Novel X-ray event type detection device and detection method based on perovskite

Abstract

The invention belongs to the technical field of event type X-rays, and discloses a novel X-ray event type detector based on perovskite and a detection method.The detector comprises a three-dimensional perovskite single crystal and a positive electrode, a negative electrode and a common electrode which are arranged on the three-dimensional perovskite single crystal; wherein a positive voltage and a negative voltage are correspondingly applied to the positive electrode and the negative electrode, and a voltage between the positive voltage and the negative voltage is applied to the common electrode; the common electrode is used for collecting light current, and positive voltage and negative voltage correspondingly applied to the positive electrode and the negative electrode enable the light current to be zero; when an event occurs, the light intensity of the X-ray incident to the three-dimensional perovskite single crystal changes instantaneously, and a light pulse signal is generated on the three-dimensional perovskite single crystal; event detection is performed based on the optical pulse signal. The invention also correspondingly provides a detection method and a preparation method of the novel X-ray event type detector based on perovskite. According to the invention, the sensitivity and accuracy of X-ray event type detection can be improved.

Description

Technical Field

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

[0002] X-rays are electromagnetic waves with very short wavelengths (0.01-10nm) and high energy. Since the wavelength of X-rays is very short, between ultraviolet rays and gamma rays, it has strong penetrating power. X-ray-based detection technology has been widely used in different fields, but there are still some limitations. For example: (1) X-ray detection technology needs to achieve extremely high time resolution in order to capture the dynamic process of matter on an extremely short time scale; (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 can effectively solve the above-mentioned limitations of X-ray detection due to its unique detection characteristics. Event-based detection only focuses on specific events or changes in conditions, so it only records these events or changes in conditions, rather than continuously recording all data. It has important applications in data processing and monitoring systems, especially in scenarios where large amounts of data need to be processed. Its advantage is that it can significantly reduce the amount of data, thereby improving data processing efficiency, reducing storage costs, and speeding up response time.

[0004] However, due to the inherent principle limitations of event-type detection itself, it is difficult to apply it in the X-ray field. At present, the devices that realize event-type detection are mainly realized through circuits. Most of the circuit designs realize detection through the principle of signal difference. A basic idea of ​​difference is to calculate the rate of change of data; through difference, the change can be calculated from the original data, so as to better understand the trend and dynamics of the data. First of all, this differential principle will greatly reduce the sensitivity of the detector, causing the detector to be unable to accurately and timely detect weak light changes, resulting in false detection in applications requiring high-precision measurement, and it is 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 presents nonlinear changes, periodic changes or jump changes, the differential method may not accurately describe the changing law of the data, which will lead to detection distortion. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a new X-ray event type detection device and detection method based on perovskite, which aims 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 novel X-ray event detection device based on perovskite 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 the positive electrode and the negative electrode are respectively applied with positive and negative voltages, and the common electrode is applied with a voltage between the positive and negative voltages; the common electrode is used to collect photocurrent, and the positive and negative voltages respectively applied to the positive electrode and the negative electrode make the photocurrent zero;

[0008] The photocurrent is the current generated by the three-dimensional perovskite single crystal under the incidence of X-rays;

[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 the positive and negative voltages applied to the positive electrode and the negative electrode respectively;

[0011] The novel X-ray event-type 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 bromide perovskite single crystal, a cesium bromide perovskite single crystal or a methylamino 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, a novel method for detecting X-ray events based on perovskite is provided, 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 light intensity of the X-rays incident on the three-dimensional perovskite single crystal changes instantaneously, 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 a new X-ray event type detection device based on perovskite 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 novel X-ray event-type detection device based on perovskite 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 novel 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 bromide perovskite single crystal, a cesium bromide perovskite single crystal or a methylamino bromide perovskite single crystal.

[0025] According to a third aspect of the present invention, there is provided a method for preparing a novel X-ray event-type detection device based on perovskite 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 novel perovskite-based X-ray event-type detection device;

[0027] Wherein, the metal electrode includes a positive electrode, a negative electrode and a common electrode, and the voltage applied to the common electrode is a voltage between the positive voltage and the negative voltage.

[0028] Furthermore, the three-dimensional perovskite single crystal is a methylamino bromide perovskite single crystal, a cesium bromide perovskite single crystal or a methylamino 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 novel X-ray event-type detector based on perovskite in the present invention is based on applying different bias voltages on different electrodes to adjust 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 by the common electrode from the positive electrode and the electrons collected from the negative electrode, a light pulse signal with a very short duration will be generated on the three-dimensional perovskite single crystal. After the light is stable, the two carriers collected by the common electrode tend to balance again, and the generated light pulse signal disappears. Based on this, the present invention cleverly uses the difference in the mobility of the two carriers in the three-dimensional perovskite single crystal to realize the detection of "light events", without the need for electronic components, and without the need for differential integration of electrical signals. 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, without signal loss, and 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 the dark current are both zero.

[0032] (3) Preferably, 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 realization.

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

[0034] In summary, the novel event-type X-ray detector in the present invention has extremely fast detection speed and extremely high sensitivity, is very sensitive to changes in external radiation, and can keenly capture slight changes in radiation intensity. Therefore, this device structure has significant advantages over existing event-type 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] FIG. 2( 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] FIG. 2( 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] FIG. 3( a ) is a schematic diagram of a detector with a four-electrode structure according to an embodiment of the present invention.

[0039] FIG. 3( b ) is a top view of a detector having a four-electrode structure according to an embodiment of the present invention.

[0040] FIG. 3( c ) is a bottom view of the detector with four electrodes in an embodiment of the present invention.

[0041] FIG. 4( a ) is a schematic diagram of a simulated electric field structure corresponding to a four-electrode structure detector in an embodiment of the present invention.

[0042] FIG. 4( b ) is a diagram showing the X-ray light response of the detector with a four-electrode structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain 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 can be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] like Figure 1 As shown, in an embodiment of the present invention, a new X-ray event-type detection device based on perovskite is provided, 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] At the moment when the intensity of X-rays incident on the three-dimensional perovskite single crystal changes, corresponding to the occurrence of an event, 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 formamidite 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 equal areas, 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 realization.

[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 under the action of positive and negative voltages applied to the positive electrode and the negative electrode respectively; correspondingly, the novel X-ray event-type detection device in the embodiment of the present invention also includes an adjustment electrode on the three-dimensional perovskite single crystal, which is used to adjust the dark current to zero under the action of the applied voltage to improve the signal-to-noise ratio of the detection. In the embodiment of the present invention, the adjustment electrode is a ring electrode; in other embodiments, it can also be a C-type electrode, etc.

[0051] Below Figure 1 Taking the new X-ray event type detection device shown as an example, the detection principle of the present invention is further explained. Two independently adjustable positive electrodes and negative electrodes are evaporated on the FAPbBr3 single crystal through a mask plate, and a common electrode for collecting current signals (dark current and photocurrent) is below, and the voltage is 0V. At this time, the voltage of the fixed "+" electrode is positive, and when the voltage of the "-" electrode is adjusted to be positive, if light is irradiated to the FAPbBr3 single crystal, the photocurrent and dark current generated by the FAPbBr3 single crystal will flow into the bottom common electrode; when the voltage of the "-" electrode is adjusted to be negative and large enough, if light is irradiated to the FAPbBr3 single crystal, the photocurrent and dark current generated by the FAPbBr3 single crystal will flow out from the bottom common electrode. Therefore, there must be a negative voltage applied to the "-" electrode, which makes the photocurrent zero under light conditions. In the embodiment of the present invention, the "+" electrode is the positive electrode, and the "-" electrode is the negative electrode.

[0052] When the "+" electrode is applied with positive voltage, the "-" electrode is applied with negative voltage. Under illumination conditions, the FAPbBr3 single crystal generates electron-hole pairs at the negative and positive electrodes, which drift under the action of the electric field. For the bottom common electrode, on the one hand, it collects holes transmitted from the "+" electrode side, and on the other hand, it also collects electrons transmitted from the "-" electrode side. Under stable illumination conditions, the transmission speeds of electrons and holes are the same, and the photocurrent is zero; at this time, the common electrode collects the same number of electrons and holes at every moment, so the combination of the two carriers will not generate a light signal. When an event occurs, the intensity of the X-ray will change instantly. The transmission speeds of the two carriers are different, and the electrons and holes collected by the bottom common electrode are different, which will generate a light pulse signal with a very short duration on the single crystal. When the illumination is stable, the two carriers collected by the bottom common electrode tend to be balanced again, and the generated light pulse signal disappears. Therefore, event detection can be achieved based on the generated light pulse signal.

[0053] To verify the correctness of the theory, the following Figure 1 The three-electrode structure shown in the figure has a corresponding simulated electric field structure as shown in Figure 2(a). The value of the electric field strength is symmetrically distributed inside the single crystal, but the directions are opposite near the positive and negative electrodes. Therefore, the generated electrons and holes have the same moving 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 does not change when the X-rays continue to act, and the response pulse signal is only generated at the moment when the X-ray tube is switched on; among them, the switch light is turned on at 2s and turned off at about 3.8s, and a positive and a negative light pulse signal are generated. The positive light pulse signal corresponds to an increase in light intensity, and the negative light pulse signal corresponds to a decrease in light intensity, which is related to the intrinsic characteristics of the three-dimensional perovskite single crystal. That is, from the above experiments, it can be seen that the designed detector only generates signals for changes in light intensity, and can achieve event-type detection effects.

