A method for three-dimensional visualization of space charge transfer based on in-situ photo-assisted xps

Abstract

This invention discloses a three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS, belonging to the fields of energy materials technology and material surface analysis methods. The method comprises the following steps: First, an FTO / WO3@Au device material is prepared as the research object. This material has a heterojunction structure between stacked interfaces. Noble metal doping can improve the charge transfer efficiency. Through the plasma effect and electronic mediation of Au, a highly efficient synergistic path from light absorption, charge separation to surface reaction is constructed. Etching is performed on the FTO / WO3@Au surface, so that different layers yield peak intensities of different strengths under XPS spectral analysis. Under XPS spectral imaging, a series of spectra at binding energies are obtained by sampling every 0.1 eV. The data is output in a data table, and then a 3D view is plotted using the best fit formula, which visualizes the charge transfer process and intuitively shows the transfer path of photogenerated charge.

Description

Technical Field

[0001] This invention belongs to the fields of energy materials technology and material surface analysis methods, and specifically relates to a method for fabricating a noble metal-doped FTO / WO3@Au device, the data processing after in-situ light-assisted XPS imaging, and its application in exploring space charge transfer. Background Technology

[0002] With the increasing severity of the global energy crisis and environmental problems, the development of efficient and clean energy conversion and storage technologies has become a frontier and core area of ​​scientific research. Solar energy, as a widely distributed and inexhaustible sustainable energy source, is one of the key ways to solve these challenges through its efficient utilization. The performance of devices such as photoelectrochemical water splitting for hydrogen production, carbon dioxide reduction, and high-performance solar cells fundamentally depends on the ability of photoactive materials to capture sunlight, as well as the separation, migration, and surface reaction efficiency of photogenerated charges (electron-hole pairs). Among these, the efficient regulation of charge behavior is the Achilles' heel for improving device performance. A deep understanding and intuitive characterization of the transfer paths and dynamic processes of charges in complex material systems, especially at heterojunction interfaces, is a prerequisite for achieving this regulation and a major scientific challenge currently facing the field of energy materials.

[0003] To optimize photoactive materials, researchers are dedicated to designing sophisticated micro- and nanostructures. Tungsten trioxide (WO3), as an important n-type semiconductor, possesses a suitable band gap, good chemical stability, and abundant resources, demonstrating its application potential in photoelectrochemistry. However, pure WO3 suffers from intrinsic defects such as high photogenerated carrier recombination rates and a limited visible light absorption range. Therefore, constructing heterojunctions and introducing noble metals have become two effective modification strategies. Combining WO3 with another band-matching semiconductor (such as TiO2) can form a hybrid heterojunction, utilizing a built-in electric field to drive the spatial separation of photogenerated electrons and holes. On the other hand, loading noble metal nanoparticles such as gold and platinum can enhance light absorption through their localized surface plasmon resonance effect and act as efficient electron trapping centers, accelerating interfacial charge transfer.

[0004] In recent years, traditional characterization of charge transfer behavior has mainly relied on a series of indirect or integral measurement methods. For example, photoelectrochemical testing can obtain macroscopic photocurrent density, reflecting the overall performance of the device; fluorescence spectroscopy and transient absorption spectroscopy can detect carrier lifetime and recombination dynamics. Patent CN119757508A discloses a method for in-situ determination of interfacial charge transfer dynamics, which can conveniently achieve quantitative acquisition of solid / liquid interface reaction kinetics information, and can promote the study of interfacial charge transfer dynamics mechanisms in photoelectrocatalysis and the optimization of related device process performance.

[0005] However, these methods cannot provide information on the distribution and changes of charge in the specific spatial location of the material, and cannot answer key questions such as "where the charge is generated, where it accumulates, and along what path it migrates." X-ray photoelectron spectroscopy (XPS), as a powerful surface analysis technique, can accurately reflect the chemical state and local electron density changes of elements by measuring the shift (chemical shift) of the inner-shell electron binding energy, theoretically providing the possibility for detecting surface charge rearrangement caused by illumination. The traditional "illumination-spectral measurement" mode, which involves acquiring XPS broad or narrow spectra under dark and illuminated conditions respectively, and inferring the direction of charge transfer by comparing the changes in the binding energy of specific elements, is widely used. However, its essence is to obtain the spatial average of all information within the detection area. For materials with complex microstructures and non-uniform distribution of composition and potential, this averaged signal severely masks the spatial heterogeneity of charge transfer. In short, the traditional XPS method provides a one-dimensional "line spectrum" but loses crucial two-dimensional "spatial spectrum" and even three-dimensional "depth spectrum" information, leaving the analysis of charge transfer paths at the level of empirical speculation and model calculation, lacking intuitive and conclusive image evidence.

