Excitation modulation frequency domain ultraviolet visible near infrared spectrum test system and method based on portable spectrograph and application of excitation modulation frequency domain ultraviolet visible near infrared spectrum test system and method

Abstract

The invention discloses an excitation modulation frequency domain ultraviolet visible near infrared spectrum test system based on a portable spectrometer. The test system comprises an excitation modulation system, a spectrum acquisition system, a data analysis system and a LabView upper computer system, the LabView upper computer system comprises LabView software, the LabView software comprises a LabView wave function generation program and a LabView spectral data post-processing program, and the LabView wave function generation program is used for controlling parameter setting (including light intensity and voltage) of the excitation modulation system; and the post-processing system is used for post-processing the data acquired by the data analysis system. According to the test system and method provided by the invention, data is post-processed by virtue of the high-speed spectrum acquisition capability of the portable spectrograph in combination with a phase-locked amplification algorithm, and compared with the existing solution, the test system and method provided by the invention can realize rapid full-wave-band spectrum acquisition, so that the test efficiency is greatly improved, and feasibility is provided for batch and large-scale test.

Description

Technical Field

[0001] The invention relates to an excitation modulation frequency domain ultraviolet visible near infrared spectrum testing system, method and application based on a portable spectrometer, belonging to the technical field of material characterization. Background Art

[0002] Some materials will change color under external stimulation such as voltage or light due to reversible physical and chemical processes in the bulk or surface interface of the material. This phenomenon is called electrochromism or photochromism. In order to dynamically characterize the color changes of these materials, the inventors have developed a technology in their previous work to measure the frequency domain response of the ultraviolet-visible-near-infrared absorption spectrum by modulating the external stimulation - excitation modulation frequency domain ultraviolet-visible-near-infrared absorption spectrum. This technology uses a phase-locked amplifier to extract the dynamic spectral response changes of the material that are only related to the periodically modulated excitation part. It can not only achieve high time resolution, but also remove errors caused by drift caused by instrument noise or environment, thereby greatly improving signal resolution. Using similar test principles and test systems, this type of excitation modulation frequency domain spectroscopy technology can also be used to study materials that can produce electroluminescence and photoluminescence (including fluorescence and phosphorescence) under external stimulation conditions. Therefore, it can be collectively referred to as excitation modulated spectroscopy (EMS). Among them, according to the type of excitation, it can be divided into light modulated spectroscopy (LMS) and voltage modulated spectroscopy (PMS).

[0003] However, the traditional EMS technology with high time resolution detects monochromatic light one by one after the detection light passes through a monochromator. In particular, since the common phase-locked amplifier can only process single-channel analog signals, it can only be collected at a single wavelength in sequence. Therefore, in order to achieve higher wavelength resolution, especially at lower modulation frequencies, it takes a lot of time, which seriously limits the test efficiency of this technology. In addition, due to the instrument test accuracy of the phase-locked amplifier, the appropriate range needs to be adjusted before testing. When the signal is not within the instrument range, the data needs to be preprocessed.

[0004] Therefore, in order to solve the above problems, a reliable and efficient test system is needed to centrally control and manage various components (mainly including spectrometers and wave function generators); in addition, the test system must take into account data acquisition, data processing, data export and graphic display functions. Summary of the invention

[0005] The purpose of the present invention is: to address the deficiencies in the prior art, the present invention provides an excitation modulation frequency domain ultraviolet, visible and near-infrared spectroscopy testing system, method and application based on a portable spectrometer. The present invention separates spectral acquisition from data analysis. First, the excellent cache capacity of the spectrometer is used to store spectral data. After the acquisition is completed, the spectral data is post-processed using a LabView spectral data post-processing program (phase-locked amplification algorithm program), thereby realizing a single full-band EMS acquisition.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an excitation modulation frequency domain ultraviolet visible near infrared spectroscopy test system based on a portable spectrometer, comprising an excitation modulation system, a spectrum acquisition system, a data analysis system, and a LabView host computer system; the excitation modulation system comprises a modulation voltage system and / or a modulation light intensity system, the spectrum acquisition system comprises a sample stage, a detection light source, an optical fiber, an optical fiber coupler, and a portable optical fiber spectrometer, the data analysis system comprises a data acquisition computer and AvaSoft8 software provided with the spectrometer, and the LabView host computer system comprises a host computer and LabView software; the data acquisition computer and the host computer share the same computer or are two independent computers (data sharing and post-processing are performed between the two computers through data transmission);

[0008] The excitation modulation system and the data analysis system are respectively controlled by a LabView host computer system;

[0009] The LabView software includes a LabView wave function generation program and a LabView spectrum data post-processing program, wherein the LabView wave function generation program is used to control the parameter setting of the excitation modulation system; and the LabView spectrum data post-processing program is used to post-process the data collected by the data analysis system;

[0010] The modulation voltage and / or modulation light intensity emitted by the excitation modulation system are respectively applied to the sample to be tested, and the excitation modulation system outputs a pulse signal to the external triggering end of the portable optical fiber spectrometer at the start time of modulation;

[0011] The detection light emitted by the detection light source is coupled to the optical fiber through the optical fiber coupler under the action of the modulated voltage or modulated light and irradiates the sample on the sample stage. The transmitted light passing through the sample is coupled to the optical fiber through another optical fiber coupler and input into the portable optical fiber spectrometer. After the data collected by the portable optical fiber spectrometer is transmitted to the data acquisition computer, it is read by the software provided by the spectrometer in the absorption or intensity mode, and finally transmitted to the LabView host computer system, and the LabView spectral data post-processing program performs post-processing and graphical display on the spectral data.

