Ultraviolet light communication system and communication method based on perovskite ultraviolet photodetector

Abstract

The present invention discloses an ultraviolet light communication system based on a perovskite ultraviolet photodetector. The perovskite ultraviolet photodetector serves as a signal receiver to collect encoded ultraviolet light signals, convert the light signals into current signals, and output them. The perovskite ultraviolet photodetector comprises a substrate, a single-crystal perovskite thin film formed on the substrate surface, and electrodes for collecting the current signals. Furthermore, the present invention discloses an ultraviolet light communication method using the above-described ultraviolet light communication system. The ultraviolet light communication system and method provided by the present invention can be used to transmit encoded ultraviolet light signals, achieving high-speed ultraviolet light communication.

Description

Technical Field

[0001] The present invention belongs to the field of optical devices, and in particular relates to an ultraviolet light communication system and a communication method based on a perovskite ultraviolet photodetector. Background Art

[0002] As part of wireless communication technology, ultraviolet communication systems have important applications in areas such as missile tracking and environmental monitoring. The ultraviolet photodetectors that serve as signal receivers must exhibit fast response speeds and high sensitivity. However, ultraviolet photodetectors based on traditional wide-bandgap materials (such as zinc oxide, gallium nitride, and gallium oxide) typically require high-temperature preparation and complex processing, and suffer from slow response speeds. This has hindered the development of ultraviolet communication technology and related fields.

[0003] Perovskite materials have garnered widespread attention in recent years due to their high carrier mobility, long carrier lifetime, and tunable band gap. Simple solution synthesis techniques allow the preparation of perovskite materials in various geometries, enabling the fabrication of low-cost, large-area, lightweight devices. These advantages have led to their application in numerous optoelectronic devices, including light-emitting diodes and solar cells. However, their application in ultraviolet communications remains limited. Summary of the Invention

[0004] To solve the above problems, the present invention proposes an ultraviolet light communication system and communication method based on perovskite ultraviolet photodetectors, wherein the perovskite-based ultraviolet photodetector serves as a signal receiver in the ultraviolet light communication system, and the detector is further integrated into the ultraviolet light communication system as a signal receiver. The ultraviolet light communication system based on perovskite ultraviolet photodetectors can transmit encoded ultraviolet light signals at high speed.

[0005] The specific technical solutions of the present invention include:

[0006] Solution 1: A UV communication system uses a perovskite UV photodetector as a signal receiver to collect encoded UV light signals, and converts the light signals into current signals for output; the perovskite UV photodetector includes a substrate, a single crystal perovskite thin film formed on the surface of the substrate, and an electrode for collecting current signals.

[0007] As a preferred embodiment, the single crystal perovskite film is any one of methylamine lead bromide, methylamine lead chloride, methylamine lead iodide, formamidine lead bromide, formamidine lead chloride, formamidine lead iodide, cesium lead bromide, cesium lead chloride, and cesium lead iodide single crystals.

[0008] As a preferred solution, the single crystal perovskite film is grown on the substrate surface by a low temperature solution method.

[0009] As a preferred solution, the thickness of the single crystal perovskite film is 10 to 2000 nm.

[0010] As a preferred solution, the substrate is mica, quartz or alumina material.

[0011] As a preferred solution, the substrate is a flexible mica sheet prepared by a mechanical stripping method, and the thickness of the mica sheet is less than 40 μm.

[0012] As a preferred solution, the electrode is made of gold, silver, copper or aluminum and has a thickness of 30 to 200 nm.

[0013] As a preferred embodiment, the material of the frequency doubling crystal is any one of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dideuterium phosphate, cesium dideuterium arsenate, cesium dihydrogen arsenate, gallium arsenide, indium arsenide, zinc sulfide, cadmium telluride, tellurium, selenium, barium metaborate, and lithium triborate.

