Method for driving perovskite X-ray detector by pulse voltage and perovskite X-ray array detection system

Abstract

The invention provides a method for driving a perovskite X-ray detector through pulse voltage and a perovskite X-ray array detection system, and belongs to the technical field of photoelectric detection.According to the method, the pulse voltage is used for weakening ion migration and current injection in a perovskite material, so that drifting of dark current and light current of the perovskite X-ray detector is restrained, and the performance of the perovskite X-ray detector is improved. The energy consumption and heat accumulation of the detector are reduced, specifically, pulse voltage acts on the two ends of an electrode of the perovskite X-ray detector, and a current signal in the pulse voltage excitation application process is recorded. Based on the method provided by the invention, the radiation detection current stability of the perovskite X-ray detector can be improved, the device energy consumption and the element cost are further reduced, and the commercialization pace of the perovskite X-ray detector is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of perovskite photoelectric detection, and specifically relates to a method for enhancing the stability of a perovskite X-ray detector with pulse voltage and a perovskite X-ray array detector. Background Art

[0002] X-rays are widely used in medicine and defense, and stable and accurate measurement of X-rays is of great significance. Halide perovskite materials have excellent photoelectric properties such as large radiation absorption coefficient and balanced carrier mobility lifetime product, and are considered to be ideal materials for the next generation of ionizing radiation detection.

[0003] DC bias is the simplest way to drive the perovskite X-ray detector, but because the perovskite material is an ionic crystal, its soft lattice structure makes the interaction between the components weak, and ion migration and charge carrier injection will occur under the action of the DC bias electric field. In particular, long-term operation under high bias voltage will prevent the migration of ions from being restored, resulting in drift of dark current and photocurrent, and electrochemical corrosion of the cathode, which seriously affects the working stability of the perovskite X-ray detector. Existing reports mostly improve the material device itself, but the stability of its passivation, doping and other processing processes is controversial; AC drive optimization as a post-processing method is not limited by the material device processing process, and has also been recognized in improving the ion migration of the perovskite absorption layer and the long-term stability of the device, but the continuous application of voltage increases energy consumption, leading to heat accumulation problems under long-term power-on operation, especially for array detectors. Summary of the invention

[0004] The present invention aims to solve the current drift problem under DC bias and the component energy consumption cost problem existing in the working process of the above-mentioned existing perovskite X-ray detectors. The main purpose of the present invention is to provide a method for enhancing the light response stability of the perovskite X-ray detector by using pulse voltage, thereby effectively weakening ion migration and charge carrier injection, achieving the suppression of dark current and photocurrent drift and cathode interface electrochemical corrosion, reducing component energy consumption and heat accumulation under continuous bias, and promoting the commercialization of perovskite X-ray detectors.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] A method for driving a perovskite X-ray detector using a pulse voltage:

[0007] The perovskite X-ray detector is connected to a pulse voltage, which drives the perovskite X-ray detector and records the current signal during the pulse voltage action stage with or without X-ray irradiation.

[0008] The pulse voltage is a periodic voltage signal, including several pulse voltage cycles.

[0009] The pulse voltage cycle includes a pulse voltage application phase and a waiting phase without voltage application.

[0010] The time of the application phase is t1,

[0011] The waiting period is t2.

[0012] Preferably, t1 and t2 satisfy the following conditions:

[0013] t2≥2t1, and 0s<t1≤50ms.

[0014] Preferably, the amplitude m of the pulse voltage satisfies 0<m≤200V.

[0015] Preferably, the pulse voltage is composed of any waveform of a rectangular wave, a trapezoidal wave, a sine wave, a triangular wave, and waves generated by calculation thereof.

[0016] The current signal includes a dark current signal and a photocurrent signal.

[0017] The dark current signal is the current signal during the complete action phase of the pulse voltage without X-ray irradiation.

[0018] The photocurrent signal is a current signal during the complete action phase of the pulse voltage during the X-ray irradiation process.

[0019] A perovskite X-ray array detection system, characterized in that:

[0020] 1) A perovskite absorption layer, with a first gate electrode and a second gate electrode disposed on two sides thereof;

[0021] 2) The pulse voltage source is connected to the first gate electrode and the second gate electrode respectively through two multi-channel switch chips;

[0022] 3) The ammeter is connected in series between the pulse voltage source and the multi-channel switch chip to read the current signal generated by the pulse voltage signal.

[0023] The two layers of gate electrodes are orthogonal to each other; wherein, the orthogonal positions of the gate electrodes are the working pixels of the array detector, and the array pixels are selected by a multi-channel switch chip.

[0024] The gate electrode is a single-layer or multi-layer electrode deposited by vacuum thermal evaporation or magnetron sputtering.

[0025] The perovskite absorption layer is a three-dimensional perovskite single crystal prepared by one or both of a solution method and a melt method.

[0026] Compared with the prior art, the advantages of the present invention include:

[0027] 1) The present invention adopts pulse voltage to work, which can effectively weaken the ion migration of the perovskite material compared with the DC bias voltage of the existing working mode, thereby suppressing the dark current and photocurrent drift, and improving the working stability of the perovskite X-ray detector.

