Barium nickel niobate-potassium niobate ferroelectric thin film material, preparation method and application thereof
By employing an inorganic mica substrate and a flexible substrate to modulate the bending strain gradient on KBNNOx thin films, the problems of low photocurrent and irreversible modulation of KBNNOx thin films were solved, achieving dynamic enhancement and stable output of photocurrent, which is suitable for photovoltaic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI NORMAL UNIVERSITY
- Filing Date
- 2022-11-25
- Publication Date
- 2026-07-24
AI Technical Summary
Existing KBNNOx thin films have low photocurrent and irreversible modulation, making it difficult to enhance photocurrent output dynamically.
Using inorganic mica as a substrate, a flexible all-inorganic [KNbO3]0.9[BaNi1/2Nb1/2O3]0.1 thin film was epitaxially grown. The photocurrent was modulated by the bending strain gradient of the flexible substrate, thereby enhancing the photocurrent of the KBNNO thin film.
It achieves effective dynamic control of photocurrent, has stable photoelectric performance, and is suitable for the field of photovoltaic devices.
Smart Images
Figure CN115763597B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ferroelectric thin film materials, and in particular to a barium nickel niobate-potassium niobate ferroelectric thin film material, its preparation method, and its application. Background Technology
[0002] Unlike traditional PN junction photovoltaic devices, photovoltaic devices based on ferroelectric semiconductor oxides do not require an interface potential difference. Utilizing a built-in electric field formed by spontaneous polarization, they can enhance carrier separation, thereby promoting efficient absorption of positive and negative charges, and have significant application prospects in photovoltaic devices. The development of novel ferroelectric oxides with good flexibility, stable light response output, and multifunctionality has become a focus of international research. Potassium niobate-based ferroelectrics are a class of bandgap-tunable semiconductor materials developed in recent years, attracting considerable attention due to their structural and performance stability, broad-spectral absorption, and environmental friendliness. Among them, [KNbO3]... 1-x [BaNi 1 / 2 Nb 1 / 2 O 3-δ ] x (KBNNO x The material possesses stable photovoltaic output performance and shows great promise for applications in photodetectors. However, current reports regarding KBNNO... x Thin films suffer from low photocurrent, and most methods attempt to control the photocurrent output by changing the doping concentration, but the effect is not only insignificant but also irreversible. Considering that the photocurrent of ferroelectric semiconductors is closely related to its absorption process, the separation, migration, and collection of photogenerated carriers, previous reports have utilized the flexoelectric effect to control the transport properties of BiFeO3 thin films, effectively increasing its photocurrent output. However, the flexoelectric field generated is produced through interfacial mismatch, resulting in static and irreversible control of the film's photocurrent. To explore new approaches to improve the photocurrent of KBNNO... x If a novel approach can be found to dynamically and reversibly control and enhance the photocurrent of thin film materials, it would be beneficial. x The output of thin-film photocurrent will be of great significance. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a barium nickel niobate-potassium niobate ferroelectric thin film material, its preparation method, and its application. This invention utilizes inorganic mica (which possesses exceptional flexibility and a melting point up to 1100℃, meeting the requirements of KBNNO). x The thin film preparation requires using [KNbO3] as a substrate for epitaxial growth of a flexible, all-inorganic [KNbO3] film. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1(KBNNO) thin film: Prepare KBNNO ferroelectric thin film material, and regulate the photocurrent of the enhanced KBNNO ferroelectric thin film material by the bending strain gradient of the flexible substrate, so as to meet its application in related photovoltaic device fields.
[0004] The objective of this invention can be achieved through the following technical solutions:
[0005] The first objective of this invention is to provide a barium nickel niobate-potassium niobate ferroelectric thin film material (KBNNO ferroelectric thin film material), comprising, from bottom to top, a substrate, a bottom electrode layer, a thin film layer, and a transparent top electrode layer; the substrate is an inorganic mica substrate; the thin film layer is barium nickel niobate-potassium niobate, with a chemical composition of [KNbO3]. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 .
