JP2013098407A - Solar battery related sample measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery related sample measurement system which preferably conducts characteristics measurement of a sample using a photoluminescence method.SOLUTION: A sample measurement system 1A is composed of a solar simulator 10 and an additional measurement device 20. The solar simulator 10 has a stage 11 on which a sample S is placed, a white light supply part 13, and a housing part 15. The additional measurement device 20 has a body part 21 and a PL measurement unit 22 formed so as to move between a measurement position where the PL measurement unit 22 is inserted into a position on a measurement optical path and a stand-by position where the PL measurement unit 22 is departed from the measurement path. Further, the PL measurement unit 22 has: an optical filter 23 converting white light from the supply part 13 to excitation light; a measured light detection part 24 detecting measured light emitted from the sample S to which the excitation light is radiated; and a unit frame part 25 integrally holding the filter 23 and the detection part 24.

Description

  The present invention relates to a solar cell related sample measurement system for measuring the characteristics of a sample related to a solar cell by a photoluminescence method.

  In recent years, solar cells have been actively developed from the viewpoint of preventing global warming. In research and development of such solar cells, it is important to measure and inspect the characteristics of solar cell materials, cells, panels, and other samples related to solar cells, for example, with regard to improving conversion efficiency in solar cells. (For example, see Patent Documents 1 and 2).

JP-A-8-235903 Special table 2009-512198

  In the conversion efficiency measurement (IV measurement), which is the most important in the development of solar cells, the solar cell-related sample is irradiated with white light that becomes pseudo sunlight under a predetermined wavelength spectrum and predetermined irradiation conditions. A solar simulator is used. In this case, a sample such as a solar battery cell or a module is irradiated with white light by a solar simulator, and a probe or the like is applied to an electrode on the solar battery cell to measure its electrical characteristics.

  In the measurement of the electrical characteristics of the sample such as the IV characteristic, a measurement result including all the factors in the entire solar battery cell is obtained. Therefore, if a cell with a problem in characteristics such as conversion efficiency is found, the electrical characteristics measurement results indicate which process in the manufacturing process is a failure and the identification of the location where the defect is occurring. I can't do it. In order to investigate the cause of the failure of such a solar battery cell, a method other than electrical measurement, for example, a photoluminescence (PL) method or an electroluminescence (EL) method is used.

  The principle of photoluminescence measurement (PL measurement) is that the target sample is irradiated with excitation light having an energy (short wavelength) higher than its band gap energy Eg, so that carriers (electrons or holes) are generated in the sample. The generated light is detected when carriers are recombined in the vicinity of the PN junction. In such a method, the electronic state inside the material can be observed from the obtained two-dimensional image of PL emission or the wavelength spectrum of PL emission.

  Here, the solar cell is usually evaluated using a solar simulator, as described above, for example, conditions such as 1 SUN close to the intensity of sunlight by white light such as AM1.5G having a wavelength spectrum close to sunlight. It is done below. On the other hand, when physical properties other than the conversion efficiency of solar cells and inspection of defects are performed by PL imaging, spectrum measurement, or the like, such PL measurement is usually performed by irradiating a sample with laser light.

  Regarding inspection of solar cell related samples using photoluminescence, it is suggested that there is a correlation between PL emission and solar cell characteristics in terms of material properties. That is, in the PL measurement, a strong light emission tends to have high conversion efficiency or few defective portions. However, a CIGS (Cu, In, Ga, Se compound) solar cell that is a compound thin film solar cell, for example, may not have linearity in the electrical characteristics with respect to light and the excitation light intensity with respect to PL emission. In this case, it is difficult to select the optimum excitation light intensity as a parameter that can be correlated with the conversion efficiency.

  Further, PL measurement by laser light excitation is excitation by light of a single wavelength, and therefore has an excitation light spectrum that is absolutely different from measurement of conversion efficiency using white light. When a laser light source is used as an excitation light source for a sample, a practical excitation light wavelength is a specific wavelength such as 532 nm or 808 nm caused by a laser material or the like, and the excitation light wavelength in this case is not necessarily measured. Not optimized for the sample in question.

  For example, when light with an extremely short wavelength (for example, 355 nm) that is not appropriate for the material to be measured is used as excitation light, information including other than the object of PL measurement near the surface due to the problem of light penetration length There is a possibility that a phenomenon completely different from the data that can be correlated with the target conversion efficiency may be measured. In addition, regarding solar cells, there are a wide range of strict requirements such as the irradiation angle or uniformity on the sample surface for the light irradiating the sample, and the PL imaging and spectrum measurement are also close to the requirements. It is desirable to perform measurement in the state.

  The present invention has been made to solve the above-described problems, and a solar cell related sample measurement system capable of suitably measuring the characteristics of a sample by a photoluminescence method for a sample related to a solar cell. The purpose is to provide.

