Lead scandium tantalate film with high energy storage performance and high electrocaloric performance and preparation method of lead scandium tantalate film
The preparation of lead scandium tantalum films through sol-gel method and layer-by-layer annealing solves the problems of insufficient energy density and high production cost of ferroelectric films, achieving high energy storage and high electric card effects, and is suitable for dielectric energy storage and thermal management of electronic devices.
Patent Information
- Application Number
- CN202510588775.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2025-07-08
AI Technical Summary
The energy density of existing ferroelectric films needs to be improved, the preparation method is complex and costly, and the traditional refrigeration method is low in efficiency. We look for materials that have high energy storage and high electric card effects and simple and low-cost preparation methods.
The lead scandium tantalum film was prepared by the sol-gel method. Through layer by layer annealing treatment, the annealing temperature was between 700-850℃, and a lead scandium tantalum film with high energy storage and high electrical card performance was prepared.
Achieve high energy storage density and adiabatic temperature change in a wide temperature zone, reduce production costs, and is suitable for dielectric energy storage and thermal management of electronic devices, with good application prospects.
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Abstract
Description
Technical Field
[0001] This application belongs to the field of electronic functional materials and devices, and specifically relates to a lead scandium tantalate thin film with both high energy storage and high electrocaloric performance and a preparation method thereof. Background Art
[0002] Energy storage pulsed power capacitors have extremely important applications in frontier fields such as laser technology, nuclear technology, accelerators, and electron beams, and they need to meet the performance of storing and releasing a large amount of energy in an extremely short time. Among various devices that can be used for energy storage, ferroelectric thin film capacitors stand out with their ultra-fast charge and discharge speed and ultra-high power density, and play an important role in electronic circuits. However, the energy density of ferroelectric thin films needs to be improved. Therefore, seeking materials with high energy storage density, high energy storage efficiency, and good temperature stability is an important research direction for realizing miniaturization and integration of energy storage. On the other hand, the current refrigeration still uses the air compression refrigeration method, which has problems such as low efficiency, high noise, large volume, and heavy pollution. With the miniaturization and integration of electronic devices, the heat generation phenomenon becomes more significant, which will seriously affect the working performance and service life of the devices. Therefore, there is an urgent need for a compact and efficient thermal management technology. The electrocaloric effect refers to the phenomenon that the temperature of a material changes by changing the entropy value of dipoles under adiabatic conditions through an electric field. The solid-state refrigeration technology using the electrocaloric effect has the advantages of being miniaturizable, high working efficiency, and noise-free, and is expected to replace traditional refrigeration technology. Therefore, seeking electrocaloric materials with a large electrocaloric effect and good temperature stability is of great significance.
[0003] Among inorganic ferroelectric thin films, lead-based materials can obtain high polarization values and high electrocaloric temperature changes at low electric fields. In addition, they also have good cycling performance. Therefore, compared with organic materials, lead-based thin films have better advantages in dielectric energy storage and low-energy-consumption electrocaloric refrigeration. Among them, the advantage of lead scandium tantalate (PbSc 0.5 Ta 0.5 O3, PST) materials is that their Curie temperature is near room temperature and the polarization value is relatively high, which creates conditions for obtaining high energy storage performance and high electrocaloric effect. In addition, the polarization intensity and breakdown field strength can be regulated through process optimization, which is also an effective means to improve the electrocaloric effect. In addition, at present, the thin film preparation methods mainly include magnetron sputtering method, metal organic chemical vapor deposition method, etc., and their preparation processes are relatively complex, the preparation cycle is long, and the equipment is expensive. In addition, most of the sol preparation processes in the current sol-gel method require vacuum distillation, heating and stirring operations, the process is relatively complex and the cost is high. Therefore, finding a thin film preparation method with a simple preparation process and a low preparation cost is also an urgent problem to be solved. Summary of the Invention
[0004] Aiming at the above existing problems, the purpose of this application is to provide a lead scandium tantalate thin film ferroelectric film with both high energy storage and high electrocaloric performance. The second purpose of this application is to provide a preparation method for the above ferroelectric film. Lead scandium tantalate thin film has a high polarization value and breakdown field strength within a wide temperature range, and also has a relatively high adiabatic temperature change within a wide temperature range. Based on this, lead scandium tantalate thin film is applied in the fields of energy storage and refrigeration to improve the energy storage performance and refrigeration efficiency of ferroelectric films. In addition, a thin film preparation method with low cost, short preparation cycle and simple operation will also be provided to meet the actual production applications.
