In-situ analysis system and method for the sources of performance degradation in perovskite solar cells

Abstract

This application belongs to the field of photovoltaic device testing technology and discloses an in-situ analysis system for the sources of performance degradation in perovskite solar cells. The system includes an electrical measurement unit, an aging test unit, an analysis light source unit, a frequency modulation unit, an optical detection unit, and a data processing and analysis unit. This data processing and analysis unit is communicatively connected to both the electrical measurement unit and the optical detection unit to correlate electrical parameters and photoluminescence signal parameters at the same time point to analyze the sources of performance degradation in perovskite solar cells. This system can obtain the electrical performance of the device and the optical performance of the perovskite thin film in situ without interrupting stability testing, establishing a direct correlation between macroscopic performance degradation and microscopic material changes, accurately locating the sources of degradation, and providing a clear research direction for improving device stability. This application also discloses an in-situ analysis method for the sources of performance degradation in perovskite solar cells, which has the same advantages as the aforementioned system.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic device testing technology, and in particular relates to an in-situ analysis system and method for identifying the sources of performance degradation in perovskite solar cells. Background Technology

[0002] Perovskite solar cells, as an emerging photovoltaic technology, have made significant progress in power conversion efficiency; however, their long-term stability remains a key bottleneck restricting their application. Currently, industry-standard light stability testing (usually conducted in maximum power point tracking mode) primarily monitors the macroscopic electrical parameters of the device, such as open-circuit voltage, short-circuit current, fill factor, and efficiency, over time. However, this traditional testing method has a significant drawback: it can only indicate that the device's performance has degraded, but cannot reveal the cause of the degradation. Perovskite solar cells are multilayered devices, and performance degradation may originate from the degradation of the perovskite light-absorbing layer itself (such as lattice structure disruption, ion migration, and phase separation), or from the damage to the interface layer or the deterioration of the charge transport layer. Relying solely on the degradation of electrical parameters cannot accurately distinguish and pinpoint the root cause of the degradation, which poses a significant challenge to the targeted optimization of device structure and fabrication processes.

[0003] Therefore, there is an urgent need for a method that can simultaneously and in situ acquire more multi-dimensional information during stability testing, especially information that can directly reflect the quality changes of the perovskite thin film itself, so as to achieve in-depth tracing and analysis of the degradation mechanism of perovskite solar cells. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides an in-situ analysis system and method for identifying the sources of performance degradation in perovskite solar cells. This system can obtain the electrical performance of the device and the optical performance of the perovskite thin film in situ without interrupting stability testing, establish a direct correlation between macroscopic performance degradation and microscopic material changes, accurately pinpoint the sources of degradation, and provide a clear research direction for improving device stability.

[0005] The in-situ analysis system for the sources of performance degradation in perovskite solar cells provided by this invention includes:

[0006] An electrical measurement unit is electrically connected to the perovskite solar cell to obtain electrical parameters in real time.

[0007] An aging test unit is positioned facing the front of the perovskite solar cell to perform photo-aging under maximum power point tracking.

[0008] The light source unit is positioned facing the front of the perovskite solar cell to emit light with wavelengths within the absorption range of the perovskite material of the perovskite solar cell.

[0009] A frequency modulation unit, in conjunction with the analysis light source unit, generates frequency-modulated light, which is used to excite a photoluminescence signal from the perovskite solar cell.

[0010] An optical detection unit is communicatively connected to the frequency modulation unit, and its front end is connected to a photoelectric conversion device for receiving parameters of the photoluminescence signal. The reference signal of the photoelectric conversion device comes from the frequency modulation unit.

[0011] The data processing and analysis unit is communicatively connected to both the electrical measurement unit and the optical detection unit, and is used to correlate the electrical parameters and the parameters of the photoluminescence signal at the same time point to analyze the sources of performance degradation of perovskite solar cells.

[0012] Preferably, in the above-mentioned in-situ analysis system for the sources of performance degradation of perovskite solar cells, the electrical measurement unit is used to obtain the voltage, current and efficiency of the perovskite solar cell at its maximum power point in real time.

[0013] Preferably, in the in-situ analysis system for the sources of performance degradation of the perovskite solar cells described above, the aging test unit is an LED lamp or a xenon lamp used to simulate the solar spectrum.