  In order to achieve such an object, a sample measurement system for solar cell related samples according to the present invention comprises (1) a solar simulator for measuring characteristics of a sample related to solar cells, and (2) a solar simulator. And an additional measuring device used for measuring the sample by the photoluminescence method. (3) The solar simulator is a sample stage on which the sample is placed, and artificial sunlight is applied to the sample. A white light supply unit that supplies white light and a housing unit that integrally holds the sample stage and the white light supply unit. (4) The additional measurement device is additionally provided at a predetermined position with respect to the solar simulator. The measurement device main unit and the measurement device main unit are attached to the solar simulator and inserted into the measurement light path from the white light supply unit to the sample stage. A photoluminescence measurement unit configured to be movable between the measured measurement position and a standby position off the measurement optical path. (5) The photoluminescence measurement unit has the photoluminescence measurement unit disposed at the measurement position. Sometimes, the white light supplied from the white light supply unit to the sample stage is emitted from the optical filter that converts the white light to excitation light having a predetermined wavelength spectrum and the sample irradiated with the excitation light from the optical filter. A measurement light detector that detects the measurement light; and a unit frame that holds the optical filter and the measurement light detector integrally, and is attached to the measurement device main body so as to be movable between the measurement position and the standby position. It is characterized by having.

  In the solar cell-related sample measurement system described above, a solar simulator configured to supply white light that is simulated sunlight to samples such as solar cell-related materials, cells, panels, etc., for inspection. An additional measuring device having a photoluminescence measuring unit (PL measuring unit) is additionally installed. In addition, the PL measurement unit is configured by an optical filter (wavelength selection filter) that converts white light into excitation light, a measured light detection unit that detects light from a sample, and a unit frame that integrally holds them.

  And for the apparatus main body of the solar simulator and the additional measuring apparatus, this PL measurement unit supplies the white light to the sample in the solar simulator, the measurement position including the measurement optical path defined by the irradiation range, and the measurement optical path. It is configured to be movable between the deviated standby position. According to such a configuration, in the state where the PL measurement unit is arranged at the standby position, it is possible to measure the electrical characteristics such as the IV characteristic measurement similar to the conventional one, and the PL measurement unit is located at the measurement position. In this state, it is possible to perform PL measurement on the sample using the light component of white light that has passed through the optical filter as excitation light. Thereby, about the sample relevant to a solar cell, it becomes possible to perform the measurement of the characteristic of the sample by a photo-luminescence method suitably.

  Here, as for the configuration of the detection unit that detects the measurement light from the sample used in the PL measurement unit, the measurement light detection unit uses a configuration having an imaging device that acquires a two-dimensional image of the measurement light. be able to. In such a configuration, the characteristics of the sample can be evaluated by PL imaging measurement.

  Alternatively, the measurement light detection unit can have a configuration including a spectroscope that divides the measurement light and a photodetector that detects the measurement light dispersed by the spectroscope. In such a configuration, the characteristics of the sample can be evaluated by PL spectrum measurement by detecting each wavelength component of the dispersed measured light with one or a plurality of photodetectors.

  The photoluminescence measurement unit is disposed between the sample stage and the measured light detection unit, and selectively passes a light component within a predetermined wavelength range of the measured light to the measured light detection unit. It is preferable to have two optical filters. In this way, by providing the second optical filter in the previous stage of the measured light detector, only the light component in the wavelength range suitable for evaluating the characteristics of the sample is selectively detected from the light from the sample. be able to.

  In addition, the photoluminescence measurement unit may include a lighting device that is used for obtaining a normal image of a sample. Here, when the PL measurement unit is located at the measurement position, the optical filter is inserted in the measurement optical path, so the light from the solar simulator is detected by a camera or the like that constitutes the measured light detection unit. It may not include light in the possible wavelength range. On the other hand, by providing the illumination device in the PL measurement unit as described above, a normal image such as a pattern image of the sample can be suitably acquired even when the PL measurement unit is arranged at the measurement position. .

  In addition to the solar simulator and the additional measurement device, the sample measurement system may include a control device that controls the photoluminescence measurement of the sample by the solar simulator and the additional measurement device. Such a control device may be, for example, a configuration attached to or built in the additional measurement device. In this case, the control device may be configured to control the operation of a shutter provided between the white light supply unit and the sample stage in the solar simulator.

  In addition, the sample measurement system may be configured to further include an electrical characteristic measurement device that is provided for the solar simulator and measures the electrical characteristics of the sample. Thereby, in addition to PL measurement with respect to the sample, measurement of electrical characteristics such as IV characteristic measurement using a solar simulator can be suitably performed. In addition, such an electrical characteristic measuring device may have a configuration attached to or built in a solar simulator, for example.

  According to the solar cell related sample measurement system of the present invention, an additional measurement device having a PL measurement unit is provided for a solar simulator that performs measurement by supplying white light to the sample, and the PL measurement unit is excited with white light. The PL measurement unit is movable between a measurement position including the measurement optical path for the sample and a standby position outside the measurement optical path. With the configuration, it is possible to suitably measure the characteristics of the sample by the photoluminescence method for the sample related to the solar cell.

