Method and device for strengthening performance and repairing defects of perovskite photodetector

Abstract

The application discloses a method and device for strengthening performance and repairing defects of a perovskite photoelectric detector, and belongs to the technical field of perovskite photoelectric detectors. The application controls the working temperature of a photoelectric detector, controls and improves the carrier transmission and collection capacity by using the different behaviors of various trap states and ion migration in the material at different temperatures, can inhibit the noise of the detector, improve the detection performance, and also can improve the working stability of the detector, so that a high-efficiency and stable perovskite photoelectric detector is obtained. By irradiating the photoelectric detector with photons lower than the band gap of the material during or after working, the ion movement in the material is promoted, which is helpful to repairing the damaged lattice of the material and filling the charge defects in the material, so that the noise of the device and the carrier transmission properties are reduced, and the photoelectric detection performance of the detector is improved. The two methods are combined to further improve the performance.

Description

Technical Field

[0001] This invention belongs to the field of perovskite photodetector technology, specifically relating to a method and apparatus for enhancing the performance of perovskite photodetectors and repairing defects. Background Technology

[0002] Semiconductor photodetectors, especially high-energy radiation detectors, have important applications in national security, medical imaging, space applications, and scientific research. In recent years, metal halide perovskite materials have become the main candidate materials for next-generation photodetectors due to their advantages such as high atomic number, balanced carrier mobility, rapid carrier extraction capability, and low-cost large-scale fabrication. Their key performance indicators in visible light and high-energy radiation detectors have significantly surpassed those of traditional semiconductor detector materials.

[0003] In photoelectric detection, especially in low-dose detection, the carrier concentration generated per photon is low. When the well state density is greater than or equal to the carrier concentration generated by the photon, it will significantly affect carrier transport and extraction in perovskite photodetectors. Generally, carrier extraction can be promoted by increasing the electric field strength, or carrier mobility can be improved or crystal defect density can be reduced through alloying doping. In the fabrication of various semiconductor materials, although defect concentration can be reduced by controlling material growth, various deep-level or shallow-level defects are still unavoidable, which will significantly affect the performance of the fabricated devices. Furthermore, perovskite materials are prone to ion migration under high electric fields, which can cause device baseline drift and the generation of new defects. Summary of the Invention

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of existing perovskite photodetectors, such as various defects and poor device performance resulting from long-term operation. This invention enhances the performance and stability of perovskite photodetectors through external field environments such as light, heat, and force, and repairs internal material defects through light fields, thereby restoring detector performance. In this invention, photodetectors prepared from metal halide perovskite materials improve device performance and repair material defects through methods such as illumination, electric fields, and temperature control, achieving simultaneous improvement in device stability and performance.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] A method for enhancing the performance and repairing defects in a perovskite photodetector, wherein the photon energy range detectable by the perovskite photodetector includes high-energy rays such as conventional X-rays and gamma rays, as well as lower-energy visible light photons.

[0007] The specific performance enhancement method is as follows:

[0008] 1) Control the operating temperature of the perovskite photodetector device to be lower than the ion activation temperature of the perovskite photodetector device material.

[0009] and / or

[0010] 2) Irradiate the perovskite photodetector with photons of energy lower than the material's bandgap transition energy during or after operation; the wavelength of the irradiating photon is based on the relationship between the material's bandgap transition energy and wavelength:

[0011]

[0012] Planck's constant h = 4.1356676969 × 10 -15 eV·s, speed of light c = 3 × 10 17 nm·s -1 Choose a wavelength higher than the calculated result.

[0013] The ion activation temperature is calculated by fitting the conductivity test results at different temperatures.

[0014] The perovskite photodetector device described in this invention is a single-pixel photodetector or a multi-pixel array photodetector.

[0015] The apparatus of the present invention, based on the method for enhancing the performance and repairing defects of perovskite photodetectors, comprises a cooling device for controlling the operating temperature of the perovskite photodetector and / or a device for irradiating the perovskite photodetector with photons.

[0016] Preferably, the cooling device is an operating temperature control module disposed around the detector.

[0017] Preferably, the cooling device controls the operating temperature of the detector by applying cold gas around the detector or by immersing, wrapping, or contacting the detector with a light-transmitting and heat-conducting medium.