[0005] In order to achieve the above purpose, the following technical solutions are adopted in this application.
[0006] A lead scandium tantalate thin film and a preparation method thereof with both high energy storage and high electrocaloric performance according to the present invention include the following steps:
[0007] (1) According to the chemical stoichiometry of PbSc 0.5 Ta 0.5 O3, scandium nitrate, ethylene glycol methyl ether, concentrated nitric acid, lead acetate, tantalum ethoxide and ethanolamine are mixed to obtain a precursor solution. The precursor solution is aged to obtain a lead scandium tantalate sol.
[0008] (2) The lead scandium tantalate sol is transferred onto a Si / SiO2 / Ti / Pt substrate and spin-coated into a film to obtain a gel film. The gel film is dried and pyrolyzed to obtain a pyrolyzed film. The pyrolyzed film is annealed to obtain a lead scandium tantalate thin film.
[0009] Among them, step (2) is repeated multiple times, and finally a lead scandium tantalate thin film with a certain thickness is obtained.
[0010] A further improvement of the present invention lies in that the preparation method of the lead scandium tantalate sol in step 1 is relatively simple.
[0011] A further improvement of the present invention lies in that the annealing method in step 2 is layer-by-layer annealing.
[0012] A further improvement of the present invention lies in that the annealing holding time in step 2 is 300 s.
[0013] A further improvement of the present invention lies in that the annealing temperature in step 2 is 700 - 850 °C.
[0014] The above technical solutions of this application have the following beneficial technical effects:
[0015] 1. A lead scandium tantalate thin film with both high energy storage and high electrocaloric performance provided by this application. Preferably, the annealing temperature is 750 °C, and the energy storage density can reach 40.4 J / cm under a medium electric field of 2145 kV / cm 3, the energy storage efficiency exceeds 71.8%; under a low electric field of 667 kV / cm, the adiabatic temperature change can reach 4.06 K, and the adiabatic temperature change remains above 2 K in the wide temperature range of 20 - 200 °C, which can meet the performance requirements for applications in the field of dielectric energy storage and has good application prospects in the field of thermal management of electronic devices.
[0016] 2. A lead scandium tantalate thin film with both high energy storage and high electrocaloric properties provided by the present application. When the annealing temperature is 850 °C, the energy storage density can reach 28.56 J / cm 3 , the energy storage efficiency exceeds 65.4%; under a low electric field of 667 kV / cm, the adiabatic temperature change can reach 4.75 K, and the adiabatic temperature change remains above 2 K in the wide temperature range of 20 - 170 °C, and it has good application prospects in the fields of dielectric energy storage and thermal management of electronic devices.
[0017] 3. The preparation method of a lead scandium tantalate thin film with both high energy storage and high electrocaloric properties provided by the present application has the advantages of simple raw material composition, low production cost, and high production efficiency, and can realize the large-scale preparation of the thin film, meeting the requirements of industrial production, and has significant application potential in the semiconductor manufacturing industry. Description of the Drawings
[0018] Figure 1 It is a schematic diagram of the preparation process of lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application;
[0019] Figure 2 It is a scanning electron microscope image of lead scandium tantalate thin film according to Embodiment 1 of the present application;
[0020] Figure 3 It is an X-ray diffraction pattern of lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application;
[0021] Figure 4 It is a ferroelectric hysteresis loop diagram of lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application;
[0022] Figure 5 It is an energy storage performance diagram of lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application;
[0023] Figure 6 It is a diagram showing the variation law of the adiabatic temperature change of the electrocaloric effect with temperature for lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application;
[0024] Figure 7 It is a summary table of the maximum energy storage density and maximum adiabatic temperature change of lead scandium tantalate thin films according to Embodiments 1 - 4 of the present application. Detailed Embodiments
[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following further elaborates on this application in detail in conjunction with specific implementation manners and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of this application. Additionally, in the following descriptions, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of this application.