[0014] Option 2: A method for ultraviolet light communication, based on the ultraviolet light communication system described in Option 1 or any one of its preferred options, mainly includes: encoding the input information as required, controlling the signal generator to generate a voltage signal whose change pattern is consistent with the encoded information; using the voltage signal to control the switching time of the laser output laser through an acousto-optic modulator, thereby forming an encoded light signal; using a frequency doubling crystal to convert the light signal into an ultraviolet light signal; collecting the ultraviolet light signal through the ultraviolet photodetector and converting it into a current signal whose change pattern is consistent with the encoded ultraviolet signal light; connecting the current signal to an oscilloscope to obtain a waveform corresponding to the encoded information, and after decoding the waveform, the content of the input information is obtained.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention uses an ultraviolet photodetector made of a perovskite thin film as a signal receiver and integrates it into an ultraviolet communication system to achieve high-speed ultraviolet communication.

[0017] (2) The present invention can use a low-temperature solution method to prepare single-crystal perovskite thin films, which has a mature preparation process, is easy to process, and has a low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : (a) is a schematic diagram of the structure of the ultraviolet light communication system, in which the perovskite ultraviolet photodetector is used as a signal receiver in the communication system to receive ultraviolet light signals.

[0019] Figure 2:(a) Schematic diagram of the structure of the perovskite ultraviolet photodetector used as a receiver in the ultraviolet communication system; (b) The measured dark current of the device and the photocurrent when irradiated with a 325nm laser with a power of 4mW; (c) The normalized photocurrent response measured at a laser modulation frequency of 20kHz.

[0020] Figure 3 :(a), (b), (c) are the waveforms of the optical signal received by the UV photodetector at the rates of 10kb / s, 20kb / s, and 50kb / s respectively;

[0021] Figure 4 : (a) The photocurrent signal measured when the ultraviolet photodetector is in a flat state and the ultraviolet communication system transmits the text message "NJUPHYSICS" encrypted in Morse code; (b) The photocurrent signal measured when the ultraviolet photodetector is in a flat state and the ultraviolet communication system transmits the text message "THANK YOU" encrypted in Morse code.

[0022] Figure 5 : (a) The photocurrent signal measured when the ultraviolet photodetector is in a flexible bending state and the ultraviolet communication system transmits the text message "NJUPHYSICS" encrypted in Morse code; (b) The photocurrent signal measured when the ultraviolet photodetector is in a flexible bending state and the ultraviolet communication system transmits the text message "THANK YOU" encrypted in Morse code.

[0023] Figure labels: 1-substrate, 2-single crystal perovskite film, 3-metal electrode. Specific embodiments

[0024] Combine Figure 1As shown, the present invention provides an ultraviolet light communication system based on a perovskite ultraviolet photodetector. The system mainly comprises: a laser, a signal generator, an acousto-optic modulator, a frequency doubling crystal, a perovskite ultraviolet photodetector and an oscilloscope. The laser, signal generator, acousto-optic modulator and frequency doubling crystal constitute the transmitting end of the system, the perovskite ultraviolet photodetector and the oscilloscope constitute the receiving end of the system, and the perovskite ultraviolet photodetector serves as a signal receiver of the ultraviolet light communication system. The working principle of the ultraviolet light communication system is as follows: first, the information to be transmitted (i.e., input information) is encoded in the computer as required, and the computer controls the signal generator to generate high-voltage and low-voltage signals of different durations, whose variation pattern is consistent with the encoded information; then, the modulated voltage is used to control the acousto-optic modulator, and further control the switching time of the laser output laser to form an optical signal controlled by the input information; then, a frequency-doubling crystal is used to convert the optical signal of the above wavelength into an ultraviolet light signal. For example, the wavelength of the femtosecond pulse laser is 700-800nm, and the wavelength after frequency doubling is 350-400nm; finally, the ultraviolet photodetector collects the ultraviolet light signal and converts it into a current signal. The current signal is connected to the oscilloscope to obtain the waveform corresponding to the transmitted information, and the content of the input information can be obtained after decoding.

