In-situ characterization method and device for perovskite material electro-ionic migration

Abstract

The invention discloses an in-situ characterization method and device for perovskite material electrogenerated ion migration, and relates to material science and surface analysis. The in-situ characterization method for perovskite material electrogenerated ion migration comprises the following steps: S1, depositing a metal electrode on a perovskite film to form a channel region, and obtaining a perovskite sample; s2, applying a controllable voltage to the metal electrode of the perovskite sample by using an external power supply, performing surface bombardment on the perovskite sample by using a time-of-flight secondary ion mass spectrometry, detecting excited secondary ions through the time-of-flight secondary ion mass spectrometry to obtain ion migration information in the perovskite sample, and imaging; and representing the electro-ionic migration of the perovskite material according to the ionic migration information and the image. According to the method, in-situ monitoring, high spatial resolution and real-time dynamic observation can be realized.

Description

Technical Field

[0001] The present invention relates to materials science and surface analysis, and in particular to an in-situ characterization method and device for electroinduced ion migration of perovskite materials. Background Art

[0002] Perovskite materials are widely used in solar cells, light-emitting diodes, and photodetectors due to their excellent optoelectronic properties, such as high absorption coefficient, long carrier diffusion length, and tunable band gap. However, the long-term stability of perovskite-based devices, especially the stability degradation caused by ion migration in the material, has seriously restricted their application. Ion migration in perovskite materials, such as Cs + 、CH(NH2)2 + 、CH3NH3 + The migration of cations and anions such as I- is one of the key factors leading to device performance degradation. Therefore, developing a high-spatial-resolution characterization method that can monitor and quantify ion migration in perovskite materials in real time under the action of an electric field is crucial for understanding material failure mechanisms, optimizing device design, and improving device stability.

[0003] Currently, most techniques used to study ion migration in perovskites include electrochemical impedance spectroscopy, transient ion current analysis, fluorescent labeling and tracking, and X-ray photoelectron spectroscopy imaging. However, each of these characterization techniques has limitations: electrochemical impedance spectroscopy and transient ion current analysis provide average information about a sample or a larger area, lack high-spatial-resolution ion distribution images, and are difficult to accurately depict local ion migration behavior; while fluorescent labeling and tracking can track the migration path of specific ions, it requires the introduction of exogenous probes, which may interfere with the properties of the original material and even introduce additional impurity ions, affecting the accuracy of the experimental results; X-ray photoelectron spectroscopy images the elements at different valence states on the sample surface, but its spatial resolution is low, typically at the level of tens to hundreds of microns, which cannot meet the requirements for high-precision, micro-scale characterization of ion migration in perovskite materials. When characterizing the electroinduced ion migration behavior of perovskite materials, the above-mentioned detection technologies have failed to fully address the needs of in-situ monitoring, high spatial resolution, and real-time dynamic observation. In particular, there are obvious technical bottlenecks in exploring the laws of ion migration induced by electric fields. Summary of the Invention

[0004] The main purpose of the present invention is to provide an in-situ characterization method and device for electro-induced ion migration of perovskite materials, so as to solve the problem in the prior art that it is difficult to achieve in-situ monitoring, high spatial resolution and real-time dynamic observation when characterizing the electro-induced ion migration behavior of perovskite materials.

[0005] To achieve the above object, according to one aspect of the present invention, a method for in-situ characterization of electroinduced ion migration in perovskite materials is provided, comprising the following steps:

[0006] S1, depositing a metal electrode on the perovskite film to form a channel region to obtain a perovskite sample;

[0007] S2, applying a controllable voltage to the metal electrode of the perovskite sample using an external power supply, and simultaneously bombarding the surface of the perovskite sample using time-of-flight secondary ion mass spectrometry, detecting the excited secondary ions by time-of-flight secondary ion mass spectrometry, obtaining ion migration information in the perovskite sample and imaging it;

[0008] Characterize the electroinduced ion migration of perovskite materials based on ion migration information and imaging.

[0009] Furthermore, the material of the metal electrode includes at least one of Au, Ag, Cu, and Al.

[0010] Furthermore, the shape of the channel region includes one of a straight shape and a serpentine shape; the thickness of the metal electrode is 50 nm to 70 nm, and the width of the channel region is 100 μm to 400 μm.

[0011] Furthermore, the voltage of the external power supply is 5V to 25V, and the voltage resolution is not less than 10mV.

