Analytical methods, analytical programs, and analytical instruments

Abstract

For example, it provides evaluation methods for samples such as perovskite solar cells, or accurately identifies defects in samples such as semiconductors. [Solution] Light is irradiated onto the sample to generate fluorescence from the sample, the fluorescence intensity obtained by detecting the fluorescence from the sample is measured for each wavelength, multiple fluorescence lifetime components are calculated for each wavelength based on the change in fluorescence intensity, a fluorescence spectrum showing the relationship between the fluorescence intensity and wavelength of the same fluorescence lifetime component is generated for each fluorescence lifetime component, and the sample is analyzed based on multiple fluorescence spectra obtained from multiple measurements or fluorescence spectra for each fluorescence lifetime component.

Description

Technical Field

[0001] The present invention relates to an analysis method, an analysis program, and an analysis apparatus.

Background Art

[0002] Conventionally, for example, as shown in Patent Document 1, there is a perovskite solar cell which is a solar cell using a substance having a perovskite structure for a power generation layer. Since the perovskite solar cell is a lightweight and flexible solar cell as compared with a silicon-based solar cell, the development of the perovskite solar cell has been actively carried out.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, for example, solar cells such as perovskite solar cells have instability in that their characteristics change when irradiated with light. Therefore, although an analysis method for evaluating solar cells is desired, an evaluation method for solar cells has not been established at present.

[0005] \ Further, conventionally, in order to measure the stability of a sample, for example, defects of the sample are judged based on a fluorescence spectrum obtained by irradiating the sample such as a semiconductor with light. However, since the fluorescence spectra in different fluorescence lifetime components may overlap, there is a possibility of misjudging the types of defects of the sample.

[0006] Therefore, the present invention has been made in view of the above problems, and a main object thereof is to provide an evaluation method for a sample such as a perovskite solar cell, or to accurately judge defects of a sample such as a semiconductor. [Means for solving the problem]

[0007] In other words, the present invention provides an analytical method for analyzing a sample, which is a solar cell or a semiconductor, based on fluorescence obtained by irradiating the sample with light, characterized in that: light is irradiated onto the sample to generate fluorescence from the sample; fluorescence intensity obtained by detecting the fluorescence from the sample is measured for each wavelength; a plurality of fluorescence lifetime components are calculated for each wavelength based on the change in fluorescence intensity; a fluorescence spectrum showing the relationship between the fluorescence intensity of the same fluorescence lifetime component and the wavelength is generated for each fluorescence lifetime component; and the sample is analyzed based on a plurality of fluorescence spectra obtained by multiple measurements or the fluorescence spectra for each fluorescence lifetime component.

[0008] In this configuration, the fluorescence lifetime component is an important parameter indicating the stability of the sample, while the fluorescence spectrum shows the relationship between the fluorescence intensity and wavelength of the same fluorescence lifetime component. Furthermore, since multiple fluorescence spectra obtained from multiple measurements are used, the stability of the sample can be evaluated. Furthermore, since the sample is analyzed based on the fluorescence spectrum of each fluorescence lifetime component, it is possible to prevent misidentification of different defects in the sample and to accurately determine the type of defect in the sample.

[0009] Specifically, if the sample is a solar cell, the solar cell is analyzed based on multiple fluorescence spectra obtained by multiple measurements, and if the sample is a semiconductor, the semiconductor is analyzed based on the fluorescence spectra for each fluorescence lifetime component.

[0010] In the aforementioned analysis method, it is preferable to calculate the proportion of a predetermined fluorescence lifetime component to a plurality of fluorescence lifetime components for each predetermined fluorescence lifetime component.

[0011] With this configuration, the proportion of a given fluorescence lifetime component to multiple fluorescence lifetime components is calculated for each given fluorescence lifetime component, making it possible to evaluate which of the multiple fluorescence lifetime components is dominant.

[0012] The fluorescence lifetime component that accounts for the largest proportion among multiple fluorescence lifetime components exhibits the greatest change in its properties when irradiated with light. Therefore, it is preferable to generate multiple fluorescence spectra obtained by multiple measurements of the fluorescence lifetime component with the largest proportion, and to analyze the solar cell based on the multiple fluorescence spectra obtained by multiple measurements of the fluorescence lifetime component with the largest proportion.