[0012] The time resolution of the test system of the present invention depends on the sum of the time for the spectrometer signal to be transmitted to the computer and the integration time of the single spectrum test; for the spectrometer Avantes AvaSpec-ULS2048XL used in each embodiment of the present invention, the transmission time is 2.44 ms, and the integration time is t ms, so the effective time resolution is 2.44+t ms.

[0013] Preferably, the modulated light intensity system includes a wave function generator, an LED constant current driver and an LED lamp, or the modulated light intensity system includes a wave function generator, a laser driving power supply and a laser diode; the wave function generator generates a sinusoidal or square wave alternating current (AC) signal, which is output to the LED constant current driver and drives the LED lamp or is output to the laser driving power supply to drive the laser diode, so that the intensity of the excitation light fluctuates at a given AC frequency.

[0014] Preferably, the modulation voltage system comprises a function generator and a potentiostat / sourcemeter; the wave function generator generates a sinusoidal or square wave alternating current (AC) signal, which is output to the potentiostat / sourcemeter, so that the voltage applied to the sample fluctuates at a given AC frequency.

[0015] Preferably, the detection light source is a combination of one or more of a halogen lamp, a deuterium lamp, a tungsten lamp and an LED lamp.

[0016] The present invention also provides a UV-visible-near-infrared spectrum testing method, which uses the above-mentioned testing system to collect light intensity modulation or voltage modulation UV-visible-near-infrared spectrum (including absorption spectrum and / or luminescence spectrum) to achieve single full-band spectrum collection for the test sample. The testing method comprises the following steps:

[0017] Step 1: Turn on the connected test system and place the sample on the sample table;

[0018] Step 2: Adjust the optical path and set the spectrum test parameters;

[0019] Step 3: When measuring the absorption spectrum, turn off the detection light source and record the dark-state background spectrum; turn on the constant voltage or light intensity through the excitation modulation system and wait for the system to stabilize; turn on the detection light source and record the reference spectrum; when measuring the luminescence spectrum, there is no need to record the dark-state background spectrum and the reference spectrum, turn on the constant voltage or light intensity through the excitation modulation system and wait for the system to stabilize;

[0020] Step 4: Turn on the modulation voltage or light intensity by exciting the modulation system, and trigger the spectrometer to start recording at the same time;

[0021] Step 5: Collect the spectral signals obtained by the spectrometer and perform data post-processing, that is, complete the collection of the full-band ultraviolet, visible and near-infrared spectrum.

[0022] In some embodiments of the present invention, the collection of the light intensity modulation ultraviolet-visible-near infrared absorption spectrum specifically comprises the following steps:

[0023] Step A1: Connect the wave function generator and the portable fiber spectrometer to the USB port of the host computer; turn on the wave function generator and the computer;

[0024] Step A2: placing a sample on a sample stage (including a sample placement area of ​​a cuvette holder or a working electrode position of an electrochemical cell);

[0025] Step A3: connect the wave function generator signal channel 1 to the LED or laser constant current driver, and the constant current driver to the LED lamp or laser diode; adjust the optical path so that the excitation light spot is irradiated on the sample surface; connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer; when the electrochemical cell is used as the sample stage, the detection light source output optical fiber is connected to the optical fiber coupler, and the optical path is adjusted so that the detection light spot coincides with the LED light spot; in the transmission mode, another optical fiber coupler is placed on the back side of the sample and connected to the portable optical fiber spectrometer through the optical fiber, or in the mirror reflection mode, the same or another optical fiber coupler is placed on the front side of the sample and connected to the portable optical fiber spectrometer through the optical fiber; wherein, in the mirror reflection mode, when the incident light and the output light share a fiber coupler, a Y-type optical fiber must be used; when the cuvette holder is used as the sample stage, there is no need to use an independent optical fiber coupler, and the optical fiber port on the cuvette holder can be directly connected to the portable optical fiber spectrometer through the optical fiber;

[0026] Step A4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, first collect the dark-state background spectrum and reference spectrum under the conditions of the detection light source being turned off and the detection light source being turned on, respectively, and then change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode;

[0027] Step A5: After the test is completed, export the data in the "A" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the LMS spectrum.

[0028] In some embodiments of the present invention, the acquisition of the voltage-modulated ultraviolet-visible-near-infrared absorption spectrum specifically comprises the following steps:

[0029] Step B1: Connect the wave function generator and spectrometer to the USB port of the host computer; turn on the wave function generator and the computer;

[0030] Step B2: placing a sample on a sample stage (including a sample placement area of ​​a cuvette holder or a working electrode position of an electrochemical cell);

[0031] Step B3: Connect the wave function generator signal channel 1 to the modulation input interface of the constant potential instrument / source meter, and connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer; when the electrochemical cell is used as the sample stage, the detection light source output optical fiber is connected to the optical fiber coupler, and the optical path is adjusted so that the detection light spot is irradiated on the sample surface; in the transmission mode, another optical fiber coupler is placed on the back side of the sample and connected to the spectrometer through the optical fiber, or in the mirror reflection mode, the same or another optical fiber coupler is placed on the front side of the sample and connected to the portable optical fiber spectrometer through the optical fiber; wherein, in the mirror reflection mode, when the incident light and the output light share a fiber coupler, a Y-type optical fiber must be used; when the cuvette holder is used as the sample stage, there is no need to use an independent optical fiber coupler, and the optical fiber port on the cuvette holder can be directly connected to the portable optical fiber spectrometer through the optical fiber;

[0032] Step B4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, first collect the dark-state background spectrum and reference spectrum under the conditions of the detection light source being turned off and the detection light source being turned on, respectively, and then change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode;

[0033] Step B5: After the test is completed, export the data in the "A" display mode of the "Spectrum 3D" data as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the PMS spectrum.