[0012] Furthermore, the step of using the time-of-flight secondary ion mass spectrometry to perform surface bombardment on the perovskite sample includes: placing the perovskite sample in the vacuum chamber of the time-of-flight secondary ion mass spectrometry, using the primary ion beam of the time-of-flight secondary ion mass spectrometry as a bombardment source, performing surface bombardment on the channel area of ​​the perovskite sample and exciting secondary ions, and at the same time using the electron neutralization gun of the time-of-flight secondary ion mass spectrometry as a neutralization source.

[0013] Furthermore, the primary ion beam includes Bi 3+ 、Ga + At least one of the above, the ion energy of the primary ion beam is 20keV to 40keV; the vacuum chamber includes an inert gas, preferably, the inert gas includes at least one of helium and nitrogen.

[0014] Furthermore, before step S2, the method further includes: using a low-energy ion beam to clean the surface of the perovskite sample, wherein the low-energy ion beam includes Ar + Ion beam, the voltage of the low-energy ion beam is 0.5kV~3kV, the beam current intensity of the low-energy ion beam is 100nA~300nA; the cleaning time is 5s~15s.

[0015] Furthermore, the preparation method of the perovskite film includes: mixing a perovskite precursor, a first solvent and an anti-solvent to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution on a substrate, and obtaining a perovskite film after annealing; wherein the first solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, chlorobenzene, iodomethane, chloromethylamine, and lead iodide; the anti-solvent includes ethyl acetate; the spin coating speed is 5000 rpm to 7000 rpm, and the spin coating time is 15s to 45s; the annealing temperature is 80°C to 120°C, and the annealing time is 1h to 3h.

[0016] A second aspect of the present invention provides an electric field coupled time-of-flight secondary ion mass spectrometry apparatus for performing the in-situ characterization method of electric ion migration of perovskite materials according to the first aspect, the apparatus comprising a time-of-flight secondary ion mass spectrometry apparatus body and an external power supply electrically connected to the time-of-flight secondary ion mass spectrometry apparatus body;

[0017] The main body of the time-of-flight secondary ion mass spectrometer includes a vacuum chamber, a primary ion beam emission unit, and a secondary ion imaging unit. A sample holder is provided in the vacuum chamber for carrying the perovskite sample. The primary ion beam emission unit is used to emit a primary ion beam. The secondary ion imaging unit is used to image the excited secondary ions.

[0018] An external power supply is used to apply a controllable voltage to the perovskite sample.

[0019] Furthermore, the TOF-SIMS device body further includes an electron neutralization gun for neutralizing the charges generated by the bombardment of the primary ion beam.

[0020] The application of the technical solution of the present invention, by utilizing a controllable external power supply coupled to time-of-flight secondary ion mass spectrometry, helps to realize in-situ dynamic monitoring of external electric field-induced ion migration, and captures the change of ion concentration with voltage in real time, helps to build a spatiotemporal resolution model of ion migration, thereby helping to establish the relationship between electric field intensity and ion migration, and provides a basis for studying the stability degradation mechanism and ion migration kinetic mechanism of perovskite materials. In addition, the present invention avoids the interference of the introduction of exogenous probes on the sample, ensures the accuracy and reliability of the test results, and ensures that the in-situ characterization method provided by the present invention has high sensitivity and high spatial resolution. In practical applications, it helps to accelerate the development of new perovskite materials and device optimization, and lays a solid foundation for the development process of high-performance, high-stability perovskite photovoltaic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a top view of a perovskite sample according to one embodiment of the present invention;

[0022] Figure 2Schematic diagram of bombarding the surface of a perovskite sample with a high-energy ion beam in one embodiment of the present invention;

[0023] Figure 3 A diagram showing the connection relationship between a TOF-SIMS instrument and an external power supply in one embodiment of the present invention;

[0024] Figure 4 A diagram showing the connection relationship between a sample holder and an external power supply in one embodiment of the present invention;

[0025] Figure 5 ion migration distribution of different ions under different electric field strengths in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0027] As described in the background of the present invention, the prior art has difficulties in achieving in-situ monitoring, high spatial resolution, and real-time dynamic observation when characterizing the electroinduced ion migration behavior of perovskite materials. To address the above problems, in a typical embodiment of the present invention, a method for in-situ characterization of electroinduced ion migration of perovskite materials is provided, comprising the following steps:

[0028] S1, depositing a metal electrode on the perovskite film to form a channel region to obtain a perovskite sample;

[0029] S2, using an external power supply to apply a controllable voltage to the metal electrode of the perovskite sample, while simultaneously bombarding the surface of the perovskite sample using time-of-flight secondary ion mass spectrometry. The excited secondary ions are detected by time-of-flight secondary ion mass spectrometry to obtain ion migration information in the perovskite sample and image it; the electroinduced ion migration of the perovskite material is characterized based on the ion migration information and imaging.