[0006] Furthermore, the bottom electrode layer is lanthanum nickelate; the transparent top electrode layer is aluminum-doped zinc oxide.
[0007] Furthermore, the thin film layer is prepared by the sol-gel method.
[0008] The second objective of this invention is to provide a method for preparing barium nickel niobate-potassium niobate ferroelectric thin film materials, comprising the following steps:
[0009] S1. Substrate preparation: The mica is peeled off, and the new surface obtained after peeling has a high degree of flatness and can be used as a substrate.
[0010] S2. Take the prepared precursor solution of the bottom electrode layer and perform the first coating on the heat-treated substrate. After the first coating is completed, perform the first annealing to crystallize it, and obtain the bottom electrode layer on the substrate to obtain the first ferroelectric thin film material.
[0011] S3. Prepare a precursor solution of barium nickel niobate-potassium niobate by taking potassium source, niobium source, barium source and nickel source. Then, perform a second coating on the bottom electrode layer of the first ferroelectric thin film material obtained in step S2. After the second coating is completed, perform a second annealing to crystallize it and obtain a thin film layer on the bottom electrode layer to obtain the second ferroelectric thin film material.
[0012] S4. Take the second ferroelectric thin film material obtained in step S3, and use a pulsed laser sputtering deposition system to sputter a transparent top electrode layer to obtain the third ferroelectric thin film material.
[0013] S5. Using a blade and tape, the third ferroelectric thin film material obtained in step S4 is thinned from the back side (when thinned to a certain extent, the obtained barium nickel niobate-potassium niobate ferroelectric thin film material has good flexibility), to obtain the barium nickel niobate-potassium niobate ferroelectric thin film material.
[0014] Furthermore, the specific process of peeling mica in step S1 is as follows: Take a mica substrate, use a blade to make a straight cut at the corner of the square mica substrate, keeping the blade parallel to the mica layers, and when the cut is extended to a certain extent, use tweezers to pick up one of the layers and peel it off slowly.
[0015] The new surface obtained after peeling not only has high flatness but is also very clean, so it can be used directly as a substrate without cleaning.
[0016] Further, in step S2, the bottom electrode layer is lanthanum nickelate, and the specific process for preparing the precursor solution of the bottom electrode layer is as follows: the nickel source and the lanthanum source are dissolved in ethylene glycol monomethyl ether respectively, then mixed and stirred, and then aged.
[0017] More preferably, the molar ratio of the nickel source to the lanthanum source is 1:1; the concentration of the precursor solution of the bottom electrode layer is 0.2-0.4M; the stirring temperature is 35°C; the stirring time is 4 hours; and the aging is carried out in a cool place for 24 hours.
[0018] Further, in step S2, the first coating is performed using spin coating. The specific process of the first coating and the first annealing is as follows: first, spin coating is performed at a speed of 3000-3500 rpm for 20-50 seconds, then drying is performed at 180-220°C, and the organic solvent is removed by pyrolysis and evaporation at 380-450°C; the above steps are repeated 3-5 times; finally, the first annealing is performed at 700-750°C for 10-30 minutes.
[0019] Further, in step S3, the potassium source is potassium acetate, the barium source is barium acetate, the niobium source is niobium ethoxide, and the nickel source is nickel acetate.
[0020] Furthermore, in step S3, the specific process for preparing the barium nickel niobate-potassium niobate precursor solution is as follows:
[0021] S31. Preparation of potassium niobate precursor solution: First, dissolve the potassium source in anhydrous ethanol solution, then add niobium ethanol and reflux to obtain potassium niobate precursor solution.
[0022] S32. Preparation of niobium-nickel-barium precursor solution: Dissolve nickel source and barium source in a mixed solution of anhydrous ethanol and glacial acetic acid, then add niobium ethanol to obtain niobium-nickel-barium precursor solution.