It is a front view which shows the structure of one Embodiment of a solar cell related sample measurement system. It is a front view which shows the structure of the sample measurement system shown in FIG. It is a side view which shows the structure of the sample measurement system shown in FIG. It is a perspective view which shows the structure of the sample measurement system shown in FIG. It is a graph which shows the wavelength spectrum of the white light used for a sample measurement, excitation light, and the to-be-measured light from a sample. It is a graph which shows the wavelength spectrum of the to-be-measured light from a sample. It is a flowchart which shows an example of the sample measuring method. It is a flowchart which shows the other example of the sample measuring method.

  Hereinafter, preferred embodiments of a solar cell related sample measurement system according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a front view showing a configuration of one embodiment of a solar cell related sample measurement system. FIG. 1 shows a state in which a later-described photoluminescence measurement unit (PL measurement unit) is arranged at the standby position. FIG. 2 is a front view showing the configuration of the solar cell related sample measurement system shown in FIG. FIG. 3 is a side view showing the configuration of the sample measurement system shown in FIG. FIG. 4 is a perspective view showing the configuration of the sample measurement system shown in FIG. 2 to 4 show a state in which the PL measurement unit is arranged at the measurement position. Moreover, in each figure, in FIGS. 1-3, the structure of a sample measurement system is shown typically, and in FIG. 4, an example of the structure is shown somewhat concretely.

  The sample measurement system 1A according to this embodiment is for inspecting and evaluating the characteristics of a sample S (hereinafter referred to as a solar cell-related sample or simply a sample) S such as a material, a cell, or a panel related to a solar cell. This is a solar cell related sample measurement system that performs measurement, and includes a solar simulator 10, an electrical characteristic measurement device 19, an additional measurement device 20, and a control device 30.

  The solar simulator 10 is for measuring the characteristics of the solar cell-related sample S, and includes a sample stage 11, a white light supply unit 13, and a housing unit 15. Further, the sample stage 11 on which the sample S to be measured is placed is moved in the x-axis direction, the y-axis direction (horizontal direction), and the z-axis direction (vertical direction) by the stage driving unit 12, and then on the stage 11. The measurement position and measurement range in the sample S can be adjusted and set.

  The white light supply unit 13 applies white light having a wavelength spectrum close to sunlight to the sample S on the stage 11 according to predetermined irradiation conditions (irradiation range, irradiation angle, irradiation light intensity distribution, etc.). Supplied as simulated sunlight for measuring the characteristics of Specifically, the white light supply unit 13 includes, for example, one or more light sources and an optical system including one or more optical elements that adjust the optical path, wavelength spectrum, and the like of light from the light sources. Further, a shutter 14 for switching ON / OFF of white light supply from the white light supply unit 13 to the sample S is provided on the measurement optical axis Ax between the white light supply unit 13 and the stage 11. Yes.

  The housing unit 15 integrally holds the sample stage 11 and the white light supply unit 13. In the present embodiment, the housing portion 15 includes an upper housing portion 16 and a lower housing portion 17. The upper housing portion 16 accommodates the white light supply portion 13 and the shutter 14 inside, and has a box shape having an opening facing the sample stage 11 below the upper housing portion 16. The white light from the white light supply unit 13 passes through the shutter 14 in the ON state (open state) and the opening below the upper housing unit 16, and is measured by the measurement optical path that extends in a predetermined range including the optical axis Ax. It is supplied to the upper sample S.

  As shown in FIG. 4, the lower housing portion 17 has a structure in which four columnar members are provided between the upper housing portion 16 and the housing bottom portion 18. In the space including the measurement optical path inside the lower housing portion 17. It is configured to be accessible from the outside. Further, the sample stage 11 and the stage driving unit 12 are installed on the housing bottom 18.

  An additional measuring device 20 is installed at a predetermined position near the solar simulator 10. The additional measuring device 20 is used for measuring the solar cell related sample S by the photoluminescence (PL) method using the solar simulator 10, and includes the measuring device main body 21 and the photoluminescence (PL). And a measurement unit 22. The measuring device main body 21 is additionally and fixedly arranged at a predetermined position with respect to the solar simulator 10 (a position on the right side of the lower housing portion 17 of the solar simulator 10 in FIG. 1).

  The PL measurement unit 22 is attached to the measurement apparatus main body 21 and is inserted into the measurement light path from the white light supply unit 13 to the sample S on the sample stage 11 with respect to the solar simulator 10 (FIG. 2). 4) and a standby position (FIG. 1) off the measurement optical path.

  When the PL measurement unit 22 is arranged at a standby position off the measurement optical path, the PL measurement unit 22 is stored in the main body 21 as shown in FIG. Further, when the PL measurement unit 22 is arranged at a measurement position (insertion position) including the measurement optical path, as shown in FIGS. By being drawn out to a space including a certain measurement optical path, it is inserted into a measurement position between the shutter 14 and the sample stage 11 on the measurement optical path.

  As shown in FIGS. 2 to 4, the PL measurement unit 22 includes an optical filter 23, a measured light detection unit 24, and a unit frame unit 25. The optical filter 23 has a predetermined wavelength in the white light supplied from the white light supply unit 13 to the sample stage 11 in the measurement optical path including the optical axis Ax when the PL measurement unit 22 is arranged at the measurement position. It is a wavelength selection filter that converts white light into excitation light having a predetermined wavelength spectrum by selectively passing light components within the range.