[0030] Specifically, in step S1, the deposition of the metal electrode can be achieved by a physical or chemical deposition process (such as evaporation, sputtering, chemical vapor deposition, etc.). The deposition of the metal electrode not only provides a path for applying the electric field, but also the selection of its metal material can ensure good contact between the electrode and the perovskite film, reduce the contact resistance, and thus improve the uniformity and effectiveness of the electric field. Metal electrodes are deposited on the perovskite film to form a specific channel area. This structure can establish electrical contact between different areas of the perovskite film, so that the migration behavior of ions in the perovskite material can be observed and measured under the action of an external power supply, which is the basis for realizing in-situ characterization of electroinduced ion migration. Among them, the metal electrode refers to a series of continuous or spaced lines or patterns formed on the perovskite film by a metal electrode. These channel areas can be parallel or serpentine in order to establish an electric field between different parts of the perovskite film. The shape and layout of the metal electrode and the channel area are controlled by a mask or micro-nano manufacturing technology.

[0031] The portion of the perovskite film that is not covered by the metal and is surrounded by the metal electrodes is called the channel region. In these uncovered areas between the metal electrodes, i.e., the channel region, ions can move in a directed manner under the action of the electric field. Therefore, the channel region is a region that can exhibit electroinduced ion migration behavior under an external voltage. When a voltage is applied between the metal electrodes, an electric field is formed in the channel region of the perovskite film, which causes the ions in the perovskite lattice (such as Cs + , FA + , I-, etc.) migrate in the forward or reverse direction of the electric field. The layout of the metal electrodes directly affects the distribution and intensity of the electric field, which in turn affects the path and efficiency of ion migration. By regulating the voltage between the metal electrodes, the electric field strength in the channel region can be adjusted, thereby controlling the migration behavior of the ions.

[0032] In the in-situ characterization method of electroinduced ion migration of perovskite materials, metal electrodes are used to apply and control the electric field, while the channel region is the place to observe the ion migration behavior under the electroinduced effect. The concentration changes and spatial distribution of different ions in the channel region are detected by time-of-flight secondary ion mass spectrometry (TOF-SIMS), thereby revealing the ion migration law of the perovskite material under the action of the electric field. In this way, the application of an external power supply causes the ions in the perovskite material to migrate, and the time-of-flight secondary ion mass spectrometry device can capture this process with a spatial resolution of microns, providing a dynamic image of ion migration. This in-situ characterization technology can not only reveal the stability degradation mechanism of perovskite materials under the action of electric fields, but also help to understand their internal charge transfer characteristics, providing key information for the optimized design of perovskite photovoltaic devices.

[0033] In step S2, the perovskite sample is loaded onto a sample holder, ensuring that the metal electrode is reliably connected to the conductive contacts on the holder so that an external power signal can be applied; the perovskite sample provided with the metal electrode is placed in the cavity of a time-of-flight secondary ion mass spectrometry (TOF-SIMS) device. Through the conductive connections on the sample holder, an external power source (such as a DC electric field) can be precisely applied to the metal electrode of the sample, forming a specific electric field strength and direction to drive ion migration. At the same time, the TOF-SIMS device is started and a primary ion beam is used to bombard the surface of the perovskite sample to excite secondary ions. These secondary ions are then separated and detected in the TOF-SIMS according to their mass-to-charge ratio, thereby obtaining elemental composition information and chemical state of the sample surface. During the application of voltage and bombardment process, the TOF-SIMS records the signal intensity and spatial distribution of different types of secondary ions in real time, forming a two-dimensional or three-dimensional spatial distribution image of the ions. By changing the voltage, electric field strength or direction of the external power supply in real time or quasi-real time while continuously collecting TOF-SIMS data, the ion migration behavior of the perovskite material under the electrogenic effect can be dynamically tracked. These data include the spatial distribution information of secondary ions, reflecting the concentration changes and migration paths of ions in perovskite films at different potentials.

