A method for constructing oxygen-defect-regulated hafnia 5d orbital electrons

Abstract

The application discloses a method for constructing oxygen defect regulation of hafnium dioxide 5d track electron, comprising the following steps: S1, using a hydrothermal method, by regulating the oxygen partial pressure in the preparation process, preparing hafnium oxide nanocrystals with different oxygen defects and calculating the oxygen defect concentration; S2, according to the first principle, calculating and constructing a hafnium dioxide crystal model under a microstructure, and modifying the corresponding model according to the experimental results of step S1; S3, according to the hafnium dioxide with oxygen defects obtained in step S2, calculating the total state density and the partial state density of the near-oxygen vacancy end hafnium atom and the far-oxygen vacancy end hafnium atom, respectively, calculating the proportion of the d atom track, and establishing a method for regulating the hafnium dioxide 5d track electron.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic materials, and in particular to a method for constructing oxygen defects to regulate 5d orbital electrons of hafnium dioxide. Background Art

[0002] Due to their shifted radial distribution function and strong spin-orbit coupling, 5d electrons exhibit properties significantly different from those of 3d or 4d electrons. This has enabled the emergence of numerous novel properties within this broad class of materials, some of which are even unique to 5d materials. Published research has demonstrated experimental verification of numerous theoretically predicted novel properties, such as the spin Hall effect and Weyl semimetals, in systems related to 5d electrons.

[0003] HfO2, with its scale-free ferroelectricity, possesses high dielectric constant, high mobility, and strong spin-orbit coupling. These unique properties make systems related to 5d electronic materials promising for the design of next-generation low-power, high-speed logic / storage devices. Therefore, research into methods for tunable 5d electrons is urgently needed. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a method for synthesizing hafnium dioxide crystals by regulating oxygen defects, thereby regulating the 5d electron orbit of Hf under the microstructure.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A method for constructing oxygen defects to regulate 5d orbital electrons of hafnium dioxide comprises the following steps:

[0007] S1: Using a hydrothermal method, by regulating the oxygen partial pressure, different hafnium oxide nanocrystals with oxygen defects were prepared, and the oxygen defect concentration of each hafnium oxide nanocrystal was calculated;

[0008] The method for regulating the oxygen partial pressure comprises: regulating the pressure in the para-polyphenol liner in the high-pressure reactor to control the volume of the hafnium dioxide solution in the high-temperature reactor, thereby controlling the oxygen partial pressure to prepare hafnium dioxide nanocrystals with different oxygen vacancy concentrations, wherein the oxygen vacancy concentration of the hafnium dioxide nanocrystals decreases with increasing the amount of aqueous hafnium dioxide solution added;

[0009] S2: Use the Materials Project material library to build an HfO2 bulk material model. According to the oxygen vacancy concentration obtained in step S1, oxygen atoms at different positions in the HfO2 bulk material model are deleted to introduce defects, and an HfO2 unit cell with oxygen defects is obtained. Density functional theory in the CASTEP module in the Materials Studio software is used to optimize the structure of HfO2, and a 1*1*2 m-HfO2 spatial structure is established. The symmetry group is selected as C2h. Based on the oxygen vacancy concentration, some oxygen atoms are removed to fit the experimental results, so as to analyze the effect of the presence of oxygen defects on the 5d orbital electrons.

[0010] S3: In Materials Studio, based on the optimized hafnium dioxide lattice structure model obtained in step S2, the hafnium atoms are divided into two categories according to their proximity to oxygen vacancies: hafnium atoms near oxygen vacancies and hafnium atoms far from oxygen vacancies. Based on first-principles density functional theory, the total density of states and partial density of states of the hafnium atoms near oxygen vacancy ends and hafnium atoms far from oxygen vacancy ends are calculated, respectively. According to the distribution of electrons in s, p, d, and f orbitals, it is determined that the oxygen defect concentration is positively correlated with the d orbital electron activity. As the oxygen vacancy concentration increases, the electron activity becomes stronger, providing a method for establishing and regulating the 5d orbital electrons of hafnium dioxide.

