Photoelectric conversion device and optical communication system comprising same

Abstract

The utility model relates to the field of optical communication, and particularly provides a photoelectric conversion device and an optical communication system comprising the same. The device is a PEC type photoelectric detector, a working electrode comprises a transparent electrode and a photoelectric conversion layer fixedly arranged on one side of the transparent electrode, the thickness of the photoelectric conversion layer is smaller than 40 nm, and a light field can penetrate through a light passing window to irradiate the photoelectric conversion layer and convert a light signal into an electric signal. The system comprises an optical signal input module, a photoelectric conversion module and an electric signal output module, the photoelectric conversion module is the photoelectric conversion device, the optical signal input module comprises a driving unit and a light-emitting unit, the driving unit is connected with the light-emitting unit, and the photoelectric conversion module is connected with the electric signal output module. Modulated light emitted by the optical signal input module irradiates the photoelectric conversion module, the photoelectric conversion module converts optical signals into electric signals, the electric signals are output through the electric signal output module, and optical communication is achieved. The accuracy of information transmission of the optical communication system is high.

Description

Technical Field

[0001] The present application relates to the field of optical communications, and in particular, to a photoelectric conversion device and an optical communication system including the device. Background Art

[0002] Optical communication is a communication technology that uses light waves to transmit information. It uses light waves as a medium for information transmission and achieves high-speed data transmission by modulating optical signals. The optical communication system is mainly composed of an optical signal transmitting module, an optical signal transmission module, and an optical signal receiving module. The optical signal transmitting module generally includes a laser or a light-emitting diode (LED), which converts electrical signals into optical signals through a driving circuit; the optical signal transmission module usually uses optical fiber for signal transmission, and the optical signal receiving module includes a photodetector, such as a photodiode or a photomultiplier tube, to convert optical signals into electrical signals. In other words, optical fiber is mainly used for the transmission of light fields, and when receiving signals, optical signals are converted into electrical signals.

[0003] However, the signal delay caused during the optical signal transmission and photoelectric conversion process will reduce the accuracy of information transmission in the optical communication system. Specifically, during the transmission process, when the optical signal is transmitted in the optical fiber, it will cause signal attenuation due to scattering, absorption and other reasons. In order to maintain the signal quality, it is necessary to use optical amplifiers or repeaters regularly to enhance the signal. The repeater needs to receive, amplify and resend the signal. Each process will bring some delay. The longer the transmission distance, the greater the signal delay and the lower the accuracy of the signal transmission. In the photoelectric conversion process, taking the photodiode as an example, this conversion process includes the steps of photoelectric detection, signal amplification, and regeneration of electrical signals. Each step will introduce a small time delay. Under the cumulative effect, it will eventually produce a larger delay, which seriously affects the accuracy of the information.

[0004] In summary, existing optical communication systems are complex and introduce long time delays, resulting in reduced accuracy of information transmission. Utility Model Content

[0005] The purpose of the utility model is to provide a photoelectric conversion device and an optical communication system including the device to address the deficiencies in the above-mentioned prior art, so as to solve the problem that the existing optical communication system is complex, introduces a long time delay, and causes a decrease in the accuracy of information transmission.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] A photoelectric conversion device is a PEC type photoelectric detector. The PEC type photoelectric detector includes an electrolytic cell, an electrolyte, a working electrode, a reference electrode, and a counter electrode. The electrolyte is arranged in the electrolytic cell. The lower ends of the working electrode, the reference electrode, and the counter electrode are immersed in the electrolyte and do not contact the bottom of the electrolytic cell. The upper ends of the working electrode, the reference electrode, and the counter electrode are fixedly arranged on the top cover of the electrolytic cell. The top cover is provided with holes for fixing the working electrode, the reference electrode, and the counter electrode. The working electrode includes a transparent electrode and a photoelectric conversion layer fixedly arranged on one side of the transparent electrode. The thickness of the photoelectric conversion layer is less than 40nm. The working electrode is arranged in the middle of the electrolytic cell. One side of the photoelectric conversion layer of the working electrode is opposite to a light-transmitting window on the wall of the electrolytic cell. The light field can be irradiated on the photoelectric conversion layer through the light-transmitting window. The reference electrode and the counter electrode are arranged on both sides of the working electrode.

[0008] Furthermore, the distance between the lower ends of the working electrode, reference electrode and counter electrode and the bottom of the electrolytic cell is greater than 1 cm; the distance between the reference electrode and the counter electrode and the working electrode in the middle is greater than 1.5 cm; and the volume of the electrolyte is two-thirds to three-quarters of the volume of the electrolytic cell.

