Photocatalytic material fluorescence quantum efficiency calibration method and system

Abstract

The invention discloses a photocatalytic material fluorescence quantum efficiency calibration method and system, and relates to the technical field of calibration systems, through combined use of a fluorescence spectrometer and an ultraviolet and visible spectrophotometer, fluorescence emission and absorption spectrums of a sample are comprehensively obtained, the accuracy of data is ensured, and secondly, the accuracy of the fluorescence quantum efficiency of the photocatalytic material is improved. In the method, control of key experimental parameters such as the distance between an excitation light source and a sample, excitation power and sample concentration is defined, interference of factors such as a fluorescence quenching effect on experimental results is remarkably reduced, the measurement accuracy is ensured, the accuracy of calculation results is ensured by introducing an error calibration step, and the method is suitable for popularization and application. According to the calibration method, the fluorescence quantum efficiency measurement of the photocatalytic material is more standardized and systematized, the reproducibility and credibility of a result are effectively improved, and powerful data support is provided for performance optimization and application research of the photocatalytic material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of calibration systems, in particular to a method and system for calibrating the fluorescence quantum yield of photocatalytic materials. BACKGROUND

[0002] The fluorescence quantum yield (QY) of photocatalytic materials is an important method for evaluating the optical properties of photocatalytic materials, especially in catalytic reactions, energy conversion and optoelectronic applications. The fluorescence quantum yield of photocatalytic materials refers to the efficiency of converting incident photon energy into fluorescent photons, which directly affects the energy conversion efficiency and reaction selectivity in the photocatalytic process.

[0003] The existing technology has the following defects: The existing method cannot effectively eliminate the interference of fluorescence quenching effect and other factors in the measurement of fluorescence quantum yield, thereby reducing the accuracy of the measurement. In addition, the traditional calibration method mostly relies on empirical methods, lacks systematic error analysis and calibration steps, and the experimental data is often affected by systematic errors, making it difficult to obtain accurate results, especially in the case of weak fluorescence signal or high concentration of materials, it is difficult to effectively avoid measurement deviation.

[0004] Therefore, the present application provides a method and system for calibrating the fluorescence quantum yield of photocatalytic materials, which introduces an error calibration step to ensure the accuracy of the calculation results. This calibration method makes the fluorescence quantum yield determination of photocatalytic materials more standardized and systematic, effectively improves the reproducibility and reliability of the results, and provides strong data support for the performance optimization and application research of photocatalytic materials. SUMMARY

[0005] The present application aims to provide a method and system for calibrating the fluorescence quantum yield of photocatalytic materials to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for calibrating the fluorescence quantum yield of photocatalytic materials, the calibration method comprising the following steps: Measure the fluorescence emission of the sample using a fluorescence spectrometer to obtain the fluorescence spectrum, generate a scanning range based on the emission peak of the sample, and record the distance between the excitation light source and the sample; Measure the absorption spectrum of the sample using a UV-Vis spectrophotometer and record the absorbance of the sample at the excitation light wavelength to obtain the absorption spectrum; According to the measured fluorescence spectrum and absorption spectrum, calculate the fluorescence quantum yield using the relative method or absolute method; The calculated result is calibrated according to the influence of the excitation source power and the fluorescence quenching effect, and a calibrated calculated result is obtained; The calibrated calculated result of the fluorescence quantum efficiency is compared with the data in the reference for data analysis, and an analysis result is output.

[0007] In a preferred embodiment, the calculated result is calibrated according to the influence of the excitation source power and the fluorescence quenching effect, and a calibrated calculated result is obtained, including the following steps: According to the recorded excitation source power in the experiment, the relationship between the fluorescence signal and the power is calculated, and if there is a nonlinear effect of the power, the fluorescence quantum efficiency is calibrated by adjusting the power or applying a nonlinear calibration factor; The calibration is performed by establishing a standard curve of concentration and fluorescence intensity, measuring the fluorescence intensity at different concentrations, and obtaining the concentration and fluorescence response relationship to calibrate the fluorescence quantum efficiency.

[0008] In a preferred embodiment, the fluorescence quantum efficiency is calculated by using a relative method or an absolute method according to the measured fluorescence spectrum and absorption spectrum, including the following steps: The relative method selects a standard substance with a known fluorescence quantum efficiency, measures the fluorescence emission of the standard substance by a fluorescence spectrometer, and obtains the fluorescence spectrum thereof; The fluorescence emission of the sample is measured by the fluorescence spectrometer, and the fluorescence emission spectrum of the sample is recorded, ensuring that the excitation wavelength of the sample is consistent with that of the standard substance, and the illumination conditions of the light source and the sample are the same; The fluorescence quantum efficiency of the sample is estimated by comparison with the standard substance with a known fluorescence quantum efficiency; The absolute method directly measures the number of fluorescence photons and the number of absorbed photons. The number of fluorescence photons is recorded by the cooperation of the fluorescence spectrometer and the photodetector under the excitation of the sample, and the photodetector records the number of photons at different wavelengths according to the emission spectrum of the sample. The number of absorbed photons is calculated by the absorbance of the sample and the number of incident photons of the light source.

[0009] In a preferred embodiment, the fluorescence emission of the sample is measured by the fluorescence spectrometer, and the fluorescence emission spectrum of the sample is recorded, ensuring that the excitation wavelength of the sample is consistent with that of the standard substance, and the illumination conditions of the light source and the sample are the same, and the expression is: wherein, is the fluorescence quantum efficiency of the sample, is the known fluorescence quantum efficiency of the standard substance, and are the fluorescence emission intensities of the sample and the standard substance, respectively, and are the absorbances of the sample and the standard substance, respectively.