[0034] In some embodiments of the present invention, the light intensity modulation ultraviolet visible near infrared luminescence spectrum collection specifically comprises the following steps:

[0035] Step C1: Connect the wave function generator and the portable fiber spectrometer to the USB port of the host computer; turn on the wave function generator and the computer;

[0036] Step C2: placing a sample on a sample stage (including an integrating sphere, or a sample placement area of ​​a cuvette holder, or a working electrode position of an electrochemical cell);

[0037] Step C3: connecting the wave function generator signal channel 1 to an LED or laser constant current driver, and the constant current driver to an LED lamp or a laser diode; adjusting the optical path or coupling optical fiber so that the excitation light spot is irradiated on the sample surface; connecting the wave function generator signal channel 2 to the external trigger interface of the spectrometer; the sample light emission signal is directly connected to the portable fiber spectrometer through the optical fiber from the output port of the sample stage or an independent optical fiber coupler;

[0038] Step C4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode;

[0039] Step C5: After the test is completed, export the data in the "S" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the LMS spectrum.

[0040] In some embodiments of the present invention, the voltage-modulated ultraviolet-visible-near-infrared luminescence spectrum collection specifically comprises the following steps:

[0041] Step D1: Connect the wave function generator and spectrometer to the USB port of the host computer; turn on the wave function generator and the computer;

[0042] Step D2: placing a sample on a sample stage (including an integrating sphere, or a sample placement area of ​​a cuvette holder, or a working electrode position of an electrochemical cell);

[0043] Step D3: Connect the wave function generator signal channel 1 to the modulation input interface of the constant potential instrument / source meter, and connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer; the sample luminescence signal is directly connected to the portable fiber optic spectrometer through the output port of the sample stage or an independent fiber optic coupler via an optical fiber;

[0044] Step D4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator AC modulation mode;

[0045] Step D5: After the test is completed, export the data in the "S" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the PMS spectrum.

[0046] The present invention also provides an application of the above-mentioned test system or test method, wherein the application is selected from any one of the following applications:

[0047] 1) Application of UV-visible-near infrared spectroscopy in dynamic characterization of materials;

[0048] 2) Application in characterizing and identifying intermediate species produced when catalytic materials undergo chemical reactions;

[0049] 3) Application in the study and evaluation of catalytic properties, color change phenomena and properties, luminescence phenomena and properties of materials or products;

[0050] 4) Application in studying the mechanisms related to the physical and chemical processes of materials or products.

[0051] Preferably, the materials include electrochromic materials, photochromic materials, electroluminescent materials, photoluminescent materials and catalytic materials; the catalytic materials include photocatalytic materials, electrocatalytic materials and photoelectrocatalytic materials; the product contains the materials, that is, the product is a device or article (other product) made of the materials.

[0052] Preferably, the dynamic characterization includes a dynamic characterization in a physical change process or a chemical reaction process, such as an electrochromic process, a photochromic process, an electroluminescent process, a photoluminescent process, or a catalytic reaction process.

[0053] In some application embodiments of the present invention, the testing system and method are used to characterize different chemical reactions of (photo)electrochemically active materials under different operating conditions, and to characterize and identify different intermediate species produced in the chemical reactions.

[0054] In some other application embodiments of the present invention, the electroluminescence phenomenon and luminescence performance of an electroluminescent device (exemplary electroluminescent devices are LEDs) are dynamically characterized.

[0055] In some other application embodiments of the present invention, the fluorescence phenomenon and fluorescence performance of articles containing fluorescent agents are dynamically characterized.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The test system and method provided by the present invention utilize the high-speed spectrum acquisition capability of a portable spectrometer and combine the LabView spectrum data post-processing program (phase-locked amplification algorithm program) to post-process the data. Compared with existing solutions, it can achieve single-shot full-band spectrum acquisition, greatly improve the acquisition efficiency, and provide feasibility for batch-scale testing. Based on the test system and method, the present invention realizes the exploration of electrochromism, photochromism, electroluminescence, photoluminescence, and catalytic reaction intermediate information under different excitation modulation frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic diagram of the principle of light intensity modulation frequency domain UV-visible near-infrared spectroscopy (LMS) testing in transmission or specular reflection mode;

[0059] Figure 2 It is a schematic diagram of the test principle of voltage modulation frequency domain UV-visible near-infrared spectroscopy (PMS) in transmission or specular reflection mode;

[0060] Figure 3 This is a schematic diagram of the test principle of diffuse reflection mode light intensity modulation frequency domain UV-visible near-infrared spectroscopy (LMS);

[0061] Figure 4 This is the test operation flow chart of the excitation modulation frequency domain UV-visible-near infrared absorption spectrum;

[0062] Figure 5 It is the interface of LabView wave function generator program;

[0063] Figure 6 It is the LabView spectrum data post-processing program operation interface-1;

[0064] Figure 7 It is the LabView spectrum data post-processing program operation interface-2;

