Ultraviolet photoelectric detector based on CsCu2I3 micron line, preparation method, distance measuring device and distance measuring method

Abstract

The invention provides an ultraviolet photoelectric detector based on CsCu2I3 micron wires, a preparation method, a distance measuring device and a distance measuring method, compared with the prior art, a distance sensor used in the ultraviolet photoelectric detector adopts a photoelectric detector formed by the CsCu2I3 micron wires as a probe, accurate real-time distance measurement can be realized on equipment with a relatively small size, and the distance measuring accuracy is greatly improved. The ultraviolet photoelectric detector distance sensor can be widely applied to various portable devices and embedded systems, and is portable and flexible. The distance between the device and the obstacle is calculated in real time by combining the distance sensor and the rear-end circuit, and the efficient distance measuring method is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of distance sensors, and in particular relates to an ultraviolet photoelectric detector based on CsCu2I3 micron wire, a preparation method, a distance measuring device and a distance measuring method. Background Art

[0002] Distance sensor is an optical measuring instrument for measuring distance, and has important applications in environmental monitoring, biomedicine, industrial automation, aerospace, etc. Ultraviolet photodetector is the core device for building distance sensor, which can convert ultraviolet radiation signal into electrical signal based on photoelectric effect.

[0003] Early UV photodetectors were mainly made of silicon materials. Although these detectors can convert UV signals into electrical signals, their measurement accuracy is limited because they also respond to visible light. Traditional UV photodetectors require bulky auxiliary equipment when used and are not easy to carry. Distance sensors built on this basis are difficult to be widely used in various portable devices and embedded systems.

[0004] With the progress of material science, new wide bandgap semiconductor materials such as gallium nitride have gradually emerged and quickly become the mainstream of the market with their high sensitivity to ultraviolet rays, fast response speed, high temperature resistance, and corrosion resistance. However, the production process of gallium nitride materials is complex and the production cost is high. In addition, gallium nitride materials are relatively rigid and are not suitable for use in flexible electronic devices.

[0005] Therefore, there is an urgent need for a highly sensitive and low-power ultraviolet photodetector based on flexible materials. Summary of the invention

[0006] In order to solve the problem that the ultraviolet photodetector in the prior art cannot simultaneously meet the requirements of high sensitivity, low power consumption, suitability for flexible electronic devices, and portability, the present invention provides a CsCu-based ultraviolet photodetector. 2 I 3 Micrometer-line ultraviolet photoelectric detector, preparation method, distance measuring device and distance measuring method.

[0007] In the first aspect, the present invention discloses a CsCu 2 I 3 Micrometer-wire UV photodetectors, including CsCu 2 I 3 Microwire, substrate, CsCu 2 I 3 The ends of the microwires are coated with metal as electrodes, and the middle part is exposed as a photosensitive surface.

[0008] In the second aspect, the present invention also discloses a CsCu 2 I 3A method for preparing a micron-wire ultraviolet photodetector comprises the following steps:

[0009] (1) mixing a solution containing dimethyl sulfoxide, N,N-dimethylformamide, CsI and CuI, stirring and heating; cooling the precursor solution obtained after stirring and heating to room temperature, and filtering through a filter;

[0010] (2) dropping methanol into the precursor solution at an appropriate speed until an insoluble precipitate just appears in the solution, and filtering the precipitate; placing the filtered precursor solution in a small container, sealing it, and nesting the small container in a large container containing methanol and heating it;

[0011] (3) After a period of time, CsCu with uniform thickness grows in the small container. 2 I 3 Micrometer wire; Using optical microscope, the synthesized CsCu 2 I 3 The micrometer wire is placed on a quartz substrate and silver paste is coated on the CsCu 2 I 3 The two ends of the microwire are used as electrodes. After the silver paste is dried, it forms an ohmic contact with the microwire, and the middle part is exposed as a photosensitive surface to construct Ag / CsCu 2 I 3 / Ag structure photodetector.