[0006] Therefore, developing a chemical state imaging method that can spatially resolve complex heterostructures under working conditions and directly visualize photogenerated charge transfer paths has become an urgent need to deepen the study of energy material mechanisms and accelerate the development of new materials. Summary of the Invention

[0007] This invention addresses the limitations of traditional XPS methods in analyzing charge transfer paths and the lack of intuitive and definitive image analysis. It proposes a three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS. This invention provides an efficient and intuitive method to detect elemental surface information and optimizes the generation of 3D views through data processing to explore the space charge transfer mechanism under light irradiation. A noble metal-doped FTO / WO3@Au device is designed. Through this imaging data processing method, this invention transforms two-dimensional image information into three-dimensional spatial information. It can detect the specific location of space charge accumulation in the longitudinal spectrum. By observing changes in color intensity and spatial scale before and after illumination, the direction of electron flow and specific reaction sites can be detected more intuitively.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0009] This invention provides a three-dimensional visualization analysis method for space charge transfer based on in-situ optically assisted XPS, comprising the following steps:

[0010] (1) Preparation of FTO / WO3@Au device: After cleaning the FTO conductive glass, surface treatment is performed. WCl6 is dissolved in a solvent to adjust the pH of the solution to obtain WO3 precursor solution, which is dropped onto the treated FTO conductive glass. After drying, annealing is performed to obtain FTO / WO3 device. Chloroauric acid solution is dropped onto the surface of FTO / WO3 device and photoreduction reaction is performed to obtain FTO / WO3@Au device. After surface etching treatment, the desired sample is obtained.

[0011] (2) Conventional XPS spectral acquisition in dark state: After placing the sample obtained in step (1) in the XPS transition chamber, turn off the light source. After the vacuum degree reaches the required level, send it into the test chamber for testing to obtain conventional dark state spectral data.

[0012] (3) XPS imaging acquisition under light assistance: Turn on the in-situ light source and perform XPS imaging on the sample surface under illumination to obtain conventional illumination spectrum data.

[0013] (4) Data processing: The signals at the same location in each image are processed using Excel. First, the data tables of each acquired spectrum are summed to obtain the total signal intensity distribution. Then, in order to avoid excessive differences between data points, which would make the drawn image difficult to read, averaging is performed to weaken other interfering data. In order to further emphasize the features of the image and weaken other interfering data, the average data is averaged again to obtain 64×64 feature data.

[0014] (5) Use the feature data obtained in step (4) to draw a three-dimensional color projection map to obtain a three-dimensional visualization analysis image.

[0015] Step (1) involves cleaning the FTO conductive glass by sequentially using deionized water, acetone, and isopropanol via ultrasonic cleaning to remove surface organic matter and particles; the surface treatment involves using an ultraviolet ozone cleaner for 15-30 minutes; the initial concentration of WCl6 is 3-5 mg / mL, the solvent is anhydrous ethanol, and the pH of the solution is adjusted to 1-2 using concentrated hydrochloric acid; the annealing temperature is 400-450℃, and the time is 1.5-3 hours; the thickness of the WO3 layer in the FTO / WO3 device is 10-100 nm.

[0016] The principle behind ultraviolet ozone cleaning is as follows: A low-pressure mercury lamp inside the machine emits short-wave ultraviolet light with a wavelength of 185nm. These high-energy photons directly break the chemical bonds of oxygen molecules in the air, converting oxygen into ozone. Simultaneously, the 254nm wavelength ultraviolet light emitted by the mercury lamp irradiates the surface of the object to be cleaned. This light has two key functions: first, it directly acts on organic pollutants, breaking their molecular bonds and making them chemically active; second, it irradiates the ozone, decomposing it into oxygen and highly reactive oxygen atoms. The reactive oxygen atoms generated in step two have extremely strong oxidizing power. They react violently with the organic pollutant molecules activated by the ultraviolet light, completely decomposing these oil stains, residual photoresist, and other organic matter into volatile small molecules such as carbon dioxide and water. These gases then dissipate from the surface, thus achieving the cleaning purpose. For convenient subsequent WO3 spin coating, the spin coating parameters are 2000 revolutions per minute for 30 seconds.