[0065] Figure 8 It is the LabView spectrum data post-processing program operation interface-3;

[0066] Fig. 9 NiFeO x 0.5 to 0.6V Hg / HgO PMS test results in the modulation range (0.5Hz);

[0067] Fig.10 For BiVO4 thin film samples at -0.5 to -0.1V Hg / HgO PMS test results in the modulation range (0.25Hz);

[0068] Fig.11 For α-Fe2O3 thin film samples at 0.6V Hg / HgO , 20 to 60 mW cm -2 LMS test results under 365nm LED light intensity modulation (0.5Hz);

[0069] Fig.12 The PMS test results of 365nm LED under sinusoidal drive voltage modulation (50Hz);

[0070] Fig.13 The PMS test results of 365nm LED under sinusoidal drive voltage modulation (5Hz);

[0071] Fig.14 The PMS test results of 365nm LED under sinusoidal drive voltage modulation (0.5Hz);

[0072] Fig.15These are the diffuse reflection mode LMS test results of Teflon standard white board and A4 printing paper under 365nm light modulation (0.5Hz). DETAILED DESCRIPTION

[0073] In order to make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0074] Example 1: Measurement of UV-visible-near infrared absorption spectra in transmission or specular reflection mode with light intensity modulation

[0075] This embodiment provides a system and method for testing the light intensity modulation ultraviolet visible near infrared absorption spectrum. The testing principle is as follows: Figure 1 As shown: the wave function generator generates a sinusoidal or square wave alternating current (AC) signal disturbance, which is output to the LED constant current driver and drives the LED lamp, so that the intensity of the excitation light fluctuates at a given AC frequency. Another signal with the same frequency and phase generated by the wave function generator is directly output to the external trigger end of the portable fiber optic spectrometer. The halogen tungsten lamp is used as the detection light source. The detection light emitted by the detection light source is coupled to the optical fiber through the fiber coupler and irradiated on the sample on the sample stage. The transmission or mirror reflection light of the sample is coupled to the optical fiber through another fiber coupler and input into the portable fiber optic spectrometer; after the data collected by the portable fiber optic spectrometer is transmitted to the computer, it is read by the spectrometer's own software (such as AvaSoft8) in the absorption mode; the specific steps are as follows:

[0076] 1. Turn on the halogen tungsten lamp and preheat for 15 minutes. Connect the wave function generator and spectrometer to the computer USB port. Turn on the computer.

[0077] 2. Place the sample on the sample stage.

[0078] 3. Connect the wave function generator signal channel 1 to the LED constant current driver, and the LED constant current driver to the LED lamp. Adjust the optical path so that the LED light spot is irradiated on the sample surface. Connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer. Connect the halogen tungsten lamp output optical fiber to the fiber coupler, and adjust the optical path so that the detection light spot coincides with the LED light spot. Place another fiber coupler on the back side (transmission mode) or front side (mirror reflection mode) of the sample and connect it to the spectrometer through the optical fiber. Turn on the constant potential instrument / source meter as needed to keep the sample in a constant potential condition.

[0079] 4. Set steady-state conditions in the LabView wave function generator and run until the sample system is stable. Open the spectrometer's built-in operating software, adjust the optical path and integration time so that the maximum spectral intensity is close to but not higher than 65500 in the intensity display mode "S". Close the halogen tungsten lamp shutter and record the dark state background spectrum. Open the halogen tungsten lamp shutter and record the reference spectrum. Switch to absorption mode "A". In the option setting "Options", in the external trigger setting "External Trigger Settings", turn on the external trigger function "Enable". The trigger mode is edge trigger "Edge". According to the spectrometer parameter information at the specified frequency displayed in the LabView wave function generator interface, set the spectrometer parameters in the spectrometer's built-in software, including the number of onboard averages and the number of collected spectra.

[0080] 5. In the Run button options, select the cache mode "Store to Ram" and click Run to put the spectrometer in a waiting trigger state.

[0081] 6. Open the AC modulation mode of the LabView wave function generator program so that the modulation signal of channel 1 and the trigger signal of channel 2 start to output at the same time. Wait for the spectrometer to complete data acquisition. At this time, "Measurements" displays 1. Click "Spectrum 3D" and select Excel output in the file "File" tab. Save the file in the pop-up Excel program.

[0082] 7. Open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, run the program to obtain the light intensity modulation UV-visible-near infrared absorption spectrum, and save the results as a csv format file in the same directory.

[0083] 8. End the test: close the software and program, turn off the excitation light source and detection light source, and turn off the constant potentiostat / source meter.

[0084] Example 2: Voltage modulation UV-visible near-infrared absorption spectrum measurement in transmission or mirror reflection mode

[0085] This embodiment provides a voltage modulation ultraviolet visible near infrared absorption spectrum testing system and method, the testing principle is as follows Figure 2As shown: the wave function generator generates a sinusoidal or square wave alternating current (AC) signal disturbance, which is output to the potentiostat / source meter, so that the voltage applied to the sample fluctuates at a given AC frequency. Another signal with the same frequency and phase generated by the wave function generator is directly output to the external trigger end of the portable fiber optic spectrometer. The halogen tungsten lamp is used as the detection light source. The detection light emitted by the detection light source is coupled to the optical fiber through the fiber coupler and irradiated on the sample on the sample stage. The transmission or mirror reflection light of the sample is coupled to the optical fiber through another fiber coupler and input into the portable fiber optic spectrometer; after the data collected by the portable fiber optic spectrometer is transmitted to the computer, it is read by the spectrometer's own software (such as AvaSoft8) in the absorption mode; the specific steps are as follows:

[0086] 1. Turn on the halogen tungsten lamp and preheat for 15 minutes. Connect the wave function generator and spectrometer to the computer USB port. Turn on the computer.