[0014] Preferably, in the above-mentioned in-situ analysis system for the sources of performance degradation of perovskite solar cells, the analysis light source unit is a laser that outputs light with a wavelength of 405nm or 520nm.

[0015] Preferably, in the above-mentioned in-situ analysis system for the sources of performance degradation of perovskite solar cells, the frequency modulation unit is a chopper or signal generator for square wave pulse modulation.

[0016] Preferably, in the in-situ analysis system for the sources of performance degradation in the above-mentioned perovskite solar cells, the photoelectric conversion device includes:

[0017] Fiber optic probes are used to collect photoluminescence signals;

[0018] Filters are used to filter out excitation laser light and aging white light.

[0019] Preferably, in the in-situ analysis system for the sources of performance degradation of the perovskite solar cells described above, the optical detection unit is a lock-in amplifier.

[0020] Preferably, in the above-mentioned in-situ analysis system for the source of performance degradation of perovskite solar cells, the data processing and analysis unit is a computer, used to correlate the electrical parameters and the parameters of the photoluminescence signal at the same time point, and to plot a first curve of the electrical parameters changing over time and a second curve of the parameters of the photoluminescence signal changing over time. When the first curve and the second curve begin to decay synchronously, it is analyzed that the source of performance degradation of the perovskite solar cell is the degradation of the perovskite material layer itself; otherwise, the source is the transport layer and the interface layer.

[0021] The in-situ analysis method for the sources of performance degradation in perovskite solar cells provided by this invention utilizes the in-situ analysis system for the sources of performance degradation in perovskite solar cells as described in any of the above claims, including:

[0022] The perovskite solar cells were subjected to light aging tests under maximum power point tracking conditions.

[0023] During the light aging test, a frequency-modulated light is applied to the perovskite solar cell.

[0024] The electrical parameters of the perovskite solar cell at its maximum power point were collected in situ.

[0025] In-situ acquisition of photoluminescence signals from perovskite materials excited by the frequency-modulated light;

[0026] By correlating the electrical parameters and the photoluminescence signal parameters at the same time point, and based on the changes in the electrical parameters and the photoluminescence signal parameters, the degradation mechanism of the perovskite solar cell is analyzed, and the sources of performance degradation of the perovskite solar cell are obtained.

[0027] Preferably, the in-situ analysis method for the sources of performance degradation in perovskite solar cells further includes:

[0028] The quality changes of the perovskite material are evaluated by analyzing the changes in the intensity or lifetime of the photoluminescence signal over time.

[0029] As described above, the in-situ analysis system for the sources of performance degradation of perovskite solar cells provided by the present invention includes: an electrical measurement unit electrically connected to the perovskite solar cell to obtain electrical parameters in real time; an aging test unit facing the front of the perovskite solar cell to perform photo-aging under maximum power point tracking; an analysis light source unit facing the front of the perovskite solar cell to irradiate light with wavelengths within the absorption range of the perovskite material of the perovskite solar cell; a frequency modulation unit cooperating with the analysis light source unit to generate frequency-modulated light, which is used to excite photoluminescence signals from the perovskite solar cell; an optical detection unit communicatively connected to the frequency modulation unit, and having a photoelectric conversion device connected at its front end for receiving parameters of the photoluminescence signal, the reference signal of which comes from the frequency modulation unit; and a data processing and analysis unit. The system is communicatively connected to the electrical measurement unit and the optical detection unit to correlate the electrical parameters and photoluminescence signal parameters at the same time point to analyze the sources of performance degradation in perovskite solar cells. Therefore, the photoluminescence signal can characterize the optical properties of the perovskite thin film. The measurement of optical properties is simultaneous with the measurement of the device's electrical properties, and the two do not interfere with each other. Furthermore, when a decrease in cell efficiency occurs, it is possible to immediately check whether the optical properties have simultaneously degraded or redshifted. This allows it to determine whether the dominant factor in performance degradation is the degradation of the perovskite layer itself, or a problem with the interface contact or transport layer. Thus, this system can acquire the electrical properties of the device and the optical properties of the perovskite thin film in situ and synchronously without interrupting stability testing, establishing a direct correlation between macroscopic performance degradation and microscopic material changes, accurately locating the source of degradation, and providing a clear research direction for improving device stability. The in-situ analysis method for the sources of performance degradation in perovskite solar cells provided by this invention has the same advantages as the aforementioned system. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 A schematic diagram of an embodiment of the in-situ analysis system for the sources of performance degradation of perovskite solar cells provided by the present invention;

