Spectral measurement device for sub-band gap photoelectric signal characterization

Abstract

The utility model belongs to the field of spectral measurement devices, and discloses a spectral measurement device for sub-band gap photoelectric signal characterization, which comprises a photo-thermal deflection characterization assembly, a quantum efficiency characterization assembly, a spectral calibration assembly and a control assembly. The photo-thermal deflection characterization assembly comprises a pump light path mechanism used for generating a pump light path and a detection light path mechanism used for generating a detection light path, and the pump light path and the detection light path are vertically intersected. The quantum efficiency characterization assembly comprises a second slit, a second chopper, a second parallel lens group, a third condensing lens group, a photovoltaic cell sample table and a current amplifier which are arranged in sequence; a second light path of the monochromator passes through the second slit; and the spectrum calibration assembly comprises a fourth condensing lens group, an optical power probe and an optical power meter which are arranged in sequence, and the beam splitter prism is used for splitting the other light path of the pump light path into the focusing lens group.

Description

Technical Field

[0001] The utility model belongs to the technical field of spectral measurement devices, and more specifically, relates to a spectral measurement device for sub-bandgap optoelectronic signal characterization. Background Art

[0002] The sub-bandgap optical absorption and photocurrent signals of photovoltaic materials are of great significance in the performance evaluation of solar cells. These signals provide important means for evaluating the electronic defects of energy levels in photovoltaic thin films and devices, and these defects directly affect the photoelectric conversion efficiency. Sub-bandgap optical absorption refers to the absorption of photons by a material with energy lower than its bandgap energy, which is usually caused by defects or impurities in the material. By measuring sub-bandgap optical absorption, information on the defect density and distribution in the material can be obtained, which is very important for understanding the material quality and optimizing the manufacturing process. Sub-bandgap photocurrent refers to the photocurrent formed by electron-hole pairs generated when the material absorbs photons under the photoelectric effect. Although sub-bandgap optical absorption can increase the absorption of low-energy photons by the material, these absorptions usually do not effectively convert into current but are dissipated in the form of heat, thereby reducing the overall device efficiency.

[0003] Currently, there are few detection devices in the field of analysis of sub-bandgap optoelectronic signals of photovoltaic thin films and photovoltaic devices, and most of them can only analyze single sub-bandgap absorption or photocurrent. Summary of the Utility Model

[0004] The purpose of the embodiment of the present application is to provide a spectral measurement device for sub-bandgap optoelectronic signal characterization to solve the technical problem of the single function of detection devices in the prior art.

[0005] To achieve the above purpose, the technical solution adopted in the present application is:

[0006] Provide a spectral measurement device for sub-bandgap optoelectronic signal characterization, including:

[0007] A photothermal deflection characterization component, including a pump optical path mechanism for generating a pump optical path and a detection optical path mechanism for generating a detection optical path, the pump optical path and the detection optical path are arranged perpendicular to each other and intersect; the pump optical path mechanism includes a xenon lamp pump light source, a first condenser lens group, a filter wheel group, a monochromator, a first slit, and a beam splitting prism arranged in sequence; the first optical path of the monochromator passes through the first slit; the detection optical path mechanism includes a lock-in amplifier and a first chopper, a first parallel lens group, a second condenser lens group, a four-dimensional automatic sample platform, a detection laser, and a laser position detector arranged in sequence; the beam splitting prism splits one optical path of the pump optical path and shoots it into the chopper; the lock-in amplifier is signal-connected to the first chopper;

[0008] The quantum efficiency characterization component includes a second slit, a second chopper, a second parallel lens group, a third condenser lens group, a photovoltaic cell sample stage, and a current amplifier arranged in sequence; the second optical path of the monochromator passes through the second slit;

[0009] The spectral calibration component includes a fourth condenser lens group, an optical power probe, and an optical power meter arranged in sequence. The beam splitter prism splits another optical path of the pumped optical path into the focusing lens group;

[0010] The control component is respectively signal-connected to the four-dimensional automatic sample platform, the laser position detector, the current amplifier, the lock-in amplifier, and the monochromator.

[0011] As a further improvement of the above technical solution:

[0012] Optionally, the output power of the xenon lamp pumping light source is 100 mW, and it is used to emit pumping light with a wavelength range of 350 nm to 2000 nm.

[0013] Optionally, the wavelength resolution of the monochromator is adjustable from 0.1 nm to 10 nm, the optical ripple is less than 0.1%, and the optical ripple is less than 1% RMS.