[0010] In a preferred embodiment, the fluorescence quantum efficiency is calculated based on the absolute method, and the calculation logic is that the fluorescence quantum efficiency is obtained by dividing the number of photons emitted by the sample by the number of photons absorbed.

[0011] In a preferred embodiment, the sample is measured by an ultraviolet visible spectrophotometer to obtain an absorption spectrum, and the absorbance of the sample at the excitation light wavelength is recorded, including the following steps: When measuring the absorption spectrum, the ultraviolet visible spectrophotometer scans the set wavelength range step by step, and records the absorbance of the sample at each wavelength point. The absorbance follows the Lambert-Beer law between the concentration of the sample and the optical path length. By recording the absorbance data of the sample at different wavelengths, the absorption spectrum is obtained.

[0012] In a preferred embodiment, the absorbance follows the Lambert-Beer law between the concentration of the sample and the optical path length, which is expressed as A=ε*c*L, where A is the absorbance, ε is the molar absorption coefficient, c is the concentration of the sample, and L is the optical path length.

[0013] In a preferred embodiment, the sample is measured by a fluorescence spectrometer to obtain a fluorescence spectrum, including the following steps: By measuring the background spectrum without exciting the sample, and making corresponding deduction in the actual measurement; The fluorescence emission measurement of each sample is repeated multiple times to eliminate accidental errors caused by equipment fluctuations or environmental factors. The instrument continuously records the fluorescence intensity of the sample at different wavelengths.

[0014] In a preferred embodiment, the scanning range is generated based on the emission peak of the sample, and the distance between the excitation light source and the sample is recorded, including the following steps: The distance between the excitation light source and the sample is adjusted according to the power of the light source and the properties of the sample; In the fluorescence spectrum, the emission peak position of the sample corresponds to the wavelength of the photons released by the sample in the process of transition from the excited state to the ground state. The scanning range covers at least twice the width of the emission peak.

[0015] The present application also provides a photocatalytic material fluorescence quantum efficiency calibration system, including a spectrum generation module, an efficiency calculation module, and an efficiency calibration module; The spectrum generation module: the sample is measured by a fluorescence spectrometer to obtain a fluorescence spectrum, the scanning range is generated based on the emission peak of the sample, and the distance between the excitation light source and the sample is recorded. The sample is measured by an ultraviolet visible spectrophotometer to obtain an absorption spectrum, and the absorbance of the sample at the excitation light wavelength is recorded. Efficiency calculation module: according to the measured fluorescence spectrum and absorption spectrum, the fluorescence quantum efficiency is calculated by using relative method or absolute method; Efficiency calibration module: according to the influence of excitation source power and fluorescence quenching effect, the calculation result is calibrated to obtain the calibrated calculation result, and the calibrated calculation result of fluorescence quantum efficiency is compared with the data in the reference to perform data analysis, and the analysis result is output.

[0016] In the above technical solution, the technical effects and advantages provided by the present application are as follows: The present application comprehensively obtains the fluorescence emission and absorption spectrum of the sample by the joint use of the fluorescence spectrometer and the ultraviolet-visible spectrophotometer, ensures the accuracy of the data, and further reduces the interference of the fluorescence quenching effect and other factors on the experimental results by controlling the key experimental parameters such as the distance between the excitation light source and the sample, the excitation power and the sample concentration, ensures the accuracy of the measurement, and ensures the accuracy of the calculation result by introducing the error calibration step, and further verifies the reliability of the result by comparing and analyzing the data in the reference, which makes the fluorescence quantum efficiency determination of the photocatalytic material more standardized and systematic, effectively improves the reproducibility and reliability of the result, and provides strong data support for the performance optimization and application research of the photocatalytic material. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments or prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0018] Figure 1 The flowchart of the calibration method of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] Embodiment: please refer to Figure 1 The photocatalytic material fluorescence quantum efficiency calibration method described in the present embodiment includes the following steps: Select the appropriate photocatalytic material sample. Ensure the uniformity and purity of the material, and adjust the sample concentration according to the experimental requirements to avoid fluorescence quenching effect caused by high concentration. The sample can be in the form of powder, film or solution, according to the experimental requirements. Select the appropriate standard substance (such as diphenyl anthracene, europium ion, etc.) as reference, and the standard substance should have known fluorescence quantum efficiency. The selection of standard substance should meet the absorption spectrum and emission spectrum range of the sample to be measured to ensure the accuracy of the comparison experiment. Select stable and adjustable light source such as xenon lamp or laser as excitation source. Set the wavelength of the light source to ensure that it matches the absorption band of the sample, and the excitation energy should be moderate to avoid nonlinear effects (such as excessive excitation of the sample). Record the wavelength, power and irradiation time of the excitation light and other parameters.

[0021] Measure the fluorescence emission of the sample by fluorescence spectrometer to obtain the fluorescence spectrum. Generate the scanning range based on the emission peak of the sample, and record the distance between the excitation light source and the sample. Ensure that the fluorescence spectrum of the sample does not interfere with the background spectrum, and perform multiple measurements to ensure the repeatability and accuracy of the data.

[0022] Measure the absorption spectrum of the sample using UV-Vis spectrophotometer. Ensure that the measurement spectrum range covers the absorption band of the sample, and record the absorbance of the sample at the excitation light wavelength to obtain the absorption spectrum. Accurate measurement of the absorption spectrum is the basis for calculating the fluorescence quantum efficiency.

[0023] According to the measured fluorescence spectrum and absorption spectrum, use relative method or absolute method to calculate the fluorescence quantum efficiency. If the relative method is used, the fluorescence quantum efficiency and spectral data of the standard substance are compared; if the absolute method is used, the ratio of the number of fluorescence photons to the number of absorbed photons is calculated.