[0018] The device used to irradiate the perovskite photodetector with photons is a light source with a specific wavelength range spectrum or a broadband light source containing a specific wavelength spectrum.

[0019] The beneficial effects of this invention are:

[0020] In step 1) of this invention, the operating temperature of the photodetector is controlled by an integrated temperature control device. By utilizing the different behaviors of various trap states in the material at different temperatures, the carrier transport behavior is controlled. For example, the activity of trap states in the material changes with temperature. At low temperatures, the activity decreases or even freezes completely, thereby avoiding the capture of photogenerated carriers. This can also improve the noise of the device to obtain a high-efficiency perovskite photodetector. It can also suppress ion migration in the material and improve the stability of the device.

[0021] In step 2) of this invention, by irradiating the photodetector with photons below the material band gap during or after operation, defect repair is promoted and ion migration in the material is accelerated. This helps to repair the damaged lattice of the material and fill the charge defects in the material, thereby reducing device noise and enhancing properties such as charge carrier transport, so as to improve the photoelectric conversion performance of the perovskite detector.

[0022] By combining the two effective enhancement methods in steps 1) and 2), the trapping of generated charge carriers by defects can be further suppressed, effectively improving the performance of the detector. Attached Figure Description

[0023] Figure 1 Comparison of device dark current at different temperatures;

[0024] Figure 2 Comparison of device noise at different temperatures;

[0025] Figure 3 The ratio of light to dark current of the device at different temperatures;

[0026] Figure 4 At different temperatures 241 Energy spectrum resolution comparison of Am;

[0027] Figure 5 Analysis of ion migration activation temperature of materials used in the fabrication of radiation detectors;

[0028] Figure 6 Comparison of dark current stability of the device before and after applying infrared light;

[0029] Figure 7 Comparison of device noise after applying infrared light;

[0030] Figure 8 Comparison of the device's X-ray sensitivity before and after the application of infrared light;

[0031] Figure 9 Comparison of device dark current before and after applying infrared light;

[0032] Figure 10 Comparison of the light and dark current step curves of the device before and after applying infrared light.

[0033] Figure 11 Light-dark step curves of photodetectors under visible light at different temperatures.

[0034] Figure 12 A schematic diagram of the performance enhancement device for the metal halide perovskite radiation detector in this invention.

[0035] In the figure: 1-Metal halide perovskite photodetector, 2-Temperature control module, 3-Photon irradiation source, 4-Transparent heat-conducting medium. Detailed Implementation

[0036] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0037] Example 1

[0038] This embodiment discloses a method for enhancing the performance and repairing defects in a perovskite photodetector, wherein the photodetector comprises a perovskite photodetector device based on perovskite material; the performance enhancement method is specifically as follows:

[0039] 1) Control the operating temperature of the perovskite photodetector device. The control temperature should be lower than the ion activation temperature of the perovskite photodetector device material, usually set to -80℃ to 20℃.

[0040] and / or

[0041] 2) Irradiate the perovskite photodetector with photons of energy lower than the material's bandgap transition energy during or after operation; the wavelength of the irradiating photon is based on the relationship between the material's bandgap transition energy and wavelength:

[0042]

[0043] Planck's constant h = 4.1356676969 × 10 -15 eV·s, speed of light c = 3 × 10 17 nm·s -1 Choose a wavelength higher than the calculated result.

[0044] The perovskite photodetector described in this embodiment is a single-pixel photodetector or a multi-pixel array photodetector.

[0045] The wavelength of the irradiating photon is selected based on the relationship between the bandgap transition energy and wavelength of the material, and the wavelength is higher than the calculated result. For example, if the radiation detection device is a methylamine lead iodide-based perovskite material with a bandgap of 1.55 eV, light with a wavelength higher than 800 nm can be selected, such as 850 nm, 940 nm, or 1200 nm; as another example, if the radiation detection device is a methylamine lead bromide-based perovskite material with a bandgap of 2.22 eV, light with a wavelength higher than 600 nm can be selected.

[0046] Effect verification

[0047] Example 1

[0048] Using X-ray detectors and gamma-ray energy-resolved detectors prepared from methylaminolead iodide perovskite single crystals as examples, we verify the effect of temperature control on enhancing the performance of photoelectric detectors.

