A method for preparing an easily peelable perovskite-type barium tantalum oxide nitride film

Abstract

The present invention belongs to the technical field of preparation and stripping of photoelectrode thin film materials for photochemical water splitting, and specifically relates to a method for preparing a perovskite-type barium tantalum oxynitride thin film that is easy to strip. The method sequentially adopts a dual-source electron beam deposition method, a high-temperature nitridation method, and a mechanical stripping method to prepare a BaTaO2N nanoparticle film. During the preparation process, by regulating the NbO x The deposited film thickness, the optimal Ba / Ta atomic ratio and the deposited film thickness enable complete peeling from the quartz substrate with high process repeatability, without the need for oxide precursor powder preparation, and the resulting BaTaO2N film has more application possibilities.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation and stripping of photoelectrode film materials for photo(electro)chemical water decomposition, and in particular relates to a method for preparing a perovskite-type barium tantalum oxide nitride film that is easy to strip. Background Art

[0002] With the increasing severity of environmental pollution and energy crises, the development and utilization of renewable energy has become an inevitable choice for sustainable economic and social development. Conversion of solar energy into hydrogen energy is currently recognized as a promising and sustainable renewable energy method. Photocatalytic and photoelectrocatalytic water splitting utilizes semiconductor materials to absorb solar energy and decompose water into hydrogen and oxygen. Existing research results indicate that semiconductor thin films are promising materials for photocatalytic and photoelectrocatalytic water splitting reactions. Among various semiconductor materials, perovskite-type oxynitride semiconductors AB(O,N)3 (A = Ba, Sr, Ca, La; B = Ta, Nb, Ti) have attracted considerable attention. Combinations of different A- and B-site transition metals can effectively tune the band gap width and widely utilize visible light. The perovskite BaTaO2N has a narrow band gap of 1.8 eV and a well-positioned band edge. Its conduction and valence band positions span the reduction and oxidation potentials of water splitting, theoretically allowing for PEC water splitting without an applied bias. Consequently, it has been extensively studied in the field of photoelectrochemical water splitting.

[0003] The exfoliation of perovskite-type BaTaO2N materials can broaden the preparation methods of materials and increase the possibilities of device construction. Currently, oxide precursor powders are mainly used to prepare thin film precursors on a conductive substrate through electrophoretic deposition, particle transfer or hydrothermal synthesis, and then converted into the desired thin film material through a high-temperature nitridation process. However, the thin film materials obtained by these methods have poor dispersion uniformity in the reaction solution, cannot grow uniformly into films on the conductive substrate, and cannot accurately control the thickness and direction of the film, and the repeatability of the experimental operation is poor. With the development of technology, physical coating methods such as electron beam evaporation and magnetron sputtering are used to prepare semiconductor films with better uniformity, but this also requires a conductive substrate that can withstand high temperatures to build devices.

[0004] Therefore, exploring a new method for film preparation, peeling and transfer and improving film quality are of positive significance for building more imaginative photocatalytic devices. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing an easily strippable perovskite-type barium tantalum nitride oxide film in response to the problems or shortcomings of the above-mentioned prior art, so as to achieve complete stripping of the BaTaO2N film, thereby improving the application possibility of the BaTaO2N film, and without the need to use oxide precursor powder for preparation.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing an easily strippable perovskite-type barium tantalum oxynitride film comprises the following steps:

[0008] Step 1, cleaning the quartz glass substrate;

[0009] Step 2: Place the Nb source into the crucible of the dual-source electron beam deposition system, and place the quartz glass substrate cleaned in step 1 into the sample stage of the electron beam deposition system. Wait for the system to be evacuated to a vacuum degree higher than 8×10 -6 Torr;

[0010] Step 3: Using a quartz crystal microbalance to detect the deposition rate and thickness of Nb2O5, a Nb2O5 intermediate layer is prepared on a quartz glass substrate using a dual-source electron beam deposition system;