[0024] Check if there are measurement errors or instrument drift problems, calibrate the calculation results according to the influence of excitation source power and fluorescence quenching effect, and get the calibrated calculation results. Ensure the reliability and accuracy of the results. Finally, compare the calibrated calculation results of fluorescence quantum efficiency with the data in the reference, analyze the data, and output the analysis results.

[0025] The application calculates the fluorescence quantum efficiency by using a relative method or an absolute method according to the measured fluorescence spectrum and absorption spectrum, calibrates the calculation result according to the influence of the excitation source power and the fluorescence quenching effect, obtains the calibrated calculation result, compares the fluorescence quantum efficiency calibrated calculation result with the data in the reference, performs data analysis, and outputs the analysis result. The calibration method ensures the accuracy of the calculation result by introducing an error calibration step. The calibration method makes the fluorescence quantum efficiency determination of the photocatalytic material more standardized and systematic, effectively improves the reproducibility and reliability of the result, and provides strong data support for the performance optimization and application research of the photocatalytic material.

[0026] The photocatalytic material fluorescence quantum efficiency calibration system described in the embodiment comprises a spectrum generation module, an efficiency calculation module and an efficiency calibration module. The spectrum generation module: a fluorescence spectrometer is used to measure the fluorescence emission of the sample, obtain the fluorescence spectrum, generate a scanning range based on the emission peak of the sample, and record the distance between the excitation light source and the sample. An ultraviolet-visible spectrophotometer is used to measure the absorption spectrum of the sample, and the absorbance of the sample at the excitation light wavelength is recorded to obtain the absorption spectrum. The fluorescence spectrum and the absorption spectrum are sent to the efficiency calculation module. The efficiency calculation module: according to the measured fluorescence spectrum and absorption spectrum, the fluorescence quantum efficiency is calculated by using a relative method or an absolute method. The fluorescence quantum efficiency calculation result is sent to the efficiency calibration module. The efficiency calibration module: according to the influence of the excitation source power and the fluorescence quenching effect, the calculation result is calibrated to obtain the calibrated calculation result. The fluorescence quantum efficiency calibrated calculation result is compared with the data in the reference to perform data analysis, and the analysis result is output.

[0027] The fluorescence spectrum of the sample is obtained by measuring the fluorescence emission of the sample by a fluorescence spectrometer. The scanning range is generated based on the emission peak of the sample, and the distance between the excitation light source and the sample is recorded. It is ensured that the fluorescence spectrum of the sample has no interference with the background spectrum, and multiple measurements are performed to ensure the repeatability and accuracy of the data.

[0028] The fluorescence emission of the sample is measured by a fluorescence spectrometer, which is one of the key steps of the photocatalytic material fluorescence quantum efficiency calibration. First, select an appropriate excitation light source and set its wavelength. Usually, the excitation wavelength is selected near the absorption peak of the sample to ensure that the excitation source can effectively excite the electronic transition of the sample. The wavelength of the excitation source should be determined according to the spectral characteristics of the sample. Too long or too short wavelength may lead to inaccurate measurement.

[0029] When performing fluorescence emission measurements, it is important to accurately record the distance between the excitation light source and the sample. Controlling this distance is crucial for ensuring uniformity of light source illumination and the intensity of excitation light received by the sample. For example, if the excitation light source is too close to the sample, it can result in excessive excitation light intensity, leading to fluorescence quenching effects. Conversely, if the distance is too far, it can result in insufficient light intensity, failing to excite the sample to achieve the desired emission effect. Therefore, the distance between the excitation light source and the sample usually needs to be finely adjusted according to the experimental setup of the light source power and the properties of the sample. Generally, the optimal distance is verified through pre-experiments before the experiment, and it is ensured to be stable under repeatable conditions.

[0030] Next, ensure that the fluorescence spectrum of the sample does not interfere with the background spectrum. The background spectrum usually refers to non-sample signals produced by other light sources in the experimental equipment or external environment, which can come from stray light of the light source, optical devices or fluorescence of other substances, etc. In the experiment, appropriate background subtraction methods are adopted to reduce interference and ensure that the measured fluorescence signal only represents the fluorescence characteristics of the sample itself. The commonly used method is to measure the background spectrum without exciting the sample, and to subtract accordingly in the actual measurement.

[0031] To ensure the reliability and accuracy of the data, the fluorescence emission measurement of each sample should be repeated multiple times, usually at least three times, and each measurement ensures that the equipment is stable and the environmental conditions are consistent. Through repeated measurements, accidental errors caused by equipment fluctuations or environmental factors can be eliminated, thereby improving the accuracy and repeatability of the data.

[0032] Determining the fluorescence spectrum scanning range based on the emission peak of the sample is an important step to ensure the completeness of the fluorescence spectrum data. In the fluorescence spectrum, the emission peak position of the sample corresponds to the wavelength of the photons released during the transition of the sample from the excited state to the ground state. The scanning range should cover at least twice the width of the emission peak to ensure that all important emission information of the sample within this range can be captured. Specifically, if the fluorescence emission peak of the sample appears at 400 nm, the scanning range should be set between 350 nm and 450 nm, so that the complete data and peak shape characteristics of the emission peak can be ensured not to be missed.

[0033] During the scanning process, the instrument will continuously record the fluorescence intensity of the sample at different wavelengths. Generally, the higher the resolution of the instrument, the more detailed the data measured. The resolution setting should be optimized according to the fluorescence characteristics of the sample, as excessive resolution can result in redundant data and increase measurement time, while insufficient resolution may fail to capture subtle changes in the sample.