[0023] S33. Preparation of barium nickel niobate-potassium niobate precursor solution: Add the potassium niobate precursor solution obtained in step S31 to the niobium-nickel-barium precursor solution obtained in step S32 to obtain the barium nickel niobate-potassium niobate precursor solution.
[0024] The amounts of potassium, niobium, barium, and nickel sources are weighed according to the proportions of each element in the final barium nickel niobate-potassium niobate ferroelectric thin film material to be produced.
[0025] More preferably, in step S31, the reflux temperature is 110–130°C, and the reflux time is 10–24 h; in step S32, acetylacetone is added to the niobium-nickel-barium precursor solution to prevent niobium ethanol hydrolysis; in step S33, ethanolamine is added to the barium nickel niobate-potassium niobate precursor solution to adjust the viscosity of the solution.
[0026] Further, in step S3, a second coating is performed using spin coating. The specific process of the second coating and the second annealing is as follows: first, spin coating is performed at a rate of 3000-4000 rpm for 20-40 seconds. After film formation, thermal decomposition is carried out at 320-400℃ for 5-15 minutes. Finally, a second annealing is performed at 600-750℃ for 5-15 minutes. The above steps are repeated 6-12 times.
[0027] Further, in step S4, a transparent aluminum-doped zinc oxide top electrode is sputtered using a pulsed laser sputtering deposition system at a sputtering temperature of 100–200°C, an oxygen pressure of 0.5–2 Pa, and a sputtering time of 30–60 min.
[0028] The third objective of this invention is to provide an application of a barium nickel niobate-potassium niobate ferroelectric thin film material. This material is applied to the field of photovoltaic devices, utilizing inorganic mica (which possesses exceptional flexibility and a melting point up to 1100℃, meeting KBNNO standards). x The thin film preparation requires using [KNbO3] as a substrate for epitaxial growth of a flexible, all-inorganic [KNbO3] film. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 (KBNNO) thin film, the above-mentioned barium nickel niobate-potassium niobate ferroelectric thin film material is obtained, and the photocurrent of the enhanced KBNNO thin film is controlled by the bending strain gradient of the flexible substrate, thereby meeting its application in related photovoltaic device fields.
[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0030] 1) The method for preparing barium nickel niobate-potassium niobate ferroelectric thin film material provided by the present invention has high flatness and good crystallinity when using flexible inorganic mica as a substrate. The preparation method is economical and environmentally friendly and the preparation process is simple.
[0031] 2) The barium nickel niobate-potassium niobate ferroelectric thin film material provided by the present invention has excellent photoelectric properties, and its photoelectric properties remain stable after multiple bending.
[0032] 3) The barium nickel niobate-potassium niobate ferroelectric thin film material provided by the present invention can effectively regulate the photocurrent through electric field and bending strain, and can achieve stable photoresponse output, thus enabling its application in the field of photovoltaic devices. Attached Figure Description
[0033] Figure 1 This is an X-ray diffraction pattern of the KBNNO ferroelectric thin film material, the inorganic mica substrate, and the mica substrate with the LNO bottom electrode layer grown on an inorganic mica substrate with a lanthanum nickelate (LNO) bottom electrode layer in an environment with a second annealing temperature of 700°C, according to Embodiment 1 of the present invention.
[0034] Figure 2 This is a surface morphology diagram of the KBNNO ferroelectric thin film material grown on an inorganic mica substrate with an LNO bottom electrode layer in an environment with a second annealing temperature of 700°C, according to Embodiment 1 of the present invention.
[0035] Figure 3 This is a cross-sectional morphology diagram of the KBNNO ferroelectric thin film material grown on an inorganic mica substrate with an LNO bottom electrode layer in an environment with a second annealing temperature of 700°C, according to Embodiment 1 of the present invention.
[0036] Figure 4 This is a JV image of a KBNNO ferroelectric thin film material grown on an inorganic mica substrate with an LNO bottom electrode layer in an environment with a second annealing temperature of 700°C under different polarization states, as shown in Embodiment 1 of the present invention.
[0037] Figure 5 This is a JV image of KBNNO ferroelectric thin film material grown on an inorganic mica substrate with an LNO bottom electrode layer in an environment with a second annealing temperature of 700°C under -9V polarization conditions with different strain gradients, as shown in Embodiment 1 of the present invention.
[0038] Figure 6 This is a JV image of a KBNNO ferroelectric thin film material grown on an inorganic mica substrate with an LNO bottom electrode layer in an environment with a second annealing temperature of 700°C under +9V polarization conditions with different strain gradients, as shown in Embodiment 1 of the present invention. Detailed Implementation
[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.
[0040] Any preparation methods, materials, structures, or composition ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.
[0041] Example 1
[0042] This embodiment provides a barium nickel niobate-potassium niobate ferroelectric thin film material (KBNNO ferroelectric thin film material), comprising, from bottom to top, a substrate, a bottom electrode layer, a thin film layer, and a transparent top electrode layer; the substrate is an inorganic mica substrate; the thin film layer is barium nickel niobate-potassium niobate, with a chemical composition of [KNbO3]. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 The bottom electrode layer is lanthanum nickelate; the transparent top electrode layer is aluminum-doped zinc oxide.
[0043] The preparation method of the above-mentioned KBNNO ferroelectric thin film material includes the following steps:
[0044] S1. Substrate preparation: Take a mica substrate and use a blade to make a straight cut at the corner of the square mica substrate, keeping the blade parallel to the mica sheet. When the cut is extended to a certain extent, you can use tweezers to pick up one sheet and slowly peel it off. This completes one peeling process. The new surface obtained after peeling has a high degree of flatness and can be used directly as a substrate.
[0045] S2. Preparation of the precursor solution for the bottom electrode layer: Weigh 1.02g Ni(CH3COO)2·4H2O (99%) and dissolve it in 20ml ethylene glycol methyl ether. Place it on a magnetic stir bar and stir at 500rpm at 35℃ until clear. Then add 1.75g La(NO3)3·6H2O (98%) and place it on a magnetic stir bar and stir at 500rpm at 35℃ for 4h. Then let it age in a cool place for 24h to obtain 20ml of 0.2M precursor solution for the bottom electrode layer.
[0046] The first coating was performed by spin coating. The precursor solution of the obtained bottom electrode layer was spin coated onto the substrate obtained in step S1. The substrate was spin-coated at 3000 rpm for 20 s, dried at 180°C, and then pyrolyzed at 450°C to remove the organic solvent. The above steps were repeated 5 times. Finally, the substrate was annealed at 750°C for 30 min to crystallize the substrate and obtain the bottom electrode layer, thus obtaining the first ferroelectric thin film material.
[0047] S3. Preparation of 15ml 0.3M barium nickel niobate-potassium niobate precursor solution: S31. Preparation of potassium niobate precursor solution: Weigh 1.071g of K(CH3COO) (99%) and dissolve it in 10ml of anhydrous ethanol. Place the solution on a magnetic stirrer at 500rpm and stir until clear. Then add 3.19g of Nb(CH3CH2O)5 (99.9%) and heat and reflux at 120℃ for 12h to obtain potassium niobate precursor solution. S32. Preparation of niobium-nickel-barium precursor solution: Weigh 0.08g of Ba(CH3COO)2 (99%) and dissolve it in 10ml of a mixed solution of anhydrous ethanol and glacial acetic acid in a ratio of 1:3. Stir the solution on a magnetic stirrer until clear. Then add 0.038g of Ni(CH3COO). 2·4H2O (98%), stirred until clear, then weighed 0.05g of Nb(CH3CH2O)5 (99.9%), and finally added 2ml of acetylacetone solution to prevent hydrolysis. Stirred for 30min to obtain niobium-nickel-barium precursor solution; S33, take 2.9ml of potassium niobate precursor solution obtained in step S31 and add it to the niobium-nickel-barium precursor solution obtained in step S32, then add 60μL of ethanolamine solution, stir at room temperature for 4h, and then age at room temperature for 24h to obtain barium nickel niobate-potassium niobate precursor solution;
[0048] After adding the solution to the first ferroelectric thin film material obtained in step S2, a second coating is performed by spin coating. The spin coating speed and time are 3000 rpm and 20 s, respectively. After film formation, the film is dried at 320°C for 10 min in a rapid annealing furnace, and then annealed for 10 min at 700°C to allow it to crystallize. The above steps are repeated 6 times to obtain the second ferroelectric thin film material.