[0012] In a third aspect, the present invention also discloses a distance measuring device having the aforementioned ultraviolet photoelectric detector, comprising a distance sensor, an MCU and a display panel; the distance sensor comprises a photoelectric probe part and a back-end circuit, wherein the photoelectric probe part comprises an ultraviolet light emitter and the ultraviolet photoelectric detector.

[0013] Furthermore, the distance sensor leads out three pins connected to an external circuit, which are an analog signal output pin, a power supply pin, and a ground pin.

[0014] Furthermore, the MCU is a microcomputer that integrates a central processing unit, a memory, and an input and output interface on an integrated circuit chip, and the memory of the MCU stores computer instructions for controlling the operation of the distance measuring device.

[0015] Furthermore, the voltage signal generated by the distance sensor is transmitted to the 12-bit ADC built into the MCU as an ADC input signal; the ADC converts the obtained voltage analog signal into a digital signal and sends it to the MCU for data processing.

[0016] Furthermore, the display panel is connected to and controlled by the MCU, and the measurement results processed by the MCU are displayed on the display panel in real time.

[0017] In a fourth aspect, the present invention further discloses a distance measurement method using the aforementioned distance measurement device, wherein the ultraviolet light emitter emits an ultraviolet signal of a specific frequency, and after being reflected by the target object, the ultraviolet signal is received by an ultraviolet photodetector; the ultraviolet photodetector uses CsCu 2 I 3 The photoelectric effect of the micron wire converts the received ultraviolet signal into an electric current signal.

[0018] Furthermore, the back-end circuit uses a transimpedance amplifier to convert the current signal obtained by the ultraviolet photodetector into a voltage signal, and the converted voltage signal is between 0 and 3.3V.

[0019] Furthermore, the MCU calculates the distance value according to the received signal, and the formula is expressed as:

[0020]

[0021] Where I is the received UV signal strength, P is the power of the UV light transmitter, and d is the distance between the UV light transmitter and the target object.

[0022] The invention discloses a CsCu-based 2 I 3 Compared with the existing technology, the micron-wire ultraviolet photodetector operates at a lower operating voltage, which directly reduces power consumption. The material has a high photoelectric conversion efficiency, which means that under the same lighting conditions, CsCu 2 I 3 Compared with traditional ultraviolet photodetectors, it can generate more current and consume less energy, and has lower energy consumption when working for a long time.

[0023] The invention discloses a CsCu-based 2 I 3 Preparation method of ultraviolet photodetector of micrometer wire, preparation of flexible CsCu by anti-solvent method 2 I 3 Micrometer wires are suitable for the design of bendable and deformable devices to meet the needs of different application scenarios. They can achieve low-power real-time distance measurement on small portable embedded devices, which are easy to transport and integrate.

[0024] The invention discloses a CsCu-based 2 I 3 The micron-line ultraviolet photodetector ranging device can realize low-power real-time distance measurement on a small portable embedded device. It is easy to transport and integrate, and has broad application prospects in environmental monitoring, medical testing, industrial applications and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1CsCu in the embodiment of the present invention 2 I 3 IV logarithmic characteristic curve of the micrometer-line UV photodetector in dark environment and under 340nm light of different powers;

[0026] Figure 2 is CsCu in the embodiment of the present invention 2 I 3 It characteristic curve of the micrometer-wire UV photodetector repeatedly switched on and off under 5V bias and light of different power density at a wavelength of 340nm;

[0027] Figure 3 is CsCu in the embodiment of the present invention 2 I 3 Photocurrent-optical power density curve of micrometer-wire UV photodetector under 5V bias and 340nm wavelength light;

[0028] Figure 4 is a circuit diagram of a distance sensor in an embodiment of the present invention;

[0029] Figure 5 This is a pin connection diagram of the MCU. DETAILED DESCRIPTION

[0030] The present patent will be further explained below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the following specific implementation methods are only used to illustrate the present patent and are not used to limit the scope of the present patent.

[0031] The invention discloses a CsCu-based 2 I 3 Micrometer-wire UV photodetector. CsCu 2 I 3 Microwires are the preferred material for preparing ultraviolet photodetectors due to their high sensitivity, controllable synthesis method, wide direct band gap, high electron mobility and small size.

