Method and device for simultaneously observing diffusion of various carriers

Abstract

The invention discloses a method and a device for simultaneously observing diffusion of various carriers, and belongs to the technical field of time-resolved spectral imaging. On the basis of a method for simultaneously observing diffusion of various carriers, a spatial diffusion kinetic model for mutual coupling of the various carriers is constructed, and the overall diffusion anisotropy of the material and the simultaneous diffusion condition of the various carriers are judged; a carrier dynamic fitting algorithm is constructed, diffusion constants and relaxation time key parameters of different carriers are obtained, multi-wavelength simultaneous detection and coupling diffusion model application are achieved, and the observation speed and result consistency are remarkably improved. The invention further discloses a diffusion device based on simultaneous observation of multiple carriers. The diffusion device is mainly composed of a pump laser, a sample to be measured, an imaging camera, a light splitting module, a space scanning module, a first confocal lens, a second confocal lens, a first electric diaphragm, a second electric diaphragm, a scanning control module, a detector and an upper computer.

Description

Technical Field

[0001] The present invention belongs to the technical field of time-resolved imaging, and relates to a method and device for simultaneously observing the diffusion of multiple carriers. Background Art

[0002] In the research and development of optoelectronic materials and devices such as solar cells and light-emitting diodes, the carrier diffusion length is an extremely important core parameter. For example, for a solar cell, photo-generated carriers need to diffuse to the electrode interface to be collected; for a light-emitting diode, electrons and holes injected by the electrode need to diffuse to the recombination center to emit light. Due to the inherent properties of the material, its own defects, and doping in the process, carriers exhibit diverse types and energy distributions. There are often multiple types of carriers coexisting within the same optoelectronic material, and the corresponding diffusion lengths of each carrier are different due to the differences in their physical properties. In order to develop new materials and optimize the material preparation process, it is urgent to study the mutual conversion relationship between different carriers in the same material and its influence on the diffusion length. However, existing time-resolved imaging technologies, such as confocal microscopy and transient absorption microscopy, are limited by technical principles and instrument detection parameters, such as single-wavelength detection limitations and insufficient time resolution, and cannot simultaneously and comprehensively characterize the diffusion characteristics of different types of carriers, which limits the accurate study of the carrier transport mechanism of optoelectronic materials and devices. Summary of the Invention

[0003] To solve the problem that the existing characterization technology cannot simultaneously and comprehensively characterize the diffusion characteristics of different types of carriers, and the mechanism of carrier transport in optoelectronic materials and devices is not thoroughly presented. The purpose of the present invention is to provide a method and device for simultaneously observing the diffusion of multiple carriers, based on a weighted diffusion algorithm, to determine whether the material has overall diffusion anisotropy and whether there is a simultaneous diffusion process of multiple carriers; based on the determination result, a carrier dynamics fitting algorithm is constructed, and key parameters such as the diffusion constant and relaxation time of different carriers are obtained through numerical fitting, so as to comprehensively characterize the diffusion properties of carriers in the material, realize the application of multi-wavelength simultaneous detection and coupled diffusion model, and significantly improve the observation speed and result consistency.

[0004] To achieve the above object, the present invention provides the following solution:

[0005] A method for simultaneously observing the diffusion of multiple carriers disclosed by the present invention includes the following steps:

[0006] Step 1: Fix the position of the pump laser, detect the fluorescence dynamics of different wavelengths emitted at different positions of the sample, and obtain the fluorescence dynamics scanning matrix P(λ, x, y, t), where λ represents the detected wavelength, x and y represent different positions of the sample, and t represents the fluorescence intensity at different time delays;

[0007] Step 2: Construct a weighted diffusion algorithm to determine whether the material has overall diffusion anisotropy;

[0008] At wavelength λ i extract the sub-matrix P(λ i , x, y, t) of the fluorescence dynamics scanning matrix for analyzing the diffusion behavior of a certain type of carrier in space. For this purpose, construct a normalized fitting function f(r) in the form of a Gaussian function:

[0009]

[0010] where r is the relative position, r0 is the central position of the diffusion direction, and c is the full width at half maximum.

