Layered periodic tunable bismuth-based oxide ion conductor thin film material and method of making same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF SCI & TECH BEIJING
- Filing Date
- 2024-03-05
- Publication Date
- 2026-06-05
Smart Images
Figure CN118125820B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of oxygen ion conductor thin film materials, specifically relating to bismuth-based oxygen ion conductor thin film materials with adjustable layered periodicity and their preparation methods. Background Technology
[0002] In recent years, oxide-based energy devices such as solid oxide fuel cells (SOFCs) and memristors have seen rapid development. However, the high operating temperature and poor low-temperature ionic conductivity of the key electrolyte—the ion conductor material—significantly hinders the further development of these devices. Therefore, there is an urgent need to develop high-performance oxygen ion conductor materials for low operating temperatures.
[0003] Among the many methods used to improve the ionic conductivity of ionic conductor materials at low temperatures, heterostructure engineering can precisely control ionic conductivity, while atomic-scale engineering is beneficial to the development of various thin-film superlattices with excellent ionic conductivity, such as CaF2 / BaF2 heterostructures with excellent ionic conductivity, Er2O3-stabilized Bi2O3 and Gd2O3-doped CeO2 heterostructures.
[0004] However, traditional methods for achieving atomic-level interfaces in heterostructures are difficult, involve complex processes, and require stringent process conditions. Summary of the Invention
[0005] In view of this, some embodiments disclose a bismuth-based oxygen ion conductor thin film material with adjustable layered periodicity. The bismuth-based oxygen ion thin film material has a layered periodic structure formed by repeated arrangement of multiple layered structures, wherein the layered structure includes a bismuth-oxygen layer and multiple perovskite layers arranged sequentially.
[0006] Some embodiments disclose bismuth-based oxygen ion conductor thin film materials with tunable layered periodicity, wherein the number of perovskite layers is 4 to 8.
[0007] Some embodiments disclose a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, including the following steps:
[0008] S1. Preparation of perovskite ceramic target material
[0009] Bi2O3, Na2CO3 and TiO2 are weighed and premixed in a ball mill as non-stoichiometric raw materials, wherein, in molar ratio, Bi element is in excess by 10-200% in the non-stoichiometric raw materials;
[0010] Perovskite powder was obtained by calcining non-stoichiometric raw materials in a muffle furnace.
[0011] Perovskite ceramic targets are obtained by cold isostatic pressing and sintering of perovskite powder.
[0012] S2, processing the substrate
[0013] The substrate was sequentially ultrasonically cleaned in acetone, ethanol, and deionized water solution.
[0014] The cleaned substrate was then acid-washed in a hydrofluoric acid-ammonium fluoride buffer solution.
[0015] The pickled substrate was annealed in a tube furnace with flowing oxygen to obtain a substrate with a single Ti-O cutoff surface.
[0016] S3. Preparation of layered, periodically tunable bismuth-based oxygen ion conductor thin film materials.
[0017] The perovskite ceramic target and substrate are placed in a high-vacuum pulsed laser deposition system, and the pulsed laser deposition parameters are adjusted to perform pulsed laser deposition.
[0018] During pulsed laser deposition, bismuth, sodium, titanium and oxygen generated by the excitation of the perovskite ceramic target self-assemble on the substrate to form a layered structure including a bismuth-oxygen layer and multiple perovskite layers. Multiple layered structures are arranged in sequence to obtain a bismuth-based oxygen ion conductor thin film material with a layered periodic structure.
[0019] In some embodiments, a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material is disclosed, in step S1:
[0020] The calcination temperature is 800–850℃, and the calcination time is 3–6 hours;
[0021] The pressure of cold isostatic pressing is 8–14 MPa;
[0022] The sintering temperature is 800–1100℃, and the sintering time is 2–6 hours.
[0023] In some embodiments of the disclosed method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, step S2 includes:
[0024] The ultrasonic cleaning time is 10–30 minutes;
[0025] The pickling time is 30-300 seconds;
[0026] The annealing temperature is 900–1100℃, and the annealing time is 1 hour.
[0027] In some embodiments, a method for preparing a layered, periodically adjustable bismuth-based oxygen ion conductor thin film material is disclosed. In step S3, the substrate is adhered to the heater with high-temperature silver paste, and the perovskite ceramic target is fixed on the target holder. The substrate and the perovskite ceramic target are placed collinearly within the spherical cavity of a high-vacuum pulsed laser deposition system. The pulsed laser deposition parameters include vacuum degree, temperature, oxygen pressure, cavity laser energy, sputtering times, and target distance.