[0017] The concentration of the chloroauric acid solution is 0.02-0.05 g / mL, the photoreduction reaction is carried out by irradiation with a xenon lamp for 15-30 min, and the surface etching treatment is carried out by pattern etching on the surface of the device using laser etching, so that the surface information of the sample at different thicknesses exhibits different binding energy intensities.

[0018] The vacuum level required in step (2) is that the vacuum value of the transition chamber reaches 10. -8 Torr below, while the vacuum value of the test chamber reaches 10. -9 Below Torr, the test transmit current is 10mA and the flux is 80.

[0019] In step (3), the light source is a monochromatic Al Kα X-ray source (1486.6 eV) as the XPS excitation source, and light with a wavelength of 365 nm is used as the in-situ light-assisted excitation source to investigate the transfer of photogenerated charge;

[0020] In XPS imaging, set it to Image stack mode, and in Excitation Settings, set Tuning to Imaging and Emission Current to 15 mA.

[0021] Lens Mode is set to FOV3 Imaging, and Resolution is set to 80.

[0022] In the image stack settings, set the step size to 0.1 eV and the binding energy range for elemental spectra, and set the time for a single acquisition to 60 s.

[0023] The spectral range selected in step (2) or step (3) is the range of XPS characteristic peaks of the element to be measured. The element to be measured includes Sn 3d, W 4f and Au 4f. The binding energy range of Sn 3d is 480-497 eV, the binding energy range of W 4f is 30-37 eV, and the binding energy range of Au 4f is 78-97 eV.

[0024] The function used to add the data tables in step (4) is shown in equation (1):

[0025] =SUM('sheet1:sheetn!A1:A1) (1),

[0026] Where n in sheetn is the number of images contained in a certain element of data;

[0027] The averaging process involves taking an average value for every 4×4 data area, and the function used is shown in equation (2):

[0028] =AVERAGE(sheetsum!A1:D4) (2),

[0029] Among them, sheetsum is a new data table obtained by summing the signal intensities of all images. After averaging, we obtained 256×256 data points that can basically reflect the chemical information of the device surface.

[0030] The re-averaging process involves taking an average value again within each 4×4 data region, and the function used is shown in equation (3):

[0031] =AVERAGE(OFFSET($A$1,(ROW()-1)×4,(COLUMN()-1)×4,4,4)) (3).

[0032] Au nanoparticles exhibit localized surface plasmon resonance, enabling them to efficiently capture visible light and localize the light energy on the WO3 surface. This significantly expands the device's utilization range of the solar spectrum and compensates for WO3's primary absorption of ultraviolet light. Through the plasmon effect and electronic mediation of Au, this device material constructs a highly efficient synergistic pathway from light absorption and charge separation to surface reaction. After surface etching, patterns of 400-800 μmd are formed on the device surface. Image data is output via a data table, and a 3D view is generated using a best-fit formula, visualizing the charge transfer process.

[0033] This invention also provides the application of the aforementioned three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS in the investigation of space charge transfer using light-assisted in-situ imaging.

[0034] The application compares the three-dimensional views of the same element under dark and illuminated conditions. By observing the increase, decrease and distribution range of the red area representing high signal intensity in three-dimensional space before and after illumination, the inflow or outflow state of photogenerated electrons can be determined, thereby intuitively reflecting the transfer direction and reaction sites of space charge.

[0035] The method for determining the inflow or outflow state of photogenerated electrons includes:

[0036] If the red area representing high signal intensity decreases in the 3D view after illumination, it is determined that photogenerated electrons have flowed into the material layer corresponding to that element.

[0037] If the red area representing high signal intensity increases in the 3D view after illumination, it is determined that photogenerated electrons are flowing out from the material layer corresponding to that element.

[0038] The beneficial effects of this invention are:

[0039] 1. This invention discloses a highly efficient and intuitive method for detecting elemental surface information and, through data processing optimization, generating 3D views to explore the space charge transfer mechanism under light irradiation. A noble metal-doped FTO / WO3@Au device is designed. Compared to single photocatalysts, noble metal doping enhances photocatalytic activity, synergistically improving the activity of the photocatalyst and making it more efficient. This FTO / WO3@Au device constructs a highly efficient synergistic pathway from light absorption, charge separation to surface reaction through the plasma effect and electronic mediation of Au. Using this imaging data processing method, two-dimensional image information can be transformed into three-dimensional spatial information, allowing detection of the specific location of space charge transfer accumulation in the longitudinal spectrum. By observing changes in color intensity and spatial scale before and after illumination, the direction of electron flow and specific reaction sites can be detected more intuitively.