[0032] In the present invention, a CsCu 2 I 3 In the preparation method of micron-wire ultraviolet photodetector, CsCu 2 I 3 The microwires are prepared by an anti-solvent method. In this embodiment, the specific steps are as follows:

[0033] First, the prepared solution containing dimethyl sulfoxide (DMSO, 1 mL), N,N-dimethylformamide (DMF, 4 mL), CsI solid (0.5 mmol) and CuI solid (1.0 mmol) was mixed in a magnetic stirring heater at 60 ° C and stirred for 6 h. The precursor solution after heating was cooled to room temperature and filtered through a 0.45 μm filter.

[0034] Then, methanol was dripped into the precursor solution at an appropriate speed until an insoluble precipitate just appeared in the solution, and then the precipitate was filtered through a 0.45μm filter. The filtered precursor solution was placed in a vial, the mouth of the vial was covered with a layer of paraffin film, and the vial was nested in a large beaker containing methanol and heated in a 60℃ oven. After more than ten minutes, CsCu was observed in the vial containing the perovskite precursor solution. 2 I 3 Microwires, whose length is controlled by varying the growth time.

[0035] After three days of growth, CsCu can be picked up from the vial with tweezers. 2 I 3 Micrometer wire. Using an optical microscope, the synthesized CsCu 2 I 3 The microwires are placed on a quartz substrate and then silver paste is coated on the CsCu 2 I 3 The two ends of the microwire are used as electrodes. After the silver paste is dried, it forms an ohmic contact with the microwire, and the middle part is exposed as a photosensitive surface to construct Ag / CsCu 2 I 3 / Ag(MSM) structure photodetector.

[0036] Figure 1 It is the IV logarithmic characteristic curve of the ultraviolet photodetector in a dark environment and under different power illumination (340nm). Figure 1 The comparative experiment under 340nm illumination and dark conditions is shown. Photocurrent is the current generated by the photodetector under illumination conditions. Connect the photodetector to the current measuring instrument and ensure that the connection is correct. Select a 340nm light source and adjust its light intensity to ensure that it illuminates the effective area of ​​the photodetector. Turn on the light source and record the photocurrent values ​​under different light intensities. Gradually adjust the intensity of the light source and record the corresponding current values ​​to draw a curve of the relationship between photocurrent and light intensity. The dark current refers to the current generated by the photodetector under no light conditions. The dark current is mainly caused by thermal excitation and defects of the material. Make sure that the photodetector is in a completely dark environment and avoid interference from any light source for testing. As can be seen from the figure, the photocurrent is greater than the dark current under a 5V bias, and the difference is close to three orders of magnitude, which proves that the photocurrent of the photodetector is sensitive to 340nm detection. The dark current of the device is extremely low, and the photocurrent generated varies significantly for different power illumination conditions.

[0037] Figure 2It is the It characteristic curve of the ultraviolet photodetector repeatedly switched under 5V bias and light of different power density (340nm). The photocurrent and dark current have obvious changes, of which the dark current is about 30pA. The photodetector converts the received light intensity into current output, and its output is positively correlated with the received light power density. The light power density refers to the light power received per unit area, which decreases as the distance between the photodetector and the light source increases. There is an indirect relationship between the output signal of the photodetector and the distance. Combined with the change in the intensity of the reflected light, the distance value can be derived from the output signal. Figure 2 The corresponding 6 different power densities are 2345W / m 2 、914.5W / m 2 、338.1W / m 2 、172.5W / m 2 、3.812W / m 2 , 2.856W / m 2 , the corresponding photocurrents are 18.3nA, 14.72nA, 11.26nA, 6.24nA, 0.924nA, and 0.396nA, and the calculation method of the photocurrent is the corresponding current average value within 10s of illumination. It can be concluded that under a bias voltage of 5V, the ultraviolet light detection effect of the ultraviolet photodetector in this embodiment is good.