[0014] Optionally, the wavelength resolution of the first chopper is adjustable from 1 Hz to 500 Hz, the frequency resolution is 1 Hz, and the frequency stability is less than 1%.

[0015] Optionally, the four-dimensional automatic sample platform includes an X-axis displacement platform, a Y-axis displacement platform, a Z-axis displacement platform, and an R-axis rotation platform; the travel of the X-axis displacement platform and the Y-axis displacement platform is ±25 mm, the positioning accuracy is 0.0025 mm, the travel of the Z-axis displacement platform is ±15 mm, the positioning accuracy is 0.004 mm; the minimum rotation accuracy of the R-axis rotation platform is 0.7°.

[0016] Optionally, the laser position detector is signal-connected to the lock-in amplifier through an I-V conversion circuit for filtering and signal amplification processing.

[0017] Optionally, the detection laser emitted by the detection laser has a minimum output optical power of 1.5 mW, and the power stability is less than 2.5%.

[0018] Optionally, the photovoltaic cell sample stage is signal-connected to the current amplifier. The current amplifier is used to amplify and filter the current signal of the photovoltaic cell sample stage; the current amplifier is also signal-connected to the lock-in amplifier to perform AC / DC conversion on the signal of the current amplifier.

[0019] Optionally, the detection optical wavelength range of the optical power probe is 600 nm to 1100 nm, the optical power detection range is 10 μW - 1 W, the optical power resolution is 1 μW, and the response time is 1.1 s.

[0020] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0021] The present application provides a spectral measurement device for sub-bandgap optoelectronic signal characterization, including a photothermal deflection characterization component, a quantum efficiency characterization component, a spectral calibration component, and a control component. The photothermal deflection characterization component includes a pump optical path mechanism for generating a pump optical path and a detection optical path mechanism for generating a detection optical path, and the pump optical path and the detection optical path are arranged perpendicular to each other and intersect. The pump optical path mechanism includes a xenon lamp pump light source, a first condenser lens group, a filter wheel group, a monochromator, a first slit, and a beam splitting prism arranged in sequence; the first optical path of the monochromator passes through the first slit; the detection optical path mechanism includes a lock-in amplifier and a first chopper, a first parallel lens group, a second condenser lens group, a four-dimensional automatic sample platform, a detection laser, and a laser position detector arranged in sequence; the beam splitting prism shoots one of the optical paths split from the pump optical path into the chopper; the lock-in amplifier is signal-connected to the first chopper; the quantum efficiency characterization component includes a second slit, a second chopper, a second parallel lens group, a third condenser lens group, a photovoltaic cell sample stage, and a current amplifier arranged in sequence; the second optical path of the monochromator passes through the second slit; the spectral calibration component includes a fourth condenser lens group, an optical power probe, and an optical power meter, and the beam splitting prism shoots the other optical path split from the pump optical path into the focusing lens group; the control component is respectively signal-connected to the four-dimensional automatic sample platform, the laser position detector, the current amplifier, the lock-in amplifier, and the monochromator.

[0022] For the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application, high-sensitivity detection with a sensitivity of 10- 3 can be achieved in the sub-bandgap region for the photovoltaic thin film absorption signal, which is 3 orders of magnitude higher than the detection range of ordinary ultraviolet-visible spectroscopy. When performing sub-bandgap photocurrent testing, set the wavelength scanning range, scanning interval, and scanning times of the monochromator according to the test band of the sample to be tested, adjust the filter of the optical filter wheel group, and set the frequency of the second chopper. After the monochromator is adjusted, the pump light source optical path is emitted through the second slit; after passing through the second chopper and the focusing lens group, it is focused on the photovoltaic cell sample stage. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the attached drawings required in the description of the embodiments or the prior art. Obviously, the attached drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other attached drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural layout diagram of the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application;

[0025] Figure 2 It is the light source spectrum diagram and the carbon film photothermal deflection signal diagram of the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application;

[0026] Figure 3 It is the photothermal deflection spectrum diagram of the organic semiconductor thin film of the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application;

[0027] Figure 4 It is the sub-bandgap photocurrent-responsivity curve of the organic photovoltaic device of the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application;

[0028] Figure 5 It is the sub-bandgap photocurrent-external quantum efficiency curve of the organic photovoltaic device of the spectral measurement device for sub-bandgap optoelectronic signal characterization of the present application.