[0032] Figure 2 A schematic diagram of an embodiment of the in-situ analysis method for the sources of performance degradation in perovskite solar cells provided by the present invention;

[0033] Figure 3 A schematic diagram showing the results of synchronous tracking of electrical parameters and photoluminescence signal parameters;

[0034] Figure 4 This is a magnified diagram of the results between 0 and 0.4h. Detailed Implementation

[0035] The core of this invention is to provide an in-situ analysis system and method for identifying the sources of performance degradation in perovskite solar cells. This system can simultaneously and in-situ acquire the electrical performance of the device and the optical performance of the perovskite thin film without interrupting stability testing. It establishes a direct correlation between macroscopic performance degradation and microscopic material changes, accurately pinpoints the sources of degradation, and provides a clear research direction for improving device stability.

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] An example of implementing the in-situ analysis system for the sources of performance degradation in perovskite solar cells provided by this invention is as follows: Figure 1 As shown, Figure 1 This is a schematic diagram of an embodiment of the in-situ analysis system for the sources of performance degradation in perovskite solar cells provided by the present invention. The system may include:

[0038] Electrical measurement unit 1 is electrically connected to perovskite solar cell 2 to obtain electrical parameters in real time. Specifically, electrical measurement unit 1 may include a source meter connected to a computer, which can run a maximum power point tracking algorithm to continuously perform maximum power point tracking, and obtain the device voltage, current and efficiency of the perovskite solar cell 2 at the maximum power point in real time. These parameters can characterize the changes in the device's power generation performance.

[0039] The aging test unit 3 is positioned facing the front of the perovskite solar cell 2 to perform light aging under maximum power point tracking (MPPT). Specifically, the aging test unit 3 can be an LED lamp or a xenon lamp used to simulate the solar spectrum, so that the cell's operating state at the maximum power point can be continuously tracked.

[0040] The analysis light source unit 4 is positioned facing the front of the perovskite solar cell 2 to irradiate light with wavelengths within the absorption range of the perovskite material of the perovskite solar cell 2. This light can excite the photoluminescence signal (PL signal) of the perovskite thin film. In a specific example, this analysis light source unit 4 can be a laser that outputs light with wavelengths of 405nm or 520nm. The 405nm laser is a blue-violet laser, and the 520nm laser belongs to the pure green light band. Both are mainly based on gallium nitride (GaN) semiconductor laser diode technology, which belongs to direct-emission semiconductor laser technology and has higher electro-optical conversion efficiency and better thermal stability. Of course, other types of light source units can be selected according to actual needs, and there are no restrictions here.

[0041] The frequency modulation unit 5, in conjunction with the analysis light source unit 4, generates frequency-modulated light. This frequency-modulated light is used to excite a photoluminescence signal from the perovskite solar cell 2. In one example, the frequency modulation unit 5 can be a chopper or signal generator for square wave pulse modulation. The excitation light for frequency modulation can be pulsed light or sinusoidal modulated light, and can, but is not limited to, square wave pulse modulation with a frequency of 1 kHz to 1 MHz. Specifically, an optical chopper is a traditional mechanical modulation scheme suitable for lower frequency square wave pulse modulation. It uses a motor-driven perforated turntable to periodically block or pass a beam of light, typically from 1 Hz to 10 kHz, with a square wave modulation waveform. The scheme using a signal generator superimposed with electro-optic modulation is a mid-frequency scheme with a frequency range of 1 kHz to 1 MHz. Alternatively, a scheme combining a signal generator with an acousto-optic modulator (AOM) can be used, achieving both square wave pulse modulation and sinusoidal wave modulation, with a wide frequency coverage and high stability.