[0040] 2. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS provided by this invention, compared with the traditional method of analyzing XPS under illumination combined with energy dispersive spectroscopy, transforms linear characteristic peak changes into planar 3D views, achieving a significant paradigm shift. By converting two-dimensional image information into three-dimensional spatial information, the specific location of space charge transfer accumulation can be detected in the vertical spectrum. By observing changes in color intensity and spatial scale before and after illumination, the direction of electron flow and specific reaction sites can be detected more intuitively. This method provides researchers with an unprecedentedly powerful tool, enabling them to intuitively and quantitatively analyze the spatial separation and transfer behavior of photogenerated charges in complex heterojunction systems. This not only greatly deepens the understanding of the microscopic mechanisms of photocatalysis, photoelectrochemistry, and other processes, but also provides direct image evidence and innovative ideas for the rational design and optimization of high-performance energy materials. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a traditional in-situ XPS sampling spectrum and a schematic diagram of the device.

[0043] Figure 2 The best-fit images for Au 4f, W 4f, and Sn 3d under both light-assisted and light-assisted imaging spectra are shown.

[0044] Figure 3 This is a 3D color projection image of Au 4f obtained from data processing.

[0045] Figure 4 This is a 3D color projection image obtained by W4f based on data processing.

[0046] Figure 5 This is a 3D color projection image of Sn3d obtained from data processing. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The examples used an X-ray photoelectron spectroscopy (XPS) instrument, model SHIMADZU AXIS SUPRA, Kratos Analytical Inc., for testing, and CasaXPS analysis software for data analysis.

[0049] Example

[0050] A three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS is proposed, with the following specific steps:

[0051] (1) Preparation of FTO / WO3@Au device: FTO conductive glass was ultrasonically cleaned for 15 minutes each in deionized water, acetone and isopropanol to remove organic matter and particles from the surface, and dried with nitrogen for later use; WO3 layer was prepared on FTO glass by sol-gel spin coating method. 0.2 g WCl6 was dissolved in 40 mL of anhydrous ethanol and magnetically stirred until completely dissolved. The pH of the solution was adjusted to 1.5 with concentrated hydrochloric acid (37%) and magnetically stirred until the solution was clear, and a light purple solution was obtained as WO3 precursor solution; the cleaned FTO glass was placed in an ultraviolet ozone cleaner for 30 minutes. After min, the WO3 precursor solution was dropped onto the FTO glass, dried, and then annealed in a Magee furnace at 400℃ for 2 hours (heating rate 2℃ / min) to improve the crystallinity of WO3, thus obtaining the FTO / WO3 device. 1g of tetrachloroauric acid hydrate was added to a brown reagent bottle containing 50mL of deionized water and stirred until completely dissolved to obtain an orange transparent chloroauric acid solution. This solution was dropped onto the surface of the FTO / WO3 device and then placed under a xenon lamp for 20 min to carry out a photoreduction reaction until the solution was completely dry. After completion, the FTO / WO3@Au device was obtained. The prepared device was placed in a sample box, vacuumed, and sealed.

[0052] (2) Traditional XPS spectroscopy in the dark: The FTO / WO3@Au device obtained in step (1) is patterned on the surface using laser etching to make the surface information of the sample at different thicknesses show different binding energy intensities; when the sample device is placed in the transition chamber, all light sources are turned off, and the vacuum value of the transition chamber is 10 -8 Torr below, while the vacuum value of the test chamber inside reaches 10. -9 When the Torr is below a certain value, the device is sent to the test chamber for testing. The test emission current is 10mA and the flux is 80. Selective testing is performed to obtain the XPS characteristic peak spectrum of the corresponding elements.

[0053] (3) Light-assisted XPS imaging acquisition: In-situ light-assisted XPS testing was conducted, and the migration pathway of photogenerated electrons at the interface of the heterostructure photocatalyst was studied using X-ray photoelectron spectroscopy (XPS). A monochromatic Al Kα X-ray source (1486.6 eV) was used for in-situ light-illuminated XPS testing. The light-assisted monochromatic light source with a wavelength of 365 nm was used as the photoexcitation source to investigate the transfer of photogenerated charges. In XPS imaging, the mode was set to image stack mode, and in the excitation settings, the tuning was set to imaging, and the emission current was set to 15 mA. The lens mode was set to FOV3 imaging, and the resolution was set to 80. In the image stack settings, the step size was set to 0.1 eV and the binding energy range for element spectral acquisition was set to 60 s, obtaining normal illumination spectrum data. Image data at integer binding energies were used for post-processing and plotting. There were 171 image data points for Sn 3d in the range of 480-497 eV, 71 image data points for W 4f in the range of 30-37 eV, and 131 image data points for Au 4f in the range of 78-91 eV.

