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

Abstract

The application provides a method for driving a perovskite X-ray detector by a pulse voltage and a perovskite X-ray array detection system, and belongs to the technical field of photoelectric detection. The method uses a pulse voltage to weaken ion migration and current injection in perovskite materials, thereby inhibiting the drift of dark current and photocurrent of the perovskite X-ray detector, reducing the energy consumption and heat accumulation of the detector. Specifically, the pulse voltage is applied across the electrodes of the perovskite X-ray detector, and the current signal during the excitation and application of the pulse voltage is recorded. The method provided by the application can improve the radiation detection current stability of the perovskite X-ray detector, further reduce the device energy consumption and element cost, and promote the commercialization pace of the perovskite X-ray detector.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite photoelectric detection, and particularly 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 fields such as medicine and defense, and stable and accurate X-ray measurement is crucial. Halide perovskites, with their excellent optoelectronic properties, such as large radiation absorption coefficients and balanced carrier mobility lifetime products, are considered ideal materials for the next generation of ionizing radiation detection.

[0003] DC bias is the simplest way to drive perovskite X-ray detectors. However, because perovskite is an ionic crystal with a soft lattice structure that results in weak interactions between components, ion migration and charge carrier injection occur under the action of a DC bias electric field. Long-term operation under high bias voltages, in particular, prevents the migration of ions from being recovered, leading to drift in dark current and photocurrent, and electrochemical corrosion of the cathode, which seriously affects the stability of perovskite X-ray detectors. Existing reports have mostly focused on improving the materials and devices themselves, but the stability of passivation and doping processes remains controversial. AC drive optimization, as a post-processing method, is not limited by the material and device processing, and has also been recognized for improving ion migration in the perovskite absorber layer and the long-term stability of the device. However, the continuous application of voltage increases energy consumption, leading to heat accumulation during long-term power-on operation, especially in array detectors. Summary of the Invention

[0004] The present invention aims to address the current drift issues and component energy cost issues associated with DC bias in existing perovskite X-ray detectors. The main objective of the present invention is to provide a method for enhancing the photoresponse stability of perovskite X-ray detectors using pulsed voltages. This method effectively reduces ion migration and charge carrier injection, suppressing dark current and photocurrent drift, and electrochemical corrosion at the cathode interface. This reduces component energy consumption and heat accumulation under continuous bias, ultimately advancing the commercialization of perovskite X-ray detectors.

[0005] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[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 in the pulse voltage action stage with and without X-ray irradiation.

[0008] The pulse voltage is a periodic voltage signal, which includes 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 selected from rectangular waves, trapezoidal waves, sine waves, triangular waves, 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 by:

[0020] 1) A perovskite absorption layer, with a first gate electrode and a second gate electrode disposed on both 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 the 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 operate, which can effectively weaken the ion migration of the perovskite material compared with the DC bias 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 operation, 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 an additional barrier layer, and reduce the cost of detector preparation.

[0029] 3) The present invention uses 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. The working pixels of the perovskite X-ray array detector are switched during the waiting time. For the array pixels, the pulse voltage drive method of the perovskite X-ray detector is used to apply pulse voltage alternately in sequence, thereby reducing component costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure 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 1 is a schematic diagram of pulse voltage parameters according to 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 voltage in Example 1 of the present invention;

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

[0034] Figure 5 is an IT curve diagram of the response of a single pixel 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 3 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 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.

[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); and 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 This is a schematic diagram of the pulse voltage cycle described in 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; and 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 confined by the aperture and irradiated onto the array pixel points of the first gate electrode of the perovskite X-ray array detector.

[0041] In this embodiment, the contrast pulse voltage source (6) is replaced by a DC voltage source for contrasting the 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. The MAPbBr3 detector is exposed to a dose of 7.814 μGy air s -1The X-ray irradiation is carried out, 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 following is an IT curve for a MAPbBr3 single-crystal detector exposed to X-rays at a 3V DC bias. The X-ray on-off response over three cycles reveals the temporal trends of the X-ray photocurrent and dark current. The DC bias causes ion migration and interface injection in the perovskite absorber, resulting in significant dark current and photocurrent drift and significant noise. The cumulative drift over 200 seconds is approximately 35nA.

