Method and system for quantifying ion migration related charge electric quantity

Abstract

The invention relates to a method and a system for quantifying ion migration related charge electric quantity. The system comprises a delay generator, a self-made switch, a steady-state light source device and an oscilloscope, the delay generator is used for controlling the self-made switch, the steady-state light source device and the oscilloscope according to a preset time sequence; the steady-state light source device is used for providing steady-state light according to the control signal to irradiate a to-be-tested perovskite solar cell sample, so that the to-be-tested perovskite solar cell sample generates photon-generated carriers; the self-made switch is used for performing charge extraction on the perovskite solar cell sample to be tested according to the control signal; and the oscilloscope is used for displaying a real-time waveform and storing data of each test period according to the control signal so as to carry out quantitative analysis on the charge electric quantity. The method can be widely applied to the field of ion migration testing.

Description

Technical Field

[0001] The present invention relates to a method and system for quantitatively analyzing the amount of electric charge related to ion migration, and in particular to a method and system for quantitatively analyzing ion migration in a perovskite solar cell device, and belongs to the field of ion migration testing. Background Art

[0002] Perovskite solar cells have excellent optoelectronic properties, such as strong light capture ability, long carrier diffusion length, high defect tolerance, and low production cost, and are expected to become a commercial net zero carbon emission energy source. However, the inherent stability problems caused by ion migration have seriously hindered the further performance development and large-scale commercial production of perovskite solar cells.

[0003] In recent years, there have been new developments in the study of ion migration. At present, there are many characterization methods for ion migration, such as SEM (scanning electron microscope), XPS (X-ray electron spectroscopy) and photothermal induced resonance (PTIR) microscopy in microscopic characterization, which can directly observe the phenomenon of ion migration; time-resolved photoluminescence spectroscopy (TRPL) technology in optical characterization can determine the increase or decrease of ion migration; electrochemical impedance spectroscopy (EIS) and thermal admittance spectroscopy (TAS) in electrical characterization can analyze and calculate the conductivity and activation energy of ion migration. However, at present, including the above-mentioned characterization methods, the existing characterization technology still cannot make a reliable quantitative analysis of the most basic parameter of ion migration - the amount of ion migration. Obviously, if this problem can be solved, it will play a vital role in further studying ion migration. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method and system for quantifying the amount of charge related to ion migration, which extracts the photogenerated carriers of the perovskite solar cell sample to be tested by a homemade switch, thereby realizing quantitative analysis of the amount of ion migration.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a system for quantitatively measuring the amount of charge associated with ion migration, comprising:

[0007] Delay generator, homemade switch, steady-state light source device and oscilloscope;

[0008] The delay generator is used to control the self-made switch, the steady-state light source device and the oscilloscope according to a preset timing sequence;

[0009] The steady-state light source device is used to provide steady-state light according to the control signal to irradiate the perovskite solar cell sample to be tested, so that it generates photogenerated carriers;

[0010] The self-made switch is used to extract charge from the perovskite solar cell sample to be tested according to the control signal;

[0011] The oscilloscope is used to display real-time waveforms and store data of each test cycle according to a control signal so as to perform quantitative analysis on the charge quantity.

[0012] Further, the steady-state light source device includes a laser, a filter and a reflector;

[0013] The laser is used to provide a steady-state light source according to the control signal of the delay generator;

[0014] The filter is used to adjust the intensity of the laser emitted by the laser;

[0015] The reflector is used to adjust the laser path so that the laser can irradiate the perovskite solar cell sample to be tested placed on the sample device rack at a preset angle, so as to generate photogenerated carriers.

[0016] Furthermore, the laser is a modulated continuous semiconductor laser or a programmable modulated semiconductor laser.

[0017] Furthermore, the filter is a neutral density filter.

[0018] Furthermore, an oscilloscope and a homemade switch are connected in parallel at both ends of the positive and negative electrodes of the perovskite solar cell sample to be tested.

