutes, add 2.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0149] (3) Weigh 1g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0150] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0151] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution GdCoO3.

[0152] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0153] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0154] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0155] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0156] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0157] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 775°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0158] Figure 12 The images show the surface and cross-sectional views of a 300 nm thick GdCoO3 film sintered at 775 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the GdCoO3 polymer-assisted deposition film is visible, with surface pore sizes ranging from 50 nm to 300 nm.

[0159] Example 8.

[0160] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0161] (2) After stirring for 8 minutes, add 1.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0162] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0163] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0164] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution GdCoO3.

[0165] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0166] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0167] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0168] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0169] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0170] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 800℃ at a heating rate of 3℃ / min and held for 4h. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0171] Figure 13 The SEM surface and cross-sectional images of a 300 nm thick GdCoO3 film sintered at 800 °C with a precursor solution concentration of 0.05 mol / L are shown. The microstructure of the GdCoO3 polymer-assisted deposition film can be seen, with surface pore sizes ranging from 10 nm to 150 nm.

[0172] Example 9.

[0173] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0174] (2) After stirring for 8 minutes, add 1.9 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0175] (3) Weigh 0.8g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0176] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0177] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.05mol / L precursor solution GdCoO3.

[0178] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0179] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0180] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0181] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0182] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0183] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 850°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0184] Figure 14 The images show the surface and cross-sectional views of a 300 nm thick GdCoO3 film sintered at 850 °C with a precursor solution concentration of 0.05 mol / L. The microstructure of the GdCoO3 polymer-assisted deposition film is visible, with surface pore sizes ranging from 20 nm to 300 nm.

[0185] Example 10.

[0186] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0187] (2) After stirring for 8 minutes, add 1.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0188] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0189] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0190] (5) Place solution C in an oil bath and heat and stir to concentrate it. Set the temperature to 60℃ and concentrate for 1.5h to finally obtain a 0.1mol / L precursor solution GdCoO3.

[0191] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0192] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0193] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0194] (9) Use a dropper to take a portion of the 0.1 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate, and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0195] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 20 layers are spin-coated and the final film thickness is 300nm.

[0196] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0197] Figure 15SEM surface and cross-sectional images of a 300 nm thick GdCoO3 film sintered at 750 °C were prepared using a precursor solution concentration of 0.1 mol / L. The microstructure of the GdCoO3 polymer-assisted deposition film can be seen, with surface pore sizes ranging from 10 nm to 100 nm.

[0198] Example 11.

[0199] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0200] (2) After stirring for 8 minutes, add 2.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0201] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0202] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0203] (5) Place solution C in an oil bath and heat and stir to concentrate. Set the temperature to 60℃ and concentrate for 3 hours to finally obtain a 0.1 mol / L precursor solution GdCoO3.

[0204] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0205] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0206] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0207] (9) Use a dropper to take a portion of the 0.1 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate, and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0208] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 30 layers are spin-coated and the final film thickness is 450nm.

[0209] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdCoO3 film.

[0210] Figure 16 Using 2 mmol of citric acid monohydrate and a precursor solution concentration of 0.1 mol / L, a 300 nm thick GdCoO3 film sintered at 750 °C was prepared. SEM surface and cross-sectional images show the microstructure of the GdCoO3 polymer-assisted deposition film, with surface pore sizes ranging from 30 nm to 100 nm.

[0211] Example 12.

[0212] (1) Weigh and mix 1 mmol of Gd, Co and Fe nitrates in a ratio of 1:(1-x):x in a beaker, add 5 mL of deionized water and stir.

[0213] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0214] (3) Weigh 1g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0215] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0216] (5) Solution C was heated and stirred in an oil bath at 60°C for 3 hours to obtain a 0.1 mol / L precursor solution GdCo. 1-x Fe x O3;

[0217] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0218] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0219] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0220] (9) Take a portion of GdCo with a concentration of 0.1 mol / L using a dropper. 1-x Fe x O3 precursor solution is dropped onto the substrate for homogenization, ensuring that the precursor solution completely covers the silicon substrate, and the process of placing the silicon wafer and homogenizing should be carried out quickly.

[0221] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 20 layers are spin-coated and the final film thickness is 300nm.

[0222] (11) After heating the film on a heating stage, it was placed in a muffle furnace and heated from room temperature to 750℃ at a heating rate of 3℃ / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain GdCo with a surface pore size of 10nm~300nm. 1-x Fe x O3 thin film.