[0029] Among them, the reference numerals in the figure are as follows:

[0030] 1. Xenon lamp pumping light source; 2. First condenser lens group; 3. Filter wheel group; 4. Monochromator; 5. First slit; 6. Beam splitting prism; 7. First chopper; 8. First collimating lens group; 9. Second condenser lens group; 10. Four-dimensional automatic sample platform; 11. Detection laser; 12. Laser position detector; 13. Second slit; 14. Second chopper; 15. Second collimating lens group; 16. Third condenser lens group; 17. Photovoltaic cell sample stage; 18. Current amplifier; 19. Lock-in amplifier; 20. Fourth condenser lens group; 21. Optical power probe; 22. Optical power meter; 23. Control component. Detailed implementation manners

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the following further details the present application in combination with the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0035] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present utility model.

[0036] As Figure 1 and Figure 2 shown, the present application provides a spectral measurement device for sub-bandgap optoelectronic signal characterization, including a photothermal deflection characterization component, a quantum efficiency characterization component, a spectral calibration component, and a control component 23.

[0037] The photothermal deflection characterization component includes a pump optical path mechanism for generating a pump optical path and a detection optical path mechanism for generating a detection optical path, and the pump optical path and the detection optical path are arranged perpendicular to each other and intersect.

[0038] The pump optical path mechanism includes a xenon lamp pump light source 1, a first condenser lens group 2, a filter wheel group 3, a monochromator 4, a first slit 5, and a beam splitting prism 6 arranged in sequence; the monochromator 4 is signal-connected to the control component 23, and the control component 23 controls parameters such as the scanning wavelength, scanning interval, filter wheel selection, slit width, and slit exit selection of the monochromator 4. When performing photothermal deflection testing, the internal mirror parameters of the monochromator 4 are adjusted so that the pump optical path passes through the first slit 5 from the first optical path of the monochromator 4 and then enters the beam splitting prism 6.

[0039] The detection optical path mechanism includes a lock-in amplifier 19, a first chopper 7, a first parallel lens group 8, a second condenser lens group 9, a four-dimensional automatic sample platform 10, a detection laser 11, and a laser position detector 12 arranged in sequence; the beam splitting prism 6 splits one optical path of the pumped optical path and shoots it into the chopper, and this split optical path is 99% of the pumped optical path. The lock-in amplifier 19 is signal-connected to the first chopper 7, and the electrical signal of the first chopper 7 is input into the lock-in amplifier 19 as a reference signal. To avoid ambient light interfering with the detection optical path, the detection optical path mechanism should be within the coverage of the dark box.

[0040] The quantum efficiency characterization component includes a second slit 13, a second chopper 14, a second parallel lens group 15, a third condenser lens group 16, a photovoltaic cell sample stage 17, and a current amplifier 18 arranged in sequence; the second optical path of the monochromator 4 passes through the second slit 13;

[0041] The spectral calibration component includes a fourth condenser lens group 20, an optical power probe 21, and an optical power meter 22 arranged in sequence. The beam splitting prism 6 splits the other optical path of the pumped optical path into the focusing lens group; this split optical path is 1% of the pumped optical path. Among them, the optical power probe 21 is used to collect spectral energy, convert the spectral energy into an electrical signal and then transmit it to the optical power meter 22, and then the optical power meter 22 transmits it to the control component 23 for analysis. The optical power spectrum measured by the spectral calibration component is used to eliminate the background signal of the photothermal deflection signal spectrum, obtain the absorbance spectrum of the sample to be measured, that is, the normalization of the photothermal deflection spectrum. This optical power spectrum is used as a reference signal in the sub-bandgap photocurrent detection process to obtain the external quantum efficiency spectrum. As Figure 2 shown, the characteristic peak of the photothermal deflection spectrum measured by the all-black carbon film with full-spectrum absorption is highly consistent with the signal wavelength position of the spectrum obtained by the detector, so as to verify the effectiveness and accuracy of the pump light spectrum information and apply it to the calibration of sub-bandgap light absorption and photocurrent.