[0038] Figure 3 This is the photocurrent-optical power density curve of the ultraviolet photodetector under 5V bias and light with a wavelength of 340nm. By analyzing the width of the linear region, the effective operating range of the photodiode under different lighting conditions is evaluated. The slope of the curve in the linear region reflects the sensitivity of the photodiode. The larger the slope, the more sensitive the photodiode is to changes in optical power. According to the characteristics of the IP curve, appropriate optoelectronic devices are selected in practical applications to meet the needs of specific applications. The curve of photocurrent and optical power density plays a key role in distance detectors, providing information on evaluation, calibration, dynamic range analysis, noise characteristics, saturation characteristics, temperature effects, and response time. The inherent properties of the device determine that there is a relationship between its photocurrent and optical power density, I=AP. θ relationship, where I, P, A, and θ represent photocurrent, light power density, a coefficient that determines the response of photocurrent to illumination, and an index that determines the response of photocurrent to illumination, respectively. Figure 3 The midpoint of the curve is collected according to Figure 2 Theoretically, the photocurrent-optical power density corresponds to I = AP θ Determine that I and P satisfy the linear relationship after taking the logarithm, such as Figure 3 As shown, the slope is 0.812 and the intercept is -9.89, that is, A = e -9.89 ,θ=0.812,I=e-9.89 ·P 0.812 Among them, A and θ are the inherent parameters of the device working under 5V conditions. A and θ are different under different supply voltages or different low-dimensional photodetection devices.

[0039] The invention also discloses a method based on CsCu 2 I 3 The distance measuring device of the micron-line ultraviolet photodetector includes a distance sensor, an MCU and a display panel. The distance sensor includes a photoelectric probe part and a back-end circuit part. The photoelectric probe part includes an ultraviolet light emitter and the aforementioned CsCu based 2 I 3 Micrometer-wire UV photodetector.

[0040] Figure 4 is the circuit diagram of the distance sensor in this embodiment. 2 I 3 Micrometer line photodetector, in this embodiment, the photodetector has a diameter of 5μm and a length of 0.3cm; X2 in the figure is an ultraviolet emitter, in this embodiment, the size of the external emitter is 0.39cm×0.39cm; the thickness of the PCB board is 3mm, and the size is 1cm×0.8cm; the three pins and their corresponding functions are: VCC is responsible for power supply, GND is grounded, and SIG is responsible for output device signals.

[0041] Figure 5 Figure 1 is a pin connection diagram of the MCU. In this embodiment, the MCU model selected is STM32F103C8T6. The PD0 and PD1 pins are used to connect to an external 72MHz crystal oscillator, PB7 and PB6 are used to connect to the display panel through I2C communication, PA14 and PA13 are used to connect to the STLink debugger for code burning, and PA0 is used to receive the analog voltage of the distance sensor and convert it into a digital signal through the MCU's built-in 12-bit ADC.

[0042] The display panel is used as an output interface for human-computer interaction, and is used to receive instructions and signals transmitted by the MCU, and display the corresponding values, showing the data output of the distance sensor. In this embodiment, the OLED driver chip is SSD1306, and I2C communication is adopted.

[0043] The invention also discloses a method based on CsCu 2 I 3 A distance measurement method for a distance measurement device of a micrometer-line ultraviolet photoelectric detector. The method uses the ultraviolet light emitter of the aforementioned distance measurement device to emit an ultraviolet signal of a specific frequency, and after being reflected by the target object, the ultraviolet signal is received by the ultraviolet photoelectric detector; the ultraviolet photoelectric detector uses CsCu 2 I3 The photoelectric effect of the micron wire converts the received ultraviolet signal into a current signal. The back-end circuit mainly uses a transimpedance amplifier to convert the CsCu 2 I 3 The current signal obtained by the photodetector is converted into a voltage signal of 0 to 3.3V and transmitted to the MCU in the ranging device.

[0044] MCU is used for data collection, calculation and command output. Specifically, it receives the digital signal obtained by the built-in ADC module, obtains the distance value through the built-in distance calculation program of the MCU, and calculates the distance value according to the light intensity. This method uses the principle of light attenuation. The light intensity decays with the increase of distance. The distance between the emission source and the target is calculated by measuring the intensity of the returned light. When light propagates in a medium, its intensity is affected by many factors, including the increase of distance, absorption and scattering of the medium, etc. According to the inverse square law, the relationship between the ultraviolet signal I and the distance d is expressed as:

[0045]

[0046] Where I is the received UV signal strength, P is the power of the UV light transmitter, and d is the distance between the UV light transmitter and the target object.

