Nanosecond time-resolved electrical excitation transient spectrum system for researching laminated photoelectric device

Abstract

The invention relates to a nanosecond time-resolved electrical excitation transient spectrum system for researching a laminated photoelectric device, and belongs to the technical field of transient absorption spectra. The transient spectrum acquisition part utilizes a signal generator to output a pulse voltage signal to trigger a photoelectric device, and acquires spectrum information in combination with elements such as a continuous white light source and a spectrograph to determine a proper wavelength; and the carrier dynamics detection part realizes research on carrier injection, migration, recombination and dynamics processes by verifying the carrier injection unit, the transient current acquisition unit and the transient photodynamics acquisition unit. The system has the advantages of being low in system building cost, high in operation stability and integration, capable of conducting multi-parameter collaborative analysis, low in light path complexity and convenient to calibrate and maintain, can be used for studying the transfer, transmission and recombination processes of carriers in photoelectric devices such as perovskite solar cells, and has great significance in understanding the working principle of the photoelectric devices and improving the performance.

Description

Technical Field

[0001] The invention belongs to the technical field of transient absorption spectroscopy, and in particular relates to a nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked photoelectric devices. Background Art

[0002] With the rapid development of human society and the rapid increase in productivity, the demand for energy is becoming increasingly enormous. However, traditional fossil energy is not only limited in reserves and non-renewable, but also comes with significant environmental pollution. In particular, the carbon dioxide emissions caused by the consumption of traditional fossil energy have led to a series of climate problems such as global warming and increased extreme weather. Therefore, in recent years, governments around the world have increasingly focused on the development of new renewable energy sources to replace traditional fossil energy, which has led to the rapid development of the photovoltaic industry. The rapid development of the photovoltaic industry is inseparable from the rapid development of solar cells, its most basic device, in recent decades. In order to obtain a new generation of solar cells with low cost, high efficiency and good stability, people have conducted in-depth research on third-generation solar cells, including dye-sensitized solar cells, quantum dot solar cells, organic solar cells and perovskite solar cells.

[0003] Among these third-generation solar cells, perovskite solar cells have become a research hotspot in recent years due to their rapid increase in photoelectric conversion efficiency in just a few years and their relatively low manufacturing costs. The carrier relaxation process is a key factor influencing their performance. Longer carrier lifetimes and faster carrier transfer contribute to improved photoelectric conversion efficiency. Therefore, the study of ultrafast carrier dynamics in perovskites is crucial.

[0004] A common approach to studying carrier dynamics in perovskite solar cells is to use time-resolved spectroscopy to directly capture the series of ultrafast microscopic physical processes occurring in materials after light excitation. Examples include pump-probe transient absorption spectroscopy, ultrafast fluorescence upconversion, and ultrafast terahertz spectroscopy. Ultrafast fluorescence upconversion captures information about the luminescent state, while transient absorption spectroscopy not only reveals the luminescent state but also the dark state and transient products of photoreactions. Optically pumped terahertz detection measures the transient dielectric properties of semiconductors and their variations. These techniques have time resolutions ranging from nanoseconds to picoseconds, with higher resolutions correspondingly shortening the measurable time window.

[0005] Although time-resolved spectroscopy has made significant progress, the following bottlenecks still exist in practical applications.

[0006] 1. The contradiction between temporal resolution and sensitivity. For example, although femtosecond pump-probe technology (transient absorption technology) can achieve high temporal resolution, it is limited by the laser pulse width and detector response speed, resulting in a low signal-to-noise ratio for weak signals. 2. Lack of multi-parameter collaborative analysis. For example, existing technologies typically only measure a single optical response (such as absorption or fluorescence), making it difficult to simultaneously obtain multi-dimensional dynamic information such as carrier concentration, energy relaxation, and transport properties. 3. The system is complex and costly. For example, core components such as ultrafast laser sources (such as titanium sapphire lasers) and high-precision delay lines are expensive and require complex optical path calibration and stability control. Summary of the Invention

[0007] The present invention provides a nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices. The system is used to study the carrier dynamics process in optoelectronic devices. It aims to solve the problems of poor system integration (poor multi-parameter collaborative analysis), high system complexity, and expensive equipment when using traditional time-resolved spectroscopy technology to study the carrier transfer, transmission, and recombination processes in optoelectronic devices.