[0049] The prepared photodetector was placed on a temperature control console, and the temperature of the device was controlled by changing the temperature of the control console. At the same time, the dark current, noise, photocurrent-to-dark-current ratio, and energy spectral resolution of the photodetector under irradiation were tested at different temperatures.

[0050] (1) where Figure 1 This is a comparison chart of the dark current of the same device at 20℃, 0℃, and -30℃.

[0051] (2) where Figure 2 A comparison of the noise levels of the same device at 20°C and -30°C.

[0052] (3) Figure 3 The ratio of photocurrent to dark current of the same device at 20℃, 0℃, and -30℃.

[0053] (4) where Figure 4 For the same device at 20℃, 0℃, and -30℃ 241 Comparison of the spectral resolution of Am sources.

[0054] By comparing the above sets of key data, it can be clearly seen that the basic properties of the same device can be improved by temperature control, which ultimately enhances the high-energy radiation spectrum resolution of metal halide perovskite photodetectors.

[0055] Example 2

[0056] Taking methylamine lead-iodine single crystal and methylamine lead-iodine polycrystalline thin films as examples, the ion migration activation temperature of single crystal and polycrystalline films was calculated by temperature variation test.

[0057] Single-crystal and polycrystalline radiation detectors were placed on a temperature control console, and their conductivity was tested at different temperatures. The ion activation temperatures of both detectors were then calculated through fitting. Figure 5 As shown.

[0058] Based on the above calculations, the ion activation temperatures of single crystal and polycrystalline are 279K (6℃) and 275K (2℃), respectively. Therefore, controlling the device operating temperature below the ion migration activation temperature can suppress ion migration in the device during operation, thereby significantly improving the working stability of the device and materials.

[0059] Example 3

[0060] Taking an X-ray detector fabricated from a single crystal of methylaminolead iodide perovskite as an example, this study verifies the performance enhancement effect of photons below the material's band gap. The absorption cutoff of methylaminolead iodide perovskite is approximately 800 nm; in this embodiment, near-infrared light at 1200 nm was selected as the experimental light.

[0061] First, the prepared X-ray detector device was subjected to high voltage damage, and then irradiated with 1200nm near-infrared light to compare the basic properties of the device before and after irradiation.

[0062] (1) where Figure 6 The dark current stability of a damaged device before and after infrared irradiation.

[0063] (2) where Figure 7 To compare the device noise before and after applying infrared light to the damaged device, and to verify the recovery effect by simply leaving it in a static state for a period of time.

[0064] (3) Figure 8 This is a comparison of the X-ray sensitivity of the radiation device before and after infrared irradiation.

[0065] By comparing the above sets of key data, it can be clearly seen that if the device is damaged by a large electric field, it will exhibit unstable dark current and high noise, and the sensitivity to X-ray detection will also decrease significantly. However, after being irradiated with infrared light, the device exhibits lower dark current and noise levels, and also improves the detection performance of X-rays.

[0066] Example 4

[0067] This embodiment uses an X-ray detector fabricated from a single crystal of methylaminolead bromide perovskite as an example to verify the performance enhancement effect of photons below the material's bandgap. The absorption cutoff of methylaminolead bromide perovskite is approximately 570 nm; therefore, this embodiment selects near-infrared light at 1200 nm and 850 nm as the experimental light sources.

[0068] First, the prepared radiation detector device was subjected to high voltage damage, and then irradiated with 1200nm near-infrared light to compare the basic properties of the device before and after irradiation.

[0069] (1) where Figure 9 The dark current stability of the device before and after irradiation with 1200nm infrared light is given.

[0070] (2) where Figure 10 The X-ray dark step response curves of the device before and after irradiation with 850nm near-infrared light are shown.

[0071] By comparing the above sets of key data, it is clear that infrared light irradiation improves the stability of the device's dark current and photoresponse, and also achieves a higher light-to-dark ratio. This also demonstrates that photons below the material's bandgap can have a similar effect on the device.

