A perovskite-based X-ray event-type detection device and detection method

Abstract

The present invention belongs to the field of event-type X-ray technology, and discloses a perovskite-based X-ray event-type detector device and detection method. The detector device includes: a three-dimensional perovskite single crystal and a positive electrode, a negative electrode, and a common electrode on the three-dimensional perovskite single crystal; wherein positive and negative voltages are applied to the positive electrode and the negative electrode respectively, and a voltage between the positive and negative voltages is applied to the common electrode; the common electrode is used to collect photocurrent, and the positive and negative voltages applied to the positive electrode and the negative electrode respectively make the photocurrent zero; when an event occurs, the light intensity of the X-ray incident on the three-dimensional perovskite single crystal changes instantaneously, generating a light pulse signal on the three-dimensional perovskite single crystal; and event detection is performed based on the light pulse signal. The present invention also provides a detection method and a preparation method for the perovskite-based X-ray event-type detector. The present invention can improve the sensitivity and accuracy of X-ray event-type detection.

Description

Technical Field

[0001] The present invention belongs to the field of event-type X-ray technology, and more specifically, relates to a perovskite-based X-ray event-type detection device and a detection method. Background Art

[0002] X-rays are electromagnetic waves with very short wavelengths (0.01-10nm) and high energy. Because their wavelengths are very short, between ultraviolet rays and gamma rays, they have strong penetrating power. X-ray-based detection technology has been widely used in various fields, but there are still some limitations. For example: (1) X-ray detection technology requires extremely high temporal resolution to capture the dynamic processes of matter on extremely short time scales; (2) Current data processing and analysis technologies still have many limitations and cannot fully meet the needs of ultrafast X-ray detection technology.

[0003] Event-based detection, with its unique detection characteristics, effectively overcomes the aforementioned limitations of X-ray detection. Focusing on specific events or changes in conditions, it records only those events or changes in conditions, rather than continuously recording all data. This type of detection has important applications in data processing and monitoring systems, particularly those that require processing large amounts of data. Its advantage lies in significantly reducing data volumes, thereby improving processing efficiency, reducing storage costs, and accelerating response times.

[0004] However, the inherent principle limitations of event-type detection make its application in the X-ray field difficult. Currently, devices that implement event-type detection are mainly implemented through circuits. Most circuit designs implement detection through the principle of signal differentiation. A basic idea of ​​differentiation is to calculate the rate of change of data; through differentiation, the changes can be calculated from the original data, thereby better understanding the trends and dynamics of the data. First, this differential principle will greatly reduce the sensitivity of the detector, resulting in the detector being unable to accurately and timely detect weak light changes, resulting in false detection in applications requiring high-precision measurements, and being more susceptible to factors such as environmental noise and interference signals. Secondly, the differential method may not be effective when processing complex changing data. When the data exhibits nonlinear changes, periodic changes, or jump changes, the differential method may not be able to accurately describe the changing patterns of the data, which will lead to detection distortion. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a perovskite-based X-ray event-type detection device and detection method, the purpose of which is to improve the sensitivity and accuracy of X-ray event-type detection.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a perovskite-based X-ray event detection device is provided, comprising:

[0007] A three-dimensional perovskite single crystal and a positive electrode, a negative electrode, and a common electrode on the three-dimensional perovskite single crystal; wherein positive and negative voltages are applied to the positive electrode and the negative electrode, respectively, and a voltage between the positive and negative voltages is applied to the common electrode; the common electrode is used to collect photocurrent, and the positive and negative voltages applied to the positive electrode and the negative electrode, respectively, make the photocurrent zero;

[0008] The photocurrent is the current generated by the three-dimensional perovskite single crystal under continuous and stable X-ray incidence;

[0009] When an event occurs, the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes instantaneously, generating a light pulse signal on the three-dimensional perovskite single crystal; and event detection is performed based on the light pulse signal.

[0010] Furthermore, the common electrode is also used to collect dark current, which is the current generated by the three-dimensional perovskite single crystal itself under the action of positive and negative voltages applied to the positive electrode and negative electrode respectively;

[0011] The X-ray event detection device further includes an adjustment electrode disposed on the three-dimensional perovskite single crystal;

[0012] The adjustment electrode is used to adjust the dark current to zero under the action of an applied voltage.

[0013] Furthermore, the adjustment electrode is a ring electrode or a C-shaped electrode.

[0014] Furthermore, the three-dimensional perovskite single crystal is a methylamino-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamino-based bromide perovskite single crystal.

[0015] Furthermore, the positive electrode and the negative electrode have equal areas.

[0016] Furthermore, the voltage of the common electrode is zero.