[0008] The technical solution adopted by the present invention is to include a transient spectrum measurement part and a carrier dynamics detection part, wherein the transient spectrum measurement part includes a continuous white light source, a spectrometer, a signal generator and an optical element. The signal generator outputs a pulse voltage signal to trigger the photoelectric device. The continuous white light source irradiates the photoelectric device through the optical element. The light reflected by the photoelectric device enters the spectrometer through the optical element, and the spectral information is then sent to a computer. The carrier dynamics detection part includes a verification carrier injection unit, a transient current collection unit and a transient photodynamic collection unit, wherein the verification carrier injection unit includes a signal generator outputting a pulse voltage signal to an oscilloscope, a continuous white light source irradiating the photoelectric device, the light reflected by the photoelectric device passing through a monochromator, and collected into a high-speed photodetector, and the waveform is displayed on the oscilloscope, and then the pulse voltage signal output by the signal generator is applied to both ends of the photoelectric device, the light reflected by the photoelectric device is collected into a high-speed photodetector, and displayed on the oscilloscope; The transient current acquisition unit applies the pulse voltage output by the signal generator to both ends of the photoelectric device, connects a resistor in series between the signal generator and the photoelectric device, and samples the transient photocurrent signal at both ends of the resistor through an oscilloscope; The transient photodynamic acquisition unit applies the pulse voltage output by the signal generator to both ends of the photoelectric device. The light reflected by the photoelectric device passes through the monochromator and then enters the high-speed photodetector. The electrical signal is displayed on the oscilloscope.

[0009] The optical elements include silver mirror 1, silver mirror 2, lens 1, lens 2, beam splitter, lens 3, silver mirror 3 and lens 4, wherein a continuous white light source outputs a beam of broad-spectrum white light, which is reflected by silver mirror 1 and silver mirror 2, and then converged onto the photoelectric device through lens 1. The photoelectric device then reflects the white light, and the reflected light is converged onto the beam splitter through lens 2. 50% of the light passes through the beam splitter and reaches silver mirror 3, and is reflected by silver mirror 3 onto lens 4, and then converged by lens 4 into the monochromator. The remaining 50% of the light is reflected by the beam splitter onto lens 3, and is converged by lens 3 into the spectrometer.

[0010] The electrical signal generated by the high-speed photodetector is connected to the oscilloscope through a preamplifier.

[0011] The electrical signal generated by the high-speed photodetector is also output to a lock-in amplifier, and the electrical signal is output to a computer.

[0012] The high-speed photodetector contains a photomultiplier tube to convert the optical signal into an electrical signal.

[0013] The light-emitting electric device adopts a perovskite solar cell.

[0014] The continuous white light source is replaced with a laser of optimal wavelength.

[0015] A 532nm green laser is used to replace the continuous white light source and is used as the light source for studying transient photodynamic processes.