[0019] Furthermore, the homemade switch includes a first branch and a second branch, the first branch is provided with a first switch and a first diode, the output end of the first switch is connected to the positive electrode of the perovskite solar cell sample to be tested, the common end is connected to the negative electrode of the perovskite solar cell sample to be tested, and the input end is connected to the delay generator; the second branch has the same structure as the first branch.

[0020] In a second aspect, the present invention provides a method for using a system for quantitatively measuring the amount of charge associated with ion migration, comprising the following steps:

[0021] Set the oscilloscope internal resistance to 1MΩ to simulate an open circuit condition;

[0022] The steady-state light source device is controlled by a time delay generator to emit laser light to illuminate the perovskite solar cell sample to be tested, so as to generate photogenerated carriers;

[0023] When the preset conditions are met, the steady-state light source device is controlled by the delay generator to stop emitting laser light;

[0024] The self-made switch is controlled to close by a delay generator, so that the photogenerated carriers on the perovskite solar cell sample to be tested are transmitted to the external circuit until all the carriers are extracted to the external circuit;

[0025] After the photovoltage signal has decayed, the delay generator is used to control the homemade switch to disconnect until the oscilloscope detects the voltage recovery signal.

[0026] Furthermore, the preset condition is that the photovoltage of the perovskite solar cell sample to be tested reaches a stable value.

[0027] The present invention adopts the above technical solution, which has the following advantages:

[0028] 1. Realize quantitative ion migration characterization: The present invention realizes quantitative analysis of the number of ion migration by extracting the carriers captured by ions, filling the gap in the characterization method of this important parameter.

[0029] 2. Simultaneous quantitative characterization of free carriers: Since free carriers are not affected by ion migration and will be extracted first, the present invention can complete the extraction of free carriers and ion-trapped carriers at one time, distinguish them, and perform quantitative analysis separately.

[0030] 3. High sensitivity and accuracy: The present invention utilizes a 400M oscilloscope (voltage resolution up to microvolts, time resolution up to picoseconds) to perform time-resolved charge extraction testing, which has high sensitivity and accuracy and can accurately analyze the dynamic behavior of different types of carriers.

[0031] 4. Repeatability and reliability: The present invention ensures the repeatability of the experiment and the reliability of the data through detailed experimental methods and data processing procedures, providing a scientific basis for material research and performance optimization.

[0032] Therefore, the present invention can be widely applied to the field of ion migration testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0034] Figure 1 : is a system structure diagram for quantitative ion migration related charge quantity provided by an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the structure of a self-made switch provided by an embodiment of the present invention;

[0036] Figure 3 It is a complete experimental waveform diagram provided by an embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of free carriers provided by an embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of ion-trapped carriers provided by an embodiment of the present invention;

[0039] Figure 6 According to an embodiment of the present invention, the corresponding carrier integrated quantity can be obtained by integrating two carrier extraction curves respectively. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] In some embodiments of the present invention, a system for quantitatively analyzing the amount of charge associated with ion migration is provided. The system achieves quantitative analysis of the amount of ion migration by extracting carriers captured by ions.

[0043] Correspondingly, in some other embodiments of the present invention, a method for quantifying the amount of charge associated with ion migration is provided.

[0044] Example 1

[0045] like Figure 1As shown, the present invention provides a system for quantitatively measuring the charge quantity related to ion migration, which is used to detect the carrier and ion dynamics of the device under continuous light irradiation. Specifically, it includes: a delay generator, a homemade switch, a steady-state light source device and an oscilloscope. Among them, the delay generator is used to control the homemade switch, the steady-state light source device and the oscilloscope according to a preset timing; the steady-state light source device is used to provide steady-state light to irradiate the perovskite solar cell sample to be tested according to a control signal, so that it generates photogenerated carriers; the homemade switch is used to extract charge from the perovskite solar cell sample to be tested according to the control signal; the oscilloscope is used to display the real-time waveform and store the data of each test cycle according to the control signal.