[0013] With this configuration, it is possible to capture the change in the fluorescence spectrum at the fluorescence lifetime component, which exhibits the largest change in properties when irradiated with light, thereby evaluating the instability of the solar cell when irradiated with light.

[0014] The solar cell is analyzed based on multiple fluorescence spectra obtained from multiple measurements, and the changes in the multiple fluorescence spectra are output to a display unit in a way that allows them to be compared with each other after multiple measurements.

[0015] With this configuration, multiple fluorescence spectra obtained from multiple measurements are displayed on the screen in a way that allows for comparison between each measurement. This enables the user to qualitatively analyze the solar cell based on the changes in the fluorescence spectrum between measurements.

[0016] The analysis method involves changing the characteristics of the solar cell, calculating the attenuation rate in multiple fluorescence spectra obtained through multiple measurements, and comparing the attenuation rate before changing the characteristics of the solar cell with the attenuation rate after changing the characteristics of the solar cell.

[0017] With this configuration, the solar cell after the modification can be analyzed by comparing the attenuation rate before the modification with the attenuation rate after the modification, thus allowing for a quantitative analysis of the modified solar cell.

[0018] One possible method is to create a correspondence table that associates the fluorescence spectrum for each fluorescence lifetime component with the type of defect, obtain the fluorescence spectrum for each fluorescence lifetime component, and estimate the type of defect based on the correspondence table.

[0019] With this configuration, a correspondence table is created that associates the fluorescence spectrum for each fluorescence lifetime component with the type of semiconductor defect, allowing for accurate estimation of the defect type based on the table.

[0020] One possible method is to calculate, for each type of defect, the proportion of a predetermined type of defect present among multiple types of defects, based on the fluorescence spectrum for each fluorescence lifetime component.

[0021] With this configuration, the prevalence of each defect type is calculated based on the fluorescence spectrum of each fluorescence lifetime component, allowing for an evaluation of which defect type is dominant in the sample.

[0022] An analysis program used in an analytical device that analyzes a sample, which is a solar cell or semiconductor, by irradiating it with light to generate fluorescence from the sample, detecting the fluorescence, and measuring the fluorescence intensity obtained for each wavelength, is characterized in that it causes a computer to perform the following functions: a fluorescence lifetime component calculation unit that calculates a plurality of fluorescence lifetime components for each wavelength based on the change in fluorescence intensity; a fluorescence spectrum generation unit that generates a fluorescence spectrum showing the relationship between the fluorescence intensity of the same fluorescence lifetime component and the wavelength for each fluorescence lifetime component; and an analysis unit that analyzes the sample based on a plurality of fluorescence spectra or the fluorescence spectra for each fluorescence lifetime component obtained by multiple measurements. Also, an analyzer that irradiates a sample, which is a solar cell or a semiconductor, with light to generate fluorescence from the sample, measures the fluorescence intensity obtained by detecting the fluorescence for each wavelength, and analyzes the sample, the analyzer comprising: a fluorescence lifetime component calculation unit that calculates a plurality of fluorescence lifetime components for each wavelength based on a change in the fluorescence intensity; a fluorescence spectrum generation unit that generates a fluorescence spectrum showing the relationship between the fluorescence intensity and the wavelength of the same fluorescence lifetime component for each fluorescence lifetime component; and an analysis unit that analyzes the sample based on a plurality of the fluorescence spectra obtained by a plurality of measurements or the fluorescence spectra for each fluorescence lifetime component.

[0023] With such a configuration, the same operational effects as those of the above-described analysis method can be obtained.

Advantages of the Invention

[0024] According to the present invention, for example, an evaluation method for a sample such as a perovskite solar cell or the like can be provided, or, for example, the determination of defects in a sample such as a semiconductor or the like can be accurately performed.