[0016] The method for systematically studying the carrier dynamics process of a stacked optoelectronic device using the present invention comprises the following steps: The first step is to measure the transient spectrum: First, the signal generator outputs a pulsed electrical signal with a low level of 0V and a high level of 1V. This signal is transmitted to the photoelectric device through a resistor. At the same time, the continuous white light source outputs a beam of broadband white light. The white light is reflected by silver mirrors 1 and 2, and then converged by lens 1 onto the photoelectric device. The photoelectric device reflects this white light, which is then converged by lens 2 onto the beam splitter. 50% of the light passes through the beam splitter and reaches silver mirror 3. The remaining 50% of the light is reflected by the beam splitter and converged by lens 3 into the spectrometer. Finally, the data in the spectrometer is sent to a computer. For spectral data, pulse voltage is used to excite the photoelectric device and induce differential spectroscopy, and the spectral data is integrated and analyzed through differential spectroscopy; The second step is to verify carrier injection: When the signal generator outputs 0V, that is, no electrical excitation is applied to the photoelectric device, the light reflected by the photoelectric device passes through lens 2 and the beam splitter to reach silver mirror 3, and is reflected by silver mirror 3 to lens 4. Then, it is converged by lens 4 to the monochromator. The reflected light passes through the monochromator and finally reaches the photomultiplier tube of the high-speed photodetector. The optical signal is converted into an electrical signal, and then the electrical signal is connected to the oscilloscope through the preamplifier. At this time, the waveform displayed by the oscilloscope is a steady-state electrical signal of continuous white light. The electrical signal generated by the high-speed photodetector is also output to the lock-in amplifier, which displays the amplitude of the electrical signal and outputs the electrical signal to the computer. When the signal generator outputs a pulse voltage, that is, when electrical excitation is applied to the photoelectric device, the above steps are still performed. At this time, the waveform displayed on the oscilloscope is the changing electrical signal generated by the continuous white light. In order to ensure the timing synchronization of the lock-in amplifier and oscilloscope in detecting the electrical signal, a signal generator is used to synchronously trigger the lock-in amplifier and oscilloscope; In order to see the obvious difference of the electrical signal on the oscilloscope, the pulse voltage signal output by the signal generator is output to the oscilloscope; The third step is transient current acquisition: the signal generator outputs a pulse voltage, which is output to the photoelectric device through a resistor. One port of the oscilloscope is connected to both ends of the resistor to sample the transient current signal at both ends of the resistor. The waveform displayed on the oscilloscope at this time is the transient photocurrent curve. In order to clearly see the attenuation change of the transient photocurrent curve, the pulse voltage output by the signal generator is displayed on the oscilloscope. Therefore, when doing the transient current acquisition experiment, two waveforms are displayed on the oscilloscope; The fourth step is transient photodynamics acquisition: first, the signal generator outputs a pulse voltage signal, which is applied to the photoelectric device through a resistor. Secondly, after the first step of transient spectrum measurement is completed, the optimal wavelength range reflecting the carrier dynamics process is obtained. After determining the optimal wavelength range for studying carrier dynamics, the continuous white light source is replaced with a green laser with the optimal wavelength; the green laser is used as the light source for studying transient photodynamics. The green laser emits a beam of green light, which is reflected by silver mirror one and silver mirror two, and then converged to the photoelectric device through lens one. The photoelectric device then reflects this green light, and this reflected light is converged to the beam splitter through lens two, and 50% of the light passes through the beam splitter to reach silver mirror three, and the other 5 0% of the light is reflected by the beam splitter to lens three, and is converged by lens three into the spectrometer. The reflected green light that reaches silver mirror three is then converged by lens four and reaches the monochromator. The green light emitted by the monochromator is incident on the high-speed photodetector. At this time, the reflected light signal is converted into an electrical signal, which is connected to the preamplifier. At this time, the amplitude of the electrical signal is amplified. The electrical signal amplified by the preamplifier is connected to the oscilloscope through the circuit. Then, the oscilloscope's multiple averaging and accumulation function is used to accumulate and average the obtained electrical signal waveform for about 20,000 times, and finally the carrier dynamics curve under pulse voltage excitation can be obtained; the electrical signal generated by the high-speed photodetector is also output to the phase-locked amplifier to display the amplitude of the electrical signal, and the electrical signal is output to the computer; By changing the pulse voltage amplitude output by the signal generator and performing the above operations, the carrier dynamics curves under different pulse voltages can be obtained.

[0017] In order to clearly see the carrier dynamics curve, two waveforms were finally selected to be displayed on the oscilloscope, namely the transient photocurrent curve obtained in the third step and the carrier dynamics curve obtained in the fourth step.

[0018] The advantages of the present invention are: 1. The system features low construction cost, high operational stability, excellent adjustability, and ease of use. It innovatively utilizes electrical pulses to excite optoelectronic devices. Conventional time-resolved spectroscopy utilizes optical pulses for excitation, requiring lasers to generate these pulses. While optical pulses offer picosecond temporal resolution, the associated laser equipment is extremely expensive. This system utilizes a continuous white light source to illuminate the surface of optoelectronic devices (such as LEDs and solar cells). This system can obtain spectral information induced by electron injection into the devices. This spectral information (relative transmittance -ΔT / T and relative reflectance ΔR / R) is combined to determine an appropriate wavelength, which is then used to reflect electron injection and recombination in the devices. Ultimately, a transient dynamics curve is generated for the devices. This information allows the excitation and recovery times of carriers in the devices under electrical excitation to be studied. This approach is primarily used to investigate carrier dynamics in perovskite solar cells, operating on a nanosecond timescale. Using a signal generator to generate electrical pulses also allows for nanosecond temporal resolution. Furthermore, electrical excitation is less susceptible to interference from ambient temperature and humidity. Therefore, this system not only greatly saves the cost of experimental equipment (about 1 / 10 of traditional equipment), but also improves the stability of system operation.

[0019] 2. The system is highly integrated, enabling multi-parameter collaborative analysis and saving experimental testing time. This system integrates transient spectroscopy measurements and carrier dynamics curve testing into a single optical path. This enables multi-parameter collaborative analysis, allowing for more accurate and rapid research into the transfer, transmission, and recombination processes of carriers within optoelectronic devices (perovskite solar cells). Using traditional time-resolved spectroscopy to study carrier dynamics often requires multiple optical systems, requiring experimenters to perform spectral measurements and dynamics curve testing sequentially. This significantly increases experimental time and costs, and due to time synchronization issues, results in poor multi-parameter collaborative analysis, which may also increase uncontrollable experimental variables. Furthermore, the improved system integration simplifies the optical path calibration process, saving labor time and costs.