[0028] Some embodiments disclose a method for preparing layered, periodically tunable bismuth-based oxygen ion conductor thin film materials, wherein the vacuum degree of pulsed laser deposition is set to less than 10. -3 Pa.
[0029] Some embodiments disclose a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, wherein the pulsed laser deposition temperature is set to 675–725°C.
[0030] Some embodiments disclose a method for preparing a layered, periodically adjustable bismuth-based oxygen ion conductor thin film material, wherein the oxygen pressure during pulsed laser deposition is set to 5–25 Pa.
[0031] Some embodiments disclose a method for preparing layered, periodically tunable bismuth-based oxygen ion conductor thin films, wherein the cavity laser energy of pulsed laser deposition is 0.75–2 J / cm. 2 The number of sputtering pulses is 1000 to 10000, and the target electrode distance for pulsed laser deposition is 40 to 60 mm.
[0032] The method for preparing a layered, periodically adjustable bismuth-based oxygen ion conductor thin film material disclosed in this invention achieves efficient layered periodicity adjustment by controlling the stoichiometric ratio of different elements. The process is simple, efficient, and widely applicable, requiring only a single target material and a single self-assembly molding process to form a superstructure. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material disclosed in this invention has an atomically flat surface, good physical properties, excellent low-temperature ion conductivity, and a wide range of applications. Attached Figure Description
[0033] Figure 1 A schematic diagram of the preparation method of layered periodically tunable bismuth-based oxygen ion conductor thin film material;
[0034] Figure 2 Example 1: STEM image of a partial cross-section of a bismuth-based oxygen ion conductor thin film material;
[0035] Figure 3 Example 1: Ionic conductivity of bismuth-based oxygen ion conductor thin film material;
[0036] Figure 4 Example 2: STEM image of a partial cross-section of a bismuth-based oxygen ion conductor thin film material;
[0037] Figure 5 Example 2: Ionic conductivity of bismuth-based oxygen ion conductor thin film material;
[0038] Figure 6 Example 3: STEM image of a partial cross-section of a bismuth-based oxygen ion conductor thin film material;
[0039] Figure 7 Example 3: Ionic conductivity of bismuth-based oxygen ion conductor thin film material.
[0040] Figure Labels
[0041] 1. Bismuth-oxygen layer 2. Perovskite layer Detailed Implementation
[0042] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.
[0043] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.
[0044] The terms “basic” and “approximately” used in this document are to describe small fluctuations. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in range format in this document are used for convenience and brevity only, and should therefore be flexibly interpreted to include not only the explicitly listed values that define the range, but also all independent values or subranges contained within that range. For example, a numerical range of “1–5%” should be interpreted to include not only the explicitly listed values from 1% to 5%, but also the independent values and subranges within the indicated range. Thus, this numerical range includes independent values such as 2%, 3.5%, and 4%, and subranges such as 1%–3%, 2%–4%, and 3%–5%, etc. This principle also applies to ranges that list only one value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.
[0045] In this document, including in the claims, conjunctions such as "comprising," "including," "with," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "consisting of" and "composed of" are closed conjunctions.
[0046] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.
[0047] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the content disclosed in the embodiments of this application. It should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" used in this application indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing technical features and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention unless they conflict with the context. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance unless they conflict with the context.
[0048] In some embodiments, the bismuth-based oxygen ion conductor thin film material with tunable layered periodicity has a layered periodic structure formed by repeated arrangement of multiple layered structures, wherein the layered structure includes a bismuth-oxygen layer and multiple perovskite layers arranged sequentially. In the layered periodic structure, multiple perovskite layers are disposed in every two adjacent bismuth-oxygen layers.
[0049] In some embodiments, the bismuth-oxygen layer is a Bi2O2 bismuth-oxygen layer.
[0050] In some embodiments, the perovskite layer is Na 0.5 Bi 0.5 TiO3 perovskite layer.
[0051] In some embodiments, the number of perovskite layers in a layered structure is 4 to 8.