[0017] According to a second aspect of the present invention, there is provided a method for detecting X-ray events based on perovskite, comprising:

[0018] Positive and negative voltages are applied to the positive electrode and negative electrode of the X-ray event-type detection device respectively, and a voltage between the positive and negative voltages is applied to the common electrode, so that the photocurrent collected by the common electrode is zero. When an event occurs, the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes instantaneously, generating a light pulse signal on the three-dimensional perovskite single crystal, and event detection is performed based on the light pulse signal; wherein, the X-ray event-type detection device is the perovskite-based X-ray event-type detection device as described in any one of the first aspects.

[0019] Furthermore, when an adjustment electrode is further provided on the three-dimensional perovskite single crystal, the method further comprises:

[0020] The voltage of the adjustment electrode is adjusted to make the dark current zero; wherein the dark current is the current generated by the three-dimensional perovskite single crystal itself under the action of the positive and negative voltages applied to the positive electrode and the negative electrode respectively.

[0021] According to a third aspect of the present invention, there is provided a method for preparing a perovskite-based X-ray event detection device as described in any one of the first aspects, comprising:

[0022] Using a MASK mask to evaporate a metal electrode on the surface of the three-dimensional perovskite single crystal to obtain the perovskite-based X-ray event-type detection device;

[0023] The metal electrodes include a positive electrode, a negative electrode and a common electrode, and the voltage applied to the common electrode is a voltage between the positive and negative voltages applied to the positive electrode and the negative electrode respectively.

[0024] Furthermore, the three-dimensional perovskite single crystal is a methylamino-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamino-based bromide perovskite single crystal.

[0025] According to a third aspect of the present invention, there is provided a method for preparing a perovskite-based X-ray event detection device as described in any one of the first aspects, comprising:

[0026] Using a MASK mask to evaporate a metal electrode on the surface of the three-dimensional perovskite single crystal to obtain the perovskite-based X-ray event-type detection device;

[0027] The metal electrodes include a positive electrode, a negative electrode and a common electrode, and the voltage applied to the common electrode is a voltage between the positive and negative voltages.

[0028] Furthermore, the three-dimensional perovskite single crystal is a methylamino-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamino-based bromide perovskite single crystal.

[0029] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0030] (1) The perovskite-based X-ray event detection device of the present invention is based on applying different bias voltages on different electrodes to control the electric field distribution in the three-dimensional perovskite single crystal to achieve zero photocurrent. When the light intensity of the X-ray incident on the three-dimensional perovskite single crystal changes (corresponding to the occurrence of an event), due to the difference in the time when the holes collected from the positive electrode and the electrons collected from the negative electrode by the common electrode are collected, a light pulse signal with a very short duration is generated on the three-dimensional perovskite single crystal. After the light is stable, the two carriers collected by the common electrode tend to be balanced again, and the generated light pulse signal disappears. Based on this, the present invention cleverly utilizes the difference in the mobility of the two carriers in the three-dimensional perovskite single crystal to realize the detection of "light events". No electronic components are required, and no differential integration of electrical signals is required. The size of the light pulse signal in the present invention is consistent with the size of the light signal corresponding to the X-ray, and there is no signal loss. It can accurately and timely detect weak light changes, thereby improving the sensitivity and accuracy of the detector. At the same time, based on the intrinsic characteristics of three-dimensional perovskite single crystals, the signal of the detector under positive and negative pressure in the present invention changes uniformly and linearly with light, and there is no defect that the existing differential method cannot accurately describe the law of data change, thus avoiding detection distortion.

[0031] (2) Furthermore, by setting an adjustment electrode to adjust the dark current to zero, the detection signal-to-noise ratio of the detector can be improved when the photocurrent and dark current are both zero.

[0032] (3) As a preference, the positive electrode and the negative electrode have equal areas, which can make the number of holes and electrons similar, and the voltages applied to the positive and negative electrodes are also relatively close, reducing the difficulty of device implementation.

[0033] (4) As a preference, the voltage of the common electrode is zero, which helps to reduce the difficulty of device implementation.

[0034] In summary, the event-based X-ray detector of the present invention boasts extremely fast detection speed and high sensitivity. It is highly sensitive to changes in external radiation and can keenly capture even the slightest changes in radiation intensity. Therefore, this device structure offers significant advantages over existing event-based X-ray detection methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of a three-electrode structure detector in an embodiment of the present invention.

[0036] FIG2( a ) is a schematic diagram of a simulated electric field structure corresponding to a three-electrode structure detector in an embodiment of the present invention.