[0009] The present application also provides an optical communication system including the above-mentioned photoelectric conversion device, the optical communication system includes an optical signal input module, a photoelectric conversion module, and an electrical signal output module, the optical signal input module includes a driving unit and a light-emitting unit, the driving unit is connected to the light-emitting unit, the driving unit is used to send a driving signal to the light-emitting unit, the driving signal carries information, the light-emitting unit includes a light-emitting element, and the light-emitting unit is used to modulate the state of the light-emitting element according to the driving signal; the photoelectric conversion module is a photoelectric conversion device, the light emitted by the light-emitting element is irradiated onto the photoelectric conversion layer of the working electrode through a light-transmitting window on the photoelectric conversion device, the working electrode and the counter electrode of the photoelectric conversion device are connected to the electrical signal output module to form an electrical circuit, and the photoelectric conversion module is connected to the electrical signal output module; the modulated light emitted by the optical signal input module is irradiated onto the photoelectric conversion module, the photoelectric conversion module converts the optical signal into an electrical signal, and the electrical signal is output through the electrical signal output module to realize optical communication.

[0010] Furthermore, the driving unit is a signal generator or a serial communication module, the serial communication module includes a serial communication board and a computer, the serial communication board is connected to the computer via a USB interface, and the computer is installed with serial communication software. The light-emitting element has a light-emitting wavelength of 300-1550nm; the driving signal is a square wave, the high level of the driving signal corresponds to the state of the light-emitting element being light-emitting, and the low level of the driving signal corresponds to the state of the light-emitting element being non-luminous.

[0011] Furthermore, the light-emitting element is a multi-color integrated LED lamp; the light-emitting unit also includes a first circuit board and an adjustable power supply, the signal input end of the first circuit board is connected to the driving unit, the power end of the first circuit board is connected to the adjustable power supply, the other end of the adjustable power supply is connected to 220V AC, the load end of the first circuit board is connected to the positive and negative poles of the light-emitting element, the driving unit is used to modulate the state of the light-emitting element, and the adjustable power supply is used to adjust the voltage across the light-emitting element.

[0012] Furthermore, the electrolyte is a solution containing conductive ions, the photoelectric conversion layer is a semiconductor material, the photoelectric conversion layer faces the light-transmitting window, the photoelectric conversion layer is used to convert changes in light into changes in electricity, and the energy band gap of the semiconductor material is less than or equal to the photon energy of the light emitted by the light-emitting element; the material of the reference electrode is Ag / AgCl and the counter electrode is Pt wire.

[0013] Furthermore, the electrical signal output module includes an electrochemical workstation, which has three connections, respectively connected to the working electrode, reference electrode and counter electrode of the PEC photodetector. The electrochemical workstation also has an output interface, which is connected to a display, and the display displays the response waveform.

[0014] Furthermore, the electrical signal output module includes an IV conversion unit and an oscilloscope. The IV conversion unit includes an IV conversion PCBA and a second circuit board, as well as a transformer, a bridge stack, a capacitor and a three-terminal voltage regulator IC integrated on the second circuit board. The two access ends of the IV conversion PCBA are respectively connected to the working electrode and the counter electrode of the PEC type photodetector. The IV conversion PCBA is connected to the second circuit board, and the output end of the second circuit board is connected to the oscilloscope. An electrical circuit is formed between the PEC type photodetector, the IV conversion unit and the oscilloscope, and the oscilloscope is used to display the response waveform.

[0015] Furthermore, an antistatic copper wire mesh is arranged outside the optical communication system, the mesh opening of the antistatic copper wire mesh is larger than 200 meshes, the antistatic copper wire mesh covers the optical communication system, and the antistatic copper wire mesh is grounded.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The optical communication system of the present application includes a PEC type photoelectric detector, which serves as a photoelectric conversion device. The thickness of the photoelectric conversion layer in the PEC type photoelectric detector is less than 40nm. The light field directly shines on the photoelectric conversion layer through the light-passing window, generating carriers. The carriers flow in a direction in the electrolyte, converting the optical signal into an electrical signal, and generating a potential difference between the reference electrode and the counter electrode. The thickness of the photoelectric conversion layer is less than 40nm, and the carriers can pass through quickly. The photoelectric conversion speed is fast, the response delay is small, and the information transmission is more accurate. At the same time, the PEC type photoelectric detector does not require signal amplification and regeneration of electrical signals, and does not introduce components that generate delays. The delay in the signal conversion process is small, and the accuracy of signal transmission is high.

[0018] In the optical communication system applied, at the receiving end or the transmitting end, the optical signal is converted into an electrical signal through a PEC type photodetector; the light field is directly irradiated on the working electrode of the PEC type photodetector, and the optical signal is converted into an electrical signal through the PEC type photodetector, and then the electrical signal is transmitted or processed. Signal transmission is mainly achieved through electrical signal transmission. The transmission of electrical signals in wires or cables is relatively stable and not easily affected by the external environment. It has higher reliability and more accurate information transmission. It can also use existing cable infrastructure to reduce costs. Frequent signal amplification and relaying are not required, delays are not likely to occur during the transmission process, and the transmission accuracy is higher.