[0052] In some implementations, such as Figure 1 As shown, the preparation method of the layered periodically tunable bismuth-based oxygen ion conductor thin film material includes the following steps:
[0053] S1. Preparation of perovskite ceramic target material
[0054] Weigh out Bi₂O₃, Na₂CO₃, and TiO₂ and premix them in a ball mill to form a non-stoichiometric raw material Bi. 0.5+x Na 0.5 TiO 3+δIn terms of molar ratio, the Bi element in the non-stoichiometric raw material is in excess by 10-200%, that is, [(0.5+x)-0.5] / 0.5 is 10-200%, where δ=3x / 2; from the perspective of charge balance, δ=3x / 2. The actual preparation process is carried out in an oxygen atmosphere, and the oxygen content is not critical, but the oxygen content will fluctuate.
[0055] Perovskite powder was obtained by calcining non-stoichiometric raw materials in a muffle furnace.
[0056] Perovskite ceramic targets are obtained by cold isostatic pressing and sintering of perovskite powder. Generally, the molar amount of bismuth in the obtained perovskite ceramic targets is the same as the molar amount of bismuth in the non-stoichiometric raw materials.
[0057] S2, processing the substrate
[0058] The substrate was ultrasonically cleaned sequentially in acetone, ethanol, and deionized water; generally, commercially available STO or NSTO single-crystal substrates were selected.
[0059] The cleaned substrate is acid-washed in hydrofluoric acid-ammonium fluoride buffer solution, which can directionally etch out Ti-O stop surfaces with a stepped structure.
[0060] Annealing the acid-washed substrate in a tube furnace with flowing oxygen to obtain a substrate with a single Ti-O cutoff surface is beneficial for the growth of high-quality bismuth-based oxygen ion conductor films.
[0061] S3. Preparation of layered, periodically tunable bismuth-based oxygen ion conductor thin film materials.
[0062] The perovskite ceramic target and substrate are placed in a high-vacuum pulsed laser deposition system, and the pulsed laser deposition parameters are adjusted to perform pulsed laser deposition.
[0063] During pulsed laser deposition, bismuth, sodium, titanium, and oxygen generated by the excitation of a perovskite ceramic target self-assemble on the substrate to form a layered structure consisting of a bismuth-oxygen layer and multiple perovskite layers. Multiple layered structures are sequentially repeated to obtain a bismuth-based oxygen ion conductor thin film material with a layered periodic structure. In the tunable layered periodic bismuth-based oxygen ion conductor thin film material, multiple perovskite layers are continuously distributed between adjacent bismuth-oxygen layers. The layered structure formed by the bismuth-oxygen layer and the perovskite layer has a periodic characteristic, and the number of perovskite layers can be controlled and adjusted. The number of periods in the bismuth-based oxygen ion conductor thin film material structure can be determined based on the number of perovskite layers.
[0064] Generally, the fabricated layered, periodically tunable bismuth-based oxygen ion conductor thin film material needs to undergo in-plane interdigitated electrode construction and AC impedance spectroscopy analysis to determine its electrical properties; among which, the in-plane interdigitated electrode construction includes:
[0065] Pt metal interdigitated electrodes were sputtered onto the surface of the prepared layered periodically tunable bismuth-based oxygen ion conductor thin film material by magnetron sputtering; the channel spacing of the Pt metal interdigitated electrodes was 100-1000 μm and the thickness was 50-200 nm.
[0066] AC impedance spectroscopy tests are conducted in different atmospheres such as air, oxygen, or nitrogen, and the perturbation voltage for AC impedance spectroscopy tests is 10–100 mV.
[0067] In some implementations, in step S1:
[0068] The calcination temperature is 800–850℃, and the calcination time is 3–6 hours;
[0069] The pressure of cold isostatic pressing is 8–14 MPa;
[0070] The sintering temperature is 800–1100℃, and the sintering time is 2–6 hours.
[0071] In some implementations, in step S2:
[0072] The ultrasonic cleaning time is 10–30 minutes;
[0073] The pickling time is 30-300 seconds; if the pickling time is less than 30 seconds, atomic-level steps will not appear on the substrate surface.
[0074] The annealing temperature is 900–1100℃, and the annealing time is 1 hour.
[0075] In some embodiments, in step S3, the substrate is bonded to the heater with high-temperature silver paste, the perovskite ceramic target is fixed on the target holder, and the substrate and the perovskite ceramic target are placed collinearly in the spherical cavity of the high-vacuum pulsed laser deposition system; the pulsed laser deposition parameters include vacuum degree, temperature, oxygen pressure, cavity laser energy, sputtering times and target distance.