[0034] When performing fluorescence emission measurements, it is crucial to ensure the repeatability and accuracy of the data. To ensure this, first, the stability of the equipment needs to be tested and ensure that the working state of the equipment is in the optimal state during the entire measurement process. For example, the spectrometer should be calibrated before and after measurement, and the standard fluorescent substance (such as fluorescent powder) should be verified to ensure that the measurement error of the instrument is within a reasonable range.

[0035] Secondly, repeated measurements are an important means to ensure the accuracy of the results. The fluorescence emission signal itself is affected by many factors, such as light source fluctuation, temperature change, sample concentration, etc. Therefore, by measuring multiple times and taking the average, it helps to eliminate the influence of these accidental factors on the experimental results. Generally, for each sample, more than three independent measurements should be performed, and the spectral results of each measurement should be recorded. Finally, the stability and accuracy of the experimental data can be evaluated by analyzing the standard deviation of multiple measurement results.

[0036] For example, if the emission peak position and peak shape of the sample change little in multiple measurements, and the standard deviation is within a reasonable range, it can be determined that the data has good repeatability and accuracy. If the standard deviation is too large, it may indicate that there is a problem with the sample during measurement, such as uneven sample, excessive fluctuation of the experimental environment, or the instrument has not been well calibrated.

[0037] Through the above steps, the fluorescence spectrum data of the sample can be effectively obtained, and the accuracy and repeatability of the measurement results can be ensured through reasonable operation. This lays a solid foundation for subsequent fluorescence quantum efficiency calculation.

[0038] Use the UV-Vis spectrophotometer to measure the absorption spectrum of the sample. Ensure that the measurement spectral range covers the absorption band of the sample, and record the absorbance of the sample at the excitation wavelength to obtain the absorption spectrum. Accurate measurement of the absorption spectrum is the basis for calculating the fluorescence quantum efficiency.

[0039] Using a UV-Vis spectrophotometer to measure the absorption spectrum of the sample is one of the core steps in the fluorescence quantum efficiency calibration of photocatalytic materials. Before starting the measurement, first, ensure that the sample handling and loading method meets the experimental requirements. The form of the sample can be solution, film or solid, etc. Generally, for solution samples, the absorbance measurement needs to ensure that the concentration of the sample is moderate, and too high concentration may cause light path saturation, thereby affecting the accuracy of the absorbance. When handling solid samples, ensure the uniformity of the light path design and the sample surface state to avoid measurement errors caused by uneven surface reflection or scattering.

[0040] At the same time, the calibration of the UV-Vis spectrophotometer is very important. Before each measurement, the instrument needs to be calibrated using standard light sources such as deuterium and tungsten lamps to ensure that the spectral response of the equipment is stable and accurate throughout the measurement wavelength range. After calibration, the zero point calibration should be performed on the blank solution or sample substrate to ensure the correct baseline of the data.

[0041] When performing absorption spectrum measurements, the appropriate wavelength range needs to be set according to the optical properties of the sample. The measurement range of the absorption spectrum usually covers the ultraviolet light (200-400 nm) to the visible light region (400-700 nm), and the specific range should be determined according to the absorption characteristics of the sample. If the absorption peak of the sample is known to be in a specific wavelength region, the scanning range of the spectrophotometer should be ensured to cover the absorption band and extend at least to both sides of the absorption band to ensure that the entire absorption spectrum can be accurately recorded.

[0042] When setting the wavelength range, attention should be paid to the wavelength resolution of the instrument. Too low resolution may not be able to clearly distinguish the small structures in the absorption band, while too high resolution may cause unnecessary time delay in the measurement process and may cause the signal-to-noise ratio to decrease. In experiments, the wavelength resolution of the instrument is usually set to 1 nm to 5 nm, and the specific selection should be optimized according to the characteristics of the sample and the experimental requirements.

[0043] When performing absorption spectrum measurements, the UV-Vis spectrophotometer will gradually scan the set wavelength range and record the absorbance of the sample at each wavelength point. The absorbance (A) and the concentration of the sample and the optical path length (L) follow the Lambert-Beer law, which is: A=ε*c*L, where A is the absorbance, ε is the molar absorption coefficient, c is the concentration of the sample, and L is the optical path length. By recording the absorbance data of the sample at different wavelengths, the absorption spectrum is obtained.

[0044] During data acquisition, the instrument will automatically measure each wavelength point according to the set step (usually 1 nm or less) and output the corresponding absorbance value. In order to reduce experimental errors, it is recommended to perform repeated measurements and compare multiple samples to ensure the consistency and accuracy of the results.

[0045] In order to ensure the accuracy and reliability of the absorbance data, several potential interference factors need to be considered during the measurement process, such as impurities in the solution, spectral drift of the equipment, etc. After obtaining the original absorbance data, first perform background calibration, i.e. measure the absorbance of the blank solution or sample substrate, and subtract this background value from the absorbance of the sample to obtain the pure absorbance of the sample.

[0046] Next, the equipment can be calibrated by comparing the absorbance of the standard substance. For some photocatalytic materials, the absorption band may have a strong nonlinear effect, such as light source non-uniformity, solvent effect, etc. At this time, a standard reference substance (such as a standard solution with known absorbance) needs to be used for calibration, and the measurement data needs to be properly calibrated.

[0047] The accurate measurement of absorbance provides a basis for subsequent fluorescence quantum efficiency calculation. After obtaining the absorbance data of the sample, the main absorption peak position of the sample needs to be identified first, and the corresponding absorbance value is recorded. Generally, the wavelength at which the peak value of the absorbance value is the maximum absorption band of the sample, and this wavelength point is also the excitation wavelength for fluorescence emission measurement. In order to ensure that the wavelength of the excitation light source can be maximally coincided with the absorption band of the sample, the most suitable excitation wavelength should be set according to the absorbance data.