[0020] 3. The system's optical path complexity is low. Traditional time-resolved spectroscopy techniques for studying carrier dynamics in perovskite solar cells require optical components such as beam splitters, optical delay lines, frequency-doubling crystals, and optical parametric amplifiers. This complexity makes equipment calibration and maintenance cumbersome. This system utilizes electrical pulse excitation, eliminating these optical components and significantly simplifying the system's optical path complexity. This system offers advantages such as rapid calibration, easy troubleshooting, and high environmental adaptability.

[0021] The present invention can be used in the following fields.

[0022] Photovoltaic device R&D optimization: Optimize the carrier lifetime and transmission efficiency of perovskite cells; accurately quantify the impact of ion migration and defect states on carrier lifetime to guide passivation layer design.

[0023] Assist in the development of new optoelectronic devices: In photodetector research, it can characterize carrier tunneling time, analyze dark current suppression effects, and optimize response speed.

[0024] Expanding industrial applications: Researching device aging, combining environmental chambers, and analyzing the evolution of carrier recombination paths during accelerated aging tests to predict the service life of industrial devices.

[0025] Interdisciplinary application: In artificial photosynthetic systems, optimize the carrier injection efficiency of photocatalytic electrodes and improve solar energy conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the present invention; Figure 2 is the induced difference spectrum; Figure 3 It is a signal diagram to verify the carrier injection; Figure 4 is the transient photocurrent signal diagram; Figure 5 is the carrier dynamics signal diagram. DETAILED DESCRIPTION

[0027] See also Figure 1 , including a transient spectrum measurement part and a carrier dynamics detection part, wherein the transient spectrum measurement part includes a continuous white light source 1, a spectrometer 9, a signal generator 18 and an optical element, the signal generator 18 outputs a pulse voltage signal to trigger the photoelectric device 5, inducing the photoelectric device to change, the continuous white light source 1 is irradiated onto the photoelectric device 5 through the optical element, the light reflected by the photoelectric device 5 enters the spectrometer 9 through the optical element, and the spectrum information is then sent to the computer 15; the carrier dynamics detection part includes a verification carrier injection unit, a transient current acquisition unit and a transient photodynamics acquisition unit, wherein the verification carrier injection unit includes a signal generator 18 output A pulse voltage signal is input into an oscilloscope 16 and is referred to as waveform 1. A continuous white light source 1 is irradiated onto a photoelectric device 5. The light reflected from the photoelectric device 5 is collected by a monochromator 12 and into a high-speed photodetector 13. The optical signal is converted into an electrical signal and displayed on the oscilloscope 16 as waveform 2. A pulse voltage signal output by a signal generator 18 is then applied to both ends of the photoelectric device 5. The light reflected from the photoelectric device 5 is collected into a high-speed photodetector 13 and displayed on the oscilloscope 16. It is found that the electrical signal of the light reflected from the continuous white light source 1 onto the photoelectric device 5 changes (i.e., waveform 2 changes), indicating the presence of a carrier injection signal. The transient current acquisition unit applies the pulse voltage output by the signal generator 18 to both ends of the photoelectric device 5, connects a resistor 19 in series between the signal generator 18 and the photoelectric device 5, and samples the transient photocurrent signal across the resistor 19 through the oscilloscope 16; the migration and recombination of carriers can be analyzed in combination with the transient photocurrent curve; The transient photodynamic acquisition unit applies the pulse voltage output by the signal generator 18 to both ends of the photoelectric device 5. The light reflected by the photoelectric device 5 passes through the monochromator 12 and then enters the high-speed photodetector 13. The electrical signal is displayed on the oscilloscope 16. After multiple accumulation and averaging, the oscilloscope 16 obtains the dynamic curve.

[0028] The optical elements include silver mirror 1 2, silver mirror 2 3, lens 1 4, lens 2 6, beam splitter 7, lens 3 8, silver mirror 3 10 and lens 4 11, wherein the continuous white light source 1 outputs a beam of wide-spectrum white light, which is reflected by silver mirror 1 2 and silver mirror 2 3, and then converged onto the photoelectric device 5 through lens 1 4. The photoelectric device 5 then reflects the white light, and the reflected light is converged onto the beam splitter 7 through lens 2 6. 50% of the light passes through the beam splitter and reaches silver mirror 3 10, and is reflected by silver mirror 3 10 onto lens 4 11, and then converged by lens 4 11 into the monochromator 12. The other 50% of the light is reflected by the beam splitter to lens 3 8, and is converged by lens 3 8 into the spectrometer 9.