[0011] According to the fact that the 5d orbital electrons of the hafnium atom near the oxygen vacancy end contribute the most to the defect energy level, it can be concluded that the existence of oxygen vacancies can greatly stimulate the activity of 5d orbital electrons.

[0012] Furthermore, in step S3, the original model is geometrically optimized first, and the GGA+PBE model is preferably used according to the first-principles calculation, and the parameters are adjusted by the calculation method of inverting the U value with the known energy band width. The relevant calculations of PDOS are performed, wherein the orbital calculations are first performed according to the different models to describe the distribution of the electron cloud. In order to provide more accurate results in terms of micro-control, the Hf atoms are classified, and the classification standard is based on the distance from the oxygen vacancy to judge the composition of the defect energy level. The calculation results are compared and analyzed. The generation of defect energy levels caused by the introduction of oxygen vacancies is related to the hafnium atoms near the oxygen vacancy end, and with the increase of the oxygen vacancy concentration, the 5d electron activity of this type of hafnium atoms is stronger, providing a method for regulating the 5d electron distribution of hafnium atoms by constructing oxygen vacancies.

[0013] Furthermore, the preparation method of hafnium oxide nanocrystals with oxygen defects is as follows: dissolving hafnium tetrachloride in deionized water to prepare a hafnium tetrachloride solution, dripping the prepared hafnium tetrachloride solution into a sodium hydroxide solution, and stirring at room temperature for 0.5 hours to obtain an aqueous hafnium dioxide solution;

[0014] The aqueous hafnium dioxide solution was placed in a para-polyphenol inner liner and placed in a high-temperature reactor for hydrothermal reaction at 130°C for 24 hours to obtain hafnium dioxide nanocrystals with oxygen defects; the oxygen defect concentration of the hafnium dioxide nanocrystals was any value between 6.5% and 13.8%; and the oxygen defect concentration of the hafnium dioxide nanocrystals decreased with the increase in the amount of aqueous hafnium dioxide solution added.

[0015] Furthermore, 0.32 g of hafnium tetrachloride powder was weighed and dissolved in 30 mL of deionized water to obtain a hafnium tetrachloride solution. The hafnium tetrachloride solution was dripped into a rapidly stirred sodium hydroxide solution and stirred at room temperature for 0.5 h to obtain an aqueous hafnium dioxide solution. Then, 5 mL, 10 mL, and 15 mL of the aqueous hafnium dioxide solution were respectively placed in a 25 mL para-polyphenol liner, and placed in a high-temperature reactor. The mixture was hydrothermally reacted at 130 ° C for 24 hours to obtain hafnium dioxide with different oxygen defect concentrations. After characterization and calculation, it was found that the oxygen defect concentration was 13.8% when 5 mL of liquid was added, 12.3% when 10 mL was added, and 6.5% when 15 mL was added.

[0016] Furthermore, in S1, the oxygen defect concentration of the prepared hafnium dioxide nanocrystals is calculated by the following formula:

[0017]

[0018] Where W is the oxygen vacancy concentration; S A It represents the area ratio of defective oxygen; S D It represents the area ratio of lattice oxygen.

[0019] Furthermore, the oxygen defect concentrations of the prepared hafnium dioxide nanocrystals are 13.8%, 12.3% and 6.5%, respectively.

[0020] Furthermore, the amount of aqueous hafnium dioxide solution added is proportional to the pressure of the reaction system, and as the pressure decreases, the oxygen defect concentration gradually decreases.

[0021] Furthermore, the hafnium tetrachloride: deionized water: sodium hydroxide solution = 0.32 g: 30 mL: 20 mL.

[0022] Furthermore, with hafnium dioxide as the substrate, within the range of oxygen defect concentration of 6.5%-13.8%, the oxygen defect concentration is positively correlated with the 5d electron activity. As the oxygen defect concentration increases, the 5d electron activity of hafnium atoms increases.