Brief Description of the Drawings

[0025] [Figure 1] Schematic diagram showing an analyzer in the first embodiment of the present invention. [Figure 2] Graph showing fluorescence intensity with respect to time at each frequency in the first embodiment. [Figure 3] Schematic diagram when calculating each fluorescence lifetime component in the first embodiment. [Figure 4] Graph showing the fluorescence spectrum for each fluorescence lifetime component in the first embodiment. [Figure 5] In the first embodiment, (a) graph showing the change in the fluorescence spectrum at the fluorescence lifetime component τ1, (b) graph showing the change in the fluorescence spectrum at the fluorescence lifetime component τ2, (c) graph showing the change in the fluorescence spectrum at the fluorescence lifetime component τ3. [Figure 6] Flowchart showing the analysis method in the first embodiment. [Figure 7]A schematic diagram showing the analytical apparatus in the second embodiment of the present invention. [Figure 8] A figure showing fluorescence spectra corresponding to the types of defects in the second embodiment of the present invention. [Figure 9] A flowchart illustrating the analysis method in the second embodiment. [Modes for carrying out the invention]

[0026] <First Embodiment> Hereinafter, an analytical apparatus and analytical method according to the first embodiment of the present invention will be described with reference to the drawings. Note that, for the sake of clarity, some figures shown below may be simplified or exaggerated for illustrative purposes. The same reference numerals are used for identical components, and their descriptions are omitted as appropriate.

[0027] <Device configuration> The analytical apparatus 100 in this embodiment analyzes a sample S, which is a solar cell such as a perovskite solar cell, based on the fluorescence obtained by irradiating the sample S with light. More specifically, the analytical apparatus 100 in this embodiment analyzes the power generation layer of a solar cell, but other parts of the power generation layer in a solar cell, such as electrodes, electron transport layers, or hole transport layers, may also be analyzed.

[0028] Specifically, as shown in Figure 1, the analytical apparatus 100 comprises a light irradiation unit 2 that irradiates light onto a sample S, a fluorescence detection unit 3 that detects fluorescence generated from the sample S by the light from the light irradiation unit 2, a control calculation unit 4 that performs various calculations based on the fluorescence intensity signal obtained by the fluorescence detection unit 3, and a display unit 5 that displays the output from the control calculation unit 4.

[0029] Let's explain each part.

[0030] The light irradiation unit 2 irradiates the sample S with excitation light, which is light at the excitation wavelength of the sample S. Specifically, the light irradiation unit 2 includes at least a light source (not shown) that emits light in a wavelength range that includes the excitation wavelength. The light irradiation unit 2 may further include a bandpass filter that transmits a predetermined wavelength component.

[0031] The fluorescence detection unit 3 detects fluorescence generated from the sample S when it is irradiated with excitation light. Specifically, the fluorescence detection unit 3 is a detector such as a photomultiplier tube, which detects fluorescence generated from the sample S at predetermined wavelengths and outputs fluorescence intensity signals for each predetermined wavelength to the control calculation device 4.

[0032] In this embodiment, the fluorescence detection unit 3 detects fluorescence at predetermined wavelengths with respect to time. However, in addition to time, fluorescence at predetermined wavelengths may also be detected with respect to measurement conditions of the sample S, such as temperature, pressure, pH, position, humidity, amount of sample S added, and / or flow rate. Furthermore, wavelength includes physical quantities equivalent to wavenumber, such as wavenumber and / or energy. The fluorescence detection unit 3 may further include a bandpass filter that transmits predetermined wavelength components.

[0033] The control arithmetic unit 4 is a general-purpose or dedicated computer equipped with a CPU, memory, AD converter, DA converter, etc. According to an image display program stored in a predetermined area of ​​memory, the CPU and / or its peripheral devices cooperate to provide at least a measurement data storage unit 41, a fluorescence lifetime component calculation unit 42, a fluorescence spectrum generation unit 43, and an analysis unit 44, as shown in Figure 1. The functions of each unit will be described below.

[0034] The measurement data storage unit 41 stores measurement data that shows the fluorescence intensity for each wavelength obtained from the fluorescence detection unit 3 paired with the time at which it was detected. As shown in Figure 2, the measurement data is created by pairing the fluorescence intensity for each wavelength λ1, λ2, λ3, λ4, λ5, ... output from the fluorescence detection unit 3 with the time at which that fluorescence intensity was obtained, on a graph with three orthogonal axes representing wavelength, time, and fluorescence intensity. The measurement data storage unit 41 then stores the created measurement data. Note that the user may create the measurement data, or a computer such as the control calculation unit 4 may create the measurement data.