[0048] When analyzing the absorption spectrum, the relationship between the number of absorbed photons and the absorption intensity of the sample can also be calculated, and the absorbance of the sample at the excitation light wavelength can be further calculated according to the concentration and optical path length of the sample. This data is crucial for calculating the fluorescence quantum efficiency and can provide the necessary input data for subsequent fluorescence spectrum measurement.

[0049] Through the accurate operation of the above steps, the UV-Vis spectrophotometer can accurately record the absorption spectrum of the sample, laying a data foundation for the calculation of fluorescence quantum efficiency. Each detail in this process can have a significant impact on the final result, so the rigor of the experimental environment, equipment calibration and data processing must be ensured.

[0050] According to the measured fluorescence spectrum and absorption spectrum, the fluorescence quantum efficiency is calculated using the relative method or the absolute method. If the relative method is used, the fluorescence quantum efficiency and spectral data of the standard substance are compared; if the absolute method is used, the ratio of the number of fluorescence photons to the number of absorbed photons is calculated.

[0051] When calculating the fluorescence quantum yield (Fluorescence-Quantum-Yield, QY), the appropriate calculation method needs to be selected first. There are two common methods for calculating fluorescence quantum yield: relative method and absolute method. Both have advantages and disadvantages, and the choice depends on the experimental conditions and the required accuracy.

[0052] Relative method: The relative method is a method of estimating the fluorescence quantum yield of the sample by comparing it with the standard substance with known fluorescence quantum yield. This method is suitable for quickly estimating the fluorescence quantum yield, but the fluorescence quantum yield and spectral data of the standard substance must be very accurate, and the standard substance should have good overlap with the emission spectrum of the sample.

[0053] Absolute method: The absolute method calculates the fluorescence quantum efficiency by directly measuring the ratio of the number of fluorescence emission photons to the number of absorbed photons of the sample. This method is more accurate and does not rely on standard materials, but requires precise photon counting technology and strict experimental control.

[0054] If the relative method is chosen, the key to the calculation process is to compare the fluorescence quantum efficiency of the sample with that of the standard material. The specific steps are as follows: 1. Select a standard material with a known fluorescence quantum efficiency, such as diphenyl anthracene (DPA), whose fluorescence quantum efficiency is usually given in the literature. Measure the fluorescence emission of the standard material by a fluorescence spectrometer to obtain its fluorescence spectrum.

[0055] 2. Measure the fluorescence emission of the sample using a fluorescence spectrometer and record the fluorescence emission spectrum of the sample. Ensure that the excitation wavelength of the sample is consistent with that of the standard material, and that the illumination conditions of the light source and the sample are the same. The formula for the relative method is: where, is the fluorescence quantum efficiency of the sample, is the known fluorescence quantum efficiency of the standard material, and are the fluorescence emission intensities of the sample and the standard material, respectively, and are the absorbances of the sample and the standard material, respectively. The function of the formula is to calculate the fluorescence quantum efficiency of the sample by comparing the differences in fluorescence intensity and absorbance between the sample and the standard material.

[0056] If the absolute method is used, the key to the calculation is to directly measure the ratio of the number of photons absorbed to the number of photons emitted by the sample. This method does not rely on standard materials, but directly measures the number of fluorescence photons and the number of absorbed photons of the sample through precise photon counting technology. The number of photons emitted by the sample can be recorded by the cooperation of the fluorescence spectrometer and the photodetector under the illumination of the excitation light. Generally, the photodetector will record the number of photons at different wavelengths according to the emission spectrum of the sample. The number of absorbed photons can be calculated by the absorbance of the sample and the number of incident photons of the light source, as described in the preamble of the description of the Lambert-Beer law. In the case where the absorbance of the sample and the molar absorption coefficient are known, the number of photons absorbed by the sample at the excitation wavelength can be calculated.

[0057] Based on the absolute method to calculate the fluorescence quantum efficiency, the calculation logic is: the fluorescence quantum efficiency is obtained by dividing the number of photons emitted by the sample by the number of photons absorbed. By accurately measuring the number of absorbed and emitted photons of the sample, the value of the fluorescence quantum efficiency can be directly obtained.

[0058] Regardless of the relative method or absolute method, strict error analysis should be performed on the data during the experiment. For example, the intensity fluctuation of the light source, the change of the sample concentration, the temperature fluctuation of the experimental environment and other factors will affect the final calculation results. Therefore, after each experiment, it is very important to perform repeated measurements and error analysis of the data. In addition, the effects of the efficiency of the photodetector, the spectral response of the instrument and other factors on the results should also be considered and properly calibrated.

[0059] Through comprehensive analysis and processing of experimental data, reliable fluorescence quantum efficiency values can be obtained, providing data support for subsequent performance optimization and application research of photocatalytic materials.

[0060] Check for measurement errors or instrument drift issues, calibrate the calculated results based on the effects of excitation source power and fluorescence quenching, and obtain the calibrated results. Ensure the reliability and accuracy of the results. Finally, compare the calibrated fluorescence quantum efficiency calculation results with the data in the reference literature, perform data analysis, and output the analysis results.

[0061] In the process of measuring fluorescence quantum efficiency, any potential error or instrument drift may affect the accuracy of the results, so these factors need to be checked in detail. First of all, it is necessary to confirm the stability of the experimental equipment and the calibration of the instrument. Instrument drift usually manifests as fluctuations in the intensity of the light source during measurement, changes in the sensitivity of the spectrometer, or changes in the response of the detector. In order to avoid the influence of instrument drift, calibration samples (such as standard fluorescent powder) should be used to calibrate the instrument regularly during the experiment, and ensure that its performance remains consistent before and after the experiment.