[0034] By comparing the differences in ion distribution of perovskite samples at different voltages, the changes in ion concentration and spatial rearrangement caused by electromigration can be identified. The ion images obtained using TOF-SIMS intuitively display the dynamic migration paths and aggregation areas of ions in the perovskite material, providing high-spatial-resolution imaging information. Based on the ion migration information and imaging results, the electro-induced ion migration mechanism of the perovskite material is analyzed, and the influence of voltage or electric field strength on the ion migration rate, direction, and distribution is evaluated, providing a scientific basis for further optimizing the performance of perovskite materials and devices. For example, the collected secondary ion data can be processed to generate a concentration distribution map of specific ions in the perovskite film. By comparing the changes in ion distribution at different voltages, the laws of ion migration in the perovskite material under the electro-induced effect are observed and analyzed, and an image of the relationship between ion migration and electric field strength is established.

[0035] In characterizing the electroinduced ion migration of perovskite materials based on ion migration information and imaging, firstly, TOF-SIMS can provide detailed ion species information based on the mass-to-charge ratio of secondary ions, including cations (such as Cs + , FA + , Pb +) and anions (such as I-, PbI3-); secondly, under the action of the electric field, some ions may migrate from one end of the metal electrode to the other, resulting in uneven distribution in the film. The present invention can determine the concentration distribution changes of specific ions in the perovskite material by analyzing the ion images collected under different electric fields; in addition, by comparing the ion images under different electric fields, the path of ion migration can be observed. As the electric field gradually increases or changes, the movement trajectory of ions in the perovskite film will be clearly reflected in the image, which helps to understand the specific effect of electric field strength on ion migration. According to the obtained image, a line scanning intensity curve is made for the intensity at different pixel points for superposition and comparison, for example, one or more scanning lines are defined in the image. The scanning line can be horizontal, vertical, a straight line at any angle, or a curve. Along the selected scanning line, the grayscale value of each pixel is extracted, and these grayscale values ​​constitute an intensity curve; the intensity curves of different scanning lines are superimposed in the same coordinate system, usually with the position on the scanning line as the horizontal coordinate and the grayscale value as the vertical coordinate. This allows for intuitive comparison of grayscale trends at different locations using the graph. By observing the superimposed intensity curves, image characteristics can be analyzed. Specifically, specific algorithms can be used to process the intensity curves, such as smoothing and filtering, to remove noise. Finally, the processed and analyzed results can be used to characterize the electroinduced ion migration of the perovskite material.

[0036] Analyzing ion migration information helps to analyze the relationship between applied potential and ion migration speed; using statistical analysis and modeling methods, a quantitative relationship between potential and ion migration behavior in perovskite materials can be established, including how the migration speed, direction and efficiency change with potential.

[0037] The high spatial resolution of TOF-SIMS can distinguish between the bulk ion migration of perovskite materials and the ion behavior at the interface (electrode-perovskite), which helps to study the long-term stability and performance degradation mechanism of perovskite devices; based on the ion migration information, the defects or trap states in the perovskite film can be revealed. For example, non-uniform ion distribution may indicate the presence of ion traps or defect locations. This information is instructive for material optimization and device performance improvement.

[0038] Therefore, the above characterization and analysis will help us to deeply understand the ion migration mode, speed and mechanism of perovskite materials under the action of electric fields. For example, based on the characteristics of electroinduced ion migration, it will help to design more stable perovskite materials and reduce the performance degradation caused by ion migration, thereby achieving the performance optimization of perovskite materials; secondly, it will help to optimize the structure and working conditions of devices such as perovskite solar cells and light-emitting diodes to improve their efficiency and stability; in addition, it will help to study the aging and failure process of perovskite materials under electric fields, light and other conditions, and provide a theoretical basis for extending the life of devices.

[0039] The in-situ characterization method of the present invention achieves in-situ, high-resolution characterization of the electro-induced ion migration of perovskite materials by real-time monitoring of electro-induced ion migration, combining metal electrodes with perovskite films, and the synergistic effect of an external power supply and a time-of-flight secondary ion mass spectrometer, thereby achieving accurate detection of ion migration behavior in perovskite materials. This in-situ characterization method can not only reveal the microstructural changes of perovskite materials under the action of an electric field, but also provide detailed information about the ion migration path and rate, which is of great significance for understanding the stability degradation mechanism of perovskite materials. By avoiding the use of exogenous probes, sample contamination and test errors are reduced, and the accuracy and reliability of the data are improved. In the field of photovoltaic material research, the application of this technology can accelerate the screening and optimization of new perovskite materials, promote the commercialization process of high-performance perovskite solar cells, and has broad market prospects and application value.