  The optical filter 23 may be any filter that removes the wavelength region where photoluminescence is generated from the white light generated from the solar simulator 10 and transmits the excitation light wavelength region. A short pass filter (SPF) that allows light components within a predetermined wavelength range to pass and cuts light components on the long wavelength side can be used. Alternatively, as the optical filter 23, a band pass filter (BPF) that allows light components within a predetermined wavelength range to pass therethrough and cuts light components on the shorter wavelength side and longer wavelength side thereof may be used.

  The measured light detector 24 detects measured light including PL light emitted from the sample S irradiated with the excitation light when the sample S is irradiated with the excitation light generated through the optical filter 23. It is a detection part to do. As shown in FIGS. 3 and 4, the detection unit 24 is located at a predetermined position outside the measurement optical path (the range in which white light and excitation light pass) from the white light supply unit 13 and the optical filter 23 to the sample stage 11. is set up.

  As for the configuration of the measured light detection unit 24, for example, the detection unit 24 can be configured by an imaging device (imaging camera) that acquires a two-dimensional image of the measured light. In such a configuration, the detection unit 24 can evaluate the characteristics of the sample S by PL imaging measurement. Alternatively, the detection unit 24 may be configured by a spectroscope that splits the measured light and a photodetector that detects the split measured light. In such a configuration, the detection unit 24 evaluates the characteristics of the sample S by PL spectrum measurement by detecting each wavelength component of the light to be measured dispersed by the spectrometer with one or more photodetectors. be able to.

  In the PL measurement unit 22, a unit frame portion 25 is provided for the optical filter 23 and the measured light detection unit 24. The unit frame 25 is attached to the measurement apparatus main body 21 so as to hold the optical filter 23 and the measured light detection unit 24 integrally and to be movable between the measurement position and the standby position described above. In the configuration example shown in FIG. 4, a rail 25 a is provided on the side surface of the unit frame portion 25, and PL measurement including the unit frame portion 25 is performed by the rail 25 a and a rail provided inside the main body portion 21. The unit 22 is configured to move in the horizontal direction (left-right direction).

  In the PL measurement unit 22 according to the present embodiment, a band pass filter (BPF) 26 is provided between the sample stage 11 of the solar simulator 10 and the measured light detector 24 of the PL measurement unit 22. The band pass filter 26 receives light components within a predetermined wavelength range (for example, light components including PL light emission from the sample S due to excitation light irradiation) in the light to be measured from the sample S on the stage 11. This is a second optical filter that selectively passes to the measurement light detection unit 24 and is fixed to the front side (sample stage 11 side) of the detection unit 24. As the second optical filter, a wavelength selection filter other than the band pass filter may be used according to the wavelength range of the light component to be detected by the detection unit 24.

  In the PL measurement unit 22, an illumination device 27 is provided on the sample stage 11 side with respect to the optical filter 23 at a position off the measurement optical path. The illumination device 27 is used when acquiring a normal image of the sample S in a state where the PL measurement unit 22 is arranged at the measurement position. For example, an infrared illumination device such as an infrared LED is used. .

  In the sample measurement system 1A according to the present embodiment, in addition to the solar simulator 10 and the additional measurement device 20, an electrical characteristic measurement device 19 and a control device 30 are provided. The electrical property measuring device 19 is provided for the solar simulator 10 and is connected to the sample S on the sample stage 11 by a predetermined wiring as shown in FIG. It is used when measuring IV characteristics. 2 to 4, the electrical characteristic measuring device 19 is not shown.

  Further, the control device 30 is provided connected to the solar simulator 10 and the additional measuring device 20, and as shown in FIG. 2, the operation of each part of the solar simulator 10 and the additional measuring device 20 is controlled, thereby allowing a sample by them. Controls the execution of PL measurement for S. For example, the control device 30 controls the operation of the shutter 14 provided in the solar simulator 10 according to the execution state of the PL measurement. Thus, the configuration for controlling the shutter operation is effective when the solar simulator 10 has a shutter status output or the like.

  A display device 31 and an input device 32 are connected to the control device 30. The display device 31 displays information related to the measurement of the characteristics of the solar cell related sample S in the measurement system 1A to the operator. The input device 32 is used for inputting information and instructions necessary for measurement. 1, 3, and 4, the control device 30, the display device 31, and the input device 32 are not shown.

  The effect of the solar cell related sample measurement system according to the present embodiment and the sample measurement method using the solar cell related sample measurement system will be described.

  In the solar cell related sample measurement system 1A shown in FIG. 1 to FIG. 4, PL measurement is performed on a solar simulator 10 configured to perform inspection by supplying white light as pseudo sunlight to the sample S. An additional measuring device 20 having a unit 22 is additionally installed. The PL measurement unit 22 includes an optical filter 23 that converts white light into excitation light, a measurement light detection unit 24 that detects measurement light from the sample S, and a unit frame 25 that integrally holds them. To do.