[0035] The fluorescence lifetime component calculation unit 42 calculates multiple fluorescence lifetime components for each wavelength based on the change in fluorescence intensity. Here, the fluorescence lifetime component indicates the slope from the peak value to a predetermined value, such as 1 / e of the peak value. In this embodiment, the change in fluorescence intensity refers to the change in fluorescence intensity over time, but is not limited to this. For example, the change in fluorescence intensity may be a change in fluorescence intensity in response to measurement conditions of the sample S, such as temperature, pressure, pH, position, humidity, amount of sample S added, and / or flow rate.

[0036] Specifically, as shown in Figure 3, at a certain wavelength λ1, a fluorescence intensity decay curve is created by plotting the normalized fluorescence intensity against time in a graph where two orthogonal axes represent time and normalized fluorescence intensity. Then, assuming the existence of three fluorescence lifetime components, parameter fitting is performed on the fluorescence intensity decay curve to obtain three fluorescence lifetime components τ1, τ2, and τ3 at a certain wavelength λ1. Similarly, for each wavelength λ2, λ3, λ4, λ5, etc., parameter fitting is performed on the fluorescence intensity decay curve to obtain three fluorescence lifetime components τ1, τ2, and τ3 for each wavelength λ2, λ3, λ4, λ5, etc. Alternatively, if a fluorescence lifetime component at a certain wavelength with a characteristic peak is obtained, that fluorescence lifetime component may be used to fit other wavelengths to the decay curve of that fluorescence lifetime component. Note that the number of fluorescence lifetime components at each wavelength is not limited to three; there may be one or more.

[0037] Furthermore, the fluorescence lifetime component calculation unit 42 calculates the proportion of a predetermined fluorescence lifetime component to a plurality of fluorescence lifetime components at a given wavelength. Here, the proportion of a predetermined fluorescence lifetime component to a plurality of fluorescence lifetime components corresponds to the area ratio of the triangle formed by the fluorescence lifetime component, the intersection of the fluorescence lifetime component in the normalized fluorescence intensity and time 0, and the intersection of the fluorescence lifetime component and the normalized fluorescence intensity at 1 / e times the peak value, as shown in Figure 3.

[0038] Specifically, as shown in Figure 3, at a certain wavelength λ1, the areas of the triangles for fluorescence lifetime component τ1, fluorescence lifetime component τ2, and fluorescence lifetime component τ3 are calculated (hatched area in Figure 3). Then, based on the area ratios of these triangles, the proportions of fluorescence lifetime components τ1, τ2, and τ3 are calculated. Similarly, at each wavelength λ2, λ3, λ4, λ5, etc., the proportions of fluorescence lifetime components τ1, τ2, and τ3 are calculated based on the area ratios of the triangles. Here, the proportion of fluorescence lifetime component τ3 is the largest, but fluorescence lifetime component τ3 is not the only one with the largest proportion.

[0039] The fluorescence spectrum generation unit 43 generates fluorescence spectra for each fluorescence lifetime component, showing the relationship between the fluorescence intensity and wavelength of the same fluorescence lifetime component. Specifically, the fluorescence spectrum generation unit 43 obtains the fluorescence intensity of the same fluorescence lifetime component at each wavelength from the fluorescence lifetime component calculation unit 42 for each fluorescence lifetime component. Then, the fluorescence spectrum generation unit 43 plots the fluorescence intensity of the same fluorescence lifetime component at each wavelength for each fluorescence lifetime component on a graph with two orthogonal axes representing fluorescence intensity and wavelength. This generates fluorescence spectra for each fluorescence lifetime component.