[0046] Furthermore, the steady-state light source device includes a laser, a filter and a reflector. The laser is used to provide a steady-state light source according to the control signal of the delay generator; the filter is used to adjust the intensity of the laser emitted by the laser; and the reflector is used to adjust the laser path so that the laser can irradiate the perovskite solar cell sample to be tested placed on the sample device frame at a preset angle (for example, a vertical angle) to generate photogenerated carriers.

[0047] Furthermore, the laser adopts a modulated continuous semiconductor laser or a programmable modulated semiconductor laser.

[0048] Furthermore, the filter is a neutral density filter.

[0049] Furthermore, an oscilloscope and a homemade switch are connected in parallel to the positive and negative terminals of the perovskite solar cell sample to be tested.

[0050] Furthermore, if Figure 2 As shown, the self-made switch contains a 50Ω parallel branch. Specifically, it includes a first branch and a second branch. The first branch is provided with a first switch and a first diode, and the input end (IN1) of the first switch is connected to the delay generator, and the output end (NO1) and the common end are respectively connected to the positive and negative electrodes of the perovskite solar cell sample to be tested. The second branch has the same structure as the first branch and is used as a backup for the first branch. The present invention will not be repeated here.

[0051] In this embodiment, the two ends of the 50Ω resistor in the homemade switch are connected to the positive and negative electrodes of the device respectively, and the passage will only occur when the delay generator sends a signal. At this time, since the 50Ω resistor is extremely small, the carriers will be quickly transmitted to the external circuit and finally recombine. From the original 1MΩ to 50Ω, the carrier transmission rate is greatly accelerated. The data shows that the steady-state photovoltage will drop from nearly 1V to several mV within a few μs. It can be considered that this process is similar to charge extraction.

[0052] Example 2

[0053] Based on a system for quantitatively measuring the amount of charge associated with ion migration provided in Example 1, this embodiment provides a method for using the system for quantitatively measuring the amount of charge associated with ion migration, which includes the following steps:

[0054] 1) Simulate open circuit: Set the internal resistance of the oscilloscope to 1MΩ to simulate open circuit conditions.

[0055] 2) Laser illumination: The steady-state light source device is controlled by a time delay generator to emit laser light to illuminate the perovskite solar cell sample to be tested, generating photogenerated carriers for a period of time until a stable maximum photovoltage is reached (which can be determined by observing an oscilloscope).

[0056] 3) Remove the laser: The steady-state light source device is controlled by the delay generator to stop emitting the laser. At this time, the perovskite solar cell sample to be tested no longer generates new photogenerated carriers, and the photovoltage is about to begin to decay.

[0057] 4) Charge extraction: The 50Ω branch of the homemade switch is closed by controlling the delay generator, so that the photogenerated carriers on the perovskite solar cell sample to be tested are quickly transmitted to the external circuit, simulating the charge extraction situation. The photovoltage (actually the photocurrent signal) decays rapidly until all carriers are extracted to the external circuit.

[0058] 5) Open circuit recovery: After the photovoltage signal has decayed, the 50Ω branch of the homemade switch is disconnected using a delay generator. At this time, the circuit is restored to an open circuit state, and a weak voltage recovery signal appears, which is used to evaluate the completion of the extraction of ion-trapped carriers.

[0059] Example 3

[0060] like Figure 3 The following is a complete experimental waveform diagram. Figure 3 In the figure, when t is greater than 0.9s, a voltage recovery signal appears, and the voltage rises again from 0mV. This is because after the open circuit is restored, some ion-trapped carriers that have not been extracted due to slow migration accumulate again at the interface between the transport layer and the perovskite layer, forming a potential difference. The size of this recovery voltage can be used to evaluate the completion of the extraction of ion-trapped carriers. If its size is less than about 5% of the steady-state photovoltage, it can be considered that the ion-trapped carriers have been completely extracted (even if the extraction time of the remaining slowly migrating ion-trapped carriers is increased several times, it is difficult to completely extract them, that is, there is still a voltage recovery signal), so restoring the open circuit and obtaining the voltage recovery signal is conducive to accurately evaluating the completion of the extraction of ion-trapped carriers and increasing the credibility of the test method.