[0029] The electrical signal generated by the high-speed photodetector 13 is connected to the oscilloscope 16 through the preamplifier 17.

[0030] The electrical signal generated by the high-speed photodetector 13 is also output to the lock-in amplifier 14 , and the electrical signal is output to the computer 15 .

[0031] The high-speed photodetector 13 contains a photomultiplier tube to convert the optical signal into an electrical signal.

[0032] The light-emitting device 5 is a perovskite solar cell.

[0033] The continuous white light source 1 is replaced with a laser of optimal wavelength.

[0034] A 532nm green laser is used to replace the continuous white light source 1, and the green laser is used as the light source for studying transient photodynamic processes.

[0035] How the system works The transient spectroscopy diagnostic system provided by the present invention uses electric pulse excitation instead of traditional light pulse excitation, and combines transient spectroscopy with dynamic analysis to study the carrier dynamics process of optoelectronic devices (such as perovskite solar cells).

[0036] Spectral measurement: During the spectral measurement stage, we use continuous white light to illuminate the device and use a spectrometer to collect the difference spectrum of the reflected light before and after the electric pulse excitation to determine the optimal wavelength of the carrier response.

[0037] Detection of dynamic processes: During the detection of dynamic processes, the first step is to confirm whether carrier injection has occurred by comparing the changes in the electrical signal of the reflected light when there is an electrical pulse or not. Secondly, a resistor is connected in series with the photoelectric device, and the transient photocurrent signal at both ends of the resistor is sampled by an oscilloscope to obtain a curve that can reflect the separation and recombination of carriers in the photoelectric device. Finally, the white light source is replaced by a laser with an optimal wavelength. The light reflected by the photoelectric device passes through a monochromator and a photomultiplier tube and is finally displayed on an oscilloscope. The oscilloscope is used to accumulate and average the reflected signal waveform for about 20,000 times to obtain the carrier dynamics decay curve.

[0038] The method for studying the carrier dynamics of a photovoltaic device (such as a perovskite solar cell) using the system of the present invention comprises the following steps: The first step is to measure the transient spectrum: first, the signal generator 18 outputs a pulse electrical signal with a low level of 0V and a high level of 1V. This signal is transmitted to the optoelectronic device 5 (such as a perovskite solar cell) through the resistor 19, thereby applying electrical excitation to the optoelectronic device 5. At the same time, the continuous white light source 1 outputs a beam of broadband white light, which is reflected by the silver mirror 1 2 and the silver mirror 2 3, and then converged onto the optoelectronic device 5 through the lens 1 4. The optoelectronic device 5 then reflects this beam of white light, which is then converged onto the beam splitter 7 through the lens 2 6, and 50% of the light passes through the beam splitter to reach the silver mirror 3 10. The remaining 50% of the light is reflected by the beam splitter to the lens 3 8, and then converged by the lens 3 8 to the spectrometer 9. Finally, the data in the spectrometer 9 is sent to the computer 15. After the above steps, the measurement of the transient spectrum is completed. For spectral data, pulse voltage is used to stimulate the photoelectric device and induce differential spectroscopy, and the spectral data is integrated and analyzed through differential spectroscopy. The specific ideas are as follows, Figure 2 As shown: Figure 2 In (a), the horizontal axis is time T, and the vertical axis is voltage U. The dotted line indicates no voltage is applied, and the solid line indicates a constant voltage of 1 V is applied. At 0 V (i.e., no electrical excitation is applied to the photoelectric device), the reflection spectrum of the continuous white light source is collected to obtain the spectrum without electrical excitation, as shown in Figure 1. Figure 2 The spectrum S1 presented in (b) is shown in Figure 1. The horizontal axis is the wavelength λ and the vertical axis is the relative transmittance -ΔT / T. When the pulse voltage excites the optoelectronic device, it induces its spectrum to change, and the spectrum under applied electrical excitation is obtained, as shown in Figure 1. Figure 2 The spectrum S2 presented in (b) is shown in Figure 1. By making a difference ΔS=S2-S1, we can get the difference spectrum, as shown in Figure 1. Figure 2The spectrum ΔS shown in (c) is shown in Figure 1. Differential spectroscopy differentially amplifies the target signal and removes background interference, making it suitable for studying subtle changes in complex systems. The horizontal axis of the differential spectral data is wavelength, and the vertical axis is relative transmittance -ΔT / T. The spectrum shows the wavelength at which the relative transmittance -ΔT / T is maximum. This wavelength is called the optimal wavelength, reflecting information about carrier injection and recombination in the optoelectronic device. This optimal wavelength will be used as the light source wavelength in the fourth step to excite the optoelectronic device and obtain the carrier dynamics curve in the optoelectronic device.