[0046] Figure 4 The following is an IT curve for a MAPbBr3 single-crystal detector exposed to X-rays at a 3V pulsed bias. Three cycles of X-ray on-off response reveal the temporal trends of the X-ray photocurrent and dark current. This indicates that the pulsed voltage suppresses ion migration and accumulation within the perovskite material, resulting in highly stable dark current and photocurrent over time, with no significant drift or noise.

[0047] Figure 3 and Figure 4 All of them are actual test result figures. 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, shortens the voltage action time, and also reduces the occurrence of interfacial electrochemical reactions, reducing 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 method. 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. 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 following is an IT curve for a CsPbBr3 single-crystal detector exposed to X-rays at a 5V DC bias. The X-ray on-off response over three cycles reveals the temporal trends of the X-ray photocurrent and dark current. The DC bias causes ion migration and interface injection in the perovskite absorber layer, resulting in significant dark current and photocurrent drift, with a cumulative drift of approximately 2 nA over 170 seconds.

[0051] Figure 6 The following is an IT curve for a CsPbBr3 single-crystal detector exposed to X-rays at a 120V pulsed bias. The X-ray switching response over three cycles reveals the temporal trends of the X-ray photocurrent and dark current. This indicates that the pulsed voltage suppresses ion migration and accumulation within the perovskite material, resulting in very stable dark current and photocurrent over time, with negligible drift.

[0052] Figure 5 and Figure 6 All of them are actual test result figures. 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, shortens the voltage action time, and also reduces the occurrence of interfacial electrochemical reactions, reducing 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 examples demonstrate that, compared to DC bias, pulsed voltage can effectively improve the stability of perovskite X-ray detectors. Furthermore, pulsed voltage can effectively reduce energy consumption and mitigate the heat generated by long-term power-on of the detector. The method of the present invention is applicable to perovskite X-ray detectors made of various perovskite materials and structures, particularly perovskite X-ray array detectors.

[0054] 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 X-ray array detection system, characterized in that: From top to bottom, it includes: A perovskite absorption layer, wherein a first side surface of the perovskite absorption layer is provided with a plurality of first gate electrodes, and a second side surface of the perovskite absorption layer is provided with a plurality of second gate electrodes; A pulse voltage source, used for generating a pulse voltage signal; a first multi-channel switch chip and a second multi-channel switch chip, wherein the plurality of output terminals of the first multi-channel switch chip are respectively connected to the plurality of first gate electrodes, the plurality of output terminals of the second multi-channel switch chip are respectively connected to the plurality of second gate electrodes, and the pulse voltage source is connected to the selected first gate electrode and the second gate electrode through the first multi-channel switch chip and the second multi-channel switch chip; An ammeter, connected in series to the loop between the pulse voltage source and the multi-channel switch chip, for reading the current signal generated by the pulse voltage signal; The first gate electrode and the second gate electrode are orthogonal to each other, and their orthogonal positions constitute the working pixel points of the array detection system.

2. The perovskite X-ray array detection system according to claim 1, characterized in that: The pulse voltage is a periodic voltage signal, including several pulse voltage cycles; each pulse voltage cycle includes a pulse voltage application phase and a waiting phase without voltage application; the application phase lasts for t1; the waiting phase lasts for t2; t1 and t2 satisfy the following conditions: t2≥2t1, and 0s<t1≤50ms.

3. The perovskite X-ray array detection system according to claim 1 or 2, characterized in that: The amplitude m of the pulse voltage satisfies 0<m≤200V.

4. The perovskite X-ray array detection system 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 perovskite X-ray array detection system according to claim 1, characterized in that: The current signal includes a dark current signal and a photocurrent signal; the dark current signal is the current signal during the complete action stage of the pulse voltage during the process without X-ray irradiation; the photocurrent signal is the current signal during the complete action stage of the pulse voltage during the process with X-ray irradiation.

6. The perovskite X-ray array detection system according to claim 1, characterized in that: The gate electrode is a single-layer or multi-layer electrode deposited by vacuum thermal evaporation or magnetron sputtering.

7. 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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