[0087] 2. Place the sample on the sample stage.

[0088] 3. Connect the signal channel 1 of the wave function generator to the modulation input interface of the constant potential instrument / source meter, and connect the signal channel 2 to the external trigger interface of the spectrometer. Connect the output fiber of the halogen tungsten lamp to the fiber coupler, and adjust the optical path so that the detection light spot is irradiated on the sample surface. Place another fiber coupler on the back side (transmission mode) or the front side (mirror reflection mode) of the sample and connect it to the spectrometer through the optical fiber.

[0089] 4. Set steady-state conditions in the LabView wave function generator and run until the sample system is stable. Open the spectrometer's built-in operating software, adjust the optical path and integration time so that the maximum spectral intensity is close to but not higher than 65500 in the intensity display mode "S". Close the halogen tungsten lamp shutter and record the dark state background spectrum. Open the halogen tungsten lamp shutter and record the reference spectrum. Switch to absorption mode "A". In the option setting "Options", in the external trigger setting "External Trigger Settings", turn on the external trigger function "Enable". The trigger mode is edge trigger "Edge". According to the spectrometer parameter information at the specified frequency displayed in the LabView wave function generator interface, set the spectrometer parameters in the spectrometer's built-in software, including the number of onboard averages and the number of collected spectra.

[0090] 5. In the Run button options, select the cache mode "Store to Ram" and click Run to put the spectrometer in a waiting trigger state.

[0091] 6. Open the AC modulation mode of the LabView wave function generator program so that the modulation signal of channel 1 and the trigger signal of channel 2 start to output at the same time. Wait for the spectrometer to complete data acquisition. At this time, "Measurements" displays 1. Click "Spectrum 3D" and select Excel output in the file "File" tab. Save the file in the pop-up Excel program.

[0092] 7. Open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, run the program to obtain the voltage-modulated UV-visible-near-infrared absorption spectrum, and save the results as a csv format file in the same directory.

[0093] 8. End the test: close the software and program, turn off the detection light source, and turn off the constant potentiostat / source meter.

[0094] Example 3: Diffuse reflection mode light intensity modulation UV-visible near-infrared luminescence spectrum measurement

[0095] This embodiment provides a system and method for testing the ultraviolet, visible and near-infrared luminescence spectrum of light intensity modulation. The testing principle is as follows: Figure 3 As shown: the wave function generator generates a sinusoidal or square wave alternating current (AC) signal disturbance, which is output to the laser driver and drives the laser diode, so that the intensity of the excitation light fluctuates at a given AC frequency. Another signal with the same frequency and phase generated by the wave function generator is directly output to the external trigger end of the portable fiber optic spectrometer. The excitation light is coupled to the optical fiber through the fiber coupler through the input port of the integrating sphere and irradiated on the sample. The resulting reflected light is input into the portable fiber optic spectrometer through another optical fiber through the output port on the integrating sphere cavity; after the data collected by the portable fiber optic spectrometer is transmitted to the computer, it is read by the spectrometer's own software (such as AvaSoft8) in the absorption mode; the specific steps are as follows:

[0096] 1. Connect the wave function generator and spectrometer to the computer USB port. Turn on the computer.

[0097] 2. Place the sample in the integrating sphere sample placement area.

[0098] 3. Connect the wave function generator signal channel 1 to the laser driver, and the laser driver to the laser diode. Adjust the optical path so that the laser spot is irradiated on the sample surface. Connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer. Connect the integrating sphere output port to the spectrometer via an optical fiber. Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition.

[0099] 4. Set steady-state conditions in the LabView wave function generator and run until the sample system is stable. Open the spectrometer's built-in operating software, adjust the optical path and integration time so that the maximum spectral intensity is close to but not higher than 65500 in the intensity display mode "S". In the option setting "Options", the external trigger setting "External Trigger Settings", turn on the external trigger function "Enable". The trigger mode is edge trigger "Edge". According to the spectrometer parameter information at the specified frequency displayed in the LabView wave function generator interface, set the spectrometer parameters in the spectrometer's built-in software, including the number of onboard averages and the number of collected spectra.

[0100] 5. In the Run button options, select the cache mode "Store to Ram" and click Run to put the spectrometer in a waiting trigger state.

[0101] 6. Open the AC modulation mode of the LabView wave function generator program so that the modulation signal of channel 1 and the trigger signal of channel 2 start to output at the same time. Wait for the spectrometer to complete data acquisition. At this time, "Measurements" displays 1. Click "Spectrum 3D" and select Excel output in the file "File" tab. Save the file in the pop-up Excel program.

[0102] 7. Open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, run the program to obtain the light intensity modulation UV-visible-near infrared absorption spectrum, and save the results as a csv format file in the same directory.

[0103] 8. End the test: close the software and program, turn off the excitation light source, and turn off the constant potential instrument / source meter.

[0104] The above test operation process is as follows Figure 4 The interface of the LabView wave function generator program is as shown in Figure 5 As shown in the figure, the LabView spectral data post-processing program operation interface is as follows Figure 6 , Figure 7 , Figure 8 shown.