[0040] Specifically, the fluorescence spectrum generation unit 43 acquires the fluorescence intensity of fluorescence lifetime component τ1 at each wavelength λ1, λ2, λ3, λ4, λ5..., the fluorescence intensity of fluorescence lifetime component τ2 at each wavelength λ1, λ2, λ3, λ4, λ5..., and the fluorescence intensity of fluorescence lifetime component τ3 at each wavelength λ1, λ2, λ3, λ4, λ5.... The fluorescence spectrum generation unit 43 then plots the fluorescence intensity of fluorescence lifetime component τ1 at each wavelength λ1, λ2, λ3, λ4, λ5... on a graph with two orthogonal axes representing fluorescence intensity and wavelength. Similarly, the fluorescence spectrum generation unit 43 plots the fluorescence intensity of fluorescence lifetime component τ2 at each wavelength λ1, λ2, λ3, λ4, λ5..., and the fluorescence intensity of fluorescence lifetime component τ3 at each wavelength λ1, λ2, λ3, λ4, λ5... on a graph with two orthogonal axes representing fluorescence intensity and wavelength. As a result, fluorescence spectra for each fluorescence lifetime component τ1, τ2, and τ3 are generated, as shown in Figure 4. In addition, as shown in Figure 4, in this embodiment, a fluorescence spectrum is also generated that integrates the fluorescence spectrum of fluorescence lifetime component τ1, the fluorescence spectrum of fluorescence lifetime component τ2, and the fluorescence spectrum of fluorescence lifetime component τ1.

[0041] The analysis unit 44 analyzes the sample S based on multiple fluorescence spectra obtained from multiple measurements. In this embodiment, the fluorescence spectrum generation unit 43 generates one fluorescence spectrum for each fluorescence lifetime component in a single measurement, and the analysis unit 44 acquires the fluorescence spectra generated one for each fluorescence lifetime component from the fluorescence spectrum generation unit 43 after each measurement.

[0042] The analysis unit 44 then analyzes the sample S based on the changes in the fluorescence spectra generated for each fluorescence lifetime component that occur with multiple measurements. The changes in the fluorescence spectra generated for each fluorescence lifetime component that occur with multiple measurements refer, for example, to the change in the magnitude of the peak intensity of the fluorescence spectrum and / or the change in the position of the peak intensity of the fluorescence spectrum that occur with multiple measurements. Furthermore, the analysis of the sample S refers to evaluating the stability of the sample S, such as the crystal structure of the sample S, when the sample S is, for example, a perovskite solar cell, to the extent to which the properties of the sample S, such as the crystal structure of the sample S, have changed as a result of being irradiated with light.

[0043] Here, as shown in Figure 5, the analysis unit 44 acquires the fluorescence spectrum of fluorescence lifetime component τ1 obtained from multiple measurements (Figure 5(a)), the fluorescence spectrum of fluorescence lifetime component τ2 obtained from multiple measurements (Figure 5(b)), and the fluorescence spectrum of fluorescence lifetime component τ3 obtained from multiple measurements (Figure 5(c)). Since fluorescence lifetime component τ3, which has the largest proportion among fluorescence lifetime components τ1, τ2, and τ3, contributes most to the change in the characteristics of sample S, the analysis unit 44 calculates the change in the fluorescence spectrum associated with multiple measurements based on the fluorescence spectrum of fluorescence lifetime component τ3 obtained from multiple measurements and analyzes sample S. In this embodiment, Figure 5 shows the fluorescence spectrum obtained from four measurements, but the number of measurements is not limited to four; two or more measurements are acceptable.

[0044] Furthermore, the analysis unit 44 outputs multiple fluorescence spectra to the display unit 5 in a manner that allows them to be compared with each other after multiple measurements. Here, "displayed in a manner that allows for comparison" means that the user can visually identify which fluorescence spectrum was obtained from which measurement on the display unit 5, and more specifically, that the user can visually identify them based on information such as line type and color that is assigned to each of the multiple measurements.

[0045] For example, as shown in Figure 5, when displaying the fluorescence spectra for each fluorescence lifetime component in four measurements, the fluorescence spectrum from the first measurement is shown as a thick line, the fluorescence spectrum from the second measurement as a thin line, the fluorescence spectrum from the third measurement as a dashed line, and the fluorescence spectrum from the fourth measurement as a dotted line.

[0046] The display unit 5 is, for example, a display, and displays the analysis results obtained by the analysis unit 44. Specifically, the display unit 5 displays a graph showing the fluorescence spectra for each fluorescence lifetime component in multiple measurements, and / or numerical values ​​such as the value of the fluorescence lifetime component, the peak intensity in the fluorescence spectrum, and the peak position in the fluorescence spectrum.