[0023] In summary, the present invention has the following beneficial effects:

[0024] The present invention discloses a method for constructing oxygen defects to regulate the 5d orbital electrons of hafnium dioxide. The oxygen partial pressure is regulated by adding an aqueous hafnium dioxide solution during the preparation process. It is calculated that when 5 mL of hafnium dioxide solution is added, the pressure in the container is 0.18 MPa, which is about 1.8 atmospheres of pressure. When 10 mL of hafnium dioxide solution is added, the pressure in the container is 0.24 MPa, which is about 2.4 atmospheres of pressure. When 15 mL of hafnium dioxide solution is added, the pressure in the container is 0.37 MPa, which is about 3.6 atmospheres of pressure. The pressure in the container affects the hafnium dioxide crystals, thereby regulating the oxygen defect concentration in the hafnium dioxide crystals. Characterization and calculation show that the oxygen defect concentration is 13.8% when 5 mL of liquid is added, 12.3% when 10 mL, and 6.5% when 15 ml.

[0025] Further calculations revealed that the presence of oxygen vacancies in the constructed 1*1*2 hafnium dioxide crystal introduces defect energy levels. When the oxygen vacancy concentration reaches 12.5%, analysis of the band structure and partial density of states of each element reveals that, among the s, p, d, and f orbitals, the 5d electron orbital of the Hf element contributes most to the defect energy levels. Further analysis reveals that the 5d electron orbitals of the Hf element closest to the oxygen vacancy contribute most to the defect energy levels. This model shortens the band gap, demonstrating that the regulation of oxygen vacancies can manipulate the 5d electron distribution, thereby stimulating the unique physicochemical properties of the 5d electron orbital. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 This is an X-ray energy spectrum diagram of the hafnium dioxide nanocrystal sample disclosed in Example 1 of the present invention;

[0028] Figure 2 This is an X-ray energy spectrum diagram of the hafnium dioxide nanocrystal sample disclosed in Example 2 of the present invention;

[0029] Figure 3 A 1*1*2 hafnium dioxide crystal image is created in Materials Studio in Example 2 of the present invention;

[0030] Figure 4 This is an X-ray energy spectrum diagram of the hafnium dioxide nanocrystal sample disclosed in Example 3 of the present invention;

[0031] Figure 5The hafnium dioxide crystal structure diagram of the 1*1*2 model established by Materials Studio in Example 3 of the present invention;

[0032] Figure 6 is the relationship between pressure and oxygen defect concentration;

[0033] Figure 7 The total density of states and partial density of states of type A and type B Hf atoms near the oxygen vacancy end;

[0034] Figure 8 The total density of states and partial density of states of type A and type B Hf atoms at the far oxygen vacancy end;

[0035] Figure 9 is the total density of states of HfO2. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will be combined with the appended drawings of the embodiments of the present invention. Figure 1-9 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0037] The oxygen deficiency concentration involved in this application is calculated using the following method:

[0038] The samples were characterized by X-ray photoelectron spectroscopy (Thermo Scientific TMK-AlphaTM+ spectrometer equipped with a monochromatic A1-Ka X-ray source (1486.6-eV) operating at 100 W), and the X-ray energy spectrum was obtained with the electron binding energy as the abscissa;

[0039] The characterization results were analyzed and the electron binding energies of different types of oxygen elements in the crystal were plotted. Based on the difference in electron binding energies, crystal oxygen was further divided into three categories: lattice oxygen, surface adsorbed oxygen, and defect oxygen. The oxygen defect concentration is related to the lattice oxygen and defect oxygen. It is generally believed that the ratio of the surface ratio of defect oxygen to the sum of lattice oxygen and defect oxygen is the oxygen defect concentration. It can be expressed as:

[0040]

[0041] Where W is the oxygen vacancy concentration; S A It represents the area ratio of defective oxygen; S D It represents the area ratio of lattice oxygen.

[0042] Example

[0043] Example 1

[0044] A method for constructing oxygen defects to regulate 5d orbital electrons of hafnium dioxide comprises the following steps:

[0045] S1: Weigh 0.32 g of hafnium tetrachloride powder and dissolve it in 30 mL of deionized water to obtain a hafnium tetrachloride solution; drip the hafnium tetrachloride solution into a rapidly stirred sodium hydroxide solution and stir at room temperature for 0.5 h to obtain an aqueous hafnium dioxide solution; then, place 5 mL of the aqueous hafnium dioxide solution into a 25 mL para-polyphenol liner and measure the pressure inside the para-polyphenol liner to be 0.18 MPa using a laboratory pressure gauge; then, transfer the solution to a high-temperature reactor and perform a hydrothermal reaction at 130°C for 24 h to obtain hafnium dioxide nanocrystals;

[0046] Figure 1 is an X-ray energy spectrum of the hafnium dioxide nanocrystal sample prepared in this embodiment;

[0047] The characterization results were analyzed, and the analysis data are shown in Table 1 below.