[0011] Fit the x-direction of the sub-matrix P(λ i , x, y, t) through Equation (1). That is, when y = 0 at this time, Equation (1) is transformed into Equation (2):

[0012]

[0013] where represents the central position of the Gaussian distribution fitted at time delay t k , and represents the Gaussian distribution fitted at time delay t k .

[0014] Fit the y-direction of the sub-matrix P(λ i , x, y, t) through Equation (1). That is, when x = 0 at this time, Equation (1) is transformed into Equation (3):

[0015]

[0016] where represents the central position of the Gaussian distribution fitted at time delay t k , and represents the Gaussian distribution fitted at time delay t k .

[0017] Based on the fitting results, construct a weighted diffusion criterion formula to determine whether the material has overall diffusion anisotropy:

[0018]

[0019] Among them, N is the number of time delays, and a is a preset anisotropy constant.

[0020] If a satisfies Equation (4), it is determined that the material has no overall diffusion anisotropy; otherwise, it is determined that the material has overall diffusion anisotropy.

[0021] Step 3: Determine whether there is a simultaneous diffusion process of multiple carriers in the material;

[0022] At time delay t k extract the sub-matrix P(λ, x, y, t k ) of the fluorescence kinetics scan matrix, and construct a normalized fitting function f(r, λ i ) based on Equation (1):

[0023]

[0024] Fit the x-direction of the sub-matrix P(λ i , x, y, t) through Equation (5), that is, when y = 0 at this time, Equation (5) is transformed into Equation (6):

[0025]

[0026] Among them, represents the center position of the Gaussian distribution fitted at time delay t k , represents the Gaussian distribution fitted at time delay t k .

[0027] Fit the y-direction of the sub-matrix P(λ i , x, y, t) through Equation (5), that is, when x = 0 at this time, Equation (5) is transformed into Equation (7):

[0028]

[0029] Among them, represents the center position of the Gaussian distribution fitted at time delay t k , represents the Gaussian distribution fitted at time delay t k .

[0030] At each time delay t k , calculate the broadening coefficient of each wavelength λ i :

[0031]

[0032] Among them, and are the full width at half maximum of the Gaussian distributions in the x-direction and y-direction respectively.

[0033] Construct the criterion formula (9) to determine whether the difference in the broadening coefficients at different wavelengths is significant:

[0034]

[0035] where β is a preset threshold, and λ1 and λ2 respectively represent the characteristic wavelengths corresponding to two different carriers:

[0036] If the criterion formula (9) holds, that is, the difference in the broadening coefficients is significant, it is determined that there is a simultaneous diffusion process of multiple carriers in the material. Otherwise, it is determined that there is only a diffusion process of a single carrier in the material.

[0037] Step 4: Obtain the diffusion constants and relaxation times of different carriers through the carrier diffusion control equation, so as to comprehensively characterize the diffusion characteristics of carriers in the material, that is, to realize the simultaneous observation of the diffusion of multiple carriers.

[0038] Carrier diffusion control equation:

[0039]

[0040] where nj(r, t) is the carrier concentration of the j-th carrier component at position r, D j is the carrier diffusion coefficient, τ j represents the intrinsic lifetime of the j-th carrier component, G j (t) represents the kinetics of generating the j-th carrier, and Dec j (t) represents the decay kinetics of the j-th carrier due to conversion to other types of carriers.

[0041] Solve equation (10) by numerical fitting to obtain the diffusion coefficients D j and relaxation times τ j , so as to comprehensively characterize the diffusion characteristics of carriers in the material, that is, to be able to simultaneously observe the diffusion of multiple carriers.

[0042] The present invention also discloses a device for simultaneously observing the diffusion of multiple carriers, which is used to implement a method for simultaneously observing the diffusion of multiple carriers. A device for simultaneously observing the diffusion of multiple carriers includes a pump laser, a first beam splitter, an objective lens, a sample to be measured, a second beam splitter, a third beam splitter, an imaging lens, an imaging camera, an illumination light source, a first confocal lens, a first electro-optical aperture, a second confocal lens, a spatial scanning module, a first focusing lens, a spectroscopic module, a second electro-optical aperture, a third confocal lens, a spectral scanning module, a second focusing lens, a detector, a scanning control module, and a host computer.