[0047] <Analysis method> Next, the analysis method in this embodiment will be described with reference to Figure 6.

[0048] First, light is shone onto sample S, causing fluorescence to be generated from sample S (S1).

[0049] The fluorescence detection unit 3 detects fluorescence from the sample S at each wavelength and outputs fluorescence intensity signals for each wavelength to the control calculation unit 4 (S2). Fluorescence intensity is obtained from the fluorescence intensity signals, and the measurement data storage unit 41 stores measurement data, pairing the fluorescence intensity for each wavelength with the time of detection.

[0050] The fluorescence lifetime component calculation unit 42 acquires measurement data from the measurement data storage unit 41. Then, the fluorescence lifetime component calculation unit 42 generates multiple fluorescence lifetime components for each wavelength based on the change in fluorescence intensity in the measurement data (S3).

[0051] The fluorescence spectrum generation unit 43 then obtains the fluorescence intensity of the same fluorescence lifetime component at each wavelength from the fluorescence lifetime component calculation unit 42 for each fluorescence lifetime component. The fluorescence spectrum generation unit 43 then generates a fluorescence spectrum for each fluorescence lifetime component (S4).

[0052] Steps S1 through S4 are performed in a single measurement. Once steps S4 are completed, a decision is made as to whether to proceed with the next measurement (S5).

[0053] When performing the next measurement, steps S1 to S4 are repeated in the same manner.

[0054] If multiple measurements are taken and no further measurements are taken, the analysis unit 44 analyzes the sample S based on the multiple fluorescence spectra obtained from the multiple measurements (S6). The analysis results from the analysis unit 44 are output to the display unit 5.

[0055] <Effects of the First Embodiment> According to the analytical method in this embodiment, the fluorescence lifetime component is an important parameter indicating the stability of the sample S, and the fluorescence spectrum shows the relationship between the fluorescence intensity and wavelength of the same fluorescence lifetime component. Furthermore, since multiple fluorescence spectra obtained from multiple measurements are used, the stability of the sample S can be evaluated.

[0056] <Second Embodiment> Next, an analytical apparatus and analytical method according to a second embodiment of the present invention will be described with reference to the drawings. In the following description, parts that differ from the first embodiment will be described, and identical components will be denoted by the same reference numerals.

[0057] <Device configuration> In the second embodiment, unlike the first embodiment (configuration for evaluating the stability of sample S), the analysis unit 44 is configured to analyze defects in sample S. Specifically, in the second embodiment, sample S is, for example, a semiconductor, and the analysis unit 44 analyzes defects in sample S based on the fluorescence spectrum for each fluorescence lifetime.

[0058] Specifically, as shown in Figure 7, the analyzer 100 further includes a correspondence table storage unit 45 that stores a correspondence table that associates the fluorescence spectrum for each fluorescence lifetime component with the type of defect in the sample S. The correspondence table may be created by the user or by a computer such as the control calculation unit 4. The type of defect in the sample S referred to here is the type of defect that arises from different trapping times of electrons constituting the semiconductor.

[0059] More specifically, as shown in Figure 8(a), in the correspondence table, the fluorescence spectrum of fluorescence lifetime component τa is linked to defect type a, the fluorescence spectrum of fluorescence lifetime component τb is linked to defect type b, the fluorescence spectrum of fluorescence lifetime component τc is linked to defect type c, and the fluorescence spectrum of fluorescence lifetime component τd is linked to defect type d. The created correspondence table is stored in the correspondence table storage unit 45.

[0060] The analysis unit 44 then estimates, based on the correspondence table, which type of defect in the correspondence table corresponds to the fluorescence spectrum of each fluorescence lifetime component obtained by measurement. Specifically, as shown in Figure 8(b), the analysis unit 44 estimates the type of defect by superimposing the fluorescence spectrum of each fluorescence lifetime component obtained by measurement and the fluorescence spectrum of each fluorescence lifetime component in the correspondence table onto a graph with two orthogonal axes representing fluorescence intensity and wavelength. For example, in Figure 8(a), if the analysis unit 44 determines that the shape of the fluorescence spectrum of fluorescence lifetime component τ3 obtained by measurement is similar to the shape of the fluorescence spectrum of fluorescence lifetime component τa in the correspondence table, the analysis unit 44 estimates that the fluorescence lifetime component τ1 obtained by measurement corresponds to type a of defect.