[0042] During the test of the photothermal deflection signal of the photovoltaic thin film, first adjust the sample position to make the distance between the sample to be measured and the detection laser the smallest and highly parallel, and the incident light source is completely focused on the sample surface to obtain a highly sensitive photothermal deflection signal. After completing the sample position calibration, set the wavelength scanning range, scanning interval, and scanning times of the monochromator 4 according to the test band of the sample to be measured, adjust the filter of the optical filter wheel group 3, set the frequency of the first chopper 7, and start scanning to obtain the photothermal deflection signal spectrum. The spectral calibration module performs spectral scanning with the same test parameters to obtain the background spectrum. The photothermal deflection signal spectrum is divided by the light source spectrum to obtain the absorbance spectrum of the sample to be measured. The absorbance spectrum is divided by the sample thickness to obtain the absorption ratio spectrum. By referring to the absorption coefficient extracted from the strong absorption section of the ultraviolet-visible absorption spectrum of the sample, multiplying the absorption coefficient by the absorption ratio can obtain the photothermal deflection spectrum. As Figure 3As shown, it is the photothermal deflection spectrogram of the organic photovoltaic thin film PM6:Y6. It can be seen that through the spectral measurement device characterized by the sub-bandgap optoelectronic signal of the present application, the absorption signal of the photovoltaic thin film can achieve high-sensitivity detection in the sub-bandgap region at 10- 3 , which is 3 orders of magnitude higher than the detection range of ordinary ultraviolet-visible spectroscopy.

[0043] When performing sub-bandgap photocurrent testing, set the wavelength scanning range, scanning interval, and scanning times of the monochromator 4 according to the test band of the sample to be tested, adjust the filter of the optical filter wheel group 3, and set the frequency of the second chopper 14. After the monochromator 4 is adjusted, the pump light source optical path is emitted through the second slit 13; after passing through the second chopper 14 and the focusing lens group, it is focused on the photovoltaic cell sample stage 17.

[0044] After calibrating the light source, place the reference detector on the sample stage, turn on the monochromator 4 to scan and record the current output Iref of the reference detector and the known responsivity Rref. Calculate the incident optical power at each wavelength in real time through the formula .

[0045] Measure the photocurrent of the photovoltaic device. Install the photovoltaic device on the sample stage, irradiate the light source on the photovoltaic device to be measured, record the photocurrent Iph of the photovoltaic device through the current amplifier 18, and input it into the lock-in amplifier 19. The lock-in amplifier 19 is connected to the control component 23 for data acquisition and calculates the responsivity (R) of the photovoltaic device at each wavelength in real time through the formula .

[0046] As Figure 4 shown, it is the responsivity spectrum of the PM6:Y6 photovoltaic device in the sub-bandgap region. At the same time, calculate the external quantum efficiency EQE (%) of the photovoltaic device at each wavelength through the formula for the responsivity R at different wavelengths.

[0047] As Figure 5 shown, it is the external quantum efficiency spectrum of the sub-bandgap region of the photovoltaic device calculated in real time through the responsivity spectrum of PM6:Y6.

[0048] In an embodiment of the present application, the output power of the xenon lamp pump light source 1 is 100 mW, which is much higher than other photothermal deflection pump light sources. The greater the power of the light source, the stronger the photo-thermal and optoelectronic effects it excites, thus causing higher photothermal deflection signals and sub-bandgap current signals, ensuring high-sensitivity detection. The xenon lamp pump light source 1 is used to emit pump light with a wavelength range of 350 nm to 2000 nm.

[0049] In an embodiment of the present application, the wavelength resolution of the monochromator 4 is adjustable from 0.1 nm to 10 nm, the ripple is less than 0.1%, and the ripple is less than 1% RMS.

[0050] In one embodiment of the present application, the wavelength resolution of the first chopper 7 is adjustable from 1 Hz to 500 Hz, the frequency resolution is 1 Hz, and the frequency stability is less than 1%.

[0051] In one embodiment of the present application, the four-dimensional automatic sample platform 10 includes an X-axis displacement platform, a Y-axis displacement platform, a Z-axis displacement platform, and an R-axis rotation platform; the stroke of the X-axis displacement platform and the Y-axis displacement platform is ±25 mm, and the positioning accuracy is 0.0025 mm. The stroke of the Z-axis displacement platform is ±15 mm, and the positioning accuracy is 0.004 mm; the minimum rotation accuracy of the R-axis rotation platform is 0.7°. The sample detection cell of the four-dimensional automatic sample platform 10 is filled with a fluid medium that is highly transparent in the wavelength range of 200 - 2000 nm and has a refractive index that is greatly affected by temperature changes, so as to enhance the photothermal deflection amount and improve the detection sensitivity.

[0052] In one embodiment of the present application, the laser position detector 12 is signal-connected to the lock-in amplifier 19 through an I-V conversion circuit for filtering and signal amplification processing.