[0042] The optical detection unit 6 is communicatively connected to the frequency modulation unit 5, and its front end is connected to a photoelectric conversion device 7 for receiving parameters of the photoluminescence signal. The reference signal of the photoelectric conversion device 7 comes from the frequency modulation unit 5. In one example, the photoelectric conversion device 7 may include an optical fiber probe for collecting the photoluminescence signal; a filter for filtering out the excitation laser and aging white light; and may also include a photomultiplier tube detector. Furthermore, the optical detection unit 6 can preferably be a lock-in amplifier. In this case, the output signal of the photoelectric conversion device 7 is connected to the lock-in amplifier, and the reference signal of the lock-in amplifier comes from the function generator of the frequency modulation unit 5. It can be seen that the key point of this embodiment is to lock the frequency of the excitation light modulated by the frequency modulation unit and the frequency of the PL signal received by the optical detection unit. In this way, knowing the frequency of the excitation light, the corresponding PL signal with the same frequency can be found from many rays. For example, if the excitation light is tuned to 200Hz, then the optical detection unit detects the signal generated by the solar cell after absorbing the light at the frequency of 200Hz. The frequency of the generated signal is also 200Hz. By using this frequency locking, accurate identification of the PL signal is achieved. Only in this way can in-situ synchronous detection be achieved, unlike the prior art which does not perform this frequency locking.

[0043] The data processing and analysis unit 8 is communicatively connected to the electrical measurement unit 1 and the optical detection unit 6. It is used to correlate the electrical parameters and photoluminescence signal parameters at the same time point to analyze the source of performance degradation of perovskite solar cells. Specifically, the data processing and analysis unit 8 can be a computer. It is used to correlate the electrical parameters and photoluminescence signal parameters at the same time point and plot a first curve of electrical parameters changing over time and a second curve of photoluminescence signal parameters changing over time. When the first curve and the second curve begin to decay simultaneously, it is analyzed that the source of performance degradation of perovskite solar cells is the degradation of the perovskite material layer itself; otherwise, the source is the transport layer and the interface layer.

[0044] As can be seen, the above system introduces a frequency-modulated light source as a probe light on a traditional maximum power point tracking (MPPT) aging test platform. This probe light is combined with the steady-state white light (simulating sunlight) used for aging testing in the optical path and jointly illuminates the perovskite solar cell. By using a lock-in amplifier synchronized with the modulation frequency, a weak PL signal can be extracted from the strong background light (steady-state white light) and noise with a high signal-to-noise ratio. By analyzing parameters such as the intensity (reflecting the degree of nonradiative recombination) or lifetime (reflecting the defect density) of the PL signal, the quality status of the perovskite film can be directly evaluated. If the PL signal does not weaken, it means that the perovskite film has not degraded. If the electrical performance of the cell weakens at this time, it proves that the cause is not in the perovskite film, but in other aspects. It can be seen that this allows for in-situ and synchronous analysis of the source of performance degradation during the stability test, which facilitates targeted research and treatment.

[0045] It should also be noted that existing technologies require a standard sunlight source to measure maximum power attenuation, followed by tracking electrical data such as efficiency and voltage using a multimeter. In this case, if the PL signal of the perovskite is to be measured simultaneously, directly exciting it with the light source would result in the signal being mixed with the standard sunlight source, making it impossible to distinguish which type of light is generating the PL signal. However, in this embodiment, a laser is used as the light source. Before the laser is incident, a chopper is used to convert the laser into light with a specific frequency, different from the frequency of the standard sunlight source. Simultaneously, the signal output of this chopper is connected to a lock-in amplifier. This lock-in amplifier can then capture the PL signal of the perovskite film generated by laser excitation at this frequency. Therefore, this method allows for the measurement of the PL signal inside the perovskite film under operating conditions.