[0223] In this embodiment, GdCo was prepared by taking x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 respectively. 1-x Fe x O3 thin films, denoted as samples 1-6. The thermal radiation performance of samples 1-6 in the mid-infrared band at different temperatures was tested, and the average emissivity in the mid-infrared band at 300℃ was obtained as follows: Figure 20 As shown, the average emissivity results in the mid-infrared band at 400℃ are as follows: Figure 21 As shown, the average emissivity results in the mid-infrared band at 500℃ are as follows: Figure 22 As shown above, the thin film prepared in this application possesses excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing with increasing temperature. Therefore, it has excellent application prospects in high infrared emissivity thin films.

[0224] Example 13.

[0225] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0226] (2) After stirring for 8 minutes, add 2.5 mmol of citric acid monohydrate and continue stirring. This solution is called solution A.

[0227] (3) Weigh 1.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0228] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0229] (5) Solution C was heated and concentrated in an oil bath at 60°C for 1.5 h to obtain a 0.05 mol / L precursor solution GdCoO3. (See image for the precursor solution.) Figure 3 As shown;

[0230] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0231] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0232] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0233] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0234] (10) Slowly and steadily place the first layer of film after homogenization on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 7, 13, 27, 40, 53 and 67 layers are spin coated respectively, and the final film thicknesses are 50nm, 100nm, 200nm, 300nm, 400nm and 500nm respectively.

[0235] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain GdCoO3 films of different thicknesses.

[0236] In this embodiment, GdCoO3 thin films with thicknesses of 50nm, 100nm, 200nm, 300nm, 400nm, and 500nm were selected and designated as samples 1 to 6. The thermal radiation performance of samples 1 to 6 in the mid-infrared band was tested at different temperatures. The average emissivity in the mid-infrared band at 400℃ is shown below. Figure 23 As shown, the thin film with a thickness greater than 200 nm prepared in this application demonstrates excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation; the infrared emissivity increases with increasing thickness. Therefore, it has promising applications in high infrared emissivity thin films.

[0237] Example 14

[0238] (1) Weigh and mix 1 mmol of Gd and Co nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0239] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0240] (3) Weigh 0.5g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0241] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0242] (5) Solution C was heated and concentrated in an oil bath at 60°C for 1.5 h to obtain a 0.05 mol / L precursor solution GdCoO3. (See image for the precursor solution.) Figure 3 As shown;

[0243] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0244] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0245] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0246] (9) Use a dropper to take a portion of the 0.05 mol / L GdCoO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0247] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0248] (11) After heating the film on the heating table, it was placed in a muffle furnace and heated from room temperature to 750℃, 775℃, 800℃ and 850℃ respectively at a heating rate of 3℃ / min and held for 4h. Finally, it was allowed to cool naturally to room temperature to obtain GdCoO3 film.

[0249] In this embodiment, GdCoO3 films calcined at 750℃, 775℃, 800℃, and 850℃ were designated as samples 1 to 4. The mid-infrared thermal radiation properties of samples 1 to 4 at different temperatures were tested, and the results are as follows: Figure 24 As shown, samples 1 to 4 all have high infrared emissivity.

[0250] Example 15.

[0251] (1) Weigh and mix 1 mmol of Gd and Mn nitrates in a 1:1 ratio in a beaker, add 5 mL of deionized water and stir.

[0252] (2) After stirring for 8 minutes, add 2 mmol of citric acid monohydrate and continue stirring. This solution is labeled as solution A.

[0253] (3) Weigh 1g of PEI in a beaker, add 10mL of deionized water and stir for 60min, and record it as solution B;

[0254] (4) Add solution B to solution A, and then continue chelation for 8 hours, and record it as solution C;

[0255] (5) Solution C was heated and concentrated in an oil bath at 60°C for 1.5 h to obtain a 0.05 mol / L precursor solution GdMnO3. (See image for the precursor solution.) Figure 3 As shown;

[0256] (6) Cut the polished 100 single crystal silicon wafer into a certain size, then sonicate it with acetone and anhydrous ethanol for 10 minutes respectively, and dry it for later use.

[0257] (7) Place the treated silicon substrate on a constant temperature heating table at 300℃ and preheat for 3 minutes;

[0258] (8) Set the spin coater parameters to 5000 r / min and 30 s. Transfer the preheated silicon substrate to the spin coater tray and then turn on the vacuum filter to firmly hold the silicon substrate.