[0076] In some implementations, the vacuum level of pulsed laser deposition is set to less than 10. -3 Pa, generally, the vacuum level is evacuated to 10 Pa using mechanical pumps and molecular pumps. -3 Below Pa.
[0077] In some implementations, the temperature for pulsed laser deposition is set to 675–725°C.
[0078] In some implementations, the oxygen pressure for pulsed laser deposition is set to 5–25 Pa.
[0079] In some embodiments, the cavity laser energy for pulsed laser deposition is 0.75–2 J / cm². 2The number of sputtering pulses is 1000 to 10000, and the target distance for pulsed laser deposition is 40 to 60 mm.
[0080] The technical details are further illustrated below with reference to the embodiments.
[0081] Example 1
[0082] Figure 2 This is a partial cross-sectional STEM image of the bismuth-based oxygen ion conductor thin film material disclosed in Example 1; Figure 3 The diagram shows the ionic conductivity of the bismuth-based oxygen ion conductor thin film material disclosed in Example 1.
[0083] This embodiment 1 discloses a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, including:
[0084] 12.4564 g Bi₂O₃, 0.9445 g Na₂CO₃, and 2.8467 g TiO₂ were premixed in a ball mill at 350 r / min for 6 h, and then calcined in a muffle furnace at 820 °C for 4 h to obtain perovskite powder. The perovskite powder was placed in an agate mortar and ground with PVA binder, and then cold isostatically pressed into a perovskite target with a diameter of one inch under a pressure of 14 MPa. The perovskite target was sintered at 820 °C for 4 h to obtain a dense perovskite ceramic target with a bismuth molar excess of 100-200%.
[0085] Commercial single-crystal strontium titanate substrates were ultrasonically cleaned in acetone, ethanol and deionized water for 10 mins in sequence, then acid-washed in hydrofluoric acid-ammonium fluoride buffer for 30 s. The acid-washed commercial single-crystal strontium titanate substrates were cleaned again with deionized water, and then annealed in a tube furnace at 1000℃ with flowing oxygen for 1 h to obtain strontium titanate substrates with a single Ti-O cut-off surface.
[0086] The treated strontium titanate substrate was adhered to the heater using high-temperature silver paste. The perovskite ceramic target was fixed to the target holder. The substrate and the perovskite ceramic target were placed collinearly within the spherical cavity of the high-vacuum pulsed laser deposition system. The target electrode distance was adjusted to 50 mm, the temperature was heated to 700 °C, and the vacuum level of the spherical cavity was evacuated to 10 using a mechanical pump and a molecular pump. -3 Below Pa; when the heating temperature reaches 700℃, the back vacuum is 10. -4 Pa, with flowing oxygen introduced, and the oxygen pressure inside the spherical cavity dynamically maintained at 10 Pa by adjusting the flow meter and gate valve; laser parameters are set, and the laser energy entering the cavity is adjusted to 1.25 J / cm². 2 Then, the sputtering frequency is controlled to be 1000–4000 pulses to achieve a bismuth-based oxygen ion conductor thin film thickness of 20–80 nm; as shown... Figure 2The bismuth-based oxygen ion conductor thin film material shown has four perovskite layers 2 continuously distributed between two adjacent bismuth-oxygen layers 1.
[0087] Pt metal interdigitated electrodes were magnetron sputtered onto the surface of the prepared bismuth-based oxygen ion conductor thin film. The interdigitated electrodes had a channel spacing of 150 μm and a thickness of 100 nm. AC impedance spectroscopy was then performed under different atmospheres (air, oxygen, and nitrogen) with a perturbation voltage of 50 mV. The test results are as follows: Figure 3 As shown, the bismuth-based oxygen ion conductor thin film material prepared in Example 1 exhibits excellent low-to-medium temperature ionic conductivity, with an ionic conductivity greater than 0.01 S cm⁻¹ at 400°C. -1 Typically, the temperature at which ionic conductivity reaches 0.01 Scm⁻¹ can be compared; the lower the temperature, the better the ionic conductivity.
[0088] Example 2
[0089] Figure 4 This is a partial cross-sectional STEM image of the bismuth-based oxygen ion conductor thin film material disclosed in Example 2.
[0090] This embodiment 2 discloses a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, including:
[0091] 11.0473 g Bi₂O₃, 1.2564 g Na₂CO₃, and 3.7870 g TiO₂ were premixed in a ball mill at 350 r / min for 6 h, and then calcined in a muffle furnace at 820 °C for 4 h to obtain perovskite powder. The perovskite powder was placed in an agate mortar and ground with PVA binder, and then cold isostatically pressed into a perovskite target with a diameter of one inch under a pressure of 14 MPa. The perovskite target was sintered at 850 °C for 4 h to obtain a dense perovskite ceramic target with a bismuth molar excess of 60-80%.