[0026] The schematic diagram of the layer structure according to an embodiment of this application is shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clarity, some details are enlarged and some details may be omitted. The various regions, shapes of the layers, and their relative sizes and positional relationships shown in the figures are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual requirements.
[0027] Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.
[0028] In the description of this application, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0029] In addition, the technical features involved in different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0030] The following combines the accompanying drawings to elaborate in detail on the lead scandium tantalate thin film and its preparation method provided by the embodiments of this application through specific embodiments and their application scenarios.
[0031] Example 1
[0032] A preparation method of a lead scandium tantalate thin film with both high energy storage and high electrocaloric properties is as Figure 1 shown. The process of setting the dosage of lead acetate trihydrate to be 10 wt% in excess of the stoichiometric ratio may include:
[0033] (1) Mix scandium nitrate, ethylene glycol monomethyl ether, concentrated nitric acid, lead acetate, tantalum ethoxide, and ethanolamine according to the stoichiometric ratio of PbSc 0.5 Ta 0.5 O3 to obtain a precursor solution. Age the precursor solution to obtain a lead scandium tantalate sol.
[0034] (2) Transfer the lead scandium tantalate sol to a Si / SiO2 / Ti / Pt substrate and spin-coat it into a film to obtain a gel film. Dry and pyrolyze the gel film to obtain a pyrolyzed film. Anneal the pyrolyzed film to obtain a lead scandium tantalate thin film.
[0035] Repeat step (2) multiple times to finally obtain a lead scandium tantalate thin film with a certain thickness.
[0036] For a clearer illustration, the above steps are introduced separately as follows:
[0037] (1) Prepare a lead scandium tantalate solution according to the PbSc 0.5 Ta 0.5 O3 stoichiometric ratio by the sol-gel method. Age the precursor solution to obtain a lead scandium tantalate sol. The specific steps are as follows: Weigh ethylene glycol monomethyl ether and then add concentrated nitric acid to adjust the pH to about 4. Dissolve scandium nitrate hydrate, lead acetate trihydrate, and tantalum ethoxide in the mixed solvent of ethylene glycol monomethyl ether and concentrated nitric acid in a molar ratio of 1:2:1 in sequence. Stir for half an hour and then add ethanolamine to stabilize the solution. Continue magnetic stirring at room temperature for 12 h. Finally, obtain a lead scandium tantalate solution with a concentration of 0.2 - 0.5 mol / L, preferably 0.3 mol / L. Age the solution at room temperature for 3 - 7 days, preferably 5 days, to obtain the lead scandium tantalate sol.
[0038] (2) Transfer the lead scandium tantalate sol to a Si / SiO2 / Ti / Pt substrate and spin-coat it into a film to obtain a gel film. Dry and pyrolyze the gel film to obtain a pyrolyzed film. The specific steps are as follows: Drop the prepared lead scandium tantalate precursor sol onto the substrate and perform spin-coating treatment on a spin coater at 5000 rpm for 30 s to obtain a lead scandium tantalate gel film. Dry and pyrolyze the gel film on a heating stage at 180 °C and 400 °C in sequence to obtain a pyrolyzed film for standby. Anneal the pyrolyzed film to obtain a lead scandium tantalate thin film. The specific steps are as follows: Put the pyrolyzed film into a rapid annealing furnace for high-temperature annealing treatment. First, raise the temperature to 500 °C at a rate of 20 °C / min and hold for 300 s, then raise the temperature to 750 °C at a rate of 10 °C / min and anneal for 300 s, and then rapidly cool to 100 °C. Finally, obtain a layer of lead scandium tantalate thin film. Repeat the steps of drying, pyrolyzing, and annealing multiple times to finally obtain a lead scandium tantalate thin film with a thickness of about 300 nm.
[0039] Perform X-ray diffraction, ferroelectric property testing, and electrocaloric property testing on the lead scandium tantalate thin film prepared by the above method. The specific steps are as follows:
[0040] a. Sputter Au electrodes on the lead scandium tantalate thin film in an ion sputtering instrument to finally obtain multiple small electrodes with a diameter of 200 μm and one large electrode.