[0040] In some embodiments, the material of the metal electrode includes at least one of gold, silver, copper, and aluminum. The material selection of the metal electrode (including but not limited to gold, silver, copper, and aluminum) is based on its electrical conductivity, chemical stability, and compatibility with the perovskite material. For example, gold is a commonly used electrode material because of its good electrical conductivity and chemical stability. It can effectively avoid chemical reactions with the perovskite material under the action of the electric field, reducing interference with the sample. Silver, copper, and aluminum also have excellent electrical conductivity and relatively low cost, and are suitable for large-scale testing. Through the use of these metal electrodes, the effective transmission of the electric field and the stability of the sample are ensured, thereby improving the accuracy and reliability of the ion migration information detection.

[0041] In some embodiments, the shape of the channel region includes one of a straight shape and a serpentine shape; the thickness of the metal electrode is 50 nm to 70 nm, and the width of the channel region is 100 μm to 400 μm.

[0042] Specifically, the straight channel region is surrounded by two parallel metal electrodes to form a straight channel region. The serpentine channel region is surrounded by two interdigitated metal electrodes, and its channel region is arranged in a zigzag serpentine path along the surface of the sample. The thickness of the metal electrode is in the range of 50nm to 70nm. The metal electrode of this thickness can ensure good contact between the electrode and the perovskite film and provide a stable channel for applying the electric field, but it will not be too thick to affect the optical and electrical properties of the perovskite film, especially it will not block the bombardment of the TOF-SIMS primary ion beam on the film, ensuring the accuracy and integrity of the data. The width of the channel region is 200μm to 400μm, which helps to achieve high spatial resolution and observe the details of local ion migration.

[0043] The present invention selects the most appropriate metal electrode shape and size by comprehensively considering the experimental objectives, sample characteristics, and the limitations of the detection equipment used. Controlling the shape and size of the metal electrode facilitates the application of a uniform electric field and reduces edge effects, leading to more accurate detection of ion migration in perovskite materials. The thickness and width of the electrode ensure sufficient conductivity and effective sample coverage.

[0044] In some embodiments, the voltage of the external power supply is 5V to 25V, and the voltage resolution is not less than 10mV. By controlling the parameter settings of the external power supply, it is helpful to precisely control the electric field strength in the perovskite material to study the behavior of ion migration under different electric field conditions. The high voltage resolution ensures fine-tuning of the electric field strength, which helps to study the response of the perovskite material under weak electric fields. Through this precise control, the stability of the perovskite material in actual working environments and the influence of the electric field on the material properties can be deeply studied, providing an experimental basis for the optimized design of perovskite photovoltaic devices.

[0045] In the specific implementation process of the present invention, a time-of-flight secondary ion mass spectrometer (TOF-SIMS) instrument continuously performs surface scanning imaging on the channel area of ​​the perovskite sample to record the types of different secondary ions and their spatial distribution. First, the ion distribution data of a period of time (3 minutes) is collected as a benchmark without applying a bias voltage (0V); then, the voltage applied between the two electrodes of the sample is gradually increased through an external power supply, specifically: the voltage is increased by a fixed value (such as 3V) every certain time (120 seconds) until the preset maximum voltage (such as 15V) is reached or significant ion migration is observed; at each voltage step point or during the voltage stabilization period, TOF-SIMS imaging is continuously collected; during the entire test process, different ions in the channel area (such as Cs + 、CH2N + 、CH3NH3 + 、Na + , Pb + , PbI3-, etc.) at different voltages are observed and recorded in real time, and the distribution of different ions at different electric field strengths is obtained.

[0046] In some embodiments, the step of using a time-of-flight secondary ion mass spectrometry device to perform surface bombardment on a perovskite sample includes: placing the perovskite sample in a vacuum chamber of the time-of-flight secondary ion mass spectrometry device, using the primary ion beam of the time-of-flight secondary ion mass spectrometry device as a bombardment source, performing surface bombardment on the channel area of ​​the perovskite sample and exciting secondary ions, and simultaneously using the electron neutralization gun of the time-of-flight secondary ion mass spectrometry device as a neutralization source.

[0047] Specifically, bombarding the perovskite sample with a primary ion beam from a time-of-flight secondary ion mass spectrometer under a vacuum environment effectively excites secondary ions on the sample surface. These secondary ions carry information about ion migration within the perovskite material. By controlling the beam intensity and ion energy of the primary ion beam, the mildness of the bombardment process and the efficiency of ion excitation are ensured. The use of an electron neutralization gun effectively neutralizes the charge accumulation generated during the bombardment process, preventing charge effects from interfering with secondary ion detection and improving the accuracy and resolution of the characterization.