  Then, with respect to the solar simulator 10 and the apparatus main body 21 of the additional measuring apparatus 20, the PL measuring unit 22 includes a measuring position including a measuring optical path defined by the white light supply range for the sample S in the solar simulator 10. In this configuration, it is possible to move between the standby position off the measurement optical path. According to such a configuration, in the state where the PL measurement unit 22 is arranged at the standby position, it is possible to measure the electrical characteristics such as the IV characteristic measurement similar to the conventional one using the electrical characteristic measurement device 19. In addition, in a state where the PL measurement unit 22 is disposed at the measurement position, it is possible to perform PL measurement on the sample S using the light component of white light that has passed through the optical filter 23 as excitation light. Thereby, about the solar cell related sample S, it becomes possible to suitably perform various measurements and inspections including measurement of the characteristics of the sample S by the photoluminescence method.

  In the above embodiment, in the PL measurement unit 22, the band-pass filter 26 that selectively passes light components within a predetermined wavelength range of the light to be measured between the sample stage 11 and the light to be measured detection unit 24. Is provided. As described above, by providing an optical filter such as the bandpass filter 26 in the previous stage of the detection unit 24, the light in the wavelength range suitable for evaluating the characteristics of the sample S among the light from the sample S in the detection unit 24. Only components can be selectively detected. For example, in the case where the imaging device used for the measured light detector 24 has sensitivity in a part of the wavelength range of the excitation light and interferes with PL measurement, the optical filter 26 is provided in this way. A configuration that cuts light components within the wavelength range of the excitation light is effective. However, such a filter 26 may be configured not to be provided if unnecessary.

  In addition, the PL measurement unit 22 has an illumination device 27 that is used to acquire a normal image of the sample S. Here, in the state in which the PL measurement unit 22 is arranged at the measurement position, the optical filter 23 is inserted on the measurement optical path, so that the light from the solar simulator is a camera or the like that constitutes the measured light detection unit. May not include light in the wavelength range detectable by. On the other hand, by providing the illumination device 27 in the PL measurement unit 22 as described above, a normal image such as a pattern image of the sample S is preferably obtained even when the PL measurement unit 22 is arranged at the measurement position. can do. However, such a lighting device 27 may be configured not to be provided if not necessary.

  Moreover, in the said embodiment, the control apparatus 30 which controls PL measurement is provided in 1 A of sample measurement systems. Such a control device 30 may have a configuration attached to or built in the additional measurement device 20, for example. In this case, the control device 30 may be configured to control the operation of the shutter 14 provided between the white light supply unit 13 and the sample stage 11 in the solar simulator 10 as described above.

  In the above embodiment, the electrical property measuring device 19 is provided in the sample measuring system 1A. Thereby, in addition to the PL measurement for the sample S, the measurement of electrical characteristics such as the IV characteristic measurement using the solar simulator 10 can be suitably performed. Further, such an electrical characteristic measuring device 19 may be configured to be attached to or built in the solar simulator 10, for example.

  The configuration of the solar cell related sample measurement system 1A shown in FIGS. 1 to 4 and the PL measurement executed using the sample measurement system 1A will be described more specifically.

  FIG. 5 is a graph showing wavelength spectra of white light, excitation light, and light to be measured from the sample used for sample measurement. In graphs (a), (b), and (c) of FIG. 5, the horizontal axis indicates the wavelength (nm) of light, and the vertical axis indicates the intensity of light. The solar simulator 10 is used under the conditions of AM1.5G.

  The graph (a) in FIG. 5 shows the wavelength spectrum of white light supplied from the white light supply unit 13 of the solar simulator 10. In this graph, graph A1 shows the wavelength spectrum of white light in the solar simulator 10, and graph A2 shows the wavelength spectrum of actual sunlight. Such white light also has a light component in a wavelength region where light of the target PL in PL measurement is generated.

  The graph (b) in FIG. 5 shows the wavelength spectrum of the excitation light that passes through the optical filter 23 and is applied to the sample S. In this graph, a graph B1 shows a wavelength spectrum when the optical filter 23 is applied to white light in the solar simulator 10, and a graph B2 shows a wavelength spectrum when the optical filter 23 is applied to sunlight. Specifically, here, a short-pass filter (SPF) is used as the optical filter 23, and this filter 23 is installed as a filter having a size larger than the white light beam supplied by the solar simulator 10, and PL emission is also performed. The light component in the wavelength range on the long wavelength side including the light is cut and used as the excitation light for PL measurement.

  A graph (c) in FIG. 5 shows a wavelength spectrum of the light to be measured by PL emission emitted from the sample S irradiated with the excitation light shown in the graph B1. By detecting such PL light emission by the measured light detector 24, it is possible to perform evaluation and inspection on the characteristics of the sample S. Here, when the detection unit 24 is an imaging device and a two-dimensional image of PL emission is acquired, a PL image reflecting the characteristics of the sample S is obtained. Further, when the detection unit 24 is a spectroscope + photodetector, various information such as information on the wavelength spectrum of PL emission can be obtained. Note that, as described above, detection of the light to be measured by the detection unit 24 is performed via an optical filter such as a bandpass filter 26 as necessary.