[0025] Combine Figure 2As shown in Figure (a), the perovskite UV photodetector, serving as a signal receiver for a UV communication system, primarily comprises a substrate 1, a single-crystal perovskite film 2, and a metal electrode 3, arranged in order from bottom to top. Substrate 1 can be quartz, alumina, or a mica sheet used for growing the single-crystal perovskite film. Mica substrate 1 can be prepared using mechanical exfoliation and can be made into either a flat or flexible mica sheet, depending on the application. The thickness of the mica sheet can be less than 40 μm. The single-crystalline perovskite film 2 is any one of methylamine lead bromide (MAPbBr3), methylamine lead chloride (MAPbCl3), methylamine lead iodide (MAPbI3), formamidine lead bromide (FAPbBr3), formamidine lead chloride (FAPbCl3), formamidine lead iodide (FAPbI3), cesium lead bromide (CsPbBr3), cesium lead chloride (CsPbCl3), or cesium lead iodide (CsPbI3), and has a thickness of 10 to 2000 nm. The metal electrode 3 can be a strip or other shaped structure made of gold, silver, copper, or aluminum, and has a thickness of 30 to 200 nm. Because the single-crystalline perovskite film absorbs ultraviolet light, it can be used for photoelectric detection of ultraviolet light. The perovskite ultraviolet photodetector has a fast response speed, so it can be used as a signal receiver in an ultraviolet communication system for high-speed transmission of ultraviolet signals. The above-mentioned perovskite ultraviolet photodetector used as a receiver for an ultraviolet communication system can be prepared by the following method: preparing a substrate 1; growing a single crystal perovskite film 2 on the surface of the substrate 1 by a low-temperature solution method; and then preparing a metal strip electrode 3 on the sample by electron beam evaporation.

[0026] It should be noted that the ultraviolet communication system disclosed in the present invention is not limited to the above-mentioned composition. For example, the transmitting end can be composed of a laser or other ultraviolet light source that directly generates ultraviolet light, a signal generator and an acousto-optic modulator, that is, no frequency doubling crystal is required; the oscilloscope at the receiving end can also be replaced by an ammeter, etc., as long as it has the function of outputting current signals.

[0027] The present invention is further explained below with specific embodiments and accompanying drawings:

[0028] Example 1:

[0029] We first fabricated a perovskite UV photodetector, which serves as a signal receiver for a UV communication system. We first used a low-temperature solution method to grow a 30±5 nm thick single-crystalline methylammonium lead bromide perovskite thin film on a 100±5 μm thick mica sheet. Then, using a mask, we deposited a 40±5 nm thick gold electrode on the sample via electron beam evaporation. The following tests were conducted based on the perovskite UV photodetector described in Example 1.

[0030] Figure 2(b) The dark current of the perovskite UV photodetector and the photocurrent measured under 325nm laser excitation with a power of 4mW are given. The dark current of the sample is very small and there is an obvious photocurrent response, indicating that the sample can be used for UV light detection. Figure 2 (c) shows the time-resolved photocurrent response under 20kHz laser modulation and 1V voltage. We can see that the photocurrent changes with the on / off switching of the 385nm laser signal, with rise and fall times of 3.3μs and 4μs, respectively, demonstrating that this UV photodetector has a very fast response and can be used for high-speed detection of UV light signals.

[0031] Furthermore, we provide a Figure 1 The ultraviolet light communication system shown uses the perovskite ultraviolet photodetector described in Example 1 as a signal receiver to receive ultraviolet light signals and convert them into current signals to achieve information communication. Figure 3 (a), (b), and (c) show the waveforms of digital signals received by the UV photodetector at transmission rates of 10 kb / s, 20 kb / s, and 50 kb / s, respectively. We modulated the input light with a 50% duty cycle square wave signal and detected the corresponding current waveforms from the UV photodetector, confirming that the system can transmit data at these rates. Figure 4 (a) and Figure 4 (b) The detector outputs the corresponding current signals for the encoded words "NJUPHYSICS" and "THANK YOU," respectively. The text messages "NJUPHYSICS" and "THANK YOU" were encrypted using international Morse code. The three communication states (dot, dash, and space) were obtained by varying the duration of the current. As can be seen, the encoded text messages can be transmitted via the current signals detected by the UV photodetector. This demonstrates that UV communication systems using perovskite UV photodetectors as signal receivers can achieve high-speed transmission of encoded UV signals.