[0053] In one embodiment of the present application, the detection laser emitted by the detection laser 11 has a minimum output optical power of 1.5 mW, and the power stability is less than 2.5%.

[0054] In one embodiment of the present application, the photovoltaic cell sample stage 17 is signal-connected to the current amplifier 18. The current amplifier 18 is used to amplify and filter the current signal of the photovoltaic cell sample stage 17; the current amplifier 18 is also signal-connected to the lock-in amplifier 19 to perform AC / DC conversion on the signal of the current amplifier 18.

[0055] In one embodiment of the present application, the detection light wavelength range of the optical power probe 21 is 600 nm to 1100 nm, the optical power detection range is 10 μW - 1 W, the optical power resolution is 1 μW, and the response time is 1.1 s.

[0056] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A spectral measurement device for sub-bandgap optoelectronic signal characterization, characterized in that, Including: A photothermal deflection characterization component, including a pump light path mechanism for generating a pump light path and a detection light path mechanism for generating a detection light path. The pump light path and the detection light path are arranged perpendicular to each other and intersect. The pump light path mechanism includes a xenon lamp pump light source (1), a first condenser lens group (2), a filter wheel group (3), a monochromator (4), a first slit (5), and a beam splitting prism (6) arranged in sequence. The first light path of the monochromator (4) passes through the first slit (5). The detection light path mechanism includes a lock-in amplifier (19) and a first chopper (7), a first parallel lens group (8), a second condenser lens group (9), a four-dimensional automatic sample platform (10), a detection laser (11), and a laser position detector (12) arranged in sequence. The beam splitting prism (6) splits one light path of the pump light path and shoots it into the chopper. The lock-in amplifier (19) is signal-connected to the first chopper (7). A quantum efficiency characterization component, including a second slit (13), a second chopper (14), a second parallel lens group (15), a third condenser lens group (16), a photovoltaic cell sample stage (17), and a current amplifier (18) arranged in sequence. The second light path of the monochromator (4) passes through the second slit (13). A spectral calibration component, including a fourth condenser lens group (20), an optical power probe (21), and an optical power meter (22) arranged in sequence. The beam splitting prism (6) guides another light path split from the pump light path into the focusing lens group. A control component (23), which is signal-connected to the four-dimensional automatic sample platform (10), the laser position detector (12), the current amplifier (18), the lock-in amplifier (19), and the monochromator (4) respectively.

2. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, wherein The output power of the xenon lamp pump light source (1) is 100 mW, and it is used to emit pump light with a wavelength range of 350 nm to 2000 nm.

3. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, characterized in that, The wavelength resolution of the monochromator (4) is adjustable from 0.1 nm to 10 nm, the optical ripple is less than 0.1%, and the optical ripple is less than 1% RMS.

4. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, wherein The wavelength resolution of the first chopper (7) is adjustable from 1 Hz to 500 Hz, the frequency resolution is 1 Hz, and the frequency stability is less than 1%.

5. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, characterized in that The four-dimensional automatic sample platform (10) includes an X-axis displacement platform, a Y-axis displacement platform, a Z-axis displacement platform, and an R-axis rotation platform. The stroke of the X-axis displacement platform and the Y-axis displacement platform is ±25 mm, the positioning accuracy is 0.0025 mm, the stroke of the Z-axis displacement platform is ±15 mm, and the positioning accuracy is 0.004 mm. The minimum rotation accuracy of the R-axis rotation platform is 0.7°.

6. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, characterized in that The laser position detector (12) is signal-connected to the lock-in amplifier (19) through an I-V conversion circuit for filtering and signal amplification processing.

7. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, wherein, The minimum output optical power of the detection laser (11) emitted is 1.5 mW, and the power stability is less than 2.5%.

8. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, wherein, The photovoltaic cell sample stage (17) is signal-connected to a current amplifier (18), and the current amplifier (18) is used to amplify and filter the current signal of the photovoltaic cell sample stage (17); the current amplifier (18) is also signal-connected to a lock-in amplifier (19) to perform AC / DC conversion on the signal of the current amplifier (18).

9. The spectral measurement device for sub-bandgap optoelectronic signal characterization according to claim 1, characterized in that, The detection light wavelength range of the optical power probe (21) is 600 nm to 1100 nm, the optical power detection range is 10 μW - 1 W, the optical power resolution is 1 μW, and the response time is 1.1 s.

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