[0037] FIG2( b ) is a diagram showing the measured X-ray light response of the three-electrode structure detector in an embodiment of the present invention.

[0038] FIG3( a ) is a schematic diagram of a four-electrode structure detector according to an embodiment of the present invention.

[0039] FIG3( b ) is a top view of a four-electrode structure detector according to an embodiment of the present invention.

[0040] FIG3( c ) is a bottom view of the four-electrode structure detector according to an embodiment of the present invention.

[0041] FIG4( a ) is a schematic diagram of a simulated electric field structure corresponding to a four-electrode structure detector according to an embodiment of the present invention.

[0042] FIG4( b ) is a diagram showing the measured X-ray light response of the four-electrode structure detector according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] like Figure 1 As shown, an embodiment of the present invention provides an X-ray event-type detection device based on perovskite, which mainly includes: a three-dimensional perovskite single crystal and a positive electrode, a negative electrode and a common electrode on the three-dimensional perovskite single crystal; wherein, positive and negative voltages are applied to the positive electrode and the negative electrode respectively, and the voltage applied to the common electrode is between the positive and negative voltages. In an embodiment of the present invention, the voltage applied to the common electrode is 0V, which is easy to implement; the common electrode is used to collect photocurrent, and the positive and negative voltages applied to the positive electrode and the negative electrode respectively make the photocurrent zero.

[0046] Photocurrent is the current generated when X-rays are incident on a three-dimensional perovskite single crystal.

[0047] When the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes, an event occurs, and a light pulse signal is generated on the three-dimensional perovskite single crystal; event detection is performed based on the light pulse signal.

[0048] Preferably, the three-dimensional perovskite single crystal is formamidinium bromide perovskite single crystal (FAPbBr3), cesium bromide perovskite single crystal (CsPbBr3) or methylamino bromide perovskite single crystal (MAPbBr3).

[0049] Preferably, the positive electrode and the negative electrode have the same area, so that the number of holes and electrons can be similar, and the voltages applied to the positive and negative electrodes are also closer, reducing the difficulty of device implementation.

[0050] Preferably, the common electrode is also used to collect dark current. Dark current is the current generated by the three-dimensional perovskite single crystal itself in response to the positive and negative voltages applied to the positive and negative electrodes, respectively. Accordingly, the X-ray event detection device in the embodiments of the present invention also includes a regulating electrode on the three-dimensional perovskite single crystal. This regulating electrode is used to regulate the dark current to zero under the applied voltage, thereby improving the signal-to-noise ratio of detection. In the embodiments of the present invention, this regulating electrode is a ring electrode; in other embodiments, it can also be a C-shaped electrode, etc.

[0051] Below is Figure 1 The detection principle of the present invention is further illustrated using the X-ray event-type detector shown in the figure as an example. Two independently adjustable positive and negative electrodes are deposited on the top of a FAPbBr3 single crystal through a mask. Below this is a common electrode for collecting current signals (dark current and photocurrent), with a voltage of 0V. When the voltage of the fixed "+" electrode is positive and the voltage of the "-" electrode is also adjusted to be positive, if light irradiates the FAPbBr3 single crystal, both the photocurrent and dark current generated by the FAPbBr3 single crystal flow into the bottom common electrode. When the voltage of the "-" electrode is adjusted to a sufficiently negative value, if light irradiates the FAPbBr3 single crystal, both the photocurrent and dark current generated by the FAPbBr3 single crystal flow out of the bottom common electrode. Therefore, a negative voltage must be applied to the "-" electrode to reduce the photocurrent to zero in the presence of light. In this embodiment of the present invention, the "+" electrode is the positive electrode, and the "-" electrode is the negative electrode.

[0052] When positive voltage is applied to the "+" electrode and negative voltage is applied to the "-" electrode, under illumination, electron-hole pairs are generated at the negative and positive electrodes of the FAPbBr3 single crystal, which drift under the influence of the electric field. The bottom common electrode collects holes transmitted from the "+" electrode and electrons transmitted from the "-" electrode. Under stable illumination, the transmission speeds of electrons and holes are equal, and the photocurrent is zero. In this case, the common electrode collects the same number of electrons and holes at all times, so the combination of the two carriers does not generate a light signal. When an event occurs, the X-ray intensity changes momentarily. Due to the different transmission speeds of the two carriers, the electrons and holes collected by the bottom common electrode are collected at different times, resulting in a very short light pulse signal on the single crystal. When the illumination stabilizes, the two carriers collected by the bottom common electrode reach equilibrium, and the generated light pulse signal disappears. Therefore, event detection can be achieved based on this generated light pulse signal.