[0039] The second step is to verify carrier injection: when the signal generator 18 outputs a voltage of 0V, that is, no electrical excitation is applied to the photoelectric device, the light reflected by the photoelectric device 5 passes through the lens 2 6 and the beam splitter 7 to reach the silver mirror 3 10, and is reflected by the silver mirror 3 10 to the lens 4 11, and then converged by the lens 4 11 to the monochromator 12; the reflected light passes through the monochromator 12 and finally reaches the photomultiplier tube of the high-speed photodetector 13, and the optical signal is converted into an electrical signal; the electrical signal is then connected to the oscilloscope 16 through the preamplifier 17, and the waveform displayed by the oscilloscope is a steady-state electrical signal of continuous white light; the electrical signal generated by the high-speed photodetector 13 is also output to the lock-in amplifier 14, which greatly reduces the noise background of the electrical signal, displays the amplitude of the electrical signal, and outputs the electrical signal to the computer 15; When the signal generator 18 outputs a pulse voltage, that is, applies electrical excitation to the photoelectric device, the above steps are still performed. At this time, the waveform displayed on the oscilloscope is the changing electrical signal generated by the continuous white light; In order to ensure the timing synchronization of the lock-in amplifier 14 and the oscilloscope 16 in detecting the electrical signal, the signal generator 18 is used to synchronously trigger the lock-in amplifier and the oscilloscope; In order to see the obvious difference of the electrical signal on the oscilloscope, the pulse voltage signal output by the signal generator 18 is output to the oscilloscope 16 as shown in FIG. Figure 3 The curve (1) in .

[0040] In summary, three waveforms are displayed on the oscilloscope, with the horizontal axis representing time T and the vertical axis representing voltage U. They are the pulse voltage signals output by the signal generator 18, as shown in Figure 2. Figure 3 Curve (1) in FIG. 1 ; the steady-state electrical signal generated by the light reflected by the photoelectric device is as follows: Figure 3 Curve (2) in the figure; after applying electrical excitation, the changing electrical signal generated by the light reflected by the photoelectric device is as follows Figure 3 The light reflected by the photoelectric device generates a changing electrical signal, which just proves that carrier injection has occurred in the photoelectric device.

[0041] The third step is transient current acquisition: the signal generator 18 outputs a pulse voltage, which is output to the photoelectric device 5 through the resistor; one port of the oscilloscope is connected to both ends of the resistor 19, and the transient current signal at both ends of the resistor is sampled. At this time, the waveform displayed on the oscilloscope 16 is the transient photocurrent curve, that is, Figure 4 The curve (2) in FIG. 1 is shown in FIG. 1 , where the horizontal axis is time T and the vertical axis is voltage U. The transient photocurrent curve can reflect the charge separation efficiency and recombination loss of the photoelectric device (perovskite solar cell) 5. Secondly, in order to clearly see the attenuation change of the transient photocurrent curve, the pulse voltage output by the signal generator 18 is displayed on the oscilloscope 16, as shown in FIG. Figure 4 The curve (1) in the figure shows that the horizontal axis is time T and the vertical axis is voltage U. Therefore, when doing the transient current acquisition experiment, two waveforms are displayed on the oscilloscope, namely the transient photocurrent waveform and the transient photocurrent waveform. Figure 4 Curve (2) in the figure; and the pulse voltage waveform is Figure 4 The curve (1) in .

[0042] The fourth step is transient photodynamics acquisition: first, the signal generator 18 outputs a pulse voltage signal, which is applied to the photoelectric device 5 through the resistor 19; secondly, after the first step of transient spectrum measurement is completed, the optimal wavelength range reflecting the carrier dynamics process is obtained. After determining the optimal wavelength range for studying carrier dynamics, the continuous white light source 1 is replaced with a laser with the optimal wavelength; for example, if the optimal wavelength obtained by the experimenter is around 530nm, then a 532nm green light laser will be used to replace the continuous white light source 1, and the green light laser will be used as the light source for studying transient photodynamics processes; the laser emits a beam of green light, which is reflected by silver mirror 1 2 and silver mirror 2 3, and then converged to the photoelectric device 5 through lens 1 4; then the photoelectric device 5 will reflect this beam of green light, and this beam of reflected light will be converged to the beam splitter 7 through lens 2 6, and 50% of the light passes through the beam splitter to reach the silver mirror 3 10, and the other The outer 50% of the light is reflected by the beam splitter to lens three 8, and is converged by lens three 8 to the spectrometer 9; the reflected green light reaching silver mirror three 10 is then converged by lens four 11 to reach the monochromator 12; the green light emitted by the monochromator is incident on the high-speed photodetector 13 (photomultiplier tube), and the reflected light signal is converted into an electrical signal; the electrical signal is connected to the preamplifier 17, and the amplitude of the electrical signal is amplified; the electrical signal amplified by the preamplifier 17 is connected to the oscilloscope 16 by the circuit; then, the oscilloscope's multiple averaging and accumulation function is used to accumulate and average the obtained electrical signal waveform for about 20,000 times, and finally the carrier dynamics curve under pulse voltage excitation can be obtained; the electrical signal generated by the high-speed photodetector 13 is also output to the phase-locked amplifier 14, which greatly reduces the noise background of the electrical signal, displays the amplitude of the electrical signal, and outputs the electrical signal to the computer 15.