[0041] b. The ferroelectric properties at room temperature were tested using a ferroelectric analyzer (TF Analyzer 3000, aixACCT, Germany). The area before the polarization axis of the upper half of the hysteresis loop in the first quadrant was integrated, and the result was the effective energy storage density. The area enclosed by the hysteresis loop in the first quadrant was the loss energy. The energy storage efficiency was calculated by dividing the effective energy storage density by the sum of the above two values.
[0042] c. A ferroelectric analyzer was used with a high-temperature heating stage to collect the hysteresis loops at room temperature and above. The adiabatic temperature change was calculated using the indirect method based on Maxwell's relations. The specific steps were as follows: First, the maximum polarization values in the first quadrant of the hysteresis loops of the sample at each temperature were extracted. The relationship between these values and temperature was fitted with a sixth-order polynomial. After fitting, the data was differentiated once to obtain the pyroelectric coefficient (∂P / ∂T), and the adiabatic temperature change was calculated according to Equation (1):
[0043] (Equation 1)
[0044] where T represents the test temperature, E1 is the initial electric field, E2 is the highest electric field, ρ is the density, and the density is 8.803 g / cm 3 , C E is the specific heat capacity. According to the test results of the scanning thermal probe microscope (SThM), its average value is 300 J / kg·K.
[0045] Example 2
[0046] The difference between this example and Example 1 is that the annealing temperature was set at 700 °C. The rest of the content in this example is the same as that described in Example 1.
[0047] Example 3
[0048] The difference between this example and Example 1 is that the annealing temperature was set at 800 °C. The rest of the content in this example is the same as that described in Example 1.
[0049] Example 4
[0050] The difference between this example and Example 1 is that the annealing temperature was set at 850 °C. The rest of the content in this example is the same as that described in Example 1.
[0051] Figure 2 The surface morphology and cross-sectional view of the lead scandium tantalate thin film were described, showing clear grain boundaries, no holes or cracks in the thin film, an average grain size of about 160 nm, and a thin film thickness of about 300 nm. Figure 3 The X-ray diffraction patterns of the lead scandium tantalate thin films and Pt substrates in each example were shown. Multiple diffraction peaks such as (110), (111), and (200) existed in the thin films, indicating that the thin films were perovskite structures. In addition, a small amount of pyrochlore phase also existed.Figure 4 shows the room-temperature ferroelectric hysteresis loop of the lead tantalum scandate thin film, which is in the shape of a slender "S", and the remanent polarization and coercive field remain at low values. Example 1 has the optimal ferroelectric properties.
[0052] shows the energy storage characteristics of the lead tantalum scandate thin film. In Example 1, prepared at an annealing temperature of 750 °C, the energy storage density of the thin film of the sample can reach 40.4 J / cm 3 at a medium electric field of 2145 kV / cm, and the energy storage efficiency is 71.8%; in Example 2, the annealing temperature is 700 °C, and the energy storage density of the thin film of the sample can reach 28.56 J / cm 3 at an electric field of 1711 kV / cm, and the energy storage efficiency is 70.5%; in Example 3, the annealing temperature is 800 °C, and the energy storage density of the thin film can reach 32.27 J / cm 3 at an electric field of 1872 kV / cm, and the energy storage efficiency is 65.7%; in Example 4, the annealing temperature is 850 °C, and the energy storage density of the thin film can reach 28.56 J / cm 3 at an electric field of 2789 kV / cm, and the energy storage efficiency is 65.4%.