[0053] To verify the correctness of the theory, the following experiments were designed on FAPbBr3 single crystal: Figure 1 The three-electrode structure shown in Figure 2(a) corresponds to the simulated electric field structure. The electric field strength is symmetrically distributed within the single crystal, but its direction is opposite near the positive and negative electrodes. Therefore, the generated electrons and holes have the same movement direction, that is, they all move toward the common electrode. The measured X-ray light response is shown in Figure 2(b). After adjusting the positive and negative electrode voltages, the current remains unchanged during continuous X-ray exposure, and a response pulse signal is generated only at the instant the X-ray tube is switched on and off. Turning the switch on at 2 seconds and off at approximately 3.8 seconds produces one positive and one negative light pulse signal. Positive light pulse signals correspond to increases in light intensity, while negative light pulse signals correspond to decreases in light intensity, which is related to the intrinsic characteristics of the three-dimensional perovskite single crystal. In other words, as shown in the above experiments, the designed detector only generates signals in response to changes in light intensity, achieving event-based detection.

[0054] Further, in Figure 1 Based on the three-electrode structure shown above, a ring electrode is added at the bottom, forming a four-electrode structure, as shown in Figures 3(a)-3(c). In Figure 3(b), 1 is the positive electrode, 2 is the negative electrode, 3 is the ring electrode, and 4 is the common electrode. Applying voltage to the ring electrode can balance the dark current. That is, by varying the voltage applied to the adjustment electrode, the dark current, like the photocurrent, is also zero, as shown in Figure 4(b). Under the voltage conditions applied to the three electrodes, applying a positive voltage to the ring electrode can negatively compensate for the dark current, reducing it. Conversely, applying a negative voltage to the ring electrode can positively compensate for the dark current, allowing for flexible adjustment of the voltage level based on actual needs. Theoretically, adjusting the voltage on the ring electrode can reduce the dark current to zero. Therefore, by combining the voltages of the two upper electrodes and the bottom ring electrode, extremely short-duration positive or negative signal pulses can be generated in response to changes in light intensity. The generation of positive and negative pulses depends on which carrier has a faster transmission speed. If the electron speed is fast, a negative pulse signal is generated. Otherwise, a positive pulse signal is generated. Positive and negative pulse signals do not affect detection.

[0055] A four-electrode event-type detection device, as shown in Figure 3(a), was fabricated on the semiconductor FAPbBr3 for experimental verification. The voltages of the positive electrode 1, negative electrode 2, and ring electrode 3 were adjusted, and the current signal from the common electrode 4 was collected. The corresponding simulated electric field structure is shown in Figure 4(a), and the measured X-ray light response is shown in Figure 4(b). It can be seen that light pulse signals are generated only when the light intensity changes, and no signal is generated when the light intensity remains stable. This achieves the purpose of event-type detection by detecting only changes in light intensity.

[0056] The perovskite-based X-ray event detector device of the present invention utilizes different bias voltages applied to different electrodes to control the electric field distribution in a three-dimensional perovskite single crystal to achieve zero photocurrent. At the instant the X-ray intensity incident on the three-dimensional perovskite single crystal changes (corresponding to an event), the common electrode collects holes from the positive electrode at different times than electrons from the negative electrode, generating a very short-duration light pulse signal on the three-dimensional perovskite single crystal. After the illumination stabilizes, the two carriers collected by the common electrode reach equilibrium, and the generated light pulse signal disappears. This ingeniously exploits the difference in the mobility of the two carriers in the three-dimensional perovskite single crystal to detect "light events," eliminating the need for electronic components or differential integration of electrical signals. Furthermore, the magnitude of the light pulse signal in the present invention is consistent with the magnitude of the light signal corresponding to the X-ray, eliminating signal loss. This allows for accurate and timely detection of even faint light changes, improving the sensitivity and accuracy of the detector. At the same time, based on the intrinsic characteristics of three-dimensional perovskite single crystals, the signal of the detector under positive and negative pressure in the present invention changes uniformly and linearly with light, and there is no defect that the differential method cannot accurately describe the law of data change.

[0057] Example 2

[0058] The embodiment of the present invention provides a method for detecting X-ray events based on perovskite in embodiment 1, comprising:

[0059] Applying positive and negative voltages to the positive and negative electrodes of the X-ray event detector device, respectively, so that the photocurrent collected by the common electrode is zero; wherein the X-ray event detector device is the perovskite-based X-ray event detector device in Example 1;

[0060] When the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes, an event occurs, a light pulse signal is generated on the three-dimensional perovskite single crystal, and event detection is performed based on the light pulse signal.