[0047] The present invention provides a CsCu-based 2 I 3 Micrometer line photoelectric detector and ranging method, the photoelectric detector can effectively solve the problems of traditional sensors in performance, cost and applicability through its high sensitivity and low energy consumption. 2 I 3 Microwires are flexible materials that are suitable for the design of bendable and deformable devices to meet the needs of different application scenarios. They can achieve low-power real-time distance measurement on small portable embedded devices and are easy to transport and integrate. They have broad application prospects in environmental monitoring, medical testing, industrial applications and other fields.

Claims

1. A UV photodetector based on CsCu2I3 micrometer wire, characterized in that: The invention comprises a CsCu2I3 micron wire and a substrate. Both ends of the CsCu2I3 micron wire are covered with a metal coating as electrodes, and the middle part is exposed as a photosensitive surface.

2. A method for preparing an ultraviolet photodetector based on CsCu2I3 micrometer wire, characterized in that: The following steps are involved: (1) mixing a solution containing dimethyl sulfoxide, N,N-dimethylformamide, CsI and CuI, stirring and heating; cooling the precursor solution obtained after stirring and heating to room temperature, and filtering through a filter; (2) dropping methanol into the precursor solution until an insoluble precipitate just appears in the solution, and filtering the precipitate; placing the filtered precursor solution in a small container, sealing it, and nesting the small container in a large container containing methanol and heating it; (3) After CsCu2I3 micrometer wires with uniform thickness are grown in a small container, the CsCu2I3 micrometer wires are placed on a quartz substrate, and silver paste is coated on both ends of the CsCu2I3 micrometer wires as electrodes. After the silver paste is dried, it forms an ohmic contact with the micrometer wire, and the middle part is exposed as a photosensitive surface to construct an ultraviolet photodetector with a Ag / CsCu2I3 / Ag structure.

3. A distance measuring device having the ultraviolet photoelectric detector as claimed in claim 1, characterized in that: It includes a distance sensor, an MCU and a display panel; the distance sensor includes a photoelectric probe part and a back-end circuit, wherein the photoelectric probe part includes an ultraviolet light emitter and the ultraviolet photodetector.

4. The distance measuring device according to claim 3, characterized in that: The distance sensor leads to three pins connected to the external circuit, which are an analog signal output pin, a power supply pin, and a ground pin.

5. The distance measuring device according to claim 4, characterized in that: The MCU is a microcomputer that integrates a central processing unit, a memory, and an input and output interface on an integrated circuit chip. The memory of the MCU stores computer instructions for controlling the operation of the distance measuring device.

6. The distance measuring device according to claim 5, characterized in that: The voltage signal generated by the distance sensor is transmitted to the 12-bit ADC built into the MCU as the ADC input signal; the ADC converts the obtained voltage analog signal into a digital signal and sends it to the MCU for data processing.

7. The distance measuring device according to claim 6, characterized in that: The display panel is connected to and controlled by the MCU, and the measurement results processed by the MCU are displayed on the display panel in real time.

8. A distance measurement method using the distance measurement device as claimed in claim 3, characterized in that: The ultraviolet light emitter emits an ultraviolet signal of a specific frequency, and the ultraviolet signal is received by the ultraviolet photodetector after being reflected by the target object; the ultraviolet photodetector utilizes the photoelectric effect of the CsCu2I3 micrometer line to convert the received ultraviolet signal into a current signal.

9. The distance measurement method according to claim 8, characterized in that: The back-end circuit uses a transimpedance amplifier to convert the current signal obtained by the ultraviolet photodetector into a voltage signal, and the converted voltage signal is between 0 and 3.3V.

10. The distance measurement method according to claim 9, characterized in that: The MCU calculates the distance value according to the received signal, and the formula is expressed as: Where I is the received UV signal strength, P is the power of the UV light transmitter, and d is the distance between the UV light transmitter and the target object.

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