[0048]

[0049] Combine Figure 1 As shown in Table 1, S A =1, S D =0.16, substituting into the calculation formula of oxygen deficiency concentration, we get W=0.16 / (0.16+1)≈0.1379=13.8%;

[0050] S2: Use the Materials Project material library to build an HfO2 bulk material model, use Materials Studio for simulation analysis, and use density functional theory in the CASTEP module in Materials Studio software to optimize the structure of HfO2. Establish a 1*1*2 m-HfO2 spatial structure with a symmetry group of C2h. Based on the oxygen defect concentration obtained in step S1, delete oxygen atoms at different positions in the HfO2 bulk material model to introduce defects. Obtain HfO2 with an oxygen defect concentration of 13.8%, and analyze the effect of the presence of oxygen defects on 5d orbital electrons.

[0051] S3: Prioritize geometric optimization of the original model. Based on the first-principles calculation, the generalized gradient approximation GGA method is preferred. The exchange-correlation function uses the PBE model. The parameters are adjusted by using the known energy band width to infer the U value. Carry out relevant calculations of PDOS, among which, first perform orbital calculations according to different models to describe the distribution of the electron cloud. For micro-control, it can provide more accurate results. Therefore, in Materials Studio, according to the HfO2 with an oxygen defect concentration of 13.8% obtained in step S2, the hafnium atoms are divided into two categories according to the distance between the hafnium atoms and the oxygen vacancy, namely, the hafnium atoms near the oxygen vacancy end and the hafnium atoms far from the oxygen vacancy end, in order to judge the composition of the defect energy level;

[0052] Based on the first-principles density functional theory, the total density of states and partial density of states of the hafnium atoms near the oxygen vacancy end and the hafnium atoms far from the oxygen vacancy end are calculated respectively, and the integral ratios of the s, p, d, and f orbitals to the total orbital are calculated respectively. The larger the ratio, the higher the energy of the corresponding orbital. In this way, the influence of oxygen defect concentration on the s, p, d, and f orbitals is determined, providing a predictive method for regulating the 5d orbital electrons of hafnium dioxide.

[0053] Example 2

[0054] The only difference from Example 1 is that in S1, 10 mL of aqueous hafnium dioxide solution is placed in a 25 mL para-polyphenol liner, and the pressure inside the para-polyphenol liner is measured by a laboratory pressure gauge to be 0.24 MPa.

[0055] Figure 2 is an X-ray energy spectrum of the hafnium dioxide nanocrystal sample prepared in this embodiment;

[0056] The characterization results were analyzed and the analysis data are shown in Table 2 below.

[0057]

[0058] Combine Figure 2 From Table 2, we can see that S A =1, S D =0.14, substituting into the above formula we get W=0.14 / (0.14+1)≈0.1228=12.3%.

[0059] Figure 5 Create a 1*1*2 hafnium dioxide crystal model for Materials Studio for simulation calculations.

[0060] from Figure 5As can be seen, Hf is light-colored and O is dark-colored. This model contains a total of 8 Hf atoms and 14 O atoms, and the calculated oxygen defect concentrations are 12.5%. The results obtained are consistent with the experimental results of oxygen defects in the hafnium dioxide nanocrystals prepared in step S1.

[0061] Example 3

[0062] The only difference from Example 1 is that in S1, 15 mL of aqueous hafnium dioxide solution is placed in a 25 mL para-polyphenol liner, and the pressure inside the para-polyphenol liner is measured by a laboratory pressure gauge to be 0.37 MPa.

[0063] Figure 4 is an X-ray energy spectrum of the hafnium dioxide nanocrystal sample prepared in this embodiment;

[0064] The characterization results were analyzed and the analysis data are shown in Table 3.