[0054] (4) Data processing: Image spectral acquisition is performed within the conventional binding energy range of the detected element. The data points in a single image are 256×256, and the value of each point represents the strength of the characteristic photoelectron signal at that point. It is still difficult to intuitively read the signal strength changes from the processed image. Therefore, we use ESCApe software to export the imaging data of some binding energies in CSV format. Excel is used to digitize the signal at the same position in each image to obtain the overall situation of the photoelectron signal. First, the data tables corresponding to each acquired spectrum are summed. The function used is shown in Equation (1):

[0055] =SUM('sheet1:sheetn!A1:A1) (1);

[0056] We apply this to each cell. Then, to avoid excessive differences in the values ​​between data points, which would make the drawn graph difficult to read, we take the average of the obtained overall data to weaken other interfering data. That is, we take an average value for every 4×4 data area, and the function used is shown in equation (2):

[0057] =AVERAGE(sheetsum!A1:D4) (2);

[0058] After averaging, we obtained 256×256 data points that can basically reflect the chemical information of the device surface. Next, in order to further emphasize the features of the image and weaken other interfering data, we extracted the averaged data again, that is, we averaged the data area every 4×4, and finally obtained 64×64 averaged data for drawing the image. The function used is shown in equation (3):

[0059] =AVERAGE(OFFSET($A$1,(ROW()-1)×4,(COLUMN()-1)×4,4,4)) (3).

[0060] (5) Use the feature data obtained in step (4) to draw a three-dimensional color projection map to obtain a three-dimensional visualization analysis image.

[0061] Figure 1 The XPS spectra of the FTO / WO3@Au device prepared in this invention show that, under in-situ illumination testing, Figure 1 The a-value shows that the Sn 3d peak exhibits a general trend of negative binding energy shift, proving that photogenerated electrons flow into the FTO surface under photoexcitation. Similarly, Figure 1 c shows that the Au 4f peak generally exhibits a negative shift in binding energy, proving the influx of photogenerated electrons. Figure 1 b shows that the characteristic peaks of W 4f generally exhibit a positive trend of binding energy shift, proving that photogenerated electrons flow out of WO3 under photoexcitation. Figure 1 Figure d shows a schematic diagram of the FTO / WO3@Au device after etching. To clearly observe the phenomenon, we used light-assisted imaging to obtain the following results: Figure 2 The results shown are consistent with the previous conclusions.

[0062] However, simple 2D images fail to reveal specific electron transfer sites and make it difficult to observe strong reaction regions, or pinpoint the exact area affected. This invention utilizes a 3D visualization method for space charge transfer. After data processing, a three-dimensional colored projection method using the Origin matrix perfectly visualizes the specific location where space charge transfer accumulates. Its projected portion... Figure 2 The image comparison shows a high degree of consistency, proving the scientific validity and reliability of the method. The results are as follows... Figure 3-5 As shown. Figure 3 The 3D view of Au 4f before and after illumination shows that the red area representing high binding energy is reduced, proving the influx of photogenerated electrons. Figure 4The 3D view of W4f before and after illumination shows an increase in the red area representing high binding energy, indicating the outflow of photogenerated electrons. Figure 5 The 3D views of Sn 3d before and after illumination show a reduction in the red region representing high binding energy, indicating the influx of photogenerated electrons. In summary, by observing changes in color intensity and spatial scale before and after illumination, the direction of electron flow and specific reaction sites can be detected more intuitively. Furthermore, it allows for intuitive and quantitative analysis of the spatial separation and transfer behavior of photogenerated charges in complex heterostructure systems.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS, characterized in that, Includes the following steps: (1) Preparation of FTO / WO3@Au device: After cleaning the FTO conductive glass, surface treatment is performed. WCl6 is dissolved in a solvent to adjust the pH of the solution to obtain WO3 precursor solution, which is dropped onto the treated FTO conductive glass. After drying, annealing is performed to obtain FTO / WO3 device. Chloroauric acid solution is dropped onto the surface of FTO / WO3 device and photoreduction reaction is performed to obtain FTO / WO3@Au device. After surface etching treatment, the desired sample is obtained. (2) Conventional XPS spectral acquisition in dark state: After placing the sample obtained in step (1) in the XPS transition chamber, turn off the light source. After the vacuum degree reaches the required level, send it into the test chamber for testing to obtain conventional dark state spectral data. (3) XPS imaging acquisition under light assistance: Turn on the in-situ light source and perform XPS imaging on the sample surface under illumination to obtain conventional illumination spectrum data. (4) Data processing: Use Excel to process the signal at the same location in each image. First, add the data tables of each acquired image to obtain the total signal intensity distribution. Then, perform averaging and average the average data again to obtain 64×64 feature data. (5) Use the feature data obtained in step (4) to draw a three-dimensional color projection map to obtain a three-dimensional visualization analysis image.

2. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 1, characterized in that: The FTO conductive glass cleaning in step (1) involves ultrasonic cleaning with deionized water, acetone, and isopropanol in sequence; the surface treatment involves treatment with an ultraviolet ozone cleaner for 15-30 minutes; the initial concentration of WCl6 is 3-5 mg / mL, the solvent is anhydrous ethanol, and the pH of the solution is adjusted to 1-2 using concentrated hydrochloric acid; the annealing temperature is 400-450℃, and the time is 1.5-3 hours; the thickness of the WO3 layer in the FTO / WO3 device is 10-100 nm.

3. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 2, characterized in that: In step (1), the concentration of the chloroauric acid solution is 0.02-0.05 g / mL, the photoreduction reaction is carried out by irradiation with a xenon lamp for 15-30 min, and the surface etching treatment is carried out by pattern etching on the surface of the device using laser etching.

4. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 3, characterized in that: The vacuum level required in step (2) is that the vacuum value of the transition chamber reaches 10. -8 Torr below, while the vacuum value of the test chamber reaches 10. -9 Below Torr, the test transmit current is 10mA and the flux is 80.

5. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 4, characterized in that: In step (3), the light source is a monochromatic Al Kα X-ray source as the XPS excitation source, and light with a wavelength of 365 nm is used as the in-situ light-assisted excitation source. In XPS imaging mode, set it to image pack mode, and in the excitation mode settings, set the tuning to imaging and the emission current to 15 mA. Lens mode is set to FOV3 imaging, and power is set to 80. In the image packet settings, the step size is set to 0.1 eV and the single acquisition time is set to 60 s.

6. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 5, characterized in that: The spectral range selected in step (2) or step (3) is the range of XPS characteristic peaks of the element to be measured. The element to be measured includes Sn 3d, W 4f and Au 4f. The binding energy range of Sn 3d is 480-497 eV, the binding energy range of W 4f is 30-37 eV, and the binding energy range of Au 4f is 78-97 eV.

7. The three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS according to claim 6, characterized in that: The function used to add the data tables in step (4) is shown in equation (1): =SUM('sheet1:sheetn!A1:A1) (1), Where n in sheetn is the number of images contained in a certain element of data; The averaging process involves taking an average value for every 4×4 data area, and the function used is shown in equation (2): =AVERAGE(sheetsum!A1:D4) (2), Where sheetsum is a new data table obtained by summing the signal strengths of all images; The re-averaging process involves taking an average value again within each 4×4 data region, and the function used is shown in equation (3): =AVERAGE(OFFSET($A$1,(ROW()-1)×4,(COLUMN()-1)×4,4,4)) (3).

8. The application of the three-dimensional visualization analysis method for space charge transfer based on in-situ light-assisted XPS as described in any one of claims 1-7 in light-assisted in-situ imaging for investigating space charge transfer.

9. The application according to claim 8, characterized in that: The application compares the three-dimensional views of the same element under dark and illuminated conditions. By observing the increase, decrease and distribution range of the red area representing high signal intensity in three-dimensional space before and after illumination, the inflow or outflow state of photogenerated electrons can be determined, thereby intuitively reflecting the transfer direction and reaction sites of space charge.

10. The application according to claim 9, characterized in that, The method for determining the inflow or outflow state of photogenerated electrons includes: If the red area representing high signal intensity decreases in the 3D view after illumination, it is determined that photogenerated electrons have flowed into the material layer corresponding to that element. If the red area representing high signal intensity increases in the 3D view after illumination, it is determined that photogenerated electrons are flowing out from the material layer corresponding to that element.

Images