[0072] Example 5

[0073] This embodiment uses a visible light detector prepared by methylamine dimethylamine lead-iodine single crystal as an example to verify the effect of temperature control on the performance enhancement of photodetector devices.

[0074] The prepared photodetector was placed on a temperature control console, and the temperature of the device was controlled by changing the temperature of the console. At the same time, the photoelectric response and other properties of the photodetector were tested at different temperatures.

[0075] in Figure 11 The curves showing the light and dark steps of the photodetector under visible light at different temperatures are shown.

[0076] By comparing the data above, it is clear that the performance of photoelectric detectors can be improved by controlling the temperature of the same device.

[0077] The above results verify the effectiveness and feasibility of the performance enhancement method of the present invention. Therefore, based on this method, existing photodetectors can be improved by adding a cooling device for the operating temperature of the photodetector and / or a device for irradiating the photodetector with photons, thus implementing the performance enhancement method of the present invention.

[0078] like Figure 12 As shown in (a), the cooling device is a temperature control module 2, which is set above and below the photodetector 1. The light source 3, which is used to irradiate the photodetector 1 with photons, is set on both sides of the photodetector 1. The photodetector 1 is irradiated with photons and its temperature is controlled by a light-transmitting and heat-conducting medium 4 wrapped around it.

[0079] Alternatively, one can use, such as Figure 12(b) shows that the temperature control module 2 is positioned below the photodetector 1, and the photon irradiation source 3 is positioned above the photodetector 1. Photon irradiation and temperature control are applied to the photodetector 1 through a light-transmitting and heat-conducting medium 4 that is wrapped around the photodetector 1.

[0080] Or adopt such as Figure 12 As shown in (c), the temperature control module 2 and the photon irradiation source 3 are both placed on the upper and lower sides of the photodetector 1, and photon irradiation and temperature control are applied to the photodetector 1 through the light-transmitting and heat-conducting medium 4 wrapped around the photodetector 1.

[0081] The above methods are some of the feasible solutions of the present invention, and do not represent all the feasible solutions of the present invention.

Claims

1. A method for enhancing the performance and repairing defects in a perovskite photodetector, wherein the photodetector comprises a perovskite photodetector device based on perovskite material; characterized in that, The steps of the performance enhancement method are as follows: 1) Control the operating temperature of the perovskite photodetector device to be lower than the ion activation temperature of the perovskite photodetector device material. and / or 2) Irradiate the perovskite photodetector with photons of energy lower than the material's bandgap transition energy during or after operation; the wavelength of the irradiating photon is based on the relationship between the material's bandgap transition energy and wavelength: Planck's constant h = 4.1356676969 × 10 -15 eV·s, speed of light c = 3 × 10 17 nm·s -1 Choose a wavelength higher than the calculated result.

2. The method for enhancing the performance and repairing defects of a perovskite photodetector according to claim 1, characterized in that, The ion activation temperature of the perovskite material is a standard indicator parameter in the field, which can be calculated by fitting the conductivity test results at different temperatures.

3. The method for enhancing the performance and repairing defects of a perovskite photodetector according to claim 1, characterized in that, The perovskite photodetector is a single-pixel photodetector or a multi-pixel array photodetector.

4. An apparatus for enhancing the performance and repairing defects of a perovskite photodetector based on the method of claim 1, characterized in that, The device consists of a cooling device for controlling the operating temperature of the perovskite photodetector and / or a device for irradiating the perovskite photodetector with photons.

5. The device for enhancing the performance and repairing defects of a perovskite photodetector according to claim 4, characterized in that, The cooling device is an operating temperature control module located around the detector.

6. The apparatus for enhancing the performance and repairing defects of a perovskite photodetector according to claim 4 or 5, characterized in that, The cooling device controls the operating environment temperature of the detector by applying cold gas and / or liquid medium, or by immersing, wrapping, or contacting the detector.

7. The device for enhancing the performance and repairing defects of a perovskite photodetector according to claim 4, characterized in that, The device used to irradiate perovskite photodetectors with photons is a light source that can emit photons with energy lower than the material's bandgap transition energy.

8. The device for enhancing the performance and repairing defects of a perovskite photodetector according to claim 6, characterized in that, The temperature transfer medium of the cooling device is capable of both light transmission and heat conduction.

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