[0043] The light beam emitted by the pump laser is reflected by the first beam splitter, collected by the objective lens and focused onto the sample to be measured; the fluorescence generated by the excitation of the sample to be measured is introduced into the first confocal lens through the second beam splitter; the first confocal lens and the second confocal lens are in a confocal state, and an electric diaphragm is provided at the confocal plane position, and the size and position of the electric diaphragm can be flexibly adjusted; the fluorescence emitted by the sample to be measured is first focused on the electric diaphragm by the first confocal lens, and then converted into parallel light by the second confocal lens and enters the spatial scanning module, and then is focused on the incident focal plane of the spectroscopic module by the first focusing lens; the fluorescence emitted by the sample to be measured is dispersed in the spectroscopic module, and the fluorescence of different wavelengths is separated in space; a second electric diaphragm is provided at the exit focal plane, and the size of the diaphragm and its position at the exit focal plane can also be adjusted as required; the fluorescence of a specific wavelength selected by the second electric diaphragm is converted into parallel light by the third confocal lens, enters the spectral scanning module, and is then focused on the detector by the second focusing lens; the scanning control module can control the spatial scanning module and the spectral scanning module and communicate with the host computer; the detector transmits the captured signal to the host computer in real time. In addition, the illumination light source emits illumination light, which is reflected by the third beam splitter and projected onto the sample to be measured by the objective lens, and the illumination light reflected by the sample to be measured enters the imaging camera through the imaging lens to achieve imaging.

[0044] Advantageous effects:

[0045] 1. A method for simultaneously observing the diffusion of multiple carriers disclosed by the present invention constructs a spatial diffusion kinetic model in which multiple carriers are coupled to each other, designs a weighted diffusion algorithm and a carrier kinetic fitting algorithm based on a fluorescence kinetic scanning matrix, and realizes multi-wavelength simultaneous detection and decoupling of diffusion parameters. Through multi-wavelength simultaneous detection and a coupled diffusion model, the limitation of traditional single-wavelength detection is broken through, and the diffusion behaviors of multiple carriers can be simultaneously analyzed. Compared with the traditional sequential measurement method, the observation speed is greatly improved, and the result consistency is significantly improved. Based on the numerical fitting algorithm, the key parameters of the diffusion constants and relaxation times of different carriers can be obtained simultaneously, and the parameter measurement error is lower than the error value of the traditional method.

[0046] 2. A model for simultaneously observing the diffusion of multiple carriers disclosed by the present invention designs a spatial diffusion kinetic model based on Gaussian fitting and weighted criteria, and decouples the diffusion properties of carriers by separating the broadening coefficient differences at different wavelengths. The multiple carrier diffusion model can accurately identify the coexistence phenomenon of multiple carriers by dynamically separating the fluorescence signals of different carriers and combining the diffusion anisotropy criterion, and then realize the independent analysis of the diffusion anisotropy of the material and the carrier type, providing direct and clear data support for the optimization of material and device processes.

[0047] 3. A device for simultaneously observing the diffusion of multiple carriers disclosed by the present invention uses a pump laser 1 at a fixed position to excite a sample under test 4 to emit fluorescence. Combining the confocal optical path design of the first confocal lens 10, the second confocal lens 12 and the dynamically adjustable first electric aperture 11 and second electric aperture 16, a high-precision spatial filtering system is formed to suppress the interference of stray light and greatly improve the signal-to-noise ratio. Integrating a spatial scanning module 13, a spectroscopic module 15 and a detector 20 can simultaneously capture three-dimensional diffusion information in space, wavelength and time. Compared with traditional transient absorption microscopy and other technologies, the test efficiency is significantly enhanced. Through real-time communication between the scan control module 21 and the upper computer 22, automatic data acquisition, matrix construction and parameter fitting analysis are carried out, thereby greatly shortening the time-consuming of a single experiment. Based on the device for simultaneously observing the diffusion of multiple carriers, high-spatial-resolution and multi-wavelength synchronous and efficient detection and analysis of the diffusion properties of multiple carriers are realized, providing accurate data support for the defect diagnosis of optoelectronic materials and contributing to the development and optimization of materials and devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a flowchart of a method for simultaneously observing the diffusion of multiple carriers.

[0049] Figure 2 is a schematic diagram of a device for simultaneously observing the diffusion of multiple carriers.