[0092] Commercial single-crystal strontium titanate substrates were ultrasonically cleaned in acetone, ethanol and deionized water for 10 mins in sequence, then acid-washed in hydrofluoric acid-ammonium fluoride buffer for 30 s. The acid-washed commercial single-crystal strontium titanate substrates were cleaned again with deionized water, and then annealed in a tube furnace at 1000℃ with flowing oxygen for 1 h to obtain strontium titanate substrates with a single Ti-O cut-off surface.
[0093] The treated strontium titanate substrate was adhered to the heater using high-temperature silver paste. The perovskite ceramic target was fixed to the target holder. The substrate and the perovskite ceramic target were placed collinearly within the spherical cavity of the high-vacuum pulsed laser deposition system. The target electrode distance was adjusted to 50 mm, the temperature was heated to 700 °C, and the vacuum level of the spherical cavity was evacuated to 10 using a mechanical pump and a molecular pump. -3Below Pa; when the heating temperature reaches 700℃, the back vacuum is 10. -4 Pa, with flowing oxygen introduced, and the oxygen pressure inside the spherical cavity dynamically maintained at 10 Pa by adjusting the flow meter and gate valve; laser parameters are set, and the laser energy entering the cavity is adjusted to 1.25 J / cm². 2 Then, the sputtering frequency is controlled to be 1000–4000 pulses to achieve a bismuth-based oxygen ion conductor thin film thickness of 20–80 nm; as shown... Figure 4 The bismuth-based oxygen ion conductor thin film material shown has five perovskite layers 2 continuously distributed between two adjacent bismuth-oxygen layers 1.
[0094] Pt metal interdigitated electrodes were magnetron sputtered onto the surface of the prepared bismuth-based oxygen ion conductor thin film. The interdigitated electrodes had a channel spacing of 150 μm and a thickness of 100 nm. AC impedance spectroscopy was then performed under different atmospheres (air, oxygen, and nitrogen) with a perturbation voltage of 50 mV. The test results are as follows: Figure 5 As shown.
[0095] Example 3
[0096] Figure 6 This is a partial cross-sectional STEM image of the bismuth-based oxygen ion conductor thin film material disclosed in Example 3.
[0097] This embodiment 1 discloses a method for preparing a layered, periodically tunable bismuth-based oxygen ion conductor thin film material, including:
[0098] 9.9245 g Bi₂O₃, 1.5050 g Na₂CO₃, and 4.5362 g TiO₂ were premixed in a ball mill at 350 r / min for 6 h, and then calcined in a muffle furnace at 820 °C for 4 h to obtain perovskite powder. The perovskite powder was placed in an agate mortar and ground with PVA binder, and then cold isostatically pressed into a perovskite target with a diameter of one inch under a pressure of 14 MPa. The perovskite target was sintered at 950 °C for 4 h to obtain a dense perovskite ceramic target with a bismuth molar excess of 40-50%.
[0099] Commercial single-crystal strontium titanate substrates were ultrasonically cleaned in acetone, ethanol and deionized water for 10 mins in sequence, then acid-washed in hydrofluoric acid-ammonium fluoride buffer for 30 s. The acid-washed commercial single-crystal strontium titanate substrates were cleaned again with deionized water, and then annealed in a tube furnace at 1000℃ with flowing oxygen for 1 h to obtain strontium titanate substrates with a single Ti-O cut-off surface.
[0100] The treated strontium titanate substrate was adhered to the heater using high-temperature silver paste. The perovskite ceramic target was fixed to the target holder. The substrate and the perovskite ceramic target were placed collinearly within the spherical cavity of the high-vacuum pulsed laser deposition system. The target electrode distance was adjusted to 50 mm, the temperature was heated to 700 °C, and the vacuum level of the spherical cavity was evacuated to 10 using a mechanical pump and a molecular pump. -3 Below Pa; when the heating temperature reaches 700℃, the back vacuum is 10. -4 Pa, with flowing oxygen introduced, and the oxygen pressure inside the spherical cavity dynamically maintained at 10 Pa by adjusting the flow meter and gate valve; laser parameters are set, and the laser energy entering the cavity is adjusted to 1.25 J / cm². 2 Then, the sputtering frequency is controlled to be 1000–4000 pulses to achieve a bismuth-based oxygen ion conductor thin film thickness of 20–80 nm; as shown... Figure 6 The bismuth-based oxygen ion conductor thin film material shown has eight perovskite layers 2 continuously distributed between two adjacent bismuth-oxygen layers 1.