[0062] Secondly, it is very important to check the power fluctuation of the excitation source. The power fluctuation of the excitation source will directly affect the excitation intensity of the sample, thus causing changes in the fluorescence signal. If the excitation source power is unstable, it may cause changes in the fluorescence emission intensity of the sample, thereby affecting the calculation results of the fluorescence quantum efficiency. Generally, a power meter can be used to monitor the output power of the excitation light source in real time, and the excitation source power can be adjusted to maintain stability.

[0063] In the calculation of fluorescence quantum efficiency, the power of the excitation source and the fluorescence quenching effect are the three important factors that affect the accuracy of the results.

[0064] Excitation source power: too high excitation source power may cause light saturation effect, leading to nonlinear changes in fluorescence signal; too low power may cause the sample to be insufficiently excited. Therefore, the power of the excitation source should be optimized to be within the linear range of the fluorescence response of the sample.

[0065] Sample concentration: When the sample concentration is too high, the absorption and scattering of light increase, which may cause fluorescence quenching effect. Quenching effect reduces the fluorescence quantum efficiency, so the concentration of the sample needs to be controlled. Usually, the concentration is controlled by diluting the sample or adjusting the optical path length.

[0066] Fluorescence quenching effect: Fluorescence quenching effect refers to the phenomenon that the sample cannot effectively emit fluorescence after being irradiated by excitation light due to intermolecular interaction, solvent effect, etc. To eliminate the interference of fluorescence quenching effect, appropriate solvents can be used, the temperature and concentration of the sample can be adjusted, or appropriate stabilizers can be added to reduce the effect.

[0067] These factors may cause the actual measurement results to deviate from the true value, so calibration is needed in the calculation process.

[0068] Once the potential measurement errors and influencing factors are identified, the calculation results need to be calibrated according to the experimental data. The purpose of the calibration process is to calibrate the deviations caused by excitation source power and fluorescence quenching effect. The following are common calibration methods: Excitation source power calibration: According to the recorded excitation source power in the experiment, the relationship between fluorescence signal and power is calculated to ensure that the measured fluorescence intensity is linearly related to the power. If there is a nonlinear effect of power, calibration needs to be done by adjusting the power or applying a nonlinear calibration factor.

[0069] Fluorescence quenching calibration: To eliminate the fluorescence quenching effect caused by concentration, calibration can be done by establishing a standard curve of concentration and fluorescence intensity. By measuring the fluorescence intensity at different concentrations, the relationship between concentration and fluorescence response can be obtained, so that high concentration samples can be properly calibrated, and the fluorescence quenching effect can be calibrated. A common method is to measure the fluorescence quantum efficiency at different concentrations and establish the relationship between concentration and quantum efficiency, so that the fluorescence quenching effect can be quantitatively analyzed and calibrated.

[0070] In photocatalysis and fluorescence measurement, excitation source power is a key factor affecting the intensity of fluorescence signal. Generally, there should be a certain linear relationship between fluorescence signal and excitation source power. However, in actual experiments, if the power is too high, it may cause nonlinear effects such as saturation effect or light attenuation, so nonlinear calibration of the measured fluorescence signal is needed. In ideal conditions, the relationship between excitation source power and fluorescence signal is as follows: where, is the fluorescence signal intensity, is the excitation source power, is the proportionality constant, which depends on the fluorescence characteristics of the sample, and the specific value of k depends on the properties of the sample (such as fluorescence quantum efficiency, absorbance, etc.) and experimental conditions. The value of k is usually between 103 to 10 4 orders of magnitude.

[0071] When the excitation source power increases to a certain extent, the fluorescence signal may exhibit a nonlinear response. The nonlinear effect is usually manifested in that the fluorescence intensity no longer increases linearly, but tends to be saturated. At this time, the relationship between the fluorescence signal and the excitation source power can be described by the following nonlinear equation: wherein, is an exponential coefficient, which is usually obtained by fitting experimental data. For a low power range, is close to 1, indicating a linear relationship; while when the power is relatively high, will be less than 1, indicating a nonlinear relationship, and the exponential coefficient a describes the nonlinear relationship between the fluorescence intensity and the excitation light source power. At a relatively high excitation power, the fluorescence intensity no longer increases linearly, but tends to be saturated, and in a low power range, a is usually a ≈ 1, indicating that the relationship between the fluorescence intensity and the power is linear. When the excitation power is relatively high, a will be less than 1, indicating that the growth of the fluorescence intensity slows down and enters a saturated state. At this time, the exponential coefficient a is generally between 0.50 and 0.90. If the excitation power is very high, it may cause a serious saturation effect, and the value of a may be less than 0.5.

[0072] If a nonlinear effect is found in the experiment, it needs to be corrected by adjusting the power or applying a nonlinear correction factor. By fitting the experimental data to obtain the exponential coefficient a, the following correction formula can be applied: Through this formula, the corrected fluorescence intensity eliminates the nonlinear effect of the power and obtains a more accurate fluorescence signal.

[0073] The concentration of the sample directly affects the intensity of the fluorescence signal, especially at a relatively high concentration, the interaction between molecules may cause fluorescence quenching effect, thereby affecting the calculation of the fluorescence quantum efficiency. Therefore, by establishing a standard curve of concentration and fluorescence intensity, the fluorescence quantum efficiency can be more accurately calibrated. In a lower concentration range, the fluorescence intensity of the sample is usually linearly related to its concentration. This relationship can be represented by the following formula: wherein, is the fluorescence intensity, is the concentration and fluorescence intensity ratio constant, is the concentration of the sample, and the concentration and fluorescence intensity ratio constant reflects the linear relationship between the fluorescence intensity and the concentration of the sample in a low concentration range, the value of which is usually in the order of 10 2 to 10 4 orders of magnitude.