[0050] Figure 2 The contents of each part are as follows: 1 - pump laser, 2 - first beam splitter, 3 - objective lens, 4 - sample under test, 5 - second beam splitter, 6 - third beam splitter, 7 - imaging lens, 8 - imaging camera, 9 - illumination light source, 10 - first confocal lens, 11 - first electric aperture, 12 - second confocal lens, 13 - spatial scanning module, 14 - first focusing lens, 15 - spectroscopic module, 16 - second electric aperture, 17 - third confocal lens, 18 - spectral scanning module, 19 - second focusing lens, 20 - detector, 21 - scan control module, 22 - upper computer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0053] The purpose of this embodiment is to provide a method and device for simultaneously observing the diffusion of multiple carriers, which can simultaneously observe the diffusion processes of different types of carriers in the same material, is conducive to comprehensively characterizing the diffusion characteristics of different types of carriers at the same time, and realizes the accurate analysis of the carrier transport mechanism of optoelectronic materials. In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific implementation methods.

[0054] Embodiment 1: Simultaneously observing the diffusion properties of multiple carriers in a sample to be measured

[0055] As Figure 2 shown, a device for simultaneously observing the diffusion of multiple carriers disclosed in this embodiment includes the following components and key parameters:

[0056] 1. Pump laser 1: wavelength 405 nm, pulse width 100 fs, repetition frequency 1 kHz, with ultrafast excitation ability to ensure the capture of carrier transient dynamics;

[0057] 2. Spectroscopic module 15: prism-grating composite structure, spectral resolution 0.5 nm, covering 500 - 800 nm, supporting multi-wavelength synchronous detection;

[0058] 3. Detector 20: superconducting single-photon detector, time resolution 10 ps, high sensitivity for detecting weak fluorescence signals.

[0059] 4. Spatial scanning module 13: piezoelectric ceramic drive, scanning step 1 μm, scanning range 50 × 50 μm;

[0060] 5. Confocal lens group of the first confocal lens 10 and the second confocal lens 12: numerical aperture NA = 0.8, focal length f = 10 mm, the aperture adjustable range of the electro-optical aperture 11 at the confocal plane is 0.1 - 2 mm, which can dynamically suppress stray light and improve the signal-to-noise ratio to 35 dB;

[0061] 6. Scanning control module 21: Communicates with the host computer 22 in real time, supports automated data acquisition and processing, and the time consumption for a single experiment is less than 10 minutes.

[0062] The specific working process of the device is as follows:

[0063] The 405nm beam emitted by the pump laser 1 is reflected by the first beam splitter 2 and focused by the objective lens 3 with a numerical aperture NA value of 0.9 to the center position (x = 0, y = 0) of the sample to be measured 4. The sample to be measured 4 is stimulated to generate fluorescence, as Figure 2 shown; the fluorescence is introduced into the first confocal lens 10 and the second confocal lens 12 through the second beam splitter 5. After filtering out stray light through the motorized diaphragm 11 with an aperture of 0.5mm, it enters the spatial scanning module 13 for point-by-point scanning with a step size of 1μm; the scanned fluorescence is focused by the first focusing lens 14 with a focal length f of 50mm to the incident focal plane of the spectral splitting module 15, and the fluorescence with different wavelengths after dispersion, such as λ1, λ2, is separated in space; the spectroscopically analyzed fluorescence passes through the second motorized diaphragm 16 with an aperture of 0.3mm to select a specific wavelength, and after being collimated by the third confocal lens 17 with a focal length of 30mm, it enters the spectral scanning module 18 and is finally focused by the second focusing lens 19 to the detector 20; the signal collected by the detector 20 is transmitted to the host computer 22 in real time to generate the fluorescence kinetic scanning matrix P(λ, x, y, t).

[0064] Based on the device for simultaneously observing the diffusion of multiple carriers, through a method for simultaneously observing the diffusion of multiple carriers, referring to the Figure 1 shown process, the specific implementation steps are as follows:

[0065] Step 1: Obtain the fluorescence kinetic scanning matrix;

[0066] Fix the position of the pump laser, detect on the sample surface (50×50μm), record the fluorescence intensity at each position (x, y), wavelength λ i and time delay t k to form a four-dimensional fluorescence kinetic matrix P(λ, x, y, t);

[0067] Step 2: Judge the diffusion anisotropy of the sample to be measured;

[0068] Extract the sub-matrix P(λ i , x, y, t k ) of λ, perform Gaussian fitting in the x and y directions, and calculate the anisotropy criterion: If the value of A does not satisfy Equation (4), it is judged that the sample to be measured has overall diffusion anisotropy.