[0046] As described above, the in-situ analysis system for the sources of performance degradation of perovskite solar cells provided by the present invention includes: an electrical measurement unit electrically connected to the perovskite solar cell to obtain electrical parameters in real time; an aging test unit facing the front of the perovskite solar cell to perform photo-aging under maximum power point tracking; an analysis light source unit facing the front of the perovskite solar cell to irradiate light with wavelengths within the absorption range of the perovskite material of the perovskite solar cell; a frequency modulation unit cooperating with the analysis light source unit to generate frequency-modulated light, which is used to excite photoluminescence signals from the perovskite solar cell; an optical detection unit communicatively connected to the frequency modulation unit, and having a photoelectric conversion device connected at its front end for receiving parameters of the photoluminescence signal, the reference signal of which comes from the frequency modulation unit; and a data processing and analysis unit simultaneously connected to the electrical measurement unit. The measurement unit and the optical detection unit are connected to correlate the electrical parameters and photoluminescence signal parameters at the same time point to analyze the source of performance degradation in perovskite solar cells. Therefore, the photoluminescence signal can be used to characterize the optical performance of the perovskite film. The measurement of optical performance is carried out simultaneously with the measurement of the device's electrical performance, and the two do not interfere with each other. Moreover, when the cell efficiency declines, it is possible to immediately check whether the optical performance has also degraded or redshifted. This allows it to determine whether the dominant factor in performance degradation is the degradation of the perovskite layer itself, or a problem with the interface contact or transport layer. Thus, it can be seen that the system can acquire the electrical performance of the device and the optical performance of the perovskite film in situ and synchronously without interrupting stability testing, establish a direct correlation between macroscopic performance degradation and microscopic material changes, accurately locate the source of degradation, and provide a clear research direction for improving device stability.

[0047] An example of the implementation of the in-situ analysis method for the sources of performance degradation in perovskite solar cells provided by this invention is... Figure 2 As shown, Figure 2 This is a schematic diagram of an embodiment of the in-situ analysis method for the sources of performance degradation in perovskite solar cells provided by the present invention. Using the in-situ analysis system for the sources of performance degradation in perovskite solar cells as described in any of the above claims, the following steps may be included:

[0048] S1: The perovskite solar cells were subjected to light aging tests under maximum power point tracking conditions;

[0049] S2: During the photo-aging test, a frequency-modulated light beam is applied to the perovskite solar cell;

[0050] S3: In-situ collection of electrical parameters of perovskite solar cells at the maximum power point;

[0051] S4: In-situ acquisition of photoluminescence signals from perovskite materials excited by frequency-modulated light;

[0052] S5: Correlate the electrical parameters and photoluminescence signal parameters at the same time point, and analyze the degradation mechanism of perovskite solar cells based on the changes in the electrical parameters and photoluminescence signal parameters to obtain the sources of performance degradation of perovskite solar cells.

[0053] In a specific example, the prepared perovskite solar cell is first placed on a test stage, the electrodes are connected, and then a white light source is turned on to ensure the light intensity meets standard test conditions (e.g., AM 1.5G, 100mW / cm²). 2 Then, the electrical measurement unit is activated to bring the battery into and maintain its maximum power point operating state. The frequency-modulated laser is then turned on, the lock-in amplifier is activated, and synchronous recording begins. Simultaneously, the computer records time t and the maximum power point voltage V. max Maximum power point current J max and maximum power P max The test was conducted for several hours to hundreds of hours, along with the PL intensity signal output by the lock-in amplifier. After the test, the data was analyzed, and efficiency-time curves and PL intensity-time curves were plotted. The decay mechanism was analyzed by observing the starting point, rate, and correlation of the decay of the two curves. For example, if the two curves started decaying almost synchronously, it strongly indicated that the degradation of the perovskite thin film layer itself was the main cause of device failure. In this case, the perovskite thin film layer needed to be treated.

[0054] In a specific embodiment of the above-mentioned in-situ analysis method for the sources of performance degradation in perovskite solar cells, the following steps may also be included:

[0055] By analyzing the changes in the intensity or lifetime of the photoluminescence signal over time, the quality changes of perovskite materials can be evaluated, thus enabling a deeper analysis of the attenuation mechanism. It should be noted that when V... max J max P max If PL does not decrease under the condition of attenuation, it indicates that the quality of the perovskite film has not changed significantly, suggesting that the cause of device failure originates from the transport layer and interface layer. When J max Without decay, V max P max The decrease in PL (Power Probe) and voltage indicates that the perovskite film has not undergone significant degradation, but has generated a large number of defects and non-radiative recombination, leading to a decrease in PL and voltage. Generally, PL decreases, and P... max All will decay.