[0105] The following application examples illustrate application examples of the LMS and PMS test systems and methods provided by the above embodiments of the present invention:

[0106] Application Example 1

[0107] More transition metal hydroxides (such as NiFeO x) can not only show good electrocatalytic water decomposition and oxygen evolution reaction performance in alkaline solution, but also show electrochromic phenomenon under different bias conditions. The color change of this type of material is caused by the intermediate species formed during the oxygen evolution reaction. Quantitative analysis of the intermediate species can help evaluate the catalytic reaction mechanism of the material. x The film was loaded on a transparent conductive glass substrate and fixed on a working electrode clip. The voltage window between the sample and the reference electrode in a three-electrode electrolytic cell system (working electrode: sample; reference electrode: Hg / HgO; counter electrode: platinum wire; electrolyte: 1M KOH) was modulated by a potentiostat to record the NiFeO x Voltage modulation UV-visible near-infrared absorption spectrum response; the voltage modulation range used is 0.5 to 0.6V Hg / HgO , the modulation frequency is 0.5Hz. Fig. 9 As shown, NiFeO x Under this condition, a wide UV-visible-near infrared absorption response is formed, and its absorption characteristics are similar to the results of steady-state UV-visible-near infrared spectroscopy difference spectrum in the literature. At the same time, its phase angle remains stable in this wavelength range, proving that the measured results are generated by a single substance.

[0108] Application Example 2

[0109] BiVO4 is a common semiconductor electrode material used for photoelectrocatalytic water oxidation and oxygen evolution reaction. It is usually accompanied by some structural defects, and these defect states are easily modulated by electrochemical bias. This application embodiment uses voltage-modulated ultraviolet-visible near-infrared absorption spectra to observe the ultraviolet-visible near-infrared absorption response caused by the above-mentioned structural changes, which can be further used to infer the nature of its chemical structure. To this end, this application embodiment loads the BiVO4 film on a transparent conductive glass substrate and fixes it on a working electrode clip. The voltage window of the sample and the reference electrode in the three-electrode electrolytic cell system (working electrode: sample; reference electrode: Ag / AgCl; counter electrode: platinum wire; electrolyte: 0.1M Na2B4O7, solution pH adjusted to 9.0) is modulated by a constant potential instrument; the voltage modulation interval used is -0.5 to -0.1V Ag / AgCl , the modulation frequency is 0.25Hz.

[0110] The test results found that (such as Fig.10 As shown in FIG. 1 , different from the result of Application Example 1, under 0.5 Hz modulation, the phase cannot be kept constant within a given wavelength range. Fig.10 As shown in the figure, the response below 550nm is at about -30°, while above 600nm is at about 170°. This shows that the spectral responses of the two bands correspond to different chemical substances. Since the phase of the band above 600nm is closer to the real axis (180°), it can be inferred that the chemical reaction rate is faster.

[0111] Application Example 3

[0112] α-Fe2O3 is another common semiconductor electrode material used for photoelectrocatalytic water oxidation and oxygen evolution reaction. When light is applied under a specific bias voltage, a photoanode current can be generated. During the reaction, intermediate products such as Fe(IV)=O will accumulate on the surface of α-Fe2O3, and this species has ultraviolet, visible and near-infrared absorption responses. For this reason, this application example uses LMS to record this phenomenon. First, the α-Fe2O3 film is loaded on a transparent conductive glass substrate, fixed on a working electrode clip and placed in a three-electrode electrolytic cell system (working electrode: sample; reference electrode: Hg / HgO; counter electrode: platinum wire; electrolyte: 1M KOH); the voltage of the sample relative to the reference electrode is set to 0.6V Hg / HgO ; The 365nm LED used has an intensity modulation range of 20 to 60mWcm -2 , the modulation frequency is 0.5Hz. Fig.11 This is the LMS spectrum of the α-Fe2O3 photoelectrocatalytic water oxidation and oxygen evolution reaction. The phase value remains stable within the wavelength range, so it can be inferred that the spectrum is composed of a single species or process.

[0113] Application Example 4

[0114] In addition to studying the color change phenomenon, PMS can also be used to dynamically characterize the electroluminescence phenomenon. This application example uses a sinusoidal modulation potential to control the 365nm LED light intensity to simulate an electroluminescent device and display its PMS spectrum. Fig.12 , Fig.13 , Fig.14 A clear peak signal can be observed near 365nm, indicating that the detection light increases with the modulation voltage. When the LED is modulated at 50Hz, 5Hz, and 0.5Hz, the signal strength shows no signs of attenuation with increasing frequency, and the phase angle is stable at about 0° near 365nm, proving that the LED has a fast response in this frequency range. The phase angle fluctuates greatly in the area far above or below 365nm, proving that there is no effective PMS signal.

[0115] Application Example 5

[0116] Common commercial A4 printing paper contains fluorescent whitening additives, and the LMS test system and method of the present invention can also be used to dynamically characterize fluorescence phenomena. To this end, this embodiment adopts an experimental idea similar to that of Application Example 4, and uses a 375nm semiconductor laser as an excitation light source to irradiate the sample through an optical fiber. This application embodiment uses an integrating sphere to detect diffuse reflection signals to obtain a fluorescence spectrum. The integrating sphere is composed of a hemispherical reflection cavity, an optical fiber input port pointing to the sample, and an optical fiber output port on the cavity wall. When the sample to be tested is irradiated with excitation light, a small amount of diffuse reflection light and fluorescence are derived from the output port. It is then transmitted to the detector of the spectrometer after the 375nm excitation light component is suppressed by a 400nm longwave pass filter. By analyzing the light intensity returned by the detector, the spectral information of the sample to be tested can be obtained. Fig.15 As shown, when a Teflon standard white board is used as a control group, similar results to those in Application Example 4 can be observed. First, an unfiltered excitation light feature appears at 375nm. For the Teflon standard white board, no other spectral features appear. When A4 printing paper is used as a sample, a strong fluorescence signal peak can be observed at 400 to 550nm. This signal can be attributed to the fluorescence phenomenon caused by the whitening agent in the sample. At the same time, the phase angle corresponding to the signal is also at about 0°, proving that the fluorescence process also has a faster response relative to the modulation frequency (0.5Hz).