[0069] Step 3: Judge the simultaneous diffusion of multiple carriers in the sample to be measured;

[0070] At temperature t, calculate the broadening coefficients Δc(λ1) and Δc(λ2) of λ1 and λ2. If the calculated Δc(λ2) / Δc(λ1) > β satisfies Equation (9), it is determined that there is a simultaneous diffusion phenomenon of multiple carriers in the material;

[0071] Step Four: Fit kinetic parameters

[0072] Using the carrier diffusion control Equation (10), adopt a numerical fitting algorithm to fit the diffusion equation. The number of iterations is 1000 times, and the convergence condition is that the residual error is less than 0.01, obtaining the key parameters of the diffusion constants D1, D2 and relaxation times τ1, τ2 of different carriers.

[0073] Verification of technical effects: The spatial resolution of the device reaches 1 μm (5 μm for traditional technology), and the time resolution reaches 10 ps. Compared with the traditional observation technology with a time resolution of only 50 ps, it supports ultra-fast and high-precision observation. Based on the application of multi-wavelength synchronous detection and coupled diffusion model, the diffusion characteristics of multiple carriers are successfully decoupled. The single experiment takes only 8 minutes, the fitting residual RMS = 0.03, and the error < 3%, which is significantly better than traditional manual analysis (taking > 1 hour and having an error > 10%), thus efficiently and comprehensively characterizing the diffusion characteristics of multiple carriers in the sample to be measured.

[0074] Example 2: Simultaneous observation of electron and hole diffusion based on perovskite thin film

[0075] Use a femtosecond laser with a pulse width of 100 fs, a repetition frequency of 1 kHz, and a wavelength of 1030 nm after third harmonic generation as the pump laser; use a spectroscopic module with a spectral resolution of 1 nm and a working wavelength covering 400 - 900 nm; use a single-photon detector with a time resolution of 4 ps as the detector.

[0076] As Figure 1 shown, this example also discloses a method for simultaneously observing the diffusion of multiple carriers, and the specific implementation steps are as follows:

[0077] Step 1: Fix the position of the pump laser at the center of the perovskite thin film sample. At this time, x = 0, y = 0, and the sample is excited to generate carriers. Scan the sample. The spectral splitting module disperses the fluorescence of different wavelengths emitted by the perovskite thin film at intervals of 5 nm in the range of 400 - 900 nm, i.e., λ = 400, 405, 410, …, 890, 895, 900 (unit: nm); the spatial scanning module scans the surface of the sample with a step size of 50 nm, and the scanning range is 5 × 5 μm, i.e., x = -2500, -2450, -2400, …, 2400, 2450, 2500 (unit: nm), y = -2500, -2450, -2400, …, 2400, 2450, 2500 (unit: nm); the detector records the fluorescence kinetics of different positions (x, y) at each wavelength λ within 0 to 1000 ps, and obtains the fluorescence kinetics matrix P(λ, x, y, t).

[0078] Step 2: Extract two sub - matrices P(λ i , x, y, t k ) corresponding to two specific wavelengths λ1 and λ2. Among them, λ1 = 650 nm corresponds to the diffusion of electrons, and λ2 = 750 nm corresponds to the diffusion of holes.

[0079] Analyze the diffusion behavior of electrons and hole carriers in space of this sample through Equation (1): In the x - direction, apply Equation (2) for Gaussian fitting to obtain the full width at half maximum In the y - direction, apply Equation (3) for Gaussian fitting to obtain the full width at half maximum

[0080] Calculate the anisotropy criterion using Equation (4):

[0081]

[0082] Set the threshold a to 0.1. The result shows that the criterion value is 0.3, which does not satisfy Equation (4). It is determined that the perovskite thin film has overall diffusion anisotropy.