[0061] <Analysis method> Next, the analysis method in this embodiment will be described with reference to Figure 9.

[0062] First, the user or computer creates a correspondence table. The created correspondence table is stored in the correspondence table storage unit 45 (S1).

[0063] Next, light is shone onto sample S, causing fluorescence to be generated from sample S (S2).

[0064] The fluorescence detection unit 3 detects fluorescence from the sample S at each wavelength and outputs fluorescence intensity signals for each wavelength to the control calculation unit 4 (S3). Fluorescence intensity is obtained from the fluorescence intensity signals, and the measurement data storage unit 41 stores measurement data, pairing the fluorescence intensity for each wavelength with the time of detection.

[0065] The fluorescence lifetime component calculation unit 42 acquires measurement data from the measurement data storage unit 41. Then, the fluorescence lifetime component calculation unit 42 generates multiple fluorescence lifetime components for each wavelength based on the change in fluorescence intensity in the measurement data (S4).

[0066] The fluorescence spectrum generation unit 43 then obtains the fluorescence intensity of the same fluorescence lifetime component at each wavelength from the fluorescence lifetime component calculation unit 42 for each fluorescence lifetime component. The fluorescence spectrum generation unit 43 then generates a fluorescence spectrum for each fluorescence lifetime component (S5).

[0067] The analysis unit 44 obtains fluorescence spectra from the fluorescence spectrum generation unit 43 and obtains a correspondence table from the correspondence table storage unit 45. Then, based on the correspondence table, the analysis unit 44 estimates which type of defect each fluorescence spectrum obtained by measurement corresponds to (S6). The type of defect analyzed by the analysis unit 44 is displayed in the display unit 5.

[0068] <Effects of the second embodiment> According to the analysis method in this embodiment, since the sample S is analyzed based on the fluorescence spectrum of each fluorescence lifetime component, it is possible to prevent the identification of different defects in the sample S and to accurately determine the type of defect in the sample S.

[0069] <Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0070] In the first embodiment described above, the analysis unit 44 may calculate the attenuation rate of fluorescence intensity in multiple fluorescence spectra obtained by multiple measurements and analyze the sample S based on that attenuation rate. Here, the attenuation rate of fluorescence intensity is calculated based on the change in the magnitude of the peak intensity in each fluorescence spectrum from the multiple measurements.

[0071] The characteristics of the solar cell may be changed. In this case, the analysis unit 44 calculates the attenuation rates in multiple fluorescence spectra obtained by multiple measurements of the solar cell after the characteristics have been changed. The analysis unit 44 may then compare the attenuation rates before and after the characteristics change, using the attenuation rate obtained for the solar cell before the characteristics change as an index. This allows for a quantitative analysis of the stability of the solar cell after the characteristics have been changed.

[0072] In the first embodiment described above, the analysis unit 44 analyzed the sample S based on the change in the fluorescence spectrum at the fluorescence lifetime component τ3, which contributes most to the change in the characteristics of the sample S, but is not limited thereto. The analysis unit 44 may also analyze the sample S based on the change in the fluorescence spectrum for each fluorescence lifetime component, regardless of the proportion of fluorescence lifetime components.

[0073] In the second embodiment, the analysis unit 44 may calculate the proportion of a predetermined type of defect corresponding to a plurality of defect types for each defect type, based on the fluorescence spectrum for each fluorescence lifetime component.

[0074] In the second embodiment described above, the correspondence table was prepared before irradiating the sample S with light, but it is not limited to this. The correspondence table may be prepared after the fluorescence spectrum has been generated.