[0053] Figure 6 shows the electrocaloric characteristics of the lead tantalum scandate thin film. For the sample of Example 1 under the action of an electric field of 667 kV / cm, the maximum adiabatic temperature change is 4.06 K (@135 °C), and an adiabatic temperature change exceeding 2 K can be maintained in the temperature range of 20 - 200 °C. The thin film prepared in this example has the optimal energy storage characteristics and maintains high electrocaloric performance; for Example 2, the maximum adiabatic temperature change is 3.19 K (@120 °C), and an adiabatic temperature change exceeding 2 K can be maintained in the temperature range of 40 - 170 °C; for Example 3, the maximum adiabatic temperature change is 4.19 K (@123 °C), and an adiabatic temperature change exceeding 2 K can be maintained in the temperature range of 20 - 170 °C; the maximum adiabatic temperature change is 4.75 K (@143 °C), and an adiabatic temperature change exceeding 2 K can be maintained in the temperature range of 20 - 180 °C. Figure 7 is the data summary of the energy storage density and adiabatic temperature change at different annealing temperatures. The lead tantalum scandate thin film prepared in Example 1 maintains high values in both energy storage and electrocaloric performance.
[0054] In summary, the lead tantalum scandate thin film materials prepared by the above example methods all have characteristics such as high energy storage and electrocaloric performance. The high energy storage performance can meet the requirements of dielectric energy storage, and the high electrocaloric performance has good application prospects in the field of thermal management such as electronic devices. Moreover, the preparation method of the above examples has a simple raw material composition, greatly reduces the production cost and preparation difficulty, and can realize the large-size preparation of the thin film, meeting the industrial production requirements and having significant application potential in the semiconductor manufacturing industry.
[0055] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them fall within the protection scope of the present application.
Claims
1. A lead tantalum scandate thin film with both high energy storage and high electrocaloric performance and a preparation method thereof, characterized in that: The chemical formula of the thin film is PbSc 0.5 Ta 0.5 O3 and has a perovskite structure.
2. A lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to claim 1, characterized in that: The annealing temperature is 700 - 850 °C.
3. A lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to claim 1, characterized in that: The lead tantalum scandate thin film has an energy storage density of up to 28.56 - 40.4 J / cm³ under medium electric fields of 1711 - 2789 kV / cm 3 , and an electrocaloric adiabatic temperature change of up to 3.19 - 4.75 K under low electric fields of 667 kV / cm, and has good temperature stability.
4. A method for preparing a lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to any one of claims 1-3, characterized in that, The steps are as follows: (1) Preparation of the precursor solution: Scandium nitrate, ethylene glycol methyl ether, concentrated nitric acid, lead acetate, ethoxytantalum, and ethanolamine are successively mixed to obtain a lead scandium tantalate solution with a certain concentration. The concentration of the solution is 0.2 - 0.5 mol / L, preferably 0.3 mol / L. After aging, lead scandium tantalate sol is obtained. (2) Preparation of the ferroelectric thin film: The lead scandium tantalate sol obtained in step (1) is dropped onto a Pt substrate, and then placed on a spin coater for spin coating to obtain a lead scandium tantalate gel film; the gel film is placed on a heating table for drying and pyrolysis to obtain a lead scandium tantalate pyrolysis film; the pyrolysis film is placed in a rapid annealing furnace for annealing treatment to obtain a lead scandium tantalate thin film. The above process is repeated multiple times, and finally a lead scandium tantalate thin film with a certain thickness is obtained.
5. According to the method for preparing a lead scandium tantalate thin film with both high energy storage and high electrocaloric performance as described in claim 4, the aging time of the solution is 3 - 7 days, preferably 5 days.
6. The preparation method of a lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to claim 4, characterized in that, The process of the spin coating is that the rotation speed is 3000 - 6000 rpm, preferably 4000 - 5000 rpm, and the spin coating time is 30 s.
7. According to the method for preparing a lead scandium tantalate thin film with both high energy storage and high electrocaloric performance as described in claim 4, the process of the drying and pyrolysis is to first keep warm on a heating table at 180 °C for 120 s, and then transfer it to a heating table at 400 °C for 300 s.
8. The preparation method of a lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to claim 4, characterized in that, The process of the annealing treatment in the rapid annealing furnace is to rise to 500 °C at 20 °C / min and keep warm for 300 s, then rise to 700 - 850 °C at 10 °C / min and keep warm for 300 s, and rapidly cool down to below 100 °C.
9. The preparation method of a lead tantalum scandate thin film with both high energy storage and high electrocaloric performance according to claim 4, characterized in that, A conductive gold large electrode and a small electrode are sputtered on the obtained thin film by using an ion sputtering instrument.