[0117] The above description is only a preferred embodiment of the present invention and is not any formal or substantial limitation of the present invention. It should be pointed out that a person skilled in the art can make several improvements and supplements without departing from the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. An excitation modulation frequency domain ultraviolet visible near infrared spectroscopy test system based on a portable spectrometer, characterized in that: It includes an excitation modulation system, a spectrum test system, a data analysis system, and a LabView host computer system; the excitation modulation system includes a modulation voltage system and / or a modulation light intensity system, the spectrum acquisition system includes a sample stage, a detection light source, an optical fiber, an optical fiber coupler, and a portable optical fiber spectrometer, the data analysis system includes a data acquisition computer and the spectrometer's own software AvaSoft8; the LabView host computer system includes a host computer and LabView software; The excitation modulation system and the data analysis system are respectively controlled by a LabView host computer system; The LabView software includes a LabView wave function generation program and a LabView spectrum data post-processing program, wherein the LabView wave function generation program is used to control the parameter setting of the excitation modulation system; and the LabView spectrum data post-processing program is used to post-process the data collected by the data analysis system; The modulation voltage and / or modulation light intensity emitted by the excitation modulation system are respectively applied to the sample to be tested, and the excitation modulation system outputs a pulse signal to the external triggering end of the portable optical fiber spectrometer at the start time of modulation; The detection light emitted by the detection light source is coupled to the optical fiber through the optical fiber coupler under the action of the modulated voltage or modulated light and irradiates the sample on the sample stage. The transmitted light passing through the sample is coupled to the optical fiber through another optical fiber coupler and input into the portable optical fiber spectrometer. After the data collected by the portable optical fiber spectrometer is transmitted to the data acquisition computer, it is read by the software provided by the spectrometer in the absorption mode and finally transmitted to the LabView host computer system. The LabView spectral data post-processing program performs post-processing and graphical display on the spectral data.

2. The excitation modulation frequency domain ultraviolet visible near infrared spectroscopy test system according to claim 1, characterized in that: The light intensity modulation system includes a wave function generator, an LED constant current driver and an LED lamp; the wave function generator generates a sinusoidal or square wave alternating current (AC) signal, which is output to the LED constant current driver and drives the LED lamp, so that the light intensity of the excitation light fluctuates at a given AC frequency.

3. The excitation modulation frequency domain ultraviolet visible near infrared spectroscopy test system according to claim 1, characterized in that: The modulation voltage system includes a function generator and a potentiostat / sourcemeter; the wave function generator generates a sinusoidal or square wave alternating current (AC) signal, which is output to the potentiostat / sourcemeter, so that the voltage applied to the sample fluctuates at a given AC frequency.

4. The excitation modulation frequency domain ultraviolet visible near infrared spectroscopy test system according to claim 1, characterized in that: The detection light source is a combination of one or more of a halogen lamp, a deuterium lamp, a tungsten lamp and an LED lamp.

5. A UV-visible near-infrared spectroscopy testing method, characterized in that: The test system described in any one of claims 1 to 4 is used to collect light intensity modulation or voltage modulation ultraviolet visible near infrared spectrum, so as to realize the collection of a single full-band ultraviolet visible near infrared absorption spectrum and / or luminescence spectrum for the test sample, and the test method comprises the following steps: Step 1: Turn on the connected test system and place the sample on the sample table; Step 2: Adjust the optical path and set the spectrum test parameters; Step 3: When measuring the absorption spectrum, turn off the detection light source and record the dark-state background spectrum; turn on the constant voltage or light intensity through the excitation modulation system and wait for the system to stabilize; turn on the detection light source and record the reference spectrum; when measuring the luminescence spectrum, there is no need to record the dark-state background spectrum and the reference spectrum, turn on the constant voltage or light intensity through the excitation modulation system and wait for the system to stabilize; Step 4: Turn on the constant voltage or light intensity by exciting the modulation system and wait for the system to stabilize; Step 5: Collect the spectral signals obtained by the spectrometer and perform data post-processing, that is, complete the collection of the full-band ultraviolet, visible and near-infrared spectrum.