[0075] Furthermore, the present invention can be modified in various ways, as long as it does not contradict its spirit. [Explanation of symbols]

[0076] 100...Analyzer 2 ···Light irradiation section 3. Fluorescence detection unit 4. Control and calculation unit 41...Measurement data storage unit 42 ···Fluorescence lifetime component calculation unit 43 ···Fluorescence spectrum generation section 44...Analysis Department 45 ···Correspondence Table Storage Section 5...Display section S ···Sample

Claims

1. An analytical method for analyzing a sample, which is a solar cell or semiconductor, based on fluorescence obtained by irradiating the sample with light, The sample is irradiated with light to generate fluorescence from the sample. The fluorescence intensity obtained by detecting the fluorescence from the aforementioned sample is measured for each wavelength. Based on the change in fluorescence intensity, multiple fluorescence lifetime components are calculated for each wavelength. A fluorescence spectrum showing the relationship between the fluorescence intensity of the same fluorescence lifetime component and the wavelength is generated for each fluorescence lifetime component. An analytical method for analyzing a sample based on multiple fluorescence spectra obtained by multiple measurements or on fluorescence spectra for each fluorescence lifetime component.

2. If the sample is the solar cell, the solar cell is analyzed based on multiple fluorescence spectra obtained by multiple measurements. The analytical method according to claim 1, wherein, if the sample is the semiconductor, defects in the semiconductor are analyzed based on the fluorescence spectrum for each fluorescence lifetime component.

3. The analytical method according to claim 1 or 2, wherein the proportion of a predetermined fluorescence lifetime component to a plurality of fluorescence lifetime components is calculated for each predetermined fluorescence lifetime component.

4. Multiple fluorescence spectra are generated by multiple measurements of the fluorescence lifetime component with the largest proportion. The analytical method according to claim 3, comprising analyzing the solar cell based on a plurality of fluorescence spectra obtained by multiple measurements of the fluorescence lifetime component with the largest proportion.

5. The solar cell is analyzed based on multiple fluorescence spectra obtained from multiple measurements. The analysis method according to any one of claims 1 to 4, wherein multiple fluorescence spectra are output to a display unit so that they can be compared with each other after multiple measurements.

6. The decay rate of the fluorescence intensity in multiple fluorescence spectra obtained by multiple measurements is calculated. The analysis method according to any one of claims 1 to 5, comprising analyzing the solar cell based on the aforementioned attenuation rate.

7. The characteristics of the solar cell are changed, and the decay rate is calculated in the multiple fluorescence spectra obtained by multiple measurements. The analysis method according to claim 6, comprising comparing the attenuation rate before changing the characteristics of the solar cell with the attenuation rate after changing the characteristics of the solar cell.

8. A correspondence table is created that associates the fluorescence spectrum for each fluorescence lifetime component with the type of defect in the sample. The analytical method according to claim 1, comprising obtaining the fluorescence spectrum for each fluorescence lifetime component and estimating the type of defect in the sample based on the correspondence table.

9. The analytical method according to claim 8, wherein, based on the fluorescence spectrum for each of the fluorescence lifetime components, a predetermined proportion of the existence of one type of defect is calculated for each type of defect relative to a plurality of types of defects.

10. An analytical program used in an analytical device that analyzes a sample, which is a solar cell or semiconductor, by irradiating it with light to generate fluorescence from the sample, detecting the fluorescence, and measuring the fluorescence intensity obtained for each wavelength, wherein It functions as a fluorescence lifetime component calculation unit that calculates multiple fluorescence lifetime components for each wavelength based on the change in fluorescence intensity, It functions as a fluorescence spectrum generating unit that generates a fluorescence spectrum for each of the same fluorescence lifetime components showing the relationship between the fluorescence intensity of that component and the wavelength, An analysis program characterized by causing a computer to perform the function of an analysis unit that analyzes the sample based on multiple fluorescence spectra obtained by multiple measurements or the fluorescence spectra for each fluorescence lifetime component.

11. An analytical apparatus for analyzing a sample, which is a solar cell or semiconductor, by irradiating it with light to generate fluorescence from the sample, detecting the fluorescence, and measuring the fluorescence intensity obtained for each wavelength, A fluorescence lifetime component calculation unit calculates multiple fluorescence lifetime components for each wavelength based on the change in fluorescence intensity, A fluorescence spectrum generation unit that generates a fluorescence spectrum for each of the same fluorescence lifetime components showing the relationship between the fluorescence intensity of the fluorescence lifetime component and the wavelength, An analytical apparatus comprising an analytical unit that analyzes the sample based on multiple fluorescence spectra obtained by multiple measurements or the fluorescence spectra for each fluorescence lifetime component.

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