[0056] The in-situ analysis system and method for the source of performance degradation in perovskite solar cells provided in this application have the following advantages: First, they are synchronous and in-situ, enabling online diagnosis of electrical performance and thin film quality under actual device operating conditions, avoiding errors and interference that may be introduced by traditional offline testing. Second, they have strong mechanism tracing capabilities; by accurately correlating the macroscopic electrical degradation curve with the microscopic PL change curve, they can effectively distinguish whether the degradation originates from the bulk degradation of the perovskite light-absorbing layer or interface / transport layer problems, providing direct evidence for precise optimization. For example, if the efficiency decreases and the PL intensity decreases sharply, the problem mainly lies in the perovskite layer; if the efficiency decreases but the PL change is not significant, the problem may lie in the charge extraction and transport interface. Third, they have high sensitivity and accuracy; the use of frequency modulation and synchronous detection technology greatly suppresses background noise, making it possible to accurately measure the PL signal under strong white light aging light background, and the measurement results are reliable. Finally, they provide clear guidance; the data obtained by this scheme can directly guide the subsequent research and development direction, such as whether to focus on improving the crystal quality of the perovskite thin film or to optimize the electron or hole transport layer material.

[0057] The analysis process will be explained in detail below with a specific example:

[0058] refer to Figure 3 , Figure 3 A schematic diagram showing the results of synchronous tracking of electrical parameters and photoluminescence signal parameters, including the maximum power P. max The intensity of photoluminescence (PL) and the voltage V corresponding to the maximum power point. max Current density J corresponding to the maximum power point max Therefore, V max and J max The decay trend and time with P max The correspondence is consistent. Because P max V max J max Both parameters directly correspond to device parameters, while PL directly corresponds to perovskite thin film parameters. Device-related factors may include the perovskite, the perovskite-transport layer interface, the transport layer, the transport layer-electrode interface, and the electrodes; while PL's impact is primarily on the perovskite and perovskite interface. Before 0.63 hours, PL increases. In the early stages of illumination, photogenerated carriers can fill deep-level defects, suppressing Shockley-Read-Hall (SRH) nonradiative recombination. Therefore, the proportion of radiative recombination increases, and the PL intensity rises. Simultaneously, initial ions migrate to the HTL and ETL interface, forming a reverse electric field that shields the built-in electric field, making charge carrier transport difficult. After 0.63 hours, photogenerated carriers are insufficient to fill defects, instead forming new defect centers, exacerbating ion migration and lattice stress accumulation, leading to increased nonradiative recombination, and thus increasing PL and P.max V max J max Simultaneous descent.

[0059] refer to Figure 4 , Figure 4 This is a magnified schematic diagram of the results between 0 and 0.4 hours. In stage I, the maximum power P is between 0 and 0.014 hours. max As the intensity of photoluminescence (PL) rises rapidly, the intensity of PL decreases. Under this condition, the initial tracking power is low, lower than the true MMPT, and further V... MMPT Both are increasing, the internal carrier transport efficiency of the device increases, carriers are effectively extracted, internal recombination decreases, so PL drops rapidly. In stage II, within 0.014h to 0.08h, P... max The actual power has been tracked. As the illumination time progresses, some surface ion migration and charge accumulation occur, leading to P max The voltage decreases, but the charge accumulation at the interface generates an electric field opposite to the built-in electric field, causing the decrease in PL to gradually slow down. In stage III after 0.08 hours, P... max The decline continues slowly. The gradual increase in PL is due to the filling of defects in photogenerated carriers and the partial shielding of the built-in electric field.