[0048] In some embodiments, the primary ion beam includes Bi 3+ 、Ga + At least one of the above, the ion energy of the primary ion beam is 20keV to 40keV; by controlling the primary ion beam under specific beam intensity and ion energy conditions, the surface analysis of the perovskite material can be performed efficiently and accurately, and the dynamic information of its ion migration under the electro-induced effect can be captured, while ensuring that the damage to the sample during the analysis process is minimized, thereby improving the quality and reliability of the experimental data.

[0049] In some embodiments, before step S2, the method further includes: using a low-energy ion beam to clean the surface of the perovskite sample, wherein the low-energy ion beam includes Ar + Ion beam, low energy ion beam voltage is 0.5kV ~ 3kV, beam current intensity is 100nA ~ 300nA. For example, low energy ion beam is 1kV, 200nA Ar + Ion beam cleaning takes 5 to 15 seconds. Surface cleaning of the perovskite sample is a critical step in ensuring the accuracy of subsequent testing. The cleaning process removes contaminants and impurities from the sample surface, reducing the impact of external factors on ion migration behavior. Furthermore, the use of a low-energy ion beam avoids sample damage, maintaining the integrity of the perovskite film and the effectiveness of the test. This pretreatment method provides a clean and stable sample surface for subsequent ion migration characterization, improving test reliability and data accuracy.

[0050] In some embodiments, a method for preparing a perovskite film includes: mixing a perovskite precursor, a first solvent, and an anti-solvent to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution on a substrate, and obtaining a perovskite film after annealing; wherein the first solvent includes at least one of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), chlorobenzene, iodomethane (CH5N2I), chloromethylamine (CH4NCl), and lead iodide (PbI2); the anti-solvent includes ethyl acetate; the spin coating speed is 5000 rpm to 7000 rpm, and the time is 15s to 45s; the annealing temperature is 80°C to 120°C, and the time is 1h to 3h.

[0051] The above-described perovskite film preparation method ensures uniformity and high quality. By precisely controlling the spin-coating speed and time, as well as the temperature and duration of the annealing treatment, the crystallinity and morphology of the perovskite film can be optimized, defects can be reduced, and the photoelectric properties of the material can be improved. This preparation method not only provides high-quality samples for subsequent ion transport characterization but also promotes the application of perovskite materials in photovoltaic devices and accelerates the development of high-performance perovskite solar cells.

[0052] On the other hand, the present invention provides an electric-field coupled time-of-flight secondary ion mass spectrometry device for performing the above-mentioned in-situ characterization method of electroinduced ion migration of perovskite materials. The device includes a time-of-flight secondary ion mass spectrometry device body and an external power supply electrically connected to the time-of-flight secondary ion mass spectrometry device body; the time-of-flight secondary ion mass spectrometry device body includes a vacuum chamber, a primary ion beam emission unit and a secondary ion imaging unit; a sample holder is provided in the vacuum chamber for carrying the perovskite sample; the primary ion beam emission unit is used to emit a primary ion beam; the secondary ion imaging unit is used to image the excited secondary ions; and the external power supply is used to apply a controllable voltage to the perovskite sample.

[0053] The use of the above-mentioned electric field-coupled time-of-flight secondary ion mass spectrometry device facilitates in-situ, real-time monitoring of ion migration behavior in perovskite materials. By precisely controlling the parameters of the external power supply and the primary ion beam, this device can excite and detect secondary ions on the surface of the perovskite sample, providing dynamic images of ion migration. The integration of the external power supply ensures the controllability and stability of the electric field, while the high resolution of the secondary ion imaging unit can reveal the details of ion migration, providing direct evidence for studying the stability mechanism of perovskite materials, helping to advance the research of perovskite materials science and providing a powerful tool for the development and optimization of high-performance perovskite photovoltaic devices.

[0054] In some embodiments, the main body of the time-of-flight secondary ion mass spectrometry device also includes an electron neutralization gun for neutralizing the charge generated by the bombardment of the primary ion beam. The use of the electron neutralization gun helps to ensure the accuracy of secondary ion mass spectrometry detection. In the process of the primary ion beam bombarding the perovskite sample, charge accumulation will occur, which may interfere with the flight path of the secondary ions and the detection results. The electron neutralization gun neutralizes these accumulated charges by emitting electrons to the sample surface, reducing the charge effect and improving the resolution and accuracy of secondary ion detection. This neutralization process is crucial for achieving ion migration imaging with micron-level spatial resolution, ensuring the reliability of the data and the repeatability of the experiment, and providing strong support for in-depth research on perovskite materials.