[0065]

[0066] Combine Figure 4 From Table 3, we can see that S A =1, S D =0.08, substituting into the above formula we get W=0.07 / (0.07+1)≈0.065=6.5%.

[0067] Figure 5 Create a 1*1*2 hafnium dioxide crystal model for Materials Studio for simulation calculations.

[0068] from Figure 5 As can be seen, Hf is blue and O is red. This model has a total of 8 Hf atoms and 15 O atoms, and the calculated oxygen defect concentration is 6.25%. The obtained result is consistent with the experimental results of oxygen defect in the hafnium dioxide nanocrystals prepared in step S1.

[0069] Figure 6 is the relationship between pressure and oxygen defect concentration;

[0070] Combined with Examples 1-3 and Figure 6 It can be seen that when the liquid volume is 5mL, the pressure in the container is 0.24MPa and the oxygen deficiency concentration is 13.8%. When the liquid volume is 10mL, the pressure in the container is 0.24MPa and the oxygen deficiency concentration is 12.3%. When the liquid volume is 15mL, the pressure in the container is 0.37MPa and the oxygen deficiency concentration is 6.5%. Therefore, as the pressure gradually decreases, the oxygen deficiency concentration tends to gradually decrease.

[0071] The HfO2 provided in Example 2 and Example 3 were respectively subjected to PDOS calculations. In order to better describe how different types of Hf atoms affect the defect energy level composition under conditions with different concentrations of oxygen vacancies, the next step will be to conduct a classification discussion. Figure 7-9 In the figure, type A Hf is Hf atoms near the oxygen defect end, and type B Hf is Hf atoms far from the oxygen vacancy end. HfO2 with an oxygen defect concentration of 6.25% is used as sample No. 1, and HfO2 with an oxygen defect concentration of 12.5% ​​is used as sample No. 2. The total state density and partial state density of type A and type B Hf atoms are calculated respectively. After that, the existing data are re-analyzed and simply calculated to draw the following 6 pictures. Figure 7-8 .

[0072] in Figure 7 (a) is the total state density of type A and type B HfO2 near the oxygen vacancy end; 7(b) is the partial state density of HfO2 with an oxygen defect concentration of 6.25% at the hafnium atom near the oxygen vacancy end; 7(c) is the partial state density of HfO2 with an oxygen defect concentration of 12.5% ​​at the hafnium atom near the oxygen vacancy end;

[0073] in Figure 8 (a) is the total state density of type A and type B HfO2 far from the oxygen vacancy end; 8(b) is the partial state density of HfO2 with an oxygen defect concentration of 6.25%, and 8(c) is the partial state density of HfO2 with an oxygen defect concentration of 12.5%;

[0074] The specific composition of defect energy levels can only be determined by comparing the Hf element itself with the distribution state density of the Hf element itself. Figure 7 (b) and Figure 7 (c) and Figure 8 (b) and Figure 8 (c) It can be seen from the comparison that with the increase of oxygen vacancy concentration, the electronic activity of each layer of hafnium atoms is improved to a certain extent.

[0075] Figure 9 is the total state density of HfO2, 9(a) is the total state density of HfO2 with an oxygen defect concentration of 6.25%, and 9(b) is the total state density of HfO2 with an oxygen defect concentration of 12.5%;

[0076] Combine Figure 7-8 and Figure 9 It can be seen that the presence of oxygen defects within the hafnium dioxide crystal increases the activity of 5d electrons, thereby introducing defect energy levels in the band structure. As the concentration of oxygen defects increases, the defect energy levels shift further downward, demonstrating that 5d electrons can influence the band structure within a controllable range.