[0028] 2) The present invention adopts pulse voltage to work, which can effectively reduce the electrochemical corrosion of the electrode interface compared with the DC bias of the existing working mode, avoid the introduction of additional barrier layers, and reduce the detector preparation cost.

[0029] 3) The present invention adopts pulse voltage to drive the perovskite X-ray detector, which can effectively reduce the energy consumption and heat accumulation problems during the DC bias application process, switch the working pixel points of the perovskite X-ray array detector during the waiting time, and apply pulse voltage drive alternately in sequence to the array pixel points according to the method of driving the perovskite X-ray detector with pulse voltage, thereby reducing component costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a method for driving a perovskite X-ray detector with a pulse voltage and a perovskite X-ray array detector system according to the present invention;

[0031] Figure 2 is a schematic diagram of pulse voltage parameters of the present invention;

[0032] Figure 3 is an IT curve diagram of the response of the perovskite X-ray detector to the X-ray switch obtained under a 3V DC bias in Example 1 of the present invention;

[0033] Figure 4 is an IT curve diagram of the response of the perovskite X-ray detector to the X-ray switch obtained under a pulse voltage of 3V in Example 1 of the present invention;

[0034] Figure 5 is an IT curve diagram of the response of a single pixel point of a perovskite X-ray array detector to an X-ray switch obtained under a 5V DC bias in Example 2 of the present invention;

[0035] Figure 6 It is an IT curve diagram of the response of the perovskite X-ray detector to the X-ray switch obtained under a 120V pulse bias in Example 2 of the present invention. DETAILED DESCRIPTION

[0036] 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.

[0037] Figure 1 The present invention is a schematic diagram of the working structure of the perovskite X-ray array detector. The perovskite X-ray array detector working structure involved in the method comprises a first gate electrode (1); a perovskite absorption layer (2); a second gate electrode (3); multi-channel switch chips (4) and (5); a pulse voltage source (6), which is connected in series with any electrode in the first gate electrode (1) and any electrode in the second gate electrode (3) through the multi-channel switch chip (4) (5), and is used to apply the pulse voltage of any one of claims 1 to 4 to the perovskite absorption layer (2); an ammeter (7), which is used to measure and record the current signal flowing through the pixel point of the perovskite array.

[0038] Figure 2 The pulse voltage cycle schematic diagram of the present invention. The pulse voltage application time and waiting time described in the method constitute a single pulse voltage cycle, wherein the pulse voltage application time t1 and the waiting time t2 satisfy t2≥2t1, and 0s<t1≤50ms; the pulse voltage amplitude m satisfies 0<m≤200V.

[0039] In this example, the material in the perovskite absorber is a three-dimensional perovskite single crystal, and the first gate electrode C is deposited in sequence through a mask. 60 , BCP and Au; second gate electrode Au.

[0040] In this embodiment, the X-rays are irradiated onto the array pixel points of the first gate electrode of the perovskite X-ray array detector after being constrained by the aperture.

[0041] In this embodiment, the comparison pulse voltage source (6) is replaced by a DC voltage source for comparison of X-ray switch current response under DC bias, taking a single pixel as an example.

[0042] The following are specific embodiments:

[0043] Implementation Case 1:

[0044] The material in the perovskite absorption layer in this example is MAPbBr3 single crystal prepared by solution method, and the MAPbBr3 detector is exposed to a dose of 7.814 μGy air s -1X-ray irradiation, the X-ray cycle is 60s, the DC voltage source provides a DC bias voltage of 3V for the MAPbBr3 single crystal detector; the pulse voltage source provides a pulse voltage for the MAPbBr3 single crystal detector, and the pulse voltage parameters are application time t1=50ms and waiting time t2=1s.

[0045] Figure 3 The IT curve of the MAPbBr3 single crystal detector irradiated by X-rays under a DC bias of 3V. Through three cycles of X-ray switching response, we get the trend of X-ray photocurrent and dark current over time. It can be seen that under the action of DC bias, ion migration and interface injection occur in the perovskite absorption layer, causing serious dark current and photocurrent drift, obvious noise, and the accumulated drift of about 35nA in 200s.

[0046] Figure 4 This is the IT curve of the MAPbBr3 single crystal detector irradiated by X-rays under a pulse bias of 3V. Through three cycles of X-ray switching response, we can obtain the changing trend of X-ray photocurrent and dark current over time. It can be seen that the internal ion migration accumulation of the perovskite material is suppressed under the action of the pulse voltage, so the obtained dark current and photocurrent are very stable over time, without obvious drift and noise.

[0047] Figure 3 and Figure 4 All of them are actual test result diagrams. The comparison shows that the method of the present invention effectively solves the current injection and ion migration problems caused by DC bias, reduces the drift of photocurrent and dark current, and shortens the voltage action time, which also weakens the occurrence of interfacial electrochemical reactions and reduces energy consumption. The method provided by the present invention drives the perovskite X-ray detector through pulse voltage, which significantly improves the stability of the device.