6. The testing method according to claim 5, characterized in that: The acquisition of light intensity modulation ultraviolet visible near infrared absorption spectrum specifically includes the following steps: Step A1: Connect the wave function generator and the portable fiber spectrometer to the USB port of the host computer; turn on the wave function generator and the computer; Step A2: placing a sample on a sample stage; Step A3: connect the wave function generator signal channel 1 to the LED or laser constant current driver, and the constant current driver to the LED lamp or laser diode; adjust the optical path so that the excitation light spot is irradiated on the sample surface; connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer; when the electrochemical cell is used as the sample stage, the detection light source output optical fiber is connected to the optical fiber coupler, and the optical path is adjusted so that the detection light spot coincides with the LED light spot; in the transmission mode, another optical fiber coupler is placed on the back side of the sample and connected to the portable optical fiber spectrometer through the optical fiber, or in the mirror reflection mode, the same or another optical fiber coupler is placed on the front side of the sample and connected to the portable optical fiber spectrometer through the optical fiber; wherein, in the mirror reflection mode, when the incident light and the output light share a fiber coupler, a Y-type optical fiber must be used; when the cuvette holder is used as the sample stage, the optical fiber port on the cuvette holder is connected to the portable optical fiber spectrometer through the optical fiber; Step A4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, first collect the dark-state background spectrum and reference spectrum under the conditions of the detection light source being turned off and the detection light source being turned on, respectively, and then change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode; Step A5: After the test is completed, export the data in the "A" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectrum data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the LMS spectrum; The acquisition of voltage-modulated UV-visible-near-infrared absorption spectrum specifically includes the following steps: Step B1: Connect the wave function generator and spectrometer to the USB port of the host computer; turn on the wave function generator and the computer; Step B2: placing a sample on a sample stage; Step B3: Connect the signal channel 1 of the wave function generator to the modulation input interface of the constant potential instrument / source meter, and connect the signal channel 2 of the wave function generator to the external trigger interface of the spectrometer; when the electrochemical cell is used as the sample stage, the output optical fiber of the detection light source is connected to the optical fiber coupler, and the optical path is adjusted so that the detection light spot is irradiated on the sample surface; in the transmission mode, another optical fiber coupler is placed on the back side of the sample and connected to the spectrometer through the optical fiber, or in the mirror reflection mode, the same or another optical fiber coupler is placed on the front side of the sample and connected to the portable optical fiber spectrometer through the optical fiber; wherein, in the mirror reflection mode, when the incident light and the output light share a fiber coupler, a Y-type optical fiber must be used; when the cuvette holder is used as the sample stage, the optical fiber port on the cuvette holder is connected to the portable optical fiber spectrometer through the optical fiber; Step B4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, first collect the dark-state background spectrum and reference spectrum under the conditions of the detection light source being turned off and the detection light source being turned on, respectively, and then change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode; Step B5: After the test is completed, export the data in the "A" display mode of the "Spectrum 3D" data as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the PMS spectrum.

7. The testing method according to claim 5, characterized in that: The collection of light intensity modulation ultraviolet visible near infrared luminescence spectrum specifically includes the following steps: Step C1: Connect the wave function generator and the portable fiber spectrometer to the USB port of the host computer; turn on the wave function generator and the computer; Step C2: placing a sample on a sample stage; Step C3: connecting the wave function generator signal channel 1 to an LED or laser constant current driver, and the constant current driver to an LED lamp or a laser diode; adjusting the optical path so that the excitation light spot is irradiated on the sample surface; connecting the wave function generator signal channel 2 to an external trigger interface of the spectrometer; the sample light emission signal is directly connected to a portable fiber spectrometer through an optical fiber from an output port of the sample stage or an independent fiber coupler; Step C4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode; Step C5: After the test is completed, export the data in the "S" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectrum data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the LMS spectrum; The acquisition of voltage-modulated UV-visible-near-infrared luminescence spectrum specifically includes the following steps: Step D1: Connect the wave function generator and spectrometer to the USB port of the host computer; turn on the wave function generator and the computer; Step D2: placing a sample on a sample stage; Step D3: Connect the wave function generator signal channel 1 to the modulation input interface of the constant potential instrument / source meter, and connect the wave function generator signal channel 2 to the external trigger interface of the spectrometer; the sample luminescence signal is directly connected to the portable fiber optic spectrometer through the output port of the sample stage or an independent fiber optic coupler via an optical fiber; Step D4: Turn on the potentiostat / source meter as needed to keep the sample in a constant potential condition; set the steady-state conditions in the LabView wave function generator and run until the sample system is stable; in the spectrometer's built-in software, change the measurement mode to the external trigger mode "External Trigger" and the cache mode "Store to Ram" and run; turn on the LabView wave function generator program AC modulation mode; Step D5: After the test is completed, export the data in the "S" data display mode of "Spectrum 3D" as an Excel file; open the LabView spectral data post-processing program, select the file path, set the frequency value to be the same as the modulation frequency in the LabView wave function generation program, and run the program to obtain the PMS spectrum.

8. The test system according to any one of claims 1 to 5, or the use of the test method according to any one of claims 6 to 7, characterized in that: The application is selected from any one of the following applications: 1) Application of UV-visible-near infrared spectroscopy in dynamic characterization of materials; 2) Application in characterizing and identifying intermediate species produced when catalytic materials undergo chemical reactions; 3) Application in the study and evaluation of catalytic properties, color change phenomena and properties, and luminescence phenomena and properties of materials; 4) Application in the study and evaluation of catalytic properties, color change phenomena and properties, luminescence phenomena and properties of materials or products; 5) Application in studying the mechanisms related to the physical and chemical processes of materials or products.

9. The use according to claim 8, characterized in that: The materials include electrochromic materials, photochromic materials, electroluminescent materials, photoluminescent materials and catalytic materials; the catalytic materials include photocatalytic materials, electrocatalytic materials and photoelectrocatalytic materials; the products contain the materials.

10. The use according to claim 8, characterized in that: The dynamic characterization includes the dynamic characterization during a chemical reaction.

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