[0019] In addition, the LED lamp in the PEC type photodetector has better thermal stability than the laser, and the thermal stability of the PEC type photodetector is also good, which makes the optical communication system of the present application more reliable. The wavelength range emitted by the light-emitting element of the present application is 300-1550nm, and the wavelength can be adjusted according to demand, and optical signals of multiple bands can be emitted simultaneously, which can improve the bandwidth and rate of data transmission and realize the transmission of large amounts of data. The optical signal input module in the optical communication system of the present application can generate modulated light of multiple different wavelengths; the driving signal is a square wave, and the modulation and demodulation process is simpler and the cost is lower. The anti-static copper wire mesh enables the optical communication system to avoid interference signals in the test environment, which is beneficial to the accurate detection of tiny signals. The optical communication system of the present application also has the advantages of being simple and portable, low-cost and easy to expand. It is simple to operate, easy to build and low-cost. At the same time, it can realize a variety of test functions by matching different input and output components. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of an optical communication system provided by the utility model;

[0021] Figure 2 A physical schematic diagram of an optical communication system provided by the utility model, wherein WE represents a working electrode, RE represents a reference electrode, and CE represents a counter electrode;

[0022] Figure 3 A schematic diagram of a first circuit board circuit in an optical communication system provided by the utility model;

[0023] Figure 4 A schematic diagram of a second circuit board circuit in an optical communication system provided by the utility model;

[0024] Figure 5 A demonstration diagram of the optical communication system provided by the utility model, in which the sample to be tested (GaS) transmits the letter NWU ASCII code under the irradiation of a 380 nm light source with an optical power of 2 mW;

[0025] Figure 6 The optical communication system provided by the utility model tests the photocurrent density curve of a sample (GaS) under different electrolytes and different incident light wavelengths;

[0026] Figure 7 The frequency response curve of a sample (GaS) tested in different electrolytes in an optical communication system provided by the utility model;

[0027] Figure 8 The utility model provides an optical communication system for performing a long-term stability test on a sample to be tested (GaS) under a bias voltage of 0 V.

[0028] Icon: 10 - optical signal input module; 11 - driving unit; 12 - light-emitting unit; 20 - photoelectric conversion module; 30 - electrical signal output module. DETAILED DESCRIPTION

[0029] In order to make the implementation process of the utility model clearer, it will be described in detail below with reference to the accompanying drawings.

[0030] A photoelectric conversion device, specifically a PEC type photodetector, includes an electrolytic cell, an electrolyte, a working electrode, a reference electrode, and a counter electrode, a three-electrode system constructed with a chemical battery as a carrier. The electrolytic cell is provided with a top cover for fixing the three electrodes. The upper ends of the working electrode, the reference electrode, and the counter electrode are fixedly arranged on the top cover of the electrolytic cell, and the top cover is provided with holes for fixing the working electrode, the reference electrode, and the counter electrode. The lower ends of the working electrode, the reference electrode, and the counter electrode are immersed in the electrolyte and do not contact the bottom of the electrolytic cell. The distance between the lower ends of the working electrode, the reference electrode, and the counter electrode and the bottom of the electrolytic cell is greater than 1 cm. The working electrode is arranged in the middle of the electrolytic cell, and the reference electrode and the counter electrode are arranged on both sides of the working electrode. The working surface of the working electrode is opposite to the light-transmitting window on the side wall of the electrolytic cell, and the distance between the reference electrode and the counter electrode and the working electrode in the middle is greater than 1.5 cm. The electrolyte is a solution containing conductive ions, which can be organic / inorganic solutions of various acidity and alkalinity of any concentration, as well as rivers, lakes and seawater in real environments. The electrolyte in the embodiment of the present application is tested with seawater and 1 mol / L Na2SO4 solution, and the volume of the electrolyte is two-thirds to three-quarters of the volume of the electrolytic cell. The electrolytic cell is a transparent quartz light window chemical electrolytic cell. The material of the reference electrode is Ag / AgCl, and the counter electrode is Pt wire. The working electrode includes a transparent electrode and a photoelectric conversion layer (working surface) fixedly arranged on one side of the transparent electrode, one side of the photoelectric conversion layer is opposite to the light-transmitting window on the wall of the electrolytic cell, and the light field can be irradiated on the photoelectric conversion layer through the light-transmitting window. The photoelectric conversion layer is a semiconductor material, and other materials with photosensitive activity can be used as the photoelectric conversion layer in this application, as long as they can receive light signals and convert them into electrical signals (i.e., photocurrent).

[0031] The thickness of the photoelectric conversion layer is less than 40nm, so that the carriers can pass through quickly, the response speed is faster, the time delay is small, and the accuracy of information transmission is high. As an example, the photoelectric conversion layer in the embodiment of the present application is GaS. In order to increase the area of ​​action with the light field and improve the photoