CN111525021A - Sodium bismuth titanate-based film with positive and negative electrocaloric effects and preparation method thereof - Google Patents

Sodium bismuth titanate-based film with positive and negative electrocaloric effects and preparation method thereof Download PDF

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CN111525021A
CN111525021A CN202010320707.6A CN202010320707A CN111525021A CN 111525021 A CN111525021 A CN 111525021A CN 202010320707 A CN202010320707 A CN 202010320707A CN 111525021 A CN111525021 A CN 111525021A
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equal
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CN111525021B (en
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杨长红
冯超
钱进
林秀娟
程振祥
黄世峰
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University of Jinan
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Abstract

The invention belongs to the field of electronic functional materials and devices, and particularly relates to a sodium bismuth titanate-based film with positive and negative electrocaloric effects and a preparation method thereof. The sodium bismuth titanate-based thin film consists of a substrate, a bottom electrode, a ferroelectric thin film layer and a top electrode, wherein the general formula of the composition of the thin film is Na0.5×aBi0.5×b(Ti1‑x‑yWxFey)O3Wherein a is more than or equal to 1.01 and less than or equal to 1.02, b is more than or equal to 1.01 and less than or equal to 1.04, x is more than or equal to 0.01 and less than or equal to 0.02, and y is more than or equal to 0.01 and less than or equal to 0.02. Near 143 ℃, the peak values of positive adiabatic temperature change and isothermal entropy change are the maximum values reported so far: ΔT~55 K，∆S~64 J K‑1kg‑1(ii) a The peak values of the negative adiabatic temperature change and isothermal entropy change in the same refrigeration cycle, around 54 ℃, are: ΔT~‑17 K，∆S~‑26 J K‑1kg‑1. The sodium bismuth titanate-based thin film prepared by the chemical solution method has the advantages of excellent electrocaloric performance, environmental friendliness, simple process, low cost and the like, and has wide application prospects in the temperature control fields of chip refrigeration, sensors, electronic devices and the like.

Description

Sodium bismuth titanate-based film with positive and negative electrocaloric effects and preparation method thereof
Technical Field
The invention belongs to the field of electronic functional materials and devices, and particularly relates to a sodium bismuth titanate-based film with positive and negative electrocaloric effects and a preparation method thereof.
Background
The application of the refrigeration technology has penetrated the aspects of life and production of people, and has urgent needs in the fields of industrial and agricultural production, biological medical treatment, national defense industry, advanced science and technology and the like. At present, refrigeration still almost completely depends on the traditional compressor technology, and the compressor refrigeration has the problems of high energy consumption, low working efficiency, large volume, heavy weight, environmental pollution and the like. Therefore, it is urgent to develop a novel refrigeration technology with high energy conversion efficiency, miniaturization, and environmental friendliness.
The electrocaloric effect is a phenomenon that the polarization state of a polar material is changed due to the change of an applied external electric field, and the change of the degree of order of polar dipoles causes the change of the entropy of the material, so that the adiabatic temperature change or the isothermal entropy change is generated. The electric card effect is divided into positive electric card effect and negative electric card effect, and the positive electric card effect completes refrigeration under the condition of removing external electric field due to the reduction of the temperature of the electric card materialIn contrast, the negative electrocaloric effect is the cooling process performed under the application of an electric field. The key to the practicability of the electrocaloric refrigeration lies in the preparation of high-performance electrocaloric materials. Since 2006 Mischenko et al discovered the Giant electrocaloric effect in lead zirconate titanate thin film (reference: Giant electro-capacitive effect in this-filmPbZr)0.95Ti0.05O3Science, 2006, 311 (5765): 1270-. In 2009, Correia et al found in Pb (Mg)1/3Nb2/3)O3-PbTiO3Obtaining a large positive electrocaloric effect around the depolarization temperature: (T=25°C, ∆T9K) (reference: investigation of the electrolytic effect a PbMg2/3Nb1/3O3-PbTiO3relaxor thin film, appl. Phys. Lett., 200995: 182904). In 2019, Penbusuling et al induced a lead-free relaxor ferroelectric thin film 0.5 (Ba) by phase transition0.8Ca0.2)TiO3-0.5Bi(Mg0.5Ti0.5)O3In the process of generating a huge negative electric card effect (T=163°C, ∆T-42.5K) (reference: Phase-Transition Induced Giant Negative electric Effect in a Lead-FreeRelaxor Ferroelectric Thin film. Energy environ. Sci., 201912: 1708-. In order to improve the refrigeration efficiency and meet the requirement of an electric card refrigeration device, the large adiabatic temperature change valueTUndoubtedly, it is an effective method, and if there is positive and negative electric-card refrigeration in the same material, different electric-card effects can be adopted to continuously refrigerate by adjusting the direction of the electric field.
Sodium bismuth titanate (Na)0.5Bi0.5TiO3) The ferroelectric is a ferroelectric with an A-site composite lead-free perovskite structure, and a complex phase transition process exists in the range from room temperature to 520 ℃, so that the potential possibility is created for obtaining a large electric card effect. In addition, the breakdown-resistant field strength of the sodium bismuth titanate film can be improved through component design, which is an effective means for improving the electrocaloric effect. In view of the above, the sodium bismuth titanate-based film is an electric card refrigeration material with high potential application value.
Disclosure of Invention
The invention aims to provide a sodium bismuth titanate-based film with positive and negative electrocaloric effects and a preparation method thereof.
The invention is realized by the following technical scheme:
a sodium bismuth titanate-based film with positive and negative electrocaloric effects comprises a substrate, a bottom electrode, a ferroelectric film layer and a top electrode. The composition general formula of the film is Na0.5×aBi0.5×b(Ti1-x-yWxFey)O3Wherein a is more than or equal to 1.01 and less than or equal to 1.02, b is more than or equal to 1.01 and less than or equal to 1.04, x is more than or equal to 0.01 and less than or equal to 0.02, and y is more than or equal to 0.01 and less than or equal to 0.02.
The preparation method comprises the following steps:
(1) preparing a substrate and a bottom electrode
(a) Mixing Pt/Ti/SiO2and/Si is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic treatment, and is dried by an infrared lamp for later use. Selecting fluorophlogopite (Mica) with the thickness of less than 50 mu m as a substrate, sequentially placing the substrate in a mixed solution of absolute ethyl alcohol and acetone and deionized water, carrying out ultrasonic treatment for 10-30min respectively, and drying the substrate by using an infrared lamp for later use;
(b) preparation of TiO2Precursor solution: successively adding acetylacetone and tetraisopropyl titanate into ethylene glycol monomethyl ether, and stirring for 1-5 hours to obtain TiO2Precursor solution for later use;
(c) uniformly coating the precursor solution on the bottom electrode by spin coating, drying, annealing, and repeating the spin coating-drying-annealing process for 4 times to obtain TiO2Mica for standby;
(d) by direct current magnetron sputtering on TiO2Depositing Pt film on Mica to obtain Pt/TiO2Mica for use.
（2）Na0.5×aBi0.5×b(Ti1-x-yWxFey)O3Precursor solution preparation
(a) Selecting sodium acetate, bismuth acetate or bismuth nitrate, ferric nitrate, sodium tungstate, and tetraisopropyl titanate as raw materials according to Na0.5×aBi0.5×b(Ti1-x-yWxFey)O3Accurately weighing the raw materials according to the stoichiometric ratio;
(b) firstly, measuring a certain amount of acetylacetone and ethylene glycol monomethyl ether in a beaker, then dropwise adding tetraisopropyl titanate into the beaker, and magnetically stirring the mixture at room temperature for 3 to 5 hours to define a solution 1; dissolving the weighed bismuth acetate or bismuth nitrate, sodium acetate and ferric nitrate into ethylene glycol monomethyl ether, and heating and stirring at 40-70 ℃; dissolving the weighed sodium tungstate into ethylene glycol, and heating and stirring at 40-70 ℃; mixing the two solutions after the two solutions are completely dissolved, and defining the solution as a solution 2; weighing ethylene glycol 600 or polyethylene glycol 20000 with the mass being 10-30% of the total mass of the raw materials, dissolving in acetic acid, and stirring at room temperature until the raw materials are completely dissolved, wherein the solution is defined as a solution 3;
(c) and after all the solutions are cooled, sequentially adding the solution 2 and the solution 3 into the solution 1, and magnetically stirring for 10-15 hours at room temperature to obtain a precursor solution with the concentration of 0.3 mol/L for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
The precursor solution is uniformly coated on the bottom electrode by adopting a spin coating method, then the bottom electrode is placed on a hot plate for drying, then the annealing process is carried out in a rapid annealing furnace, and the processes of spin coating, drying and annealing are repeated.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
And depositing a top electrode on the sodium bismuth titanate-based film by adopting a metal Pt or Au target and using a direct-current magnetron sputtering method.
Preferably, in the step (1) (b), 0.30 ml of acetylacetone and 0.89 ml of tetraisopropyl titanate are added into 28.81 ml of ethylene glycol methyl ether in sequence and stirred for 4 h to obtain TiO with the concentration of 0.1 mol/L2Precursor solution; in the step (1) (c), the rotating speed is 3000r/min, and the time is 30 s; the drying temperature is 250 ℃, and the drying time is 3 min; annealing at 450 deg.CThe time is 8 min.
Preferably, in the steps (1) (d), the atmosphere for depositing the bottom electrode by the direct current magnetron sputtering is Ar, the vacuum degree is 0.05mbar, the current is 30mA, and the thickness of the bottom electrode is 80 nm; the atmosphere is N when the bottom electrode is pretreated2The temperature is 500 ℃ and the time is 8 min.
Preferably, in the step (3), the rotation speed during the spin coating is 3000r/min, and the time is 30 seconds; the drying temperature is 200 ℃, and the drying time is 3 min; the pretreatment temperature is 350 ℃, the pretreatment time is 2 min, and the annealing atmosphere is air or O2The annealing temperature is 500-550 ℃, and the annealing time is 6-10 min.
Preferably, the atmosphere for depositing the top electrode in the step (4) is Ar, the vacuum degree is 0.05mbar, the current is 30mA, and the diameter of the top electrode is 200 μm.
The invention has the beneficial effects
The invention prepares a sodium bismuth titanate-based film with positive and negative electrocaloric effects, and the peak values of positive adiabatic temperature change and isothermal entropy change are the maximum values in the current reports at the temperature of about 143 ℃: ΔT~55 K，∆S~64 J K-1kg-1In the same refrigeration cycle, near 54 ℃, the peak values of negative adiabatic temperature change and isothermal entropy change are obtained: ΔT~-17 K，∆S~-26 J K-1kg-1. The method has the advantages of high performance of the electrocaloric card, environmental friendliness, simple process, low cost and the like, and has wide application prospects in the fields of chip refrigeration, temperature control of sensors and electronic devices and the like.
Drawings
Fig. 1 is a schematic structural diagram of a sodium bismuth titanate-based thin film prepared by the invention.
FIG. 2 shows Na in example 10.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3X-ray diffraction pattern of the film.
FIG. 3 shows Na in example 10.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Dielectric thermogram of thin film.
FIG. 4 shows Na in example 10.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Hysteresis curves at different temperatures of the film.
FIG. 5 shows Na in example 10.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3The film has the following components: (a) adiabatic temperature change versus temperature curve, (b) isothermal entropy change versus temperature curve.
FIG. 6 shows Na in example 20.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3X-ray diffraction pattern of the film.
FIG. 7 shows Na in example 20.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3Hysteresis loop plot of the film.
FIG. 8 shows Na in example 30.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3Scanning electron micrographs of the films.
FIG. 9 shows Na in example 40.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3Hysteresis curves of the films at different temperatures.
FIG. 10 shows Na in example 40.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3The film has the following components: (a) adiabatic temperature change versus temperature curve, (b) isothermal entropy change versus temperature curve.
FIG. 11 shows Na in example 50.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3Dielectric constant versus electric field strength plot for thin films.
FIG. 12 shows Na in example 50.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3Hysteresis curves of the films.
FIG. 13 shows Na in example 60.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3Film mediumElectrical spectrum diagrams.
FIG. 14 shows Na in example 70.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3Hysteresis curves at different temperatures of the film.
FIG. 15 shows Na in example 70.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3The film has the following components: (a) adiabatic temperature change versus temperature curve, (b) isothermal entropy change versus temperature curve.
Detailed Description
The present invention will be further illustrated with reference to the following specific examples, which are intended to be illustrative only and not limiting.
Example 1
(1) Preparing a substrate and a bottom electrode
Mixing Pt/Ti/SiO2and/Si is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic treatment, and is dried by an infrared lamp for later use.
（2）Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Precursor solution preparation
(a) According to Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O30.3617 g of CH are accurately weighed3COONa 1.8072 g of (CH)3CO2)3Bi. 0.0300 g of Na2WO4·2H2O, 0.0728 g of Fe (NO)3)3·9H2O and 0.6815 g of polyethylene glycol 600.
(b) Accurately measuring 2.26 ml of acetylacetone and 2.26 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.26 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 4 hours at room temperature to define solution 1; will weigh the CH3COONa、(CH3CO2)3Bi、Fe(NO3)3·9H2O was dissolved in 11.61 ml of ethylene glycol methyl ether at 40 deg.CHeating and stirring; weighing Na2WO4·2H2Dissolving O in 7.74 ml of ethylene glycol, heating and stirring at 40 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 3.87 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions are cooled, the solution 2 and the solution 3 are added into the solution 1 in turn, and the mixture is magnetically stirred for 12 hours at room temperature to obtain Na with the concentration of 0.3 mol/L0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Standing and aging the precursor solution for 48 h, and uniformly coating the precursor solution on Pt/Ti/SiO by adopting a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 200 ℃, and the drying time is 3 min. Then the film is put into a rapid heating annealing furnace to carry out annealing process, wherein the annealing atmosphere is O2The annealing procedure is to maintain the temperature at 350 ℃ for 2 min and 500 ℃ for 10 min. The above "spin-dry-anneal" process was repeated 12 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Au target, and obtaining Na by a direct-current magnetron sputtering method0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3An Au top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 2 shows this Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3The X-ray diffraction pattern of the film indicated it to be a single polycrystalline perovskite phase. FIG. 3 is Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Film mediumElectric temperature spectrum, depolarization temperature thereofT dAbout 150 ℃ and a phase transition temperatureT mAbout 310 deg.c. At the same timeT mThe relaxation of the film is proved by a wide phase transition peak and a frequency dispersion phenomenon. FIG. 4 shows Na0.5×1.01Bi0.5×1.04(Ti0.97W0.01Fe0.02)O3Hysteresis curves at different temperatures of the film. FIG. 5 shows the calculated adiabatic temperature Δ of the filmTConstant temperature entropy changeSTemperature profile. Near 143 ℃, the peak values of positive adiabatic temperature change and isothermal entropy change are the maximum values reported so far: ΔT~55 K，∆S~64 J K-1kg-1. This is due to the change between dipole ordered and unordered states at the phase transition under control of the electric field and temperature. Simultaneously, in the same refrigeration cycle, around 54 ℃, the peak values of adiabatic temperature change and isothermal entropy change are obtained: ΔT~-17 K，∆S~-26 J K-1kg-1。
Example 2
(1) Preparing a substrate and a bottom electrode
(a) Fluorocrystal Mica (Mica) with the thickness of less than 50 mu m is selected as a substrate, sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic waves, and dried by an infrared lamp for later use.
(b) Preparation of TiO2Precursor solution: 0.30 ml of acetylacetone and 0.89 ml of tetraisopropyl titanate are added successively to 28.81 ml of ethylene glycol monomethyl ether and stirred for 3 h to obtain TiO with the concentration of 0.1 mol/L2And (5) precursor solution for later use.
(c) Uniformly coating the precursor solution on the bottom electrode by adopting a spin coating method at the rotating speed of 3000 revolutions per minute for 30 s, then drying at the drying temperature of 250 ℃ for 3 min, then carrying out annealing treatment at the annealing temperature of 450 ℃ for 8 min, repeating the processes of spin coating, drying and annealing for 4 times to obtain TiO2Mica, for use.
(d) By direct current magnetron sputtering on TiO2Depositing Pt film on Mica in Ar atmosphere and vacuum degree of 0.05mbar, and applying current30mA, and the thickness of the bottom electrode is 80 nm; the atmosphere is N when the bottom electrode is pretreated2The temperature is 500 ℃ and the time is 8 min. Obtaining Pt/TiO2Mica, for use.
（2）Na0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3Precursor solution preparation
(a) According to Na0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O30.3617 g of CH are accurately weighed3COONa 2.2942 g of Bi (NO)3)3·5H2O, 0.0300 g of Na2WO4·2H2O, 0.0728 g of Fe (NO)3)3·9H2O and 0.8276 g of polyethylene glycol 600 for use.
(b) Accurately measuring 2.26 ml of acetylacetone and 2.26 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.26 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 4 hours at room temperature to define solution 1; will weigh the CH3COONa、Bi(NO3)3·5H2O、Fe(NO3)3·9H2Dissolving O in 11.26 ml of ethylene glycol monomethyl ether, heating and stirring at 40 ℃; weighing Na2WO4·2H2Dissolving O in 8.44 ml of ethylene glycol, heating and stirring at 40 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 3.52 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions are cooled, the solution 2 and the solution 3 are added into the solution 1 in turn, and the mixture is magnetically stirred for 10 hours at room temperature to obtain Na with the concentration of 0.3 mol/L0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3Standing and aging the precursor solution for 48 hThe precursor solution is uniformly coated on Pt/Ti/SiO by a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 200 ℃, and the drying time is 3 min. Then the film is put into a rapid heating annealing furnace to carry out annealing process, wherein the annealing atmosphere is O2The annealing procedure is to maintain the temperature at 350 ℃ for 2 min and 500 ℃ for 10 min. The above "spin-dry-anneal" process was repeated 12 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Au target, and obtaining Na by a direct-current magnetron sputtering method0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3An Au top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 6 shows this Na0.5×1.01Bi0.5×1.03(Ti0.97W0.01Fe0.02)O3The X-ray diffraction pattern of the film indicated it to be a single polycrystalline perovskite phase. Fig. 7 is a hysteresis chart of the film.
Example 3
(1) Preparing a substrate and a bottom electrode
Mixing Pt/Ti/SiO2and/Si is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic treatment, and is dried by an infrared lamp for later use.
（2）Na0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3Precursor solution preparation
(a) According to Na0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3Accurately weighing 0.3542 g of CH3COONa 2.3165 g of Bi (NO)3)3·5H2O, 0.0450 g of Na2WO4·2H2O, 0.0364 g of Fe (NO)3)3·9H2O and 0.6880 g of polyethylene glycol 600 for use.
(b) Accurate and accurateMeasuring 2.27 ml of acetylacetone and 2.27 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.27 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring at room temperature for 4 hours to define a solution 1; will weigh the CH3COONa、Bi(NO3)3·5H2O、Fe(NO3)3·9H2Dissolving O in 10.91 ml of ethylene glycol monomethyl ether, heating and stirring at 50 ℃; weighing Na2WO4·2H2Dissolving O in 8.87 ml of ethylene glycol, heating and stirring at 50 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 13.41 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions were cooled, solution 2 and solution 3 were added to solution 1 in sequence and magnetically stirred at room temperature for 13 hours to obtain Na with a concentration of 0.3 mol/L0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3Standing and aging the precursor solution for 48 h, and uniformly coating the precursor solution on Pt/Ti/SiO by adopting a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 250 ℃, and the drying time is 3 min. And then putting the film in a rapid heating annealing furnace for annealing process, wherein the annealing atmosphere is air, the annealing procedure is to keep the temperature at 350 ℃ for 2 min, and keep the temperature at 520 ℃ for 8 min. The above "spin-dry-anneal" process was repeated 12 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Pt target and adopting a direct current magnetron sputtering method to obtain Na0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3A Pt top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The diameter of the top electrode is 200 mum。
FIG. 8 shows this Na0.5×1.01Bi0.5×1.04(Ti0.975W0.015Fe0.01)O3Scanning electron micrographs of the films.
Example 4
(1) Preparing a substrate and a bottom electrode
Mixing Pt/Ti/SiO2and/Si is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic treatment, and is dried by an infrared lamp for later use.
（2）Na0.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3Precursor solution preparation
(a) According to Na0.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O30.3654 g of CH are accurately weighed3COONa 1.8072 g of (CH)3CO2)3Bi. 0.0300 g of Na2WO4·2H2O, 0.0546 g Fe (NO)3)3·9H2O and 0.4514 g of polyethylene glycol 600 for use.
(b) Accurately measuring 2.27 ml of acetylacetone and 2.27 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.27 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 3 hours at room temperature to define solution 1; will weigh the CH3COONa、(CH3CO2)3Bi、Fe(NO3)3·9H2Dissolving O in 10.95 ml of ethylene glycol monomethyl ether, heating and stirring at 60 ℃; weighing Na2WO4·2H2Dissolving O in 9.02 ml of ethylene glycol, heating and stirring at 60 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 3.22 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions are cooled, the solution 2 and the solution 3 are added into the solution 1 in turn, and the mixture is magnetically stirred for 15 hours at room temperature to obtain Na with the concentration of 0.3 mol/L0.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3Standing and aging the precursor solution for 72 h, and uniformly coating the precursor solution on Pt/Ti/SiO by adopting a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 250 ℃, and the drying time is 3 min. Then the film is put into a rapid heating annealing furnace to carry out annealing process, wherein the annealing atmosphere is O2The annealing procedure is to maintain the temperature at 350 ℃ for 2 min and 500 ℃ for 10 min. The above "spin-dry-anneal" process was repeated 14 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Au target, and obtaining Na by a direct-current magnetron sputtering method0.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3An Au top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 9 shows Na in example 40.5×1.02Bi0.5×1.04(Ti0.975W0.01Fe0.015)O3Hysteresis curves of the films at different temperatures. FIG. 10 is the Δ of the filmTAnSTemperature profile. At around 138 ℃, the maximum of adiabatic temperature change and isothermal entropy change is obtained: ΔT~55 K，∆S~62 J K-1kg-1In the same refrigeration cycle, around 54 ℃, the minimum of adiabatic temperature change and isothermal entropy change is obtained: ΔT~-17 K，∆S~-26 J K-1kg-1。
Example 5
(1) Preparing a substrate and a bottom electrode
(a) Fluorocrystal Mica (Mica) with the thickness of less than 50 mu m is selected as a substrate, sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 10 min respectively by ultrasonic treatment, and dried by an infrared lamp for later use.
(b) Preparation of TiO2Precursor solution: 0.30 ml of acetylacetone and 0.89 ml of tetraisopropyl titanate are added successively to 28.81 ml of ethylene glycol monomethyl ether and stirred for 1 h to obtain TiO with a concentration of 0.1 mol/L2And (5) precursor solution for later use.
(c) Uniformly coating the precursor solution on the bottom electrode by adopting a spin coating method at the rotating speed of 3000 revolutions per minute for 30 s, then drying at the drying temperature of 250 ℃ for 3 min, then carrying out annealing treatment at the annealing temperature of 450 ℃ for 8 min, repeating the processes of spin coating, drying and annealing for 4 times to obtain TiO2Mica, for use.
(d) By direct current magnetron sputtering on TiO2Depositing a Pt film on Mica in an atmosphere of Ar, wherein the vacuum degree is 0.05mbar, the current is 30mA, and the thickness of a bottom electrode is 80 nm; the atmosphere is N when the bottom electrode is pretreated2The temperature is 500 ℃ and the time is 8 min. Obtaining Pt/TiO2Mica, for use.
（2）Na0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3Precursor solution preparation
(a) According to Na0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O30.3579 g of CH are accurately weighed3COONa 2.2719 g of Bi (NO)3)3·5H2O, 0.0450 g of Na2WO4·2H2O, 0.0728 g of Fe (NO)3)3·9H2O and 0.9617 g of polyethylene glycol 600 for use.
(b) Accurately measuring 2.25 ml of acetylacetone and 2.25 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.25 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 3 hours at room temperature to define solution 1; will weigh the CH3COONa、Bi(NO3)3·5H2O、Fe(NO3)3·9H2Dissolving O in 10.68 ml of ethylene glycol monomethyl ether, heating and stirring at 50 ℃; weighing Na2WO4·2H2Dissolving O in 9.43 ml of ethylene glycol, heating and stirring at 50 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 3.14 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions were cooled, solution 2 and solution 3 were added to solution 1 in sequence and magnetically stirred at room temperature for 11 h to obtain Na with a concentration of 0.3 mol/L0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3Standing and aging the precursor solution for 72 h, and uniformly coating the precursor solution on Pt/Ti/SiO by adopting a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 250 ℃, and the drying time is 3 min. And then putting the film in a rapid heating annealing furnace for annealing process, wherein the annealing atmosphere is air, the annealing procedure is to keep the temperature at 350 ℃ for 2 min, and the annealing procedure at 550 ℃ for 6 min. The above "spin-dry-anneal" process was repeated 14 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Pt target and adopting a direct current magnetron sputtering method to obtain Na0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3A Pt top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 11 shows Na in this example0.5×1.02Bi0.5×1.02(Ti0.965W0.015Fe0.02)O3Dielectric coefficient of the film versus electric field strength. FIG. 12 is a diagram showing a ferroelectric hysteresis loop of the thin film.
Example 6
(1) Preparing a substrate and a bottom electrode
Pick Pt up and reserveTi/SiO2and/Si is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 20min respectively by ultrasonic treatment, and is dried by an infrared lamp for later use.
（2）Na0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3Precursor solution preparation
(a) According to Na0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O30.3617 g of CH are accurately weighed3COONa 2.2719 g of Bi (NO)3)3·5H2O, 0.0300 g of Na2WO4·2H2O, 0.0364 g of Fe (NO)3)3·9H2O and 0.6750 g of polyethylene glycol 600 for use.
(b) Accurately measuring 2.28 ml of acetylacetone and 2.28 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.28 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 5 hours at room temperature to define solution 1; will weigh the CH3COONa、Bi(NO3)3·5H2O、Fe(NO3)3·9H2Dissolving O in 10.69 ml of ethylene glycol monomethyl ether, heating and stirring at 60 ℃; weighing Na2WO4·2H2Dissolving O in 9.50 ml of ethylene glycol, heating and stirring at 60 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 2.97 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions are cooled, the solution 2 and the solution 3 are added into the solution 1 in turn, and the mixture is magnetically stirred for 12 hours at room temperature to obtain Na with the concentration of 0.3 mol/L0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3Standing and aging the precursor solution for 72 h, and then adopting a spin-coating method to carry outThe precursor solution is uniformly coated on Pt/Ti/SiO2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 250 ℃, and the drying time is 3 min. And then putting the film in a rapid heating annealing furnace for annealing process, wherein the annealing atmosphere is air, the annealing procedure is to keep the temperature at 350 ℃ for 2 min, and the annealing procedure at 550 ℃ for 6 min. The above "spin-dry-anneal" process was repeated 16 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Au target, and obtaining Na by a direct-current magnetron sputtering method0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3An Au top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 13 shows Na in this example0.5×1.01Bi0.5×1.02(Ti0.98W0.01Fe0.01)O3Dielectric spectroscopy of the film.
Example 7
(1) Preparing a substrate and a bottom electrode
(a) Fluorocrystal Mica (Mica) with the thickness of less than 50 mu m is selected as a substrate, sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 30min respectively by ultrasonic waves, and dried by an infrared lamp for later use.
(b) Preparation of TiO2Precursor solution: 0.30 ml of acetylacetone and 0.89 ml of tetraisopropyl titanate are added successively to 28.81 ml of ethylene glycol monomethyl ether and stirred for 5h to obtain TiO with a concentration of 0.1 mol/L2And (5) precursor solution for later use.
(c) Uniformly coating the precursor solution on the bottom electrode by adopting a spin coating method at the rotating speed of 3000 revolutions per minute for 30 s, then drying at the drying temperature of 250 ℃ for 3 min, then carrying out annealing treatment at the annealing temperature of 450 ℃ for 8 min, repeating the processes of spin coating, drying and annealing for 4 times to obtain TiO2Mica, for use.
(d) By direct current magnetron sputtering on TiO2Depositing a Pt film on Mica in an atmosphere of Ar, wherein the vacuum degree is 0.05mbar, the current is 30mA, and the thickness of a bottom electrode is 80 nm; the atmosphere is N when the bottom electrode is pretreated2The temperature is 500 ℃ and the time is 8 min. Obtaining Pt/TiO2Mica, for use.
（2）Na0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3Precursor solution preparation
(a) According to Na0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O30.3486 g of CH are accurately weighed3COONa 1.7550 g of (CH)3CO2)3Bi. 0.0600 g of Na2WO4·2H2O, 0.0728 g of Fe (NO)3)3·9H2O and 0.6709 g of polyethylene glycol 600 for use.
(b) Accurately measuring 2.24 ml of acetylacetone and 2.24 ml of ethylene glycol methyl ether in a beaker, dropwise adding 2.24 ml of tetraisopropyl titanate into the acetylacetone, and magnetically stirring for 5 hours at room temperature to define solution 1; will weigh the CH3COONa、(CH3CO2)3Bi、Fe(NO3)3·9H2Dissolving O in 10.48 ml of ethylene glycol monomethyl ether, heating and stirring at 70 ℃; weighing Na2WO4·2H2Dissolving O in 9.89 ml of ethylene glycol, heating and stirring at 70 ℃; mixing the two solutions immediately after the two solutions are completely dissolved, and defining the solution as a solution 2; polyethylene glycol 600 was dissolved in 2.91 ml of acetic acid and stirred at room temperature until completely dissolved, defined as solution 3.
(c) After all the solutions are cooled, the solution 2 and the solution 3 are added into the solution 1 in turn, and the mixture is magnetically stirred for 14 hours at room temperature to obtain Na with the concentration of 0.3 mol/L0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3And (5) precursor solution for later use.
(3) Depositing a sodium bismuth titanate-based film on a bottom electrode
Mixing the obtained Na0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3Standing and aging the precursor solution for 72 h, and uniformly coating the precursor solution on Pt/Ti/SiO by adopting a spin coating method2On the surface of/Si, the rotating speed is 3000r/min, and the glue homogenizing time is 30 s. Then, the film is placed on a hot plate to be dried, the drying temperature is 250 ℃, and the drying time is 3 min. Then the film is put into a rapid heating annealing furnace to carry out annealing process, wherein the annealing atmosphere is O2The annealing procedure is to maintain the temperature at 350 ℃ for 2 min and 520 ℃ for 8 min. The above "spin-dry-anneal" process was repeated 16 times.
(4) Depositing a top electrode on a sodium bismuth titanate-based thin film
Adopting a metal Pt target and adopting a direct current magnetron sputtering method to obtain Na0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3A Pt top electrode was deposited on the film. The atmosphere during deposition was Ar, the vacuum was 0.05mbar, and the current was 30 mA. The top electrode diameter was 200 μm.
FIG. 14 shows Na0.5×1.015Bi0.5×1.01(Ti0.96W0.02Fe0.02)O3Hysteresis curves at different temperatures of the film.
FIG. 15 is the Δ of the filmTAnSTemperature profile. At around 140 ℃, the maximum of adiabatic temperature change and isothermal entropy change is obtained: ΔT~49 K，∆S~55 J K-1kg-1。

Claims (10)

1. The sodium bismuth titanate-based film with positive and negative electrocaloric effects is characterized in that sodium bismuth titanate is used as a base material, and iron ions and tungsten ions are compositely introduced into a B site.
2. The sodium bismuth titanate-based film according to claim 1, wherein the general composition formula of the film is Na0.5×aBi0.5×b(Ti1-x-yWxFey)O3Wherein a is more than or equal to 1.01 and less than or equal to 1.02, b is more than or equal to 1.01 and less than or equal to 1.04, x is more than or equal to 0.01 and less than or equal to 0.02, and y is more than or equal to 0.01 and less than or equal to 0.02.
3. A method for preparing a sodium bismuth titanate-based thin film according to claim 1, comprising the steps of:
(1) preparing a bottom electrode;
（2）Na0.5×aBi0.5×b(Ti1-x-yWxFey)O3preparing a precursor solution:
(a) selecting sodium acetate, bismuth acetate or bismuth nitrate, ferric nitrate, sodium tungstate, and tetraisopropyl titanate as raw materials according to Na0.5× aBi0.5×b(Ti1-x-yWxFey)O3Accurately weighing the raw materials according to the stoichiometric ratio;
(b) firstly, measuring acetylacetone and ethylene glycol monomethyl ether in a beaker, adding tetraisopropyl titanate into the beaker, and stirring the mixture for 3 to 5 hours at room temperature to define a solution 1;
dissolving the weighed bismuth acetate or bismuth nitrate, sodium acetate and ferric nitrate into ethylene glycol monomethyl ether, and heating and stirring at 40-70 ℃; dissolving the weighed sodium tungstate into ethylene glycol, and heating and stirring at 40-70 ℃; mixing the two solutions after the two solutions are completely dissolved, and defining the solution as a solution 2;
weighing polyethylene glycol 600, dissolving in acetic acid, and stirring at room temperature until the polyethylene glycol is completely dissolved to obtain a solution 3;
(c) after all the solutions are cooled to room temperature, adding the solution 2 and the solution 3 into the solution 1, and stirring for 10-15 hours at room temperature to obtain a precursor solution for later use;
(3) depositing a sodium bismuth titanate-based film on a bottom electrode
Uniformly spin-coating the precursor solution on the bottom electrode, then placing on a hot plate for drying, then performing an annealing process, and repeating the processes of spin-coating, drying and annealing;
(4) depositing a top electrode on a sodium bismuth titanate-based thin film
And depositing a top electrode on the sodium bismuth titanate-based film by adopting a metal Pt or Au target and using a direct-current magnetron sputtering method.
4. The method according to claim 3, wherein the bottom electrode is Pt/Ti/SiO2/Si or Pt/TiO2/Mica。
5. The preparation method of claim 4, wherein the bottom electrode is sequentially placed in a mixed solution of absolute ethyl alcohol and acetone and deionized water for 10-30min before use, and is dried by an infrared lamp.
6. The method according to claim 4, wherein the Pt/TiO is used as a catalyst2The preparation method of the/Mica substrate comprises the following steps:
selecting fluorine crystal Mica (Mica) with the thickness less than 50 mm as a substrate;
preparation of TiO2Precursor solution: successively adding acetylacetone and tetraisopropyl titanate into ethylene glycol monomethyl ether, and stirring to obtain TiO2Precursor solution for later use;
adding TiO into the mixture2The precursor solution is coated on Mica in a spinning way, then is dried and is annealed, and the process of spinning, drying and annealing is repeated for 3 to 5 times to obtain TiO2Mica for standby;
by direct current magnetron sputtering on TiO2Depositing Pt film on Mica to obtain Pt/TiO2/Mica。
7. The method according to claim 6, wherein the TiO is prepared2The precursor solution is prepared by sequentially adding 0.30 ml of acetylacetone and 0.89 ml of tetraisopropyl titanate into 28.81 ml of ethylene glycol monomethyl ether, and stirring for 1-5h to obtain TiO with the concentration of 0.1 mol/L2And (3) precursor solution.
8. The production method according to claim 6,
the spin coating speed is 3000r/min, and the time is 30 s; the drying temperature is 250 ℃, and the drying time is 3 min; the annealing temperature is 450 ℃, and the annealing time is 8 min;
the method of direct current magnetron sputtering is used for preparing the titanium dioxide on TiO2Deposition of Pt film on MicaThe number is as follows: when the bottom electrode is deposited by the direct current magnetron sputtering, the atmosphere is Ar, the vacuum degree is 0.05mbar, the current is 30mA, and the thickness of the bottom electrode is 80 nm; the atmosphere is N when the bottom electrode is pretreated2The temperature is 500 ℃ and the time is 8 min.
9. The method according to claim 3, wherein in the step (3), the spin coating is performed at a rotation speed of 3000 rpm for 30 seconds; the drying temperature is 200 ℃, and the drying time is 3 min; the pretreatment temperature is 350 ℃, the pretreatment time is 2 min, and the annealing atmosphere is air or O2The annealing temperature is 500-550 ℃, and the annealing time is 6-10 min.
10. The method according to claim 3, wherein the top electrode is deposited in step (4) under Ar atmosphere with a vacuum of 0.05mbar and with a current of 30mA, and the top electrode has a diameter of 200 μm.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112062563A (en) * 2020-09-17 2020-12-11 广西大学 Preparation method of PSINT-based high-entropy ferroelectric thin film material
CN112062554A (en) * 2020-09-17 2020-12-11 广西大学 Preparation method of PSTT-based high-performance ceramic electrocaloric refrigeration material

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007099279A1 (en) * 2006-03-01 2007-09-07 Alexandr Mishchenko Thick and thin films for power generation and cooling
US20090062114A1 (en) * 2007-09-05 2009-03-05 Takami Arakawa Perovskite type oxide, ferroelectric film, process for producing same, ferroelectric device, and liquid discharge apparatus
CN104987064A (en) * 2015-08-13 2015-10-21 内蒙古科技大学 Sodium-bismuth-titanate-based unleaded ceramic with negative electrocaloric effect and preparing method of sodium-bismuth-titanate-based unleaded ceramic
CN106554202A (en) * 2016-11-14 2017-04-05 山东大学 A kind of bismuth laminated bismuth-sodium titanate high temperature piezoceramics and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007099279A1 (en) * 2006-03-01 2007-09-07 Alexandr Mishchenko Thick and thin films for power generation and cooling
US20090062114A1 (en) * 2007-09-05 2009-03-05 Takami Arakawa Perovskite type oxide, ferroelectric film, process for producing same, ferroelectric device, and liquid discharge apparatus
CN104987064A (en) * 2015-08-13 2015-10-21 内蒙古科技大学 Sodium-bismuth-titanate-based unleaded ceramic with negative electrocaloric effect and preparing method of sodium-bismuth-titanate-based unleaded ceramic
CN106554202A (en) * 2016-11-14 2017-04-05 山东大学 A kind of bismuth laminated bismuth-sodium titanate high temperature piezoceramics and preparation method thereof

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CHANGHONG YANG等: "Toward Multifunctional Electronics: Flexible NBT-Based Film with a Large Electrocaloric Effect and High Energy Storage Property", 《ACS APPLIED MATERIALS & INTERFACES》 *
QIAN YAO等: "Structural, ferroelectric and dielectric properties of Na0.5Bi0.5(Ti0.98Fe0.02)O3 thin films on different substrates", 《J MATER SCI: MATER ELECTRON》 *
Y.J. HAN等: "Compensation for volatile elements to modify the microstructure and energy storage performance of (W,Ni)-codoped Na0.5Bi0.5TiO3ceramicfilms", 《CERAMICS INTERNATIONAL》 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112062563A (en) * 2020-09-17 2020-12-11 广西大学 Preparation method of PSINT-based high-entropy ferroelectric thin film material
CN112062554A (en) * 2020-09-17 2020-12-11 广西大学 Preparation method of PSTT-based high-performance ceramic electrocaloric refrigeration material
CN112062554B (en) * 2020-09-17 2022-08-19 广西大学 Preparation method of PSTT-based high-performance ceramic electrocaloric refrigeration material

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