[0011] Step 4: Place the Ba source and Ta source into the crucible of the dual-source electron beam deposition system, and place the quartz glass substrate with the niobium oxide thin film intermediate layer deposited in step 3 into the sample stage of the electron beam deposition system. Wait until the system is evacuated to a vacuum degree higher than 8×10 -6 Torr;

[0012] Step 5: Using two quartz crystal microbalances to detect the deposition rate and deposition thickness of BaF2 and Ta2O5, respectively, setting the Ba / Ta atomic ratio to 2:1, and using a dual-source electron beam deposition system to prepare barium tantalum precursor films on metal substrates and quartz glass substrates;

[0013] Step 6: High-temperature nitriding the barium tantalum precursor film obtained in step 5 to obtain a BaTaO2N nanoparticle film;

[0014] Step 7: Use a mechanical exfoliation method to peel off the BaTaO2N nanoparticle film obtained in step 6 to obtain a final BaTaO2N nanoparticle film.

[0015] Furthermore, the detailed operations of step 6 are as follows:

[0016] The barium tantalum precursor film prepared in step 5 is placed in a quartz boat and sealed in a high-temperature tube furnace. The temperature is first raised to 1074-1474K at a rate of 1-20K / min in an air atmosphere and kept in an air atmosphere for 2-8h; then the temperature is lowered to room temperature at a rate of 1-20K / min to prepare Ba5Ta4O 15 Precursor nanoparticle films;

[0017] Then, Ba5Ta4O 15The precursor nanoparticle film is placed in a quartz boat and sealed in a high-temperature tube furnace. The temperature is raised to 1074-1474K at a rate of 1-20K / min in an NH3 atmosphere, and the temperature is maintained in the NH3 atmosphere for 6-40 hours. The temperature is then cooled to room temperature at a rate of 1-20K / min to prepare a BaTaO2N nanoparticle film.

[0018] Furthermore, the detailed operations of step 7 are as follows:

[0019] The BaTaO2N nanoparticle film can be completely mechanically peeled off from the quartz substrate by sticking a clean copper foil tape on the sample and pressing it tightly, and then sticking it directly off.

[0020] Furthermore, the deposition rate of Nb2O5 in step 3 is The deposition thickness is 200 nm.

[0021] Furthermore, the deposition rate of Ta2O5 in step 5 is The deposition thickness is 300nm; the deposition rate of BaF2 is

[0022] The present invention provides a method for preparing a perovskite-type barium tantalum oxynitride film that is easy to peel off. The method sequentially adopts a dual-source electron beam deposition method, a high-temperature nitridation method, and a mechanical stripping method to prepare a BaTaO2N nanoparticle film. During the preparation process, the NbO2N2 nanoparticle film is prepared by regulating the NbO2N2 nanoparticle film in the dual-source electron beam deposition process. x The deposited film thickness, the optimal Ba / Ta atomic ratio and the deposited film thickness enable complete peeling from the quartz substrate with high process repeatability, without the need for oxide precursor powder preparation, and the resulting BaTaO2N film has more application possibilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 XRD patterns of the BaTaO2N nanoparticle films in Examples 1, 2, and 3;

[0024] Figure 2 This is a SEM image of the side angle of the BaTaO2N nanoparticle film in Example 1;

[0025] Figure 3 This is a SEM image of the side angle of the BaTaO2N nanoparticle film in Example 2;

[0026] Figure 4 The specific process of mechanical exfoliation of the BaTaO2N nanoparticle film in Example 1;

[0027] Figure 5 The integrity of the BaTaO2N nanoparticle film after mechanical exfoliation in Example 1;

[0028] Figure 6 This is an SEM image of the BaTaO2N nanoparticle film peeled off in Example 1;

[0029] Figure 7 This is a process flow chart for the preparation of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments given are not to be construed as limiting the present invention. Non-essential improvements and adjustments made by relevant technical personnel based on the contents of the present invention shall still fall within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figure 7 As shown, a method for preparing a perovskite-type barium tantalum oxynitride film that is easy to peel off includes the following steps:

[0033] The quartz glass substrate was ultrasonically cleaned in the order of precision detergent, deionized water, acetone, isopropanol, and ethanol for 20 min, and finally the substrate was blown dry with a high-purity nitrogen gun.