[0049] S4. Take the second ferroelectric thin film material obtained in step S3, and use a pulsed laser sputtering deposition system to sputter an aluminum-doped zinc oxide (AZO) electrode at a sputtering temperature of 150℃, an oxygen pressure of 1Pa, and a sputtering time of 30min to prepare a transparent top electrode layer and obtain the third ferroelectric thin film material.
[0050] S5. Using a blade and tape, the third ferroelectric thin film material obtained in step S4 is thinned from the back side to obtain the barium nickel niobate-potassium niobate ferroelectric thin film material.
[0051] X-ray diffraction analysis was performed on a barium nickel niobate-potassium niobate (KBNNO) ferroelectric thin film material obtained at 700℃ on an inorganic mica substrate with an LNO bottom electrode layer. Specifically, the analysis was as follows: Figure 1As shown, in the prepared KBNNO thin film, due to the strong orientation of the inorganic mica substrate, two distinct peaks were observed only at 22.01° and 31.38°, corresponding to the (110) and (200) directions, respectively.
[0052] SEM images of the surface and cross-section of the KBNNO ferroelectric thin film material obtained at the second annealing temperature of 700℃ are shown below. Figure 2 (Scale bar is 300nm) and Figure 3 (Scale bar is 300nm). Figure 2 The surface morphology of the KBNNO ferroelectric thin film material is shown, revealing that the KBNNO ferroelectric thin film material has a dense microstructure. Figure 3 A cross-sectional SEM image of the KBNNO ferroelectric thin film material is shown. It can be seen that the KBNNO ferroelectric thin film material has a dense microstructure, a clear and dense interface, and is tightly bonded to the substrate.
[0053] JV images of KBNNO ferroelectric thin film materials under different polarization states are as follows: Figure 4 As shown, the short-circuit current (J) of the KBNNO ferroelectric thin film material grown under illumination and with a second annealing temperature of 700℃ is... SC ) and open-circuit voltage (V OC The values were 8.09 μA / cm. 2 The JV characteristics of the KBNNO ferroelectric thin film were measured after polarization with -9V (positive voltage applied to the bottom electrode LNO) and +9V (positive voltage applied to the transparent top electrode AZO), respectively. The KBNNO ferroelectric thin film material polarized with negative voltage had the same photocurrent direction as the grown KBNNO ferroelectric thin film material, while the JV characteristics were... SC Significantly increased, when the KBNNO ferroelectric thin film material is positively polarized, the photocurrent exhibits the opposite direction. Furthermore, J SC and V OC The absolute value of J is smaller than that of the KBNNO ferroelectric thin film material under negative voltage polarization. This result indicates that the driving electric field for separating photogenerated carriers after positive polarization is smaller than that after negative polarization. This is because the interfacial electric field of the thin film may hinder polarization reversal, resulting in a smaller J value after positive polarization. SC Much smaller than J after negative polarization SC .
[0054] After polarizing the KBNNO ferroelectric thin film material at +9V and -9V respectively, the flexible KBNNO ferroelectric thin film material was bent upwards, and the JV images measured under different strain gradients are shown below. Figure 5 and Figure 6 As shown. From Figure 5 As can be seen, after polarization at -9V, J SCThe absolute value of increases with increasing strain gradient because the additional internal electric field generated by the flexoelectric effect can enhance or weaken the separation of photoexcited electron-hole pairs. Due to bending the flexible film upwards, the flexoelectric effect produces an effective upward flexoelectric polarization. Therefore, an additional built-in electric field is generated that couples with the polarization internal electric field of KBNNO, separating more electron-hole pairs to enhance the photovoltaic effect. Conversely, from Figure 6 It can be seen that when +9V is polarized, J SC The absolute value of decreases with increasing strain gradient because the additional built-in electric field generated by flexure cancels out the polarized internal electric field of KBNNO, resulting in a weakened photovoltaic effect.
[0055] Example 2
[0056] This embodiment provides a barium nickel niobate-potassium niobate ferroelectric thin film material (KBNNO ferroelectric thin film material), comprising, from bottom to top, a substrate, a bottom electrode layer, a thin film layer, and a transparent top electrode layer; the substrate is an inorganic mica substrate; the thin film layer is barium nickel niobate-potassium niobate, with a chemical composition of [KNbO3]. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 The bottom electrode layer is lanthanum nickelate; the transparent top electrode layer is aluminum-doped zinc oxide.
[0057] The preparation method of the above-mentioned KBNNO ferroelectric thin film material includes the following steps:
[0058] S1. Substrate preparation: Take a mica substrate and use a blade to make a straight cut at the corner of the square mica substrate, keeping the blade parallel to the mica sheet. When the cut is extended to a certain extent, you can use tweezers to pick up one sheet and slowly peel it off. This completes one peeling process. The new surface obtained after peeling has a high degree of flatness and can be used directly as a substrate.
[0059] S2. Preparation of the precursor solution for the bottom electrode layer: Weigh 2.03g Ni(CH3COO)2·4H2O (99%) and dissolve it in 20ml ethylene glycol methyl ether. Place it on a magnetic stir bar and stir at 500rpm at 35℃ until clear. Then add 3.48g La(NO3)3·6H2O (98%) and place it on a magnetic stir bar and stir at 500rpm at 35℃ for 4h. Then let it age in a cool place for 24h to obtain 20ml of 0.4M bottom electrode layer precursor solution.
[0060] The first coating was performed by spin coating. The precursor solution of the obtained bottom electrode layer was spin-coated onto the substrate obtained in step S1. The substrate was spin-coated at 3500 rpm for 40 s, dried at 220 °C, and then pyrolyzed at 390 °C to remove the organic solvent. The above steps were repeated 3 times. Finally, the substrate was annealed at 700 °C for 15 min to allow it to crystallize, and the bottom electrode layer was obtained on the substrate, thus obtaining the first ferroelectric thin film material.
[0061] S3. Preparation of 15ml 0.3M barium nickel niobate-potassium niobate precursor solution: S31. Preparation of potassium niobate precursor solution: Weigh 1.065g of K(CH3COO) (99%) and dissolve it in 10ml of anhydrous ethanol. Place it on a magnetic stirrer and stir at 500rpm until clear. Then add 3.17g of Nb(CH3CH2O)5 (99.9%) and heat and stir under reflux at 110℃ for 20h to obtain potassium niobate precursor solution. S32. Preparation of niobium-nickel-barium precursor solution: Weigh 0.078g of Ba(CH3COO)2 (99%) and dissolve it in 10ml of a mixed solution of anhydrous ethanol and glacial acetic acid in a ratio of 1:3. Place it on a magnetic stirrer and stir until clear. Then add 0.040g of Ni(CH3COO)2. Add 2·4H2O (98%), stir until clear, weigh 0.05g of Nb(CH3CH2O)5 (99.9%), add 2ml of acetylacetone solution to prevent hydrolysis, stir for 30min to obtain niobium-nickel-barium precursor solution; S33, add 2.9ml of potassium niobate precursor solution obtained in step S31 to niobium-nickel-barium precursor solution obtained in step S32, add 60μL of ethanolamine solution, stir at room temperature for 4h, and then age at room temperature for 24h to obtain barium nickel niobate-potassium niobate precursor solution;
[0062] After adding the solution to the first ferroelectric thin film material obtained in step S2, a second coating is performed by spin coating. The spin coating speed and time are 4000 rpm and 40 s, respectively. After film formation, the film is dried at 380°C for 5 min in a rapid annealing furnace, and then annealed for 10 min at 700°C to allow it to crystallize. The above steps are repeated 10 times to obtain the second ferroelectric thin film material.