[0054] Further, in Figure 1 Based on the three-electrode structure shown in the figure, a ring electrode is added at the bottom to form a four-electrode structure, as shown in Figure 3(a)-3(c) As shown, 1 in FIG3(b) is a positive electrode, 2 is a negative electrode, 3 in FIG3(c) is a ring electrode, and 4 is a common electrode. By applying a voltage to the ring electrode, the dark current can be balanced, that is, by changing the voltage applied to the adjustment electrode, the dark current can be made zero, the same as the photocurrent, as shown in FIG4(b). Under the voltage conditions applied by the three electrodes, applying a positive voltage to the ring electrode can reversely compensate for the dark current and reduce the dark current. Correspondingly, applying a negative voltage to the ring electrode can positively compensate for the dark current, and the voltage can be flexibly adjusted according to actual needs. In theory, the dark current can be made zero by adjusting the voltage on the ring electrode, so that the voltage of the upper two electrodes and the bottom ring electrode can be adjusted comprehensively to generate a positive signal pulse or a negative signal pulse with a very short duration when the light intensity changes. 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. The positive and negative pulse signals do not affect the detection.

[0055] A four-electrode event-type detection device as shown in Figure 3(a) was prepared on the semiconductor FAPbBr3 for experimental verification. The voltages of the positive electrode 1, the negative electrode 2, and the ring electrode 3 were adjusted comprehensively, and the current signal of 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 the light pulse signal is only generated when the light intensity changes, and no signal is generated when the light intensity is stable. This can achieve the purpose of event-type detection by only detecting the change in light intensity.

[0056] The novel X-ray event-type detector based on perovskite in the present invention is based on applying different bias voltages on different electrodes to adjust the electric field distribution in the three-dimensional perovskite single crystal to achieve zero photocurrent. At the moment 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 of the holes collected by the common electrode from the positive electrode and the electrons collected from the negative electrode, a light pulse signal with a very short duration will be generated on the three-dimensional perovskite single crystal. After the light is stable, the two carriers collected by the common electrode tend to balance again, and the generated light pulse signal disappears. Based on this, the present invention cleverly uses the difference in the mobility of the two carriers in the three-dimensional perovskite single crystal to realize the detection of "light events", without the need for electronic components, and without the need for differential integration of electrical signals. 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, without signal loss, and 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 the three-dimensional perovskite single crystal, 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 a novel X-ray event based on perovskite in embodiment 1, comprising:

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

[0060] When the intensity of X-rays incident on the three-dimensional perovskite single crystal changes, it corresponds to the occurrence of an event, 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.

[0061] Example 3

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

[0063] A MASK mask is used to evaporate a metal electrode on the surface of a three-dimensional perovskite single crystal to obtain a new X-ray event-type detection device based on perovskite; 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] At the moment when the intensity of X-rays incident on the three-dimensional perovskite single crystal changes, corresponding to the occurrence of an event, 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 novel event-type X-ray detector prepared above has extremely fast detection speed and extremely high sensitivity. It is very sensitive to changes in external radiation and can keenly capture slight changes in radiation intensity. Therefore, this device structure has 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 only 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 protection scope of the present invention.

Claims

1. A novel X-ray event detection device based on perovskite, 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 the positive electrode and the negative electrode are respectively applied with positive and negative voltages, and the common electrode is applied with a voltage between the positive and negative voltages; the common electrode is used to collect photocurrent, and the positive and negative voltages respectively applied to the positive electrode and the negative electrode make the photocurrent zero; The photocurrent is the current generated by the three-dimensional perovskite single crystal under the incidence of X-rays; 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 novel X-ray event detection device based on perovskite according to claim 1, characterized in that: 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 the negative electrode respectively; The novel X-ray event-type 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 novel X-ray event detection device based on perovskite according to claim 2, characterized in that: The regulating electrode is a ring electrode or a C-shaped electrode.

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

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

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

7. A novel 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 light intensity of the X-rays 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 a new X-ray event type detection device based on perovskite as described in any one of claims 1 to 6.

8. The novel perovskite-based X-ray event detection method 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 novel X-ray event-type detector based on perovskite 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 novel 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 methylamidine-based bromide perovskite single crystal, a cesium-based bromide perovskite single crystal or a methylamidine-based bromide perovskite single crystal.

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