[0034] Use Nb2O5 as the Nb source and place it in the crucible of the electron beam deposition system. Place the cleaned quartz glass substrate in the sample stage of the electron beam deposition system and wait for the system to be evacuated to 5×10-6Torr. Use a quartz crystal microbalance to detect the deposition rate of Nb2O5 and fix the deposition rate of Nb2O5 at And the deposition thickness is 200nm.

[0035] BaF2 and Ta2O5 were used as Ba source and Ta source respectively and placed in the crucible of the dual source electron beam deposition system, and the NbO x The quartz glass substrate was placed in the sample stage of the electron beam deposition system, and the system was evacuated to 5×10-6 Torr.

[0036] Two quartz crystal microbalances were used to detect the deposition rates of BaF2 and Ta2O5 respectively, and the deposition rate of Ta2O5 was fixed at The deposition thickness is 300nm. The deposition rate of BaF2 is set to

[0037] So that the Ba:Ta atomic ratio in the barium tantalum precursor film is 2.0:1; the total deposition thickness of BaF2 and Ta2O5 is 1098nm.

[0038] The prepared barium tantalum precursor film with niobium oxide intermediate layer was placed in a quartz boat and sealed in a high-temperature tube furnace.-1 The temperature was raised to 1174K at a rate of 10Kmin -1 The temperature was cooled to room temperature to obtain Ba5Ta4O 15 Precursor nanoparticle film, Ba5Ta4O 15 The thickness of the precursor nanoparticle film was 760nm; then the -1 The temperature was raised to 1174 K at a rate of 10 h and then heated at 10 K min -1 The prepared BaTaO2N nanoparticle film can be completely mechanically peeled off using tape.

[0039] Mechanical peeling process Figure 4 The morphology of the peeled BaTaO2N nanoparticle film is shown in Figure 5 and Figure 6 .Depend on Figure 5 and Figure 6 It can be seen that the complete exfoliation of the BaTaO2N nanoparticle film is achieved by adopting the present embodiment method.

[0040] The Nb2O5 interlayer and the Ba:Ta atomic ratio are key to whether the resulting BaTaO2N nanoparticle film can be easily peeled off. To verify this, the following examples 2 and 3 are used for verification:

[0041] Example 2

[0042] As in Example 1, the Nb2O5 deposition thickness was set to 100 nm. A BaTaO2N nanoparticle film was prepared through the same high-temperature process as in Example 1. Testing revealed that the BaTaO2N nanoparticle film of this example could not be peeled off the quartz substrate, indicating that the deposition thickness of the Nb2O5 intermediate layer is required.

[0043] Example 3

[0044] Same as Example 1, the deposition rate of BaF2 is set to A BaTaO2N nanoparticle film was prepared by subjecting the barium tantalum precursor film to a Ba:Ta atomic ratio of 2.5:1 through the same high-temperature nitridation process as in Example 1. Testing revealed that the BaTaO2N nanoparticle film of this example could not be peeled off the quartz substrate, indicating that the Ba:Ta atomic ratio plays a crucial role in its peelability.

[0045] Figure 1 The XRD patterns of the BaTaO2N nanoparticle films in Examples 1, 2, and 3 are shown in FIG. Figure 1 It can be seen that the precursor prepared by dual-source electron beam deposition can obtain pure phase Ba5Ta4O 15, pure phase BaTaO2N can be obtained after high temperature nitridation.