[0043] By changing the pulse voltage amplitude output by the signal generator 18 and performing the above operations, the carrier dynamics curves under different pulse voltages can be obtained. In order to clearly see the carrier dynamics curves, two waveforms are finally selected on the oscilloscope, namely the transient photocurrent curve (obtained in the third step) and the Figure 5 The curve (1) and the carrier dynamics curve (obtained from the fourth step) are as follows Figure 5 In the curve (2), the horizontal coordinates of curve (1) and curve (2) are all time T, and the vertical coordinates are all voltage U.

Claims

1. A nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices, characterized by: It includes a transient spectrum measurement part and a carrier dynamics detection part. The transient spectrum measurement part includes a continuous white light source, a spectrometer, a signal generator and an optical element. The signal generator outputs a pulse voltage signal to trigger the photoelectric device. The continuous white light source irradiates the photoelectric device through the optical element. The light reflected by the photoelectric device enters the spectrometer through the optical element, and the spectrum information is then sent to the computer. The carrier dynamics detection part includes a verification carrier injection unit, a transient current collection unit and a transient photodynamic collection unit, wherein the verification carrier injection unit includes a signal generator outputting a pulse voltage signal to an oscilloscope, a continuous white light source irradiating the photoelectric device, the light reflected by the photoelectric device passing through a monochromator, and collected into a high-speed photodetector, and the waveform is displayed on the oscilloscope, and then the pulse voltage signal output by the signal generator is applied to both ends of the photoelectric device, the light reflected by the photoelectric device is collected into a high-speed photodetector, and displayed on the oscilloscope; The transient current acquisition unit applies the pulse voltage output by the signal generator to both ends of the photoelectric device, connects a resistor in series between the signal generator and the photoelectric device, and samples the transient photocurrent signal at both ends of the resistor through an oscilloscope; The transient photodynamic acquisition unit applies the pulse voltage output by the signal generator to both ends of the photoelectric device. The light reflected by the photoelectric device passes through the monochromator and then enters the high-speed photodetector. The electrical signal is displayed on the oscilloscope.

2. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: The optical elements include silver mirror 1, silver mirror 2, lens 1, lens 2, beam splitter, lens 3, silver mirror 3 and lens 4, wherein a continuous white light source outputs a beam of broad-spectrum white light, which is reflected by silver mirror 1 and silver mirror 2, and then converged onto the photoelectric device through lens 1. The photoelectric device then reflects the white light, and the reflected light is converged onto the beam splitter through lens 2. 50% of the light passes through the beam splitter and reaches silver mirror 3, and is reflected by silver mirror 3 onto lens 4, and then converged by lens 4 into the monochromator. The remaining 50% of the light is reflected by the beam splitter onto lens 3, and is converged by lens 3 into the spectrometer.

3. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: The electrical signal generated by the high-speed photodetector is connected to the oscilloscope through a preamplifier.

4. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: The electrical signal generated by the high-speed photodetector is also output to a lock-in amplifier, and the electrical signal is output to a computer.

5. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, 3 or 4, characterized in that: The high-speed photodetector contains a photomultiplier tube to convert the optical signal into an electrical signal.

6. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: The light-emitting electric device adopts a perovskite solar cell.

7. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: The continuous white light source is replaced with a laser of optimal wavelength.

8. The nanosecond time-resolved electrically stimulated transient spectroscopy system for studying stacked optoelectronic devices according to claim 1, characterized in that: A 532nm green laser is used to replace the continuous white light source and is used as the light source for studying transient photodynamic processes.