[0032] Example 2:

[0033] The perovskite UV photodetector was prepared similarly to that in Example 1, except that the mica substrate was thinner, at 25±5 μm, allowing for a flexible, curved state. The perovskite UV photodetector was then placed in a flexible, curved state by bending the mica substrate. The perovskite UV photodetector was then integrated into a UV communication system as a signal receiver. The UV communication system's functionality was tested while the perovskite UV photodetector was in the flexible, curved state. Figure 5 (a) and Figure 5(b) The current signals corresponding to the codes "NJUPHYSICS" and "THANK YOU" are output by the perovskite UV photodetector when it is in a flexible, bent state. It can be seen that even when the UV photodetector is in a flexible, bent state, the encoded text information can be transmitted through the current signal detected by the perovskite UV photodetector. The UV communication function is not affected by the flexible bending state of the perovskite UV photodetector. This shows that the perovskite UV photodetector can be used as a signal receiver, not only for high-speed transmission of UV signals in a UV communication system when flat, but also for normal operation when in a flexible, bent state.

[0034] In summary, the ultraviolet light communication system based on the perovskite ultraviolet photodetector disclosed in the embodiment utilizes the characteristic of high absorption rate of perovskite in the ultraviolet light band to prepare it into an ultraviolet photodetector for ultraviolet light detection. The device has a very fast response speed. The ultraviolet light communication system integrating the perovskite ultraviolet photodetector as a receiver can be used for high-speed transmission of encoded ultraviolet light signals.

[0035] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A UV communication method based on a perovskite UV photodetector, implemented based on a UV communication system. The UV communication system uses a perovskite UV photodetector as a signal receiver to collect encoded UV light signals, convert the light signals into current signals, and output them. The perovskite ultraviolet photodetector comprises a substrate, a single crystal perovskite thin film formed on the surface of the substrate, and an electrode for collecting current signals, and is characterized by comprising: The input information is encoded as required, and the control signal generator generates a voltage signal with a variation pattern consistent with the encoded information; the voltage signal is used to control the acousto-optic modulator, and then the switching time of the laser output laser is controlled to form a coded light signal; the light signal is converted into an ultraviolet light signal using a frequency-doubling crystal; the ultraviolet light signal is collected by an ultraviolet photodetector and converted into a current signal with a variation pattern consistent with the encoded ultraviolet signal light; the current signal is connected to an oscilloscope to obtain a waveform corresponding to the encoded information, and the content of the input information is obtained after decoding the waveform.

2. The ultraviolet light communication method according to claim 1, wherein: The single crystal perovskite film is any one of methylamine lead bromide, methylamine lead chloride, methylamine lead iodide, formamidine lead bromide, formamidine lead chloride, formamidine lead iodide, cesium lead bromide, cesium lead chloride, and cesium lead iodide single crystals.

3. The ultraviolet light communication method according to claim 1, wherein: The single crystal perovskite film is grown on the substrate surface by adopting a low temperature solution method.

4. The ultraviolet light communication method according to claim 1, wherein: The thickness of the single crystal perovskite film is 10 to 2000 nm.

5. The ultraviolet light communication method according to claim 1, wherein: The substrate is made of mica, quartz or alumina.

6. The ultraviolet light communication method according to claim 1, wherein: The substrate is a flexible mica sheet prepared by a mechanical stripping method, and the thickness of the mica sheet is less than 40 μm.

7. The ultraviolet light communication method according to claim 1, wherein: The electrode is made of gold, silver, copper or aluminum and has a thickness of 30 to 200 nm.

8. The ultraviolet light communication method according to any one of claims 1 to 7, wherein: The ultraviolet light communication system further comprises a laser, a signal generator, an acousto-optic modulator, a frequency doubling crystal and an oscilloscope. The wavelength of the light emitted by the laser is located in the ultraviolet band after being frequency doubling by the frequency doubling crystal.

9. The ultraviolet light communication method according to claim 8, wherein: The material of the frequency doubling crystal is any one of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, potassium dideuterium phosphate, cesium dideuterium arsenate, cesium dihydrogen arsenate, gallium arsenide, indium arsenide, zinc sulfide, cadmium telluride, tellurium, selenium, barium metaborate, and lithium triborate.

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