[0046] Figure 2 This is the SEM image of the side angle of the BaTaO2N nanoparticle film in Example 1. Figure 3 This is an SEM image of the BaTaO2N nanoparticle film from the side angle in Example 2. Figure 2 and Figure 3 It shows that the intermediate layer of BaTaO2N nanoparticle film is generally introduced into the intermediate layer of niobium oxide film, because the precursor is sintered in air to form Ba5Ta4O 15 During the subsequent nitridation, the fluorine ions in the bulk phase cannot volatilize and gather at the interface. During the subsequent nitridation, the fluorine ions corrode the niobium oxide intermediate layer and volatilize to form a gap in the middle of the film, so the BaTaO2N nanoparticle film can be completely mechanically peeled off.

[0047] In summary, the present invention provides a method for preparing an easily peelable perovskite-type barium tantalum oxynitride film, which maintains the integrity of the perovskite-type barium tantalum oxynitride film and improves its application range and performance.

[0048] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A method for preparing an easily peelable perovskite-type barium tantalum oxynitride film, characterized in that: The following steps are involved: Step 1, cleaning the quartz glass substrate; Step 2: Place the Nb source into the crucible of the dual-source electron beam deposition system, and place the quartz glass substrate cleaned in step 1 into the sample stage of the electron beam deposition system. Wait for the system to be evacuated to a vacuum degree higher than 8×10 -6 Torr; Step 3: Using a quartz crystal microbalance to detect the deposition rate and thickness of Nb2O5, a niobium oxide thin film intermediate layer is prepared on a quartz glass substrate using a dual-source electron beam deposition system; The deposition rate of Nb2O5 in step 3 is Deposition thickness is 200nm Step 4: Place the Ba source and Ta source into the crucible of the dual-source electron beam deposition system, and place the quartz glass substrate with the niobium oxide thin film intermediate layer deposited in step 3 into the sample stage of the electron beam deposition system. Wait until the system is evacuated to a vacuum degree higher than 8×10 -6 Torr; Step 5: Use two quartz crystal microbalances to detect the deposition rate and deposition thickness of BaF2 and Ta2O5 respectively, and fix the deposition rate of Ta2O5 to The deposition thickness is 300nm; the deposition rate of BaF2 is set to so that the atomic ratio of Ba:Ta in the barium tantalum oxide precursor film is 2:1; and the barium tantalum oxide precursor film is prepared on a metal substrate and a quartz glass substrate using a dual-source electron beam deposition system; The total thickness of BaF2 and Ta2O5 deposition is 1098nm; Step 6: High-temperature nitriding the barium tantalum precursor film obtained in step 5 to obtain a BaTaO2N nanoparticle film; Step 7: Use a mechanical exfoliation method to peel off the BaTaO2N nanoparticle film obtained in step 6 to obtain a final BaTaO2N nanoparticle film.

2. The method for preparing an easily peelable perovskite-type barium tantalum oxynitride thin film according to claim 1, characterized in that: The detailed operation of step 6 is as follows: The barium tantalum precursor film prepared in step 5 is placed in a quartz boat and sealed in a high-temperature tube furnace. The temperature is first raised to 1074-1474K at a rate of 1-20K / min in an air atmosphere and kept in an air atmosphere for 2-8h; then the temperature is lowered to room temperature at a rate of 1-20K / min to prepare Ba5Ta4O 15 Precursor nanoparticle films; Then, Ba5Ta4O 15 The precursor nanoparticle film was loaded into a quartz boat and sealed in a high-temperature tube furnace. The temperature was raised to 1074-1474K at a rate of 1-20K / min in an NH3 atmosphere, and the temperature was kept in the NH3 atmosphere for 6-40h. Then, the temperature was cooled to room temperature at a rate of 1-20K / min to prepare a BaTaO2N nanoparticle film.

3. The method for preparing an easily peelable perovskite-type barium tantalum oxynitride thin film according to claim 1 or 2, characterized in that: The detailed operation of step 7 is as follows: The BaTaO2N nanoparticle film can be completely mechanically peeled off from the quartz substrate by sticking a clean copper foil tape on the sample and pressing it tightly, and then sticking it directly off.

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