[0063] S4. Take the second ferroelectric thin film material obtained in step S3, and use a pulsed laser sputtering deposition system to sputter an aluminum-doped zinc oxide (AZO) electrode at a sputtering temperature of 200℃, an oxygen pressure of 0.5Pa, and a sputtering time of 60min to prepare a transparent top electrode layer and obtain the third ferroelectric thin film material.
[0064] S5. Using a blade and tape, the third ferroelectric thin film material obtained in step S4 is thinned from the back side to obtain the barium nickel niobate-potassium niobate ferroelectric thin film material.
[0065] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A barium nickel niobate-potassium niobate ferroelectric thin film material, characterized in that, The ferroelectric thin film material comprises, from bottom to top, a substrate, a bottom electrode layer, a thin film layer, and a transparent top electrode layer; The substrate is an inorganic mica substrate; the mica is peeled off, and the flat new surface obtained after peeling is used as the substrate. The thin film layer is barium nickel niobate-potassium niobate, with the chemical composition [KNbO3]. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 ; The bottom electrode layer is lanthanum nickelate; The transparent top electrode layer is aluminum-doped zinc oxide; A flexible, all-inorganic [KNbO3] was epitaxially grown using inorganic mica as a substrate. 0.9 [BaNi 1 / 2 Nb 1 / 2 O3] 0.1 (KBNNO) thin film, prepare KBNNO ferroelectric thin film material, and regulate the photocurrent of enhanced KBNNO ferroelectric thin film material by the bending strain gradient of flexible substrate; The preparation method of barium nickel niobate-potassium niobate ferroelectric thin film material includes the following steps: S1. Substrate preparation: The mica is peeled off, and the flat new surface obtained after peeling is used as the substrate. S2. Take the prepared precursor solution of the bottom electrode layer and perform the first coating on the heat-treated substrate. After the first coating is completed, perform the first annealing to crystallize it, and obtain the bottom electrode layer on the substrate to obtain the first ferroelectric thin film material. S3. Prepare a precursor solution of barium nickel niobate-potassium niobate by taking potassium source, niobium source, barium source and nickel source. Then, perform a second coating on the bottom electrode layer of the first ferroelectric thin film material obtained in step S2. After the second coating is completed, perform a second annealing to crystallize it and obtain a thin film layer on the bottom electrode layer to obtain the second ferroelectric thin film material. S4. Take the second ferroelectric thin film material obtained in step S3, and use a pulsed laser sputtering deposition system to sputter a transparent top electrode layer to obtain the third ferroelectric thin film material. S5. Thin the third ferroelectric thin film material obtained in step S4 from the back side to obtain the barium nickel niobate-potassium niobate ferroelectric thin film material.
2. A method for preparing the barium nickel niobate-potassium niobate ferroelectric thin film material as described in claim 1, characterized in that, The preparation method includes the following steps: S1. Substrate preparation: The mica is peeled off, and the flat new surface obtained after peeling is used as the substrate. S2. Take the prepared precursor solution of the bottom electrode layer and perform the first coating on the heat-treated substrate. After the first coating is completed, perform the first annealing to crystallize it, and obtain the bottom electrode layer on the substrate to obtain the first ferroelectric thin film material. S3. Prepare a precursor solution of barium nickel niobate-potassium niobate by taking potassium source, niobium source, barium source and nickel source. Then, perform a second coating on the bottom electrode layer of the first ferroelectric thin film material obtained in step S2. After the second coating is completed, perform a second annealing to crystallize it and obtain a thin film layer on the bottom electrode layer to obtain the second ferroelectric thin film material. S4. Take the second ferroelectric thin film material obtained in step S3, and use a pulsed laser sputtering deposition system to sputter a transparent top electrode layer to obtain the third ferroelectric thin film material. S5. Thin the third ferroelectric thin film material obtained in step S4 from the back side to obtain the barium nickel niobate-potassium niobate ferroelectric thin film material.
3. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 2, characterized in that, In step S2, the bottom electrode layer is lanthanum nickelate. The specific process for preparing the precursor solution of the bottom electrode layer is as follows: dissolve the nickel source and the lanthanum source separately in ethylene glycol monomethyl ether, then mix them and stir, and then age them. The molar ratio of the nickel source to the lanthanum source is 1:1; The concentration of the precursor solution for the bottom electrode layer is 0.2~0.4 M; The stirring temperature is 35°C, the stirring time is 4 hours, and the aging process involves aging in a cool place for 24 hours.
4. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 2, characterized in that, In step S2, the first coating is applied using spin coating. The specific process of the first coating and the first annealing is as follows: First, spin the adhesive at a speed of 3000~3500 rpm for 20~50 s, then dry it at 180~220℃, and then pyrolyze and evaporate it at 380~450℃ to remove the organic solvent; repeat the above steps 3~5 times; finally, anneal it for the first time at 700~750℃ for 10~30 min.
5. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 2, characterized in that, In step S3, the potassium source is potassium acetate, the barium source is barium acetate, the niobium source is niobium ethoxide, and the nickel source is nickel acetate. In step S3, the specific process for preparing the barium nickel niobate-potassium niobate precursor solution is as follows: S31. Preparation of potassium niobate precursor solution: First, dissolve the potassium source in anhydrous ethanol solution, then add niobium ethanol and reflux to obtain potassium niobate precursor solution. S32. Preparation of niobium-nickel-barium precursor solution: Dissolve nickel source and barium source in a mixed solution of anhydrous ethanol and glacial acetic acid, then add niobium ethanol to obtain niobium-nickel-barium precursor solution. S33. Preparation of barium nickel niobate-potassium niobate precursor solution: Add the potassium niobate precursor solution obtained in step S31 to the niobium-nickel-barium precursor solution obtained in step S32 to obtain the barium nickel niobate-potassium niobate precursor solution. The amounts of potassium, niobium, barium, and nickel sources are weighed according to the proportions of each element in the final barium nickel niobate-potassium niobate ferroelectric thin film material to be produced.
6. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 5, characterized in that, In step S31, the reflux temperature is 110~130℃, and the reflux time is 10~24 h; In step S32, acetylacetone is added to the niobium-nickel-barium precursor solution to prevent niobium ethanol hydrolysis; In step S33, ethanolamine is added to the barium nickel niobate-potassium niobate precursor solution to adjust the viscosity of the solution.
7. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 2, characterized in that, In step S3, a second coating is performed using spin coating. The specific process of the second coating and the second annealing is as follows: first, spin coating is performed at a rate of 3000~4000 rpm for 20~40 s. After film formation, thermal decomposition is carried out at 320~400℃ for 5~15 min. Finally, a second annealing is carried out at 600~750℃ for 5~15 min. The above steps are repeated 6~12 times.
8. The method for preparing a barium nickel niobate-potassium niobate ferroelectric thin film material according to claim 2, characterized in that, In step S4, a transparent aluminum-doped zinc oxide top electrode is sputtered using a pulsed laser sputtering deposition system at a sputtering temperature of 100~200℃, an oxygen pressure of 0.5~2 Pa, and a sputtering time of 30~60 min.
9. The application of the barium nickel niobate-potassium niobate ferroelectric thin film material as described in claim 1 in the field of photovoltaic devices.