[0259] (9) Use a dropper to take a portion of the 0.05 mol / L GdMnO3 precursor solution and drop it onto the substrate for homogenization. Ensure that the precursor solution completely covers the silicon substrate and that the process of placing the silicon wafer and homogenizing is carried out quickly.

[0260] (10) Place the first layer of film that has been uniformly coated slowly and steadily on the constant temperature heating table to fix the thickness of the first layer of film. Then coat the second, third, fourth... layers and repeat steps (7) to (9). In this embodiment, 40 layers are spin-coated and the final film thickness is 300nm.

[0261] (11) After heating the film on a heating table, it was placed in a muffle furnace and heated from room temperature to 750°C at a heating rate of 3°C / min and held for 4 hours. Finally, it was allowed to cool naturally to room temperature to obtain a GdMnO3 film.

[0262] In this embodiment, the GdMnO3 thin films prepared were subjected to mid-infrared thermal radiation performance tests at 100℃, 200℃, 300℃, 400℃, and 500℃, respectively, and are designated as samples 1-5. The average emissivity results in the mid-infrared band are as follows: Figure 25 As shown, the thin film prepared in this application possesses excellent high infrared emissivity. Due to its porous structure, it has a large specific surface area and exhibits a certain regularity in infrared thermal radiation, with the infrared emissivity increasing with increasing temperature. Therefore, it has promising applications in high infrared emissivity thin films.

[0263] As can be seen from the above embodiments, the nanoporous film prepared in this application has a complete and continuous structure. The size of the nanopores can be adjusted by regulating the precursor solution concentration and sintering temperature. Furthermore, it exhibits a large spin-coating area and a thin thickness (nanometer-level). The film pore size ranges from 10 nm to 300 nm, and the thickness ranges from 150 nm to 450 nm. The film product provided in this embodiment has moderate pore size and thickness, avoiding significant cracking and adhesion difficulties caused by excessively large pore size or thickness. It also avoids the adverse effects of excessively small pore size or thickness on thermal infrared emissivity. This nanoporous film has broad application prospects in infrared thermal radiation.

Claims

1. A nanoporous thin film material, characterized in that, The general structural formula is A x B y O3, where A is Gd, B is one of Co or Mn, x=1, y=1; The nanoporous thin film material has a pore size of 10 nm to 300 nm and a thickness of 150 nm to 450 nm; the infrared thermal emissivity of the nanoporous thin film material is 60% to 90%; the preparation method of the nanoporous thin film material includes the following steps: S1. Preparation of A using polymer-assisted deposition method x B y O3 precursor solution; S2. Deposit A ​​on the substrate using spin coating. x B y O3, and calcined, to obtain A x B y O3 nanoporous thin film material; Specifically, it includes the following sub-steps: S11. In a salt solution containing salts A and B, citric acid is added and stirred until completely dissolved to obtain solution M; S12. Polyethyleneimine is added to deionized water and stirred until completely dissolved to obtain solution N; S13. Add solution N to solution M, and then continue chelation to obtain solution O; S14. Concentrate solution O to obtain the precursor solution; S21. Pre-treat the substrate and then preheat it; S22. Coat the precursor solution onto the preheated substrate and homogenize it. S23. Place the coated film on a constant temperature heating table to fix the film thickness; S24. Repeat steps S22-S23 until the target thickness is reached to obtain the film; S25. After calcining the film, cool it to obtain a nanoporous film material. The calcination process specifically involves heating to 750℃~850℃ at a rate of 3℃ / min and calcining for 4 hours. Both salt A and salt B are selected from nitrates or acetates; the molar ratio of salt A to salt B is 1:1; the molar ratio of the salt, citric acid, and polyethyleneimine is 1:(1.5~2.5):(5×10⁻⁶). -6 ~1×10 -4 ).

2. The nanoporous thin film material according to claim 1, characterized in that, The chelation time in step S13 is 6h~14h; the concentration temperature in step S14 is 50℃~90℃, and the concentration of the concentrated solution is 0.01mol / L~0.2mol / L.

3. The nanoporous thin film material according to claim 1, characterized in that, The preheating temperature in step S21 is 250℃~450℃, and the preheating time is 3min~10min; the spin coating speed in step S22 is 1500r / min~10000r / min; the film is placed on a constant temperature heating stage in step S23 and heated at 250℃~450℃ for 3min~10min; the target thickness in step S24 is 150nm~450nm.

4. An application of the nanoporous thin film material as described in any one of claims 1 to 3 as an infrared emitting film.

Images