[0074] When the sample concentration increases, intermolecular interactions can cause fluorescence quenching effects, affecting the intensity of the fluorescence signal. Fluorescence quenching effects make the fluorescence intensity no longer linear, but tend to be saturated. At this time, the relationship between concentration and fluorescence intensity can be described by a second-order kinetic model: where, is the fluorescence intensity at low concentration (without quenching effect), is the quenching constant, indicating the strength of fluorescence quenching, is the sample concentration, and the quenching constant indicates the strength of fluorescence quenching, which reflects the inhibitory effect of intermolecular interactions (such as collisional quenching or energy transfer) on fluorescence intensity, The value of Kq is usually in the range of 10 9 to 10 12 L·mol -1 ·s -1 . For ordinary fluorescent dyes or photocatalytic materials, usually between 10 10 and 10 11 L·mol -1 ·s -1 , at high concentrations, is larger, indicating a stronger quenching effect, which can reach 10 12 L·mol -1 ·s -1 .

[0075] By measuring the fluorescence intensity of the sample at different concentrations and plotting the concentration-fluorescence intensity curve, the standard relationship between concentration and fluorescence intensity can be established. If quenching effects occur at high concentrations, calibration can be performed by the following steps: Measure the fluorescence intensity at different concentrations: select several concentration points (such as low, medium, and high concentrations) and record the corresponding fluorescence intensity.

[0076] Fit the relationship between concentration and fluorescence intensity: through experimental data, fit the standard curve between concentration and fluorescence intensity. If the sample concentration is low, use a linear model; if the concentration is high, use a second-order kinetic model for correction.

[0077] For example, in the experiment, if the following data (concentration-fluorescence intensity relationship) is obtained: Concentration Fluorescence intensity 0.1M 50 0.5M 200 1.0M 350 2.0M 450 According to these data, use linear fitting or second-order kinetic model fitting to obtain the standard curve of concentration-fluorescence intensity, and apply the corresponding model for correction.

[0078] After obtaining a standard curve of concentration versus fluorescence intensity, these data can be used to calibrate the fluorescence quantum efficiency. For high-concentration samples, a quenching model is applied to correct for the fluorescence intensity, ultimately yielding the accurate fluorescence quantum efficiency. For example, if the measured uncalibrated fluorescence quantum efficiency is... After correcting for the concentration effect, the calibrated fluorescence quantum efficiency is... It can be represented as: This formula can correct for the quenching effect caused by concentration, and obtain the calibrated fluorescence quantum efficiency.

[0079] Suppose we are measuring the fluorescence quantum efficiency of a photocatalytic material. During the experiment, a nonlinear effect was observed at high excitation source power; therefore, a nonlinear calibration factor was applied for correction. Simultaneously, high sample concentration may cause fluorescence quenching; therefore, a concentration-fluorescence intensity standard curve was established and a quenching model was applied for calibration.

[0080] First, fluorescence signals were measured at different powers, revealing a non-linear relationship between fluorescence signal and power. By fitting the power-fluorescence signal relationship and obtaining an exponential coefficient α = 0.8, a non-linear calibration factor was applied to correct the fluorescence intensity. Fluorescence intensities at different concentrations were measured, resulting in a concentration-fluorescence intensity standard curve. A quenching model was then used to correct the fluorescence intensity at higher concentrations. Through these two calibration processes, a more accurate fluorescence quantum efficiency was obtained, reflecting the true performance of the sample and providing data support for subsequent photocatalytic performance optimization. The calibrated fluorescence quantum efficiency data needs to be compared with known data in the references to ensure its accuracy and reliability. The comparison process typically includes the following steps: The calibrated fluorescence quantum efficiency was compared with that of similar materials in the references. If the fluorescence quantum efficiency of the sample is similar to the data in the references, the calculated results are considered to be highly reliable. If there is a significant difference, further analysis of the experimental conditions, sample characteristics, or the source of measurement error is required.

[0081] By comparing experimental data with reference data using statistical methods, the standard deviation or relative error of the error can be calculated. If the error is within an acceptable range, the accuracy of the measurement and calculation process is high. Otherwise, it may be necessary to re-evaluate the experimental conditions or computational model.

[0082] By comparing and analyzing the data, the fluorescence quantum efficiency of the samples was determined, and their performance in specific applications was evaluated. For example, if the fluorescence quantum efficiency of a sample is higher than that in the literature, it may mean that the material has better performance in fields such as photocatalysis and photoelectric conversion.

[0083] After completing all data processing, calibration, and comparison work, the final analytical results should include the following: the fluorescence quantum efficiency value of the sample, along with the experimental error range. A summary of factors that may affect the measurement results should be provided, such as the effects of excitation source power, sample concentration, and fluorescence quenching. The experimental results should be compared with data from references to analyze their consistency and differences. The performance of the sample's fluorescence properties in practical applications should be considered, along with suggestions for material modification or optimization. These steps ensure the reliability, accuracy, and effectiveness of the fluorescence quantum efficiency measurement results in practical applications.

[0084] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for calibrating the fluorescence quantum efficiency of photocatalytic materials, characterized in that: The calibration method includes the following steps: The fluorescence emission of the sample is measured by a fluorescence spectrometer to obtain the fluorescence spectrum. The scanning range is generated based on the emission peak of the sample, and the distance between the excitation source and the sample is recorded. The absorption spectrum of the sample was measured using a UV-Vis spectrophotometer, and the absorbance of the sample at the excitation wavelength was recorded to obtain the absorption spectrum. Based on the measured fluorescence and absorption spectra, the fluorescence quantum efficiency is calculated using either a relative or absolute method. The calculation results were calibrated based on the effects of excitation source power and fluorescence quenching effect to obtain calibrated calculation results. The calculated results after fluorescence quantum efficiency calibration are compared with the data in the references, and the analysis results are output.

2. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 1, characterized in that: The calculation results are calibrated based on the effects of excitation source power and fluorescence quenching, resulting in calibrated calculation results. This process includes the following steps: Based on the excitation source power recorded in the experiment, the relationship between fluorescence signal and power is calculated. If there is a nonlinear effect in the power, the fluorescence quantum efficiency is calibrated by adjusting the power or applying a nonlinear calibration factor. Calibration is performed by establishing a standard curve of concentration versus fluorescence intensity, measuring fluorescence intensity at different concentrations, obtaining the relationship between concentration and fluorescence response, and then calibrating the fluorescence quantum efficiency.

3. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 2, characterized in that: Based on the measured fluorescence and absorption spectra, the fluorescence quantum efficiency is calculated using either a relative or absolute method, including the following steps: The relative method involves selecting a standard substance with a known fluorescence quantum efficiency and measuring its fluorescence emission using a fluorescence spectrometer to obtain its fluorescence spectrum. The fluorescence emission of the sample was measured using a fluorescence spectrometer, and the fluorescence emission spectrum of the sample was recorded. It was ensured that the excitation wavelength of the sample was consistent with that of the standard material, and that the light source and the irradiation conditions of the sample were the same. The fluorescence quantum efficiency of the sample is estimated by comparing it with a standard substance with known fluorescence quantum efficiency. The absolute method directly measures the number of fluorescent photons and the number of absorbed photons of the sample. The number of fluorescent photons is recorded by the combination of a fluorescence spectrometer and a photodetector, which records the number of photons emitted by the sample under excitation light. The photodetector records the number of photons at different wavelengths based on the emission spectrum of the sample. The number of absorbed photons is calculated by the absorbance of the sample and the number of incident photons from the light source.

4. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 3, characterized in that: The fluorescence emission of the sample was measured using a fluorescence spectrometer, and the fluorescence emission spectrum of the sample was recorded. It was ensured that the excitation wavelength of the sample was consistent with that of the standard substance, and that the light source and irradiation conditions were the same for both. The expression is as follows: ,in, The fluorescence quantum efficiency of the sample is given. The known fluorescence quantum efficiency of the standard material, and The fluorescence emission intensities of the sample and the standard substance are respectively. and The absorbance values ​​are for the sample and the standard substance, respectively.

5. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 3, characterized in that: The fluorescence quantum efficiency is calculated using the absolute method. The calculation logic is as follows: the fluorescence quantum efficiency is obtained by dividing the number of photons emitted by the sample by the number of photons absorbed.

6. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 5, characterized in that: The absorption spectrum of the sample is measured using a UV-Vis spectrophotometer, and the absorbance of the sample at the excitation wavelength is recorded to obtain the absorption spectrum, including the following steps: When measuring the absorption spectrum, the UV-Vis spectrophotometer scans the set wavelength range step by step and records the absorbance of the sample at each wavelength point. The absorbance follows the Lambert-Beer law with respect to the sample concentration and optical path length. By recording the absorbance data of the sample at different wavelengths, the absorption spectrum is obtained.

7. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 6, characterized in that: The absorbance follows the Lambert-Beer law with respect to the sample concentration and optical path length, expressed as: A = ε * c * L, where A is the absorbance, ε is the molar absorptivity, c is the sample concentration, and L is the optical path length.

8. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 1, characterized in that: The fluorescence emission of the sample is measured using a fluorescence spectrometer to obtain the fluorescence spectrum, including the following steps: By measuring the background spectrum without exciting the sample, and then subtracting it accordingly in the actual measurement; The fluorescence emission measurement of each sample was repeated multiple times to eliminate random errors caused by equipment fluctuations or environmental factors. The instrument continuously recorded the fluorescence intensity of the sample at different wavelengths.

9. The method for calibrating the fluorescence quantum efficiency of photocatalytic materials according to claim 1, characterized in that: The scanning range is generated based on the emission peak of the sample, and the distance between the excitation source and the sample is recorded, including the following steps: The distance between the excitation source and the sample is adjusted according to the power of the source and the properties of the sample; In fluorescence spectroscopy, the position of the emission peak of the sample corresponds to the wavelength of the photon released during the transition of the sample from the excited state to the ground state, and the scanning range covers at least twice the width of the emission peak.

10. A calibration system for the fluorescence quantum efficiency of photocatalytic materials, used to implement the calibration method according to any one of claims 1-9, characterized in that: It includes a spectrum generation module, an efficiency calculation module, and an efficiency calibration module; Spectrum generation module: The fluorescence emission of the sample is measured by a fluorescence spectrometer to obtain the fluorescence spectrum. The scanning range is generated based on the emission peak of the sample, and the distance between the excitation source and the sample is recorded. The absorption spectrum of the sample is measured by a UV-Vis spectrophotometer, and the absorbance of the sample at the excitation wavelength is recorded to obtain the absorption spectrum. Efficiency calculation module: Based on the measured fluorescence and absorption spectra, the fluorescence quantum efficiency is calculated using either a relative or absolute method. Efficiency calibration module: The calculation results are calibrated based on the effects of excitation source power and fluorescence quenching effect to obtain calibrated calculation results. The calibrated fluorescence quantum efficiency calculation results are compared with the data in the references for data analysis, and the analysis results are output.

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