[0048] Implementation Case 2:

[0049] The material of the perovskite absorption layer in this example is CsPbBr3 single crystal prepared by melt process, and the CsPbBr3 detector is exposed to a dose of 1.017 μGy air s -1 For X-ray irradiation, the DC voltage source provides a DC bias voltage of 5 V for the CsPbBr3 single crystal detector, and the X-ray light cycle is 60 s; the pulse voltage source provides a pulse voltage of 120 V for the MAP bBr3 single crystal detector, and the pulse voltage parameters are application time t1 = 50 ms, waiting time t2 = 3 s, and the X-ray light cycle is 100 s.

[0050] Figure 5The IT curve of the CsPbBr3 single crystal detector irradiated by X-rays under a DC bias of 5 V. Through three cycles of X-ray switching response, we obtain the variation trend of X-ray photocurrent and dark current over time. It can be seen that under the action of DC bias, ion migration and interface injection occur in the perovskite absorption layer, resulting in serious dark current and photocurrent drift, with a cumulative drift of about 2 nA in 170 s.

[0051] Figure 6 The IT curve of the CsPbBr3 single crystal detector irradiated by X-rays under a pulse bias of 120V. Through the X-ray switch response of three cycles, we can get the change trend of X-ray photocurrent and dark current over time. It can be seen that the internal ion migration accumulation of the perovskite material is suppressed under the action of the pulse voltage, so the obtained dark current and photocurrent are very stable over time, and the drift is negligible.

[0052] Figure 5 and Figure 6 All of them are actual test result diagrams. The comparison shows that the method of the present invention effectively solves the current injection and ion migration problems caused by DC bias, reduces the drift of photocurrent and dark current, and shortens the voltage action time, which also weakens the occurrence of interfacial electrochemical reactions and reduces energy consumption. The method provided by the present invention drives the perovskite X-ray detector through pulse voltage, which significantly improves the stability of the device.

[0053] The above embodiments can prove that compared with the DC bias voltage, the pulse voltage driving the perovskite X-ray detector can effectively improve the stability of the perovskite X-ray detector; at the same time, the pulse voltage can effectively reduce energy consumption and reduce the heat problem generated by the long-term power-on of the detector. The method of the present invention is applicable to a variety of perovskite materials and perovskite X-ray detectors of various structures, especially perovskite X-ray array detectors.

[0054] 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 method for driving a perovskite X-ray detector with a pulse voltage, characterized in that: The following steps are involved: The perovskite X-ray detector is connected to a pulse voltage, which drives the perovskite X-ray detector and records the current signal during the pulse voltage action stage with or without X-ray irradiation.

2. The method for driving a perovskite X-ray detector with a pulse voltage according to claim 1, characterized in that: The pulse voltage is a periodic voltage signal, including several pulse voltage cycles; the pulse voltage cycle includes a pulse voltage application phase and a waiting phase without voltage application; the application phase time is t1; the waiting phase time is t2; t1 and t2 meet the following conditions: t2≥2t1, and 0s<t1≤50ms.

3. The method for driving a perovskite X-ray detector with a pulse voltage according to claim 1, characterized in that: The amplitude m of the pulse voltage satisfies 0<m≤200V.

4. The method for driving a perovskite X-ray detector with a pulse voltage according to claim 1, characterized in that: The pulse voltage is composed of any waveform of a rectangular wave, a trapezoidal wave, a sine wave, a triangular wave, and waves generated by calculation thereof.

5. The method for driving a perovskite X-ray detector with a pulse voltage according to claim 1, characterized in that: The current signal includes a dark current signal and a photocurrent signal; the dark current signal is a current signal in the stage when the pulse voltage is fully applied during the process without X-ray irradiation; the photocurrent signal is a current signal in the stage when the pulse voltage is fully applied during the process with X-ray irradiation.

6. A perovskite X-ray array detection system, characterized in that: From top to bottom, it includes: 1) A perovskite absorption layer, with a first gate electrode and a second gate electrode disposed on two sides thereof; 2) The pulse voltage source is connected to the first gate electrode and the second gate electrode respectively through two multi-channel switch chips; 3) The ammeter is connected in series between the pulse voltage source and the multi-channel switch chip to read the current signal generated by the pulse voltage signal.

7. The perovskite X-ray array detection system according to claim 6, characterized in that: The two layers of gate electrodes are orthogonal to each other; wherein, the orthogonal positions of the gate electrodes are the working pixels of the array detector, and the array pixels are selected through a multi-channel switch chip.

8. The perovskite X-ray array detection system according to claims 6-7, characterized in that: The gate electrode is a single-layer or multi-layer electrode deposited by vacuum thermal evaporation or magnetron sputtering.

9. The perovskite X-ray array detection system according to claim 6, characterized in that: The perovskite absorption layer is a three-dimensional perovskite single crystal prepared by one or both of a solution method and a melt method.

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