[0101] Pt metal interdigitated electrodes were magnetron sputtered onto the surface of the prepared bismuth-based oxygen ion conductor thin film. The interdigitated electrodes had a channel spacing of 150 μm and a thickness of 100 nm. AC impedance spectroscopy was then performed under different atmospheres (air, oxygen, and nitrogen) with a perturbation voltage of 50 mV. The test results are as follows: Figure 7 As shown.
[0102] The method for preparing a layered, periodically adjustable bismuth-based oxygen ion conductor thin film material disclosed in this invention achieves efficient layered periodicity adjustment by controlling the stoichiometric ratio of different elements. The process is simple, efficient, and widely applicable, requiring only a single target material and a single self-assembly molding process to form a superstructure. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material disclosed in this invention has an atomically flat surface, good physical properties, excellent low-temperature ion conductivity, and a wide range of applications.
[0103] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.
Claims
1. A layered, periodically tunable bismuth-based oxygen ion conductor thin film material, characterized in that, The bismuth-based oxygen ion thin film material has a layered periodic structure formed by repeated arrangement of multiple layered structures, wherein the layered structure includes a bismuth-oxygen layer and multiple perovskite layers arranged sequentially. The method for preparing the layered, periodically tunable bismuth-based oxygen ion conductor thin film material includes the following steps: S1. Preparation of perovskite ceramic target material Bi2O3, Na2CO3 and TiO2 are weighed and premixed in a ball mill as non-stoichiometric raw materials, wherein, in molar ratio, Bi is in excess by 10-200% in the non-stoichiometric raw materials; The non-stoichiometric raw materials are calcined in a muffle furnace to obtain perovskite powder; the calcination temperature is 800-850℃ and the calcination time is 3-6 hours. The perovskite powder is cold isostatically pressed and sintered to obtain a perovskite ceramic target; the pressure of the cold isostatic pressing is 8-14 MPa; the sintering temperature is 800-1100℃; and the sintering time is 2-6 h. S2, processing the substrate The substrate was sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning; the ultrasonic cleaning time was 10–30 mins. The cleaned substrate was then placed in a hydrofluoric acid-ammonium fluoride buffer solution for acid washing; the acid washing time was 30-300 s. The pickled substrate is annealed in a tube furnace with flowing oxygen to obtain a substrate with a single Ti-O cutoff surface; the annealing temperature is 900-1100℃ and the annealing time is 1h. S3. Preparation of layered, periodically tunable bismuth-based oxygen ion conductor thin film materials. The perovskite ceramic target and the substrate are placed in a high-vacuum pulsed laser deposition system, and the pulsed laser deposition parameters are adjusted to perform pulsed laser deposition. During pulsed laser deposition, the perovskite ceramic target is excited to generate bismuth, sodium, titanium and oxygen, which self-assemble on the substrate to form a layered structure including a bismuth-oxygen layer and multiple perovskite layers. Multiple layered structures are arranged in sequence to obtain a bismuth-based oxygen ion conductor thin film material with a layered periodic structure.
2. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 1, characterized in that, The number of perovskite layers is 4 to 8.
3. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 1, characterized in that, In step S3, the substrate is bonded to the heater with high-temperature silver paste, the perovskite ceramic target is fixed on the target holder, and the substrate and the perovskite ceramic target are placed collinearly in the spherical cavity of the high-vacuum pulsed laser deposition system; the pulsed laser deposition parameters include vacuum degree, temperature, oxygen pressure, cavity laser energy, sputtering times and target distance.
4. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 3, characterized in that, The vacuum level is set to less than 10. -3 Pa.
5. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 3, characterized in that, The temperature is set to 675–725°C.
6. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 3, characterized in that, The oxygen pressure is set to 5–25 Pa.
7. The layered, periodically adjustable bismuth-based oxygen ion conductor thin film material according to claim 3, characterized in that, The cavity laser energy is set to 0.75–2 J / cm². 2 The number of sputtering pulses is set to 1,000 to 10,000, and the target distance is set to 40 to 60 mm.