  FIG. 6 is a graph showing the wavelength spectrum of the light to be measured including PL emission from the sample S, where the horizontal axis shows the wavelength of light (nm) and the vertical axis shows the intensity of light (au). ing. Further, in this graph, graph C1 shows the wavelength spectrum of the measurement result of PL emission when excitation light generated from white light is used in the configuration of the solar simulator 10 + additional measurement device 20, and graph C2 is The wavelength spectrum of the measurement result of PL light emission when a laser beam having a wavelength of 810 nm is used as excitation light is shown.

  As is clear from these graphs C1 and C2, almost the same PL emission spectrum is obtained in both cases where excitation light generated from white light and laser excitation light are used. Therefore, as shown in the sample measurement system 1A of FIGS. 1 to 4, the configuration in which the PL measurement unit 22 is applied to the white light of the solar simulator 10 is similar to the configuration using the laser excitation light. It turns out that it is effective for PL luminescence measurement.

  The sample measurement system 1 </ b> A according to the above embodiment is for the measurement of electrical characteristics such as IV characteristic measurement using the solar simulator 10, which is the most important measurement performed in the evaluation and inspection of solar cells. The additional measurement apparatus 20 including the PL measurement unit 22 that can move between the measurement position and the standby position without destroying the environment of the electrical measurement is additionally installed.

  According to such a configuration, before and after the electrical measurement, the function of the measurement system 1A is immediately switched by the movement of the PL measurement unit 22, and an effective means for easily finding a defective portion in the sample S by PL imaging is provided. can do. For example, it is possible to perform IV measurement using the solar simulator 10, PL imaging on the extension line of conversion efficiency measurement, PL spectrum measurement, or the like. This makes it possible to visualize the defective part immediately after measuring the electrical characteristics such as efficiency, or at the same time, by PL imaging as it is. For example, if the efficiency is poor, visualize the cause on the spot. , Could be able to identify. In particular, in the large-area sample S such as a solar cell panel, if a solar simulator for a large area is already owned, it can be applied to the PL measurement.

  Further, in the IV measurement using the solar simulator 10, when a solar battery cell to be the sample S is set in a measuring apparatus and an electrode is connected to a cell to which no lead wire or the like is attached, it is very difficult to handle the measurement. You will use your nerves. In particular, a crystalline Si solar cell such as a polycrystalline Si solar cell is easily broken, and cracks and the like are generated with a slight force, so that handling is not easy. If the sample S is cracked, the electrical characteristics including the conversion efficiency are naturally deteriorated. Moreover, if a cell having a crack is set again in another inspection apparatus, the crack may grow.

  On the other hand, if it is possible to detect cracks by PL imaging in a state where the sample S is set in the solar simulator 10 which is a measuring apparatus for performing IV measurement, it becomes easy to grasp the problem. . After performing the IV measurement, the sample measurement system 1A can perform the PL imaging measurement of the solar battery cell by simply inserting the PL measurement unit 22 of the additional measurement device 20 into the measurement optical path of the solar simulator 10. According to this, for example, in the detection of the cracks described above, it is possible to perform very efficient defect analysis.

  Further, according to the configuration in which the excitation light is generated by applying the optical filter 23 to the white light of the solar simulator 10, there is a problem of the excitation light intensity, the excitation light spectrum, and the irradiation uniformity of the excitation light on the sample S in the PL measurement. It is also possible to solve the problem. That is, in the PL measurement, when the solar cell related sample S is irradiated with excitation light, extremely high light uniformity, irradiation angle conditions, strict conditions regarding light irradiation unevenness and parallelism, and the like are required.

  On the other hand, in the above configuration in which the optical filter 23 is inserted into the portion where the light is emitted from the main body of the solar simulator 10, the uniformity of the excitation light irradiation is the solar simulator 10 side that supplies white light that is the source of the excitation light. For example, it is possible to irradiate the excitation light under ideal conditions such as uniformly irradiating the rectangular solar cell with the excitation light. In addition, with such a configuration, it is possible to retrofit various solar simulators 10, and by selecting use / non-use of the filter 23 by moving the PL measurement unit 22, it can be completely used for the past applications. The solar simulator 10 can be used as a light source for PL measurement without affecting.

  In the solar simulator 10, a multi-lens optical component called a fly-eye lens may be used inside the solar simulator in order to realize the conditions required for irradiation unevenness and parallelism. Even in the emitted part, if an optical filter smaller than the light beam is inserted, there is a possibility that uniform and parallel light cannot be obtained on the irradiation surface of the sample S. On the other hand, such a problem can be avoided by using the optical filter 23 having a size larger than the white light beam supplied from the solar simulator 10 in the PL measurement unit 22.

  The measurement system 1A takes advantage of photoluminescence, that is, non-contact and non-destructive measurement, for example, from the stage before attaching the electrode to the final stage where the electrode is attached. It can be applied to the solar cell related sample S in various states. Thereby, in each manufacturing process, the factor causing the defect can be detected in advance, and it can greatly contribute to the improvement of the yield and quality. In addition, when there is a defect in the electrode, it is possible to confirm the defect by PL measurement.