[0061] like Figure 4 and Figure 5As shown in Figure 1, the raw charge extraction data contains two types of carriers. Since ion-trapped carriers require a certain amount of de-trapping time, their extraction rate is much slower than that of free carriers. Figure 4 and Figure 5 is obtained at different voltage and time window sizes. Figure 4 The time scale is in microseconds. Figure 5 It is on the order of milliseconds to seconds, so it is easy to distinguish the two on the time scale.

[0062] like Figure 6 As shown, the corresponding carrier integrated charge can be obtained by integrating the two carrier extraction curves respectively.

[0063] Current research shows that ion migration will capture carriers. Therefore, the integrated charge of ion-captured carriers has a strong direct correlation with the amount of ion migration. Therefore, this test method achieves quantitative characterization of ion migration.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A system for quantitatively measuring the amount of charge associated with ion migration, characterized in that: include: Delay generator, homemade switch, steady-state light source device and oscilloscope; The delay generator is used to control the self-made switch, the steady-state light source device and the oscilloscope according to a preset timing sequence; The steady-state light source device is used to provide steady-state light according to the control signal to irradiate the perovskite solar cell sample to be tested, so that it generates photogenerated carriers; The self-made switch is used to extract charge from the perovskite solar cell sample to be tested according to the control signal; The oscilloscope is used to display real-time waveforms and store data of each test cycle according to a control signal so as to perform quantitative analysis on the charge quantity.

2. A system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 1, characterized in that: The steady-state light source device comprises a laser, a filter and a reflector; The laser is used to provide a steady-state light source according to the control signal of the delay generator; The filter is used to adjust the intensity of the laser emitted by the laser; The reflector is used to adjust the laser path so that the laser can irradiate the perovskite solar cell sample to be tested placed on the sample device rack at a preset angle, so as to generate photogenerated carriers.

3. A system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 2, characterized in that: The laser is a modulated continuous semiconductor laser or a program-controlled modulated semiconductor laser.

4. A system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 2, characterized in that: The filter is a neutral density filter.

5. A system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 1, characterized in that: The oscilloscope and the homemade switch are connected in parallel to the positive and negative terminals of the perovskite solar cell sample to be tested.

6. A system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 1, characterized in that: The self-made switch includes a first branch and a second branch, the first branch is provided with a first switch and a first diode, the output end of the first switch is connected to the positive electrode of the perovskite solar cell sample to be tested, the common end is connected to the negative electrode of the perovskite solar cell sample to be tested, and the input end is connected to the delay generator; the second branch has the same structure as the first branch.

7. A method for using the system for quantitatively measuring the amount of charge associated with ion migration as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Set the oscilloscope internal resistance to 1MΩ to simulate an open circuit condition; The steady-state light source device is controlled by a time delay generator to emit laser light to illuminate the perovskite solar cell sample to be tested, so as to generate photogenerated carriers; When the preset conditions are met, the steady-state light source device is controlled by the delay generator to stop emitting laser light; The self-made switch is controlled to close by a delay generator, so that the photogenerated carriers on the perovskite solar cell sample to be tested are transmitted to the external circuit until all the carriers are extracted to the external circuit; After the photovoltage signal has decayed, the delay generator is used to control the homemade switch to disconnect until the oscilloscope detects the voltage recovery signal.

8. The method for using the system for quantitatively measuring the amount of charge associated with ion migration as claimed in claim 7, characterized in that: The preset condition is that the photovoltage of the perovskite solar cell sample to be tested reaches a stable value.

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