9. A method for studying carrier dynamics in a stacked optoelectronic device using the system according to any one of claims 1 to 8, characterized in that: The following steps are involved: The first step is to measure the transient spectrum: First, the signal generator outputs a pulsed electrical signal with a low level of 0V and a high level of 1V. This signal is transmitted to the photoelectric device through a resistor. At the same time, the continuous white light source outputs a beam of broadband white light. The white light is reflected by silver mirrors 1 and 2, and then converged by lens 1 onto the photoelectric device. The photoelectric device reflects this white light, which is then converged by lens 2 onto the beam splitter. 50% of the light passes through the beam splitter and reaches silver mirror 3. The remaining 50% of the light is reflected by the beam splitter and converged by lens 3 into the spectrometer. Finally, the data in the spectrometer is sent to a computer. For spectral data, pulse voltage is used to excite the photoelectric device and induce differential spectroscopy, and the spectral data is integrated and analyzed through differential spectroscopy; The second step is to verify carrier injection: When the signal generator outputs 0V, that is, no electrical excitation is applied to the photoelectric device, the light reflected by the photoelectric device passes through lens 2 and the beam splitter to reach silver mirror 3, and is reflected by silver mirror 3 to lens 4. Then, it is converged by lens 4 to the monochromator. The reflected light passes through the monochromator and finally reaches the photomultiplier tube of the high-speed photodetector. The optical signal is converted into an electrical signal, and then the electrical signal is connected to the oscilloscope through the preamplifier. At this time, the waveform displayed by the oscilloscope is a steady-state electrical signal of continuous white light. The electrical signal generated by the high-speed photodetector is also output to the lock-in amplifier, which displays the amplitude of the electrical signal and outputs the electrical signal to the computer. When the signal generator outputs a pulse voltage, that is, when electrical excitation is applied to the photoelectric device, the above steps are still performed. At this time, the waveform displayed on the oscilloscope is the changing electrical signal generated by the continuous white light. In order to ensure the timing synchronization of the lock-in amplifier and oscilloscope in detecting the electrical signal, a signal generator is used to synchronously trigger the lock-in amplifier and oscilloscope; In order to see the obvious difference of the electrical signal on the oscilloscope, the pulse voltage signal output by the signal generator is output to the oscilloscope; The third step is transient current acquisition: the signal generator outputs a pulse voltage, which is output to the photoelectric device through a resistor. One port of the oscilloscope is connected to both ends of the resistor to sample the transient current signal at both ends of the resistor. The waveform displayed on the oscilloscope at this time is the transient photocurrent curve. In order to clearly see the attenuation change of the transient photocurrent curve, the pulse voltage output by the signal generator is displayed on the oscilloscope. Therefore, when doing the transient current acquisition experiment, two waveforms are displayed on the oscilloscope; The fourth step is transient photodynamics acquisition: first, the signal generator outputs a pulse voltage signal, which is applied to the photoelectric device through a resistor. Secondly, after the first step of transient spectrum measurement is completed, the optimal wavelength range reflecting the carrier dynamics process is obtained. After determining the optimal wavelength range for studying carrier dynamics, the continuous white light source is replaced with a green laser with the optimal wavelength; the green laser is used as the light source for studying transient photodynamics. The green laser emits a beam of green light, which is reflected by silver mirror one and silver mirror two, and then converged to the photoelectric device through lens one. The photoelectric device then reflects this green light, and this reflected light is converged to the beam splitter through lens two, and 50% of the light passes through the beam splitter to reach silver mirror three, and the other 5 0% of the light is reflected by the beam splitter to lens three, and is converged by lens three into the spectrometer. The reflected green light that reaches silver mirror three is then converged by lens four and reaches the monochromator. The green light emitted by the monochromator is incident on the high-speed photodetector. At this time, the reflected light signal is converted into an electrical signal, which is connected to the preamplifier. At this time, the amplitude of the electrical signal is amplified. The electrical signal amplified by the preamplifier is connected to the oscilloscope through the circuit. Then, the oscilloscope's multiple averaging and accumulation function is used to accumulate and average the obtained electrical signal waveform for about 20,000 times, and finally the carrier dynamics curve under pulse voltage excitation can be obtained; the electrical signal generated by the high-speed photodetector is also output to the phase-locked amplifier to display the amplitude of the electrical signal, and the electrical signal is output to the computer; By changing the pulse voltage amplitude output by the signal generator and performing the above operations, the carrier dynamics curves under different pulse voltages can be obtained.

10. The method for studying carrier dynamics in a stacked optoelectronic device according to claim 9, characterized in that: In order to clearly see the carrier dynamics curve, two waveforms were finally selected to be displayed on the oscilloscope, namely the transient photocurrent curve obtained in the third step and the carrier dynamics curve obtained in the fourth step.

Images