  Moreover, in the said structure using the white light of the solar simulator 10, by observing the electronic state inside the sample S in the wavelength spectrum and light intensity (1SUN) which are the operation conditions which evaluate conversion efficiency etc. as a solar cell. This is a measurement in a state close to actual operating conditions. Therefore, it can be expected that a measurement result that is more correlated with electrical conversion efficiency and the like can be obtained as a result of the PL measurement. The reason for this is that, for example, a problem in the depth direction of the sample S occurs due to the penetration length of the sample S to be measured, and the sample S does not necessarily have a linear electrical output with respect to light. For example, there is no guarantee that it exists, and if the excitation light intensity is not appropriate for a sample having no linearity, the result may be reversed.

  In the measurement system 1A, a long wavelength component in the white light supplied from the solar simulator 10, for example, a light component having an energy lower than the band gap energy Eg of the target solar cell material is an optical component such as SPF. It is cut by the filter 23 and the sample S is not irradiated. This means that, in principle, in PL measurement, light having energy lower than the band gap energy Eg only causes the temperature rise of the sample S which becomes an obstacle to PL measurement, and thus cuts the long wavelength component. This has little effect on PL measurement.

  The measurement system 1A is also effective in terms of safety and cost. In terms of safety, for example, using a CW laser beam having a wavelength of 808 nm as excitation light, a single cell of 12.5 cm square or the like obtains an output in a state such as 1 SUN that is uniformly close to the sunlight power with respect to the cell front surface. In such a case, it is necessary to use a Class 4 laser having a laser output of several tens of watts. In this case, a large amount of labor is required in the management and operation of the measuring device, such as using it in a device that is completely shielded from the laser, or assuming that it is used in a laser management area, and also limiting the number of users. Will be required.

  On the other hand, in the PL measurement, according to the configuration using the lamp light source or the like used in the solar simulator 10 instead of the laser light source, the safety standard is not strict and the introduction of the apparatus is easy. In addition, it is expected that damage to the sample S due to strong power at a specific wavelength due to laser light excitation is reduced by using excitation light generated from white light.

  In terms of cost, the running cost of the measuring device becomes a problem when the measuring device is fully operated at the solar cell manufacturing site, etc., but in the case of a lamp light source, it is possible to realize a lower running cost than a laser light source. It is. In addition, since a spare lamp light source can be easily prepared, loss due to downtime of the apparatus can be avoided. In addition, the cost of the entire apparatus can be reduced as compared with a system using a laser.

  The measurement and inspection method for the solar cell related sample using the sample measurement system 1A shown in FIGS. 1 to 4 will be further described.

  FIG. 7 is a flowchart illustrating an example of a sample measurement method. FIG. 7 shows an example in which the solar simulator 10 has a shutter status output. In the method shown in FIG. 7, first, the I-V of the sample S is measured by the solar simulator 10 and the electrical characteristic measuring device 19 with the PL measuring unit 22 placed at the standby position in the main body 21 of the additional measuring device 20. Electrical characteristics such as characteristics are measured (step S101).

  Next, the PL measurement unit 22 is moved to a measurement position including the optical axis Ax and the measurement optical path, and the optical filter 23, the measured light detection unit 24, etc. are set at predetermined positions (S102). Then, in this state, PL measurement for the sample S using the solar simulator 10 and the PL measurement unit 22 is started (S103).

  Based on the shutter status output from the solar simulator 10, it is confirmed whether the shutter 14 on the measurement optical path is closed (S104), and if it is open, the shutter 14 is closed (S105). Subsequently, dark current is measured in the measured light detection unit 24 (S106). Here, the measurement result by the imaging device or the photodetector used in the detection unit 24 may include noise called dark current, and background light that is not a signal needs to be removed from the measurement result. There is. Dark current measurement is performed to remove unnecessary signals and data such as noise.

  Subsequently, it is confirmed from the shutter status output from the solar simulator 10 whether the shutter 14 is open (S107), and when it is closed, the shutter 14 is opened (S108). Then, the sample S is irradiated with excitation light from the white light supply unit 13 via the optical filter 23, and the measured light emission measurement data obtained is acquired by the measured light detection unit 24 (S109). When the PL measurement is completed, the shutter 14 is closed (S110), and necessary operations such as analysis and output are performed on the acquired PL measurement data (S111).

  As specific data analysis, for example, the control device 30 performs a process of subtracting the data obtained by the dark current measurement from the data obtained by the PL measurement, and generates measurement data from which noise is removed. Then, the obtained PL light emission two-dimensional image data, wavelength spectrum data, or the like is displayed to the operator by the display device 31.

  When these operations are finished, an operation such as moving the PL measurement unit 22 to the standby position is performed as necessary (S112), and the measurement is finished. In the analysis of the PL measurement data, when it is necessary to compare with the pattern image of the sample S in order to identify the defective portion in the sample S, the shutter 14 of the solar simulator 10 is closed and the infrared illumination device 27 is turned on. Lights up to acquire a pattern image.