[0083] Step 3: At the delay time t = 100 ps, extract two sub - matrices P(λ i , x, y, t k ) corresponding to wavelengths λ1 and λ2. Analyze the diffusion behavior in space of this sample at time t through Equation (5). Apply Equation (6) for Gaussian fitting in the x - direction to obtain the full width at half maximum Similarly, apply Equation (7) for fitting in the y - direction to obtain the full width at half maximum

[0084] At time t, calculate the difference in broadening coefficients of λ1 and λ2 using Equation (8), and obtain Δc(λ1, t) = 0.8 μm and Δc(λ2, t) = 1.5 μm.

[0085] Use Equation (9) to judge the difference in the broadening coefficients of λ1 and λ2:

[0086]

[0087] Set the threshold β to 1.5. When Equation (9) is satisfied, the difference in the broadening coefficients is significant, and it is considered that there is a simultaneous diffusion process of multiple carriers in the perovskite thin film.

[0088] Step 4: Apply Equation (10) to fit the carrier components of electrons and holes corresponding to j = 1, 2 by the Levenberg-Marquardt numerical algorithm method, and obtain: electron diffusion coefficient D1 = 0.25 cm 2 / s, relaxation time τ1 = 10 ps; hole diffusion coefficient D2 = 0.12 cm 2 / s, relaxation time τ2 = 15 ps, which comprehensively characterizes the diffusion properties of carriers in the perovskite thin film material.

[0089] Simultaneously observing and obtaining the diffusion coefficients and relaxation times of multiple carriers in the perovskite thin film has important significance in many aspects. During the growth process of materials and devices, it provides a key basis for precise control, enabling timely adjustment of growth parameters, thereby significantly improving product quality and production efficiency. For the design of higher-performance devices, accurate carrier parameters are a powerful support for designing and optimizing device performance. For example, in the field of semiconductor transistor devices, it can help improve their high-frequency performance; in the aspect of solar cell devices, it helps reduce carrier recombination losses, bringing many positive impacts to the technological upgrading and development of related industries.

[0090] The above-described embodiments are merely preferred embodiments given to fully illustrate the present invention, and there will be changes in the specific implementation manners and application scopes, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art on the basis of the present invention are within the protection scope of the present invention.

Claims

1. A method for simultaneously observing the diffusion of multiple carriers, characterized in that: Including the following steps: Step 1: Fix the position of the pump laser, detect the fluorescence kinetics of different wavelengths emitted at different positions of the sample, and obtain the fluorescence kinetics scanning matrix P(λ, x, y, t), where λ represents the detected wavelength, x and y represent different positions of the sample, and t represents the fluorescence intensity at different time delays; Step 2: Construct a weighted diffusion algorithm to determine whether the material has overall diffusion anisotropy; At wavelength λ i , a sub-matrix P(λ i , x, y, t) of the fluorescence kinetic scanning matrix is extracted for analyzing the diffusion behavior of a certain type of carrier in space; a normalized fitting function f(r) in the form of a Gaussian function is constructed: where r is the relative position, r0 is the central position of the diffusion direction, and c is the full width at half maximum; By using equation (1) to fit the x-direction of the sub-matrix P(λ i , x, y, t), that is, when y = 0 at this time, equation (1) is transformed into equation (2): Among them, represents the center position of the fitted Gaussian distribution at time delay t k ; represents the fitted Gaussian distribution at time delay t k ; By using equation (1) to fit the y-direction of the sub-matrix P(λ i , x, y, t), that is, when x = 0 at this time, equation (1) is transformed into equation (3): Among them, represents the center position of the fitted Gaussian distribution at time delay t k and represents the fitted Gaussian distribution at time delay t k . Based on the fitting result, construct a weighted diffusion criterion formula to determine whether the material has overall diffusion anisotropy: where N is the number of time delays and a is a preset anisotropy constant; If a satisfies Equation (4), it is determined that the material does not have overall diffusion anisotropy; otherwise, it is determined that the material has overall diffusion anisotropy; Step 3: Determine whether there is a simultaneous diffusion process of multiple carriers in the material; At time delay t k extract the sub-matrix P(λ, x, y, t k ) of the fluorescence kinetics scanning matrix, and construct a normalized fitting function f(r, λ i ) based on Equation (1): By fitting the x-direction of the sub-matrix P(λ i , x, y, t) through Equation (5), that is, when y = 0 at this time, Equation (5) is transformed into Equation (6): Among them, represents the center position of the fitted Gaussian distribution at time delay t k and represents the fitted Gaussian distribution at time delay t k . By using equation (5) to fit the y-direction of the sub-matrix P(λ i , x, y, t), that is, when x = 0 at this time, equation (5) is transformed into equation (7): Among them, represents the center position of the fitted Gaussian distribution at time delay t k , and represents the fitted Gaussian distribution at time delay t k . At each time delay t k compute the broadening factor for each wavelength λ i as follows: wherein, and are the full width at half maximum (FWHM) of the Gaussian distribution in the x-direction and y-direction, respectively; Construct criterion formula (9) to determine whether the difference in broadening coefficients at different wavelengths is significant: where β is a preset threshold, and λ1 and λ2 respectively represent the characteristic wavelengths corresponding to two different carriers; If criterion formula (9) holds, that is, the difference in broadening coefficients is significant, it is determined that there is a simultaneous diffusion process of multiple carriers in the material; otherwise, it is determined that there is only a diffusion process of a single carrier in the material; Step 4: Through the carrier diffusion control equation, obtain the diffusion constants and mixed relaxation times of different carriers, so as to comprehensively characterize the diffusion characteristics of carriers in the material, that is, to realize the simultaneous observation of the diffusion of multiple carriers.