[0055] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0056] Example 1

[0057] 1. The electric field coupled time-of-flight secondary ion mass spectrometry device provided in this embodiment includes:

[0058] Utilize the original electrical interface (such as MS3106A 10-core electrical interface) for sample stage temperature control of commercial TOF-SIMS instruments (such as IONTOF GmbH M6) and connect it to a DC regulated external power supply via a cable. This allows the voltage applied to the sample to be precisely controlled within a range of 0 to 30 V (or other required range) with a voltage resolution of 10 mV. The connection between the TOF-SIMS instrument and the external power supply is as follows: Figure 3 As shown in the figure, the original sample holder of the TOF-SIMS instrument is redesigned. The potential originally applied to both ends of the sample heating wire is applied to the sample through lead wires. It is connected to the potential controller of the external power supply through a cable to achieve fine control of the sample surface voltage. The connection between the sample holder and the external power supply is shown in the figure. Figure 4 shown.

[0059] 2. The in-situ characterization method of electroinduced ion migration of perovskite materials in this embodiment includes the following steps:

[0060] S1, the perovskite precursor solution FA 0.95 Cs 0.05 PbI3 was deposited on clean glass by spin coating (dynamic spin coating, 6000 rpm, 30 s, and ethyl acetate was added as an anti-solvent), and then thermally annealed (100°C, 1 hour) to form a perovskite film layer. Then, a layer of metal (60 nm thick gold film) was deposited on the surface of the prepared perovskite film by physical coating (such as thermal evaporation) using a serpentine mask as a metal electrode. A channel region of a specific width (300 μm) was formed between the metal electrodes on both sides for observing ion migration, as shown in the following figure. Figure 1 The perovskite sample shown was used with a low energy ion source (1 kV, 200 nA Ar + The sample surface is briefly cleaned (10 s) by the ion source to remove impurities adsorbed on the surface and ensure that the detected ion signal mainly comes from the sample itself;

[0061] S2, the cleaned perovskite sample is loaded onto the modified sample holder, the contacts of the sample holder are reliably connected to the metal electrodes on the surface of the perovskite sample through wires and metal springs, and then the sample is sent into the ultra-high vacuum analysis chamber of the TOF-SIMS instrument, such as Figure 2 As shown, a high energy ion beam (30keV Bi 3+ions, with a beam current of 0.46 pA) as the primary ion source to bombard the sample surface and generate secondary ions, using an electron neutralization gun (21 eV electrons) and a low-pressure inert gas (such as 2×10 -6 mbar Ar gas) as a dual-beam neutralization source to compensate for the charge accumulation on the sample surface that may be caused by positive ion bombardment and secondary ion emission, ensuring the stability of the local electric field on the sample surface during the test;

[0062] After the test starts, the TOF-SIMS instrument continuously performs surface scanning imaging on the channel area of ​​the perovskite sample, recording the types of different secondary ions and their spatial distribution; first, the ion distribution data for a period of time (3 minutes) is collected as a benchmark without applying a bias voltage (0V); then, the voltage applied between the two electrodes of the sample is gradually increased through an external power supply. Specifically, the voltage is increased by a fixed value (3V) every certain time (120 seconds) until the preset maximum voltage (15V) is reached or significant ion migration is observed; TOF-SIMS data is continuously collected at each voltage step point or during voltage stabilization; the electric field strength is the voltage difference applied across the electrodes divided by the width of the adjacent electrodes. Therefore, under the condition of constant width, the electric field strength can be controlled by regulating the external voltage. During the entire test process, the different ions in the channel area (such as Cs + 、CH2N + 、Na + , Pb + , PbI3-, etc.) under different electric field strengths; According to the distribution of different ions under different electric field strengths, the test results are as follows Figure 5 shown.