[0061] Example 3

[0062] An embodiment of the present invention provides a method for preparing a perovskite-based X-ray event-type detection device as in Example 1, comprising:

[0063] A metal electrode is evaporated on the surface of a three-dimensional perovskite single crystal using a MASK mask to obtain a perovskite-based X-ray event detection device; wherein, the metal electrode includes a positive electrode, a negative electrode and a common electrode; wherein, positive and negative voltages are applied to the positive electrode and the negative electrode respectively, and the voltage of the common electrode is a voltage between the positive and negative voltages applied to the positive electrode and the negative electrode respectively; the common electrode is used to collect photocurrent and dark current, and the positive and negative voltages applied to the positive electrode and the negative electrode respectively make the photocurrent zero.

[0064] When the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes, an event occurs, and a light pulse signal is generated on the three-dimensional perovskite single crystal; event detection is performed based on the light pulse signal.

[0065] For the relevant description, please refer to the corresponding description in Example 1, which will not be repeated here.

[0066] The resulting event-type X-ray detector boasts extremely fast detection speed and high sensitivity. It is highly sensitive to changes in external radiation and can keenly detect even the slightest changes in radiation intensity. Therefore, this device structure offers significant advantages over existing event-type X-ray detection methods.

[0067] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A perovskite-based X-ray event detection device, characterized in that: include: A three-dimensional perovskite single crystal and a positive electrode, a negative electrode, and a common electrode on the three-dimensional perovskite single crystal; wherein positive and negative voltages are applied to the positive electrode and the negative electrode, respectively, and a voltage between the positive and negative voltages is applied to the common electrode; the common electrode is used to collect photocurrent, and the positive and negative voltages applied to the positive electrode and the negative electrode, respectively, make the photocurrent zero; The photocurrent is the current generated by the three-dimensional perovskite single crystal under continuous and stable X-ray incidence; When an event occurs, the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes instantaneously, generating a light pulse signal on the three-dimensional perovskite single crystal; and event detection is performed based on the light pulse signal.

2. The perovskite-based X-ray event detection device according to claim 1, characterized in that: The common electrode is further used to collect dark current, which is the current generated by the three-dimensional perovskite single crystal itself under the action of positive and negative voltages applied to the positive electrode and negative electrode respectively; The X-ray event detection device further includes an adjustment electrode disposed on the three-dimensional perovskite single crystal; The adjustment electrode is used to adjust the dark current to zero under the action of an applied voltage.

3. The perovskite-based X-ray event detection device according to claim 2, characterized in that: The regulating electrode is a ring electrode or a C-shaped electrode.

4. The perovskite-based X-ray event detection device according to any one of claims 1 to 3, characterized in that: The three-dimensional perovskite single crystal is a formamidine-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamino-based bromide perovskite single crystal.

5. The perovskite-based X-ray event detection device according to claim 4, characterized in that: The positive electrode and the negative electrode have equal areas.

6. The perovskite-based X-ray event detection device according to claim 1, characterized in that: The voltage of the common electrode is zero.

7. A method for detecting X-ray events based on perovskite, characterized in that: include: Positive and negative voltages are applied to the positive electrode and negative electrode of the X-ray event-type detection device respectively, and a voltage between the positive and negative voltages is applied to the common electrode, so that the photocurrent collected by the common electrode is zero. When an event occurs, the intensity of the X-ray incident on the three-dimensional perovskite single crystal changes instantaneously, and a light pulse signal is generated on the three-dimensional perovskite single crystal, and event detection is performed based on the light pulse signal; wherein, the X-ray event-type detection device is the perovskite-based X-ray event-type detection device according to any one of claims 1 to 6.

8. The method for detecting X-ray events based on perovskite according to claim 7, characterized in that: When an adjustment electrode is further provided on the three-dimensional perovskite single crystal, the method further comprises: The voltage of the adjustment electrode is adjusted to make the dark current zero; wherein the dark current is the current generated by the three-dimensional perovskite single crystal itself under the action of the positive and negative voltages applied to the positive electrode and the negative electrode respectively.

9. A method for preparing a perovskite-based X-ray event detection device according to any one of claims 1 to 6, characterized in that: include: Using a MASK mask to evaporate a metal electrode on the surface of the three-dimensional perovskite single crystal to obtain the perovskite-based X-ray event-type detection device; The metal electrodes include a positive electrode, a negative electrode and a common electrode, and the voltage applied to the common electrode is a voltage between the positive and negative voltages applied to the positive electrode and the negative electrode respectively.

10. The preparation method according to claim 9, characterized in that The three-dimensional perovskite single crystal is a formamidine-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamino-based bromide perovskite single crystal.

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