[0060] It can be seen that this method is a PL detection method introduced through perturbation and frequency locking technology when conducting MPPT testing under working conditions (full spectrum irradiation, simulated solar spectrum). This method has no impact on the accuracy of MPPT testing and is a non-destructive testing method.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An in-situ analysis system for the sources of performance degradation in perovskite solar cells, characterized in that, include: An electrical measurement unit is electrically connected to the perovskite solar cell to obtain electrical parameters in real time. An aging test unit is positioned facing the front of the perovskite solar cell to perform photo-aging under maximum power point tracking. The light source unit is positioned facing the front of the perovskite solar cell to emit light with wavelengths within the absorption range of the perovskite material of the perovskite solar cell. A frequency modulation unit, in conjunction with the analysis light source unit, generates frequency-modulated light, which is used to excite a photoluminescence signal from the perovskite solar cell. An optical detection unit is communicatively connected to the frequency modulation unit, and its front end is connected to a photoelectric conversion device for receiving parameters of the photoluminescence signal. The reference signal of the photoelectric conversion device comes from the frequency modulation unit. The data processing and analysis unit is communicatively connected to both the electrical measurement unit and the optical detection unit, and is used to correlate the electrical parameters and the parameters of the photoluminescence signal at the same time point to analyze the sources of performance degradation of the perovskite solar cell. The frequency modulation unit is a chopper or signal generator used for square wave pulse modulation. The optical detection unit is a lock-in amplifier; The data processing and analysis unit is a computer, used to correlate the electrical parameters and the parameters of the photoluminescence signal at the same time point, and to plot a first curve of the electrical parameters changing over time and a second curve of the parameters of the photoluminescence signal changing over time. When the first curve and the second curve begin to decay synchronously, it is analyzed that the source of the performance degradation of the perovskite solar cell is the degradation of the perovskite material layer itself; otherwise, the source is the transport layer and the interface layer. The system introduces a frequency-modulated light source as a probe light on a maximum power point tracking illumination aging test platform. The probe light and the steady-state white light used for aging testing are combined in the optical path and jointly illuminate the perovskite solar cell. By using the lock-in amplifier synchronized with the modulation frequency, a weak photoluminescence signal is extracted from the strong background light and noise with a high signal-to-noise ratio. By analyzing the intensity or lifetime parameters of the photoluminescence signal, the quality status of the perovskite film is directly evaluated. If the photoluminescence signal does not weaken, it means that the perovskite film has not degraded. If the electrical performance of the cell weakens at this time, it proves that the cause is not in the perovskite film. Thus, the source of performance degradation can be analyzed in situ and synchronously during the stability test. The system uses a laser as a light source. Before the laser is incident, a chopper is used to convert the laser into light with a certain frequency, which is different from the frequency of a standard sunlight source. At the same time, the signal output terminal of the chopper is connected to the lock-in amplifier. The lock-in amplifier can capture the photoluminescence signal with the same frequency generated by the perovskite film under laser excitation at this frequency, so as to measure the photoluminescence signal inside the perovskite film under operating conditions.

2. The in-situ analysis system for the sources of performance degradation in perovskite solar cells according to claim 1, characterized in that, The electrical measurement unit is used to obtain the voltage, current and efficiency of the perovskite solar cell at its maximum power point in real time.

3. The in-situ analysis system for the sources of performance degradation in perovskite solar cells according to claim 1, characterized in that, The aging test unit is an LED lamp or a xenon lamp used to simulate the solar spectrum.

4. The in-situ analysis system for the sources of performance degradation in perovskite solar cells according to claim 1, characterized in that, The analysis light source unit is a laser that outputs light with a wavelength of 405nm or 520nm.

5. The in-situ analysis system for the sources of performance degradation in perovskite solar cells according to claim 1, characterized in that, The photoelectric conversion device includes: Fiber optic probes are used to collect photoluminescence signals; Filters are used to filter out excitation laser light and aging white light.

6. An in-situ analysis method for the sources of performance degradation in perovskite solar cells, characterized in that, The in-situ analysis system for the sources of performance degradation in perovskite solar cells as described in any one of claims 1-5 includes: The perovskite solar cells were subjected to light aging tests under maximum power point tracking conditions. During the light aging test, a frequency-modulated light is applied to the perovskite solar cell. The electrical parameters of the perovskite solar cell at its maximum power point were collected in situ. In-situ acquisition of photoluminescence signals from perovskite materials excited by the frequency-modulated light; By correlating the electrical parameters and the photoluminescence signal parameters at the same time point, and based on the changes in the electrical parameters and the photoluminescence signal parameters, the degradation mechanism of the perovskite solar cell is analyzed, and the sources of performance degradation of the perovskite solar cell are obtained.

7. The in-situ analysis method for the sources of performance degradation in perovskite solar cells according to claim 6, characterized in that, Also includes: The quality changes of the perovskite material are evaluated by analyzing the changes in the intensity or lifetime of the photoluminescence signal over time.

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