  FIG. 8 is a flowchart showing another example of the sample measuring method. FIG. 8 shows an example in which the solar simulator 10 does not have a shutter status output. In the method shown in FIG. 8, first, the solar simulator 10 and the electrical characteristic measuring device 19 perform the IV measurement of the sample S with the PL measuring unit 22 placed at the standby position in the main body 21 of the additional measuring device 20. Electrical characteristics such as characteristics are measured (step S201).

  Next, the PL measurement unit 22 is moved to a measurement position including the optical axis Ax and the measurement optical path, and the optical filter 23, the measured light detection unit 24, etc. are set at predetermined positions (S202). In this state, the PL measurement for the sample S using the solar simulator 10 and the PL measurement unit 22 is started (S203).

  The solar simulator 10 performs an operation of closing the shutter 14 on the measurement optical path (S204), and waits until the shutter closing operation is completed (S205). Subsequently, dark current is measured in the measured light detector 24 (S206). Subsequently, the solar simulator 10 performs an operation of opening the shutter 14 (S207), and waits for completion of the shutter opening operation (S208). Then, the sample S is irradiated with excitation light, and the obtained PL emission measurement data is acquired by the measured light detection unit 24 (S209). When the PL measurement is completed, the shutter 14 is closed (S210), and necessary operations such as analysis and output are performed on the acquired PL measurement data (211). When these operations are finished, an operation such as moving the PL measurement unit 22 to the standby position is performed as necessary (S212), and the measurement is finished.

  The solar cell related sample measurement system according to the present invention is not limited to the above-described embodiments and configuration examples, and various modifications are possible. For example, the configurations of the solar simulator 10 and the additional measurement apparatus 20 are not limited to the above-described configurations, and various configurations may be used specifically. Further, the electrical characteristic measuring device 19, the control device 30 and the like may be omitted if unnecessary.

  INDUSTRIAL APPLICABILITY The present invention can be used as a sample measurement system that can suitably perform measurement of sample characteristics by a photoluminescence method for a sample related to a solar cell.

DESCRIPTION OF SYMBOLS 1A ... Solar cell related sample measurement system, S ... Solar cell related sample, Ax ... Measurement optical axis, 10 ... Solar simulator, 11 ... Sample stage, 12 ... Stage drive part, 13 ... White light supply part, 14 ... Shutter, 15 ... Housing part, 16 ... Upper housing part, 17 ... Lower housing part, 18 ... Housing bottom part, 19 ... Electrical characteristic measuring device,
DESCRIPTION OF SYMBOLS 20 ... Additional measuring apparatus, 21 ... Measuring apparatus main-body part, 22 ... Photoluminescence measuring unit (PL measuring unit), 23 ... Optical filter, 24 ... Measuring light detection part, 25 ... Unit frame part, 26 ... Band pass filter, 27 ... Illuminating device, 30 ... Control device, 31 ... Display device, 32 ... Input device.

Claims (8)

A solar simulator for measuring the properties of the sample associated with the solar cell;
Using the solar simulator, comprising an additional measuring device used for measuring the sample by a photoluminescence method,
The solar simulator is
A sample stage on which the sample is placed;
A white light supply unit that supplies white light that becomes pseudo sunlight to the sample;
A housing part that integrally holds the sample stage and the white light supply part;
The additional measuring device includes:
A measuring device main body additionally disposed at a predetermined position with respect to the solar simulator;
Attached to the measuring device main body and movable with respect to the solar simulator between a measurement position inserted on the measurement optical path from the white light supply unit to the sample stage and a standby position off the measurement optical path A photoluminescence measurement unit configured in
The photoluminescence measuring unit is
An optical filter that converts the white light supplied from the white light supply unit to the sample stage into excitation light having a predetermined wavelength spectrum when the photoluminescence measurement unit is disposed at the measurement position;
A measured light detector for detecting measured light emitted from the sample irradiated with the excitation light from the optical filter;
And a unit frame that is attached to the measurement apparatus main body so as to be movable between the measurement position and the standby position while holding the optical filter and the measured light detection unit integrally. Battery related sample measurement system.   The sample measurement system according to claim 1, wherein the measured light detection unit includes an imaging device that acquires a two-dimensional image of the measured light.   The sample according to claim 1, wherein the measured light detection unit includes a spectroscope that splits the measured light, and a photodetector that detects the measured light split by the spectroscope. Measuring system.   The photoluminescence measurement unit is disposed between the sample stage and the measured light detection unit, and selectively transmits a light component within a predetermined wavelength range of the measured light to the measured light detection unit. The sample measurement system according to claim 1, further comprising a second optical filter that allows the sample to pass therethrough.   The sample measurement system according to any one of claims 1 to 4, wherein the photoluminescence measurement unit includes an illumination device that is used to acquire a normal image of the sample.   The sample measurement system according to any one of claims 1 to 5, further comprising a control device that controls photoluminescence measurement of the sample by the solar simulator and the additional measurement device.   The sample measurement system according to claim 6, wherein the control device controls an operation of a shutter provided between the white light supply unit and the sample stage in the solar simulator.   The sample measurement system according to any one of claims 1 to 7, further comprising an electrical property measurement device that is provided for the solar simulator and measures electrical properties of the sample.