[0063] Further, according to Figure 5 The image shown is a line scan intensity curve for the intensity at different pixel points, and is superimposed and compared. Specifically, one or more scan lines are defined in the image. The scan line can be horizontal, vertical, a straight line at any angle, or a curve. Along the selected scan line, the grayscale value of each pixel is extracted (for color images, the value of a certain color channel can be extracted, or the average value of all color channels can be calculated). These grayscale values ​​constitute an intensity curve; the intensity curves of different scan lines are superimposed in the same coordinate system, usually with the position on the scan line as the horizontal coordinate and the grayscale value as the vertical coordinate. In this way, the grayscale change trend at different positions can be intuitively compared according to the chart; by observing the superimposed intensity curve, the characteristics of the image can be analyzed. In some embodiments, a specific algorithm is used to process the intensity curve, such as smoothing, filtering, etc., to remove noise; finally, the electro-induced ion migration of the perovskite material is characterized based on the results of the processing and analysis.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An in-situ characterization method for electroinduced ion migration in perovskite materials, characterized in that: The following steps are involved: S1, depositing a metal electrode on the perovskite film to form a channel region to obtain a perovskite sample; S2, applying a controllable voltage to the metal electrode of the perovskite sample using an external power supply, and simultaneously bombarding the surface of the perovskite sample using time-of-flight secondary ion mass spectrometry, detecting excited secondary ions by the time-of-flight secondary ion mass spectrometry, obtaining ion migration information in the perovskite sample and imaging it; The electroinduced ion migration of the perovskite material is characterized according to the ion migration information and the imaging.

2. The in-situ characterization method according to claim 1, characterized in that The material of the metal electrode includes at least one of Au, Ag, Cu, and Al.

3. The in-situ characterization method according to claim 1, characterized in that The shape of the channel region includes one of a straight shape and a serpentine shape; the thickness of the metal electrode is 50nm to 70nm, and the width of the channel region is 100μm to 400μm.

4. The in-situ characterization method according to claim 1, characterized in that The voltage of the external power supply is 5V to 25V, and the voltage resolution is not less than 10mV.

5. The in-situ characterization method according to claim 1, characterized in that The step of using the time-of-flight secondary ion mass spectrometer to perform surface bombardment on the perovskite sample includes: placing the perovskite sample in the vacuum chamber of the time-of-flight secondary ion mass spectrometer, using the primary ion beam of the time-of-flight secondary ion mass spectrometer as a bombardment source, performing surface bombardment on the channel area of ​​the perovskite sample and exciting secondary ions, and simultaneously using the electron neutralization gun of the time-of-flight secondary ion mass spectrometer as a neutralization source.

6. The in-situ characterization method according to claim 5, characterized in that The primary ion beam includes Bi 3+ 、Ga + At least one of the above, the ion energy of the primary ion beam is 20keV to 40keV; the vacuum chamber includes an inert gas, and preferably, the inert gas includes at least one of helium and nitrogen.

7. The in-situ characterization method according to claim 5, characterized in that Before step S2, the method further includes: using a low-energy ion beam to clean the surface of the perovskite sample, wherein the low-energy ion beam includes Ar + The ion beam has a voltage of 0.5 kV to 3 kV, a beam current of 100 nA to 300 nA, and a cleaning time of 5 s to 15 s.

8. The in-situ characterization method according to claim 5, characterized in that The preparation method of the perovskite film includes: mixing a perovskite precursor, a first solvent and an anti-solvent to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution on a substrate, and obtaining the perovskite film after annealing; wherein the first solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, chlorobenzene, iodomethane, chloromethylamine, and lead iodide; the anti-solvent includes ethyl acetate; the spin-coating speed is 5000 rpm to 7000 rpm, and the spin-coating time is 15 s to 45 s; the annealing temperature is 80°C to 120°C, and the annealing time is 1 hour to 3 hours.

9. An electric field coupled time-of-flight secondary ion mass spectrometer, characterized in that: An in-situ characterization method for performing electroinduced ion migration of a perovskite material according to any one of claims 1 to 8, the apparatus comprising a time-of-flight secondary ion mass spectrometry device body and an external power supply electrically connected to the time-of-flight secondary ion mass spectrometry device body; The main body of the time-of-flight secondary ion mass spectrometer includes a vacuum chamber, a primary ion beam emission unit and a secondary ion imaging unit; a sample holder is provided in the vacuum chamber for carrying the perovskite sample; the primary ion beam emission unit is used to emit a primary ion beam; and the secondary ion imaging unit is used to image the excited secondary ions; The external power supply is used to apply a controllable voltage to the perovskite sample.

10. The electric field coupled time-of-flight secondary ion mass spectrometer according to claim 9, characterized in that: The TOF-SIMS device body further includes an electron neutralization gun for neutralizing the charges generated by the bombardment of the primary ion beam.

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