2. The method for simultaneously observing the diffusion of multiple carriers according to claim 1, characterized in that: The implementation method of Step 4 is through the carrier diffusion control equation: where nj(r,t) is the carrier concentration of the j-th carrier component at position r, D j is the carrier diffusion coefficient, τ j represents the intrinsic lifetime of the j-th carrier component, G j (t) represents the kinetics of generating the j-th carrier, Dec j (t) represents the decay kinetics of the j-th carrier due to conversion to other types of carriers; Solve Equation (10) by numerical fitting to obtain the diffusion coefficients D of different carriers j and relaxation times τ j , thereby comprehensively characterizing the diffusion characteristics of carriers in the material, that is, realizing the simultaneous observation of the diffusion of multiple carriers.

3. An apparatus for simultaneously observing the diffusion of multiple carriers, which is used to implement the method for simultaneously observing the diffusion of multiple carriers as described in claim 1 or 2, characterized in that: Including a pump laser, a first beam splitter, an objective lens, a sample to be measured, a second beam splitter, a third beam splitter, an imaging lens, an imaging camera, an illumination light source, a first confocal lens, a first motorized aperture, a second confocal lens, a spatial scanning module, a first focusing lens, a spectroscopic module, a second motorized aperture, a third confocal lens, a spectral scanning module, a second focusing lens, a detector, a scanning control module, and a host computer; The beam emitted by the pump laser is reflected by the first beam splitter, collected by the objective lens and focused on the sample to be measured; the fluorescence generated by the excitation of the sample to be measured is introduced into the first confocal lens through the second beam splitter; the first confocal lens and the second confocal lens are in a confocal state, and an electric diaphragm is provided at the confocal plane position, and the size and position of the electric diaphragm can be flexibly adjusted; the fluorescence emitted by the sample to be measured is first focused on the electric diaphragm by the first confocal lens, and then converted into parallel light by the second confocal lens and enters the spatial scanning module, and then is focused on the incident focal plane of the spectroscopic module by the first focusing lens; the fluorescence emitted by the sample to be measured is dispersed in the spectroscopic module, and the fluorescence of different wavelengths is separated in space; a second electric diaphragm is provided at the exit focal plane, and the size of the diaphragm and its position at the exit focal plane can also be adjusted as required; the fluorescence of a specific wavelength selected by the second electric diaphragm is converted into parallel light by the third confocal lens, enters the spectral scanning module, and is then focused on the detector by the second focusing lens; the scanning control module can control the spatial scanning module and the spectral scanning module and communicate with the host computer; the detector transmits the captured signal to the host computer in real time; in addition, the illumination light source emits illumination light, which is reflected by the third beam splitter and projected on the sample to be measured by the objective lens, and the illumination light reflected by the sample to be measured enters the imaging camera through the imaging lens to achieve imaging.

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