[0077] Overall, the 5d electron concentration in sample 1 is approximately 18.3% lower than that in sample 2, indicating that the increased oxygen vacancy concentration stimulates 5d electron activity. A comparison of the partial density of states of type-A Hf atoms and type-B Hf atoms reveals that type-A Hf atoms contribute the vast majority of defect levels, while the outer-shell electrons of type-B Hf atoms contribute almost none. Calculations show that when the oxygen vacancy concentration is 6.25%, type-A Hf atoms contribute 100% of the defect levels, and when the oxygen vacancy concentration is 12.5%, they contribute approximately 92.4%. Notably, the activity of other orbital electrons in type-A Hf atoms increases with increasing oxygen vacancy concentration. Comprehensive analysis indicates that the presence of oxygen vacancies introduces defect levels, primarily composed of type-A Hf 5d electrons. Studying the properties of 5d electrons lays the foundation for the next generation of scale-free, low-energy ferroelectric materials.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing oxygen defects to regulate the 5d orbital electrons of hafnium dioxide, characterized in that: The steps include: S1: Using a hydrothermal method, by regulating the oxygen partial pressure, different hafnium dioxide nanocrystals with oxygen defects were prepared, and the oxygen defect concentration of each hafnium dioxide nanocrystal was calculated; The method for regulating the oxygen partial pressure comprises: regulating the pressure in the para-polyphenol liner in the high-pressure reactor to control the volume of the hafnium dioxide solution in the high-temperature reactor, thereby controlling the oxygen partial pressure to prepare hafnium dioxide nanocrystals with different oxygen vacancy concentrations, wherein the oxygen vacancy concentration of the hafnium dioxide nanocrystals decreases with increasing the amount of aqueous hafnium dioxide solution added; S2: Performing calculations based on first principles to construct a microstructured HfO2 crystal material model and optimizing the HfO2 crystal material model using the CASTEP module to establish the spatial structure of m-HfO2, selecting the symmetry group as C2h, and modifying the HfO2 crystal material model based on the oxygen defect concentration obtained in step S1 to obtain an HfO2 crystal model with corresponding oxygen defects; the oxygen defect concentration of the HfO2 crystal model is any value between 6.5% and 13.8%; S3: Based on the HfO2 crystal model with oxygen defects obtained in step S2, the hafnium atoms are divided into two categories based on the distance between the hafnium atoms and the oxygen vacancy, namely, the hafnium atoms near the oxygen vacancy end and the hafnium atoms far from the oxygen vacancy end. Based on the first-principles density functional theory, the total density of states and the partial density of states of the hafnium atoms near the oxygen vacancy end and the hafnium atoms far from the oxygen vacancy end are calculated respectively. According to the distribution of electrons in the d orbital, the influence of the oxygen defect concentration on the d orbital is determined to establish a method for regulating the 5d orbital electrons of hafnium dioxide.

2. The method for constructing oxygen vacancies to regulate 5d orbital electrons of hafnium dioxide according to claim 1, characterized in that: In S1, the preparation method of hafnium oxide nanocrystals with oxygen defects is as follows: dissolving hafnium tetrachloride in deionized water to prepare a hafnium tetrachloride solution, dropping the prepared hafnium tetrachloride solution into a sodium hydroxide solution, and stirring at room temperature for 0.5 hours to obtain an aqueous hafnium dioxide solution; An aqueous hafnium dioxide solution is placed in a para-polyphenol inner liner and placed in a high-temperature reactor for hydrothermal reaction at 130°C for 24 hours to obtain hafnium dioxide nanocrystals with oxygen defects; the oxygen defect concentration of the hafnium dioxide nanocrystals is any value between 6.5% and 13.8%.

3. The method for constructing oxygen vacancies to regulate 5d orbital electrons of hafnium dioxide according to claim 1, characterized in that: In S1, the oxygen deficiency concentration is calculated by the following formula: Where W is the oxygen vacancy concentration; S A It represents the area ratio of defective oxygen; S D It represents the area ratio of lattice oxygen.

4. The method for constructing oxygen vacancies to regulate 5d orbital electrons of hafnium dioxide according to claim 1, characterized in that: In S1, the oxygen defect concentrations of the prepared hafnium dioxide nanocrystals were 13.8%, 12.3% and 6.5%, respectively.

5. The method of constructing oxygen vacancies to regulate 5d orbital electrons of hafnium dioxide according to claim 2, characterized in that: The hafnium tetrachloride: deionized water: sodium hydroxide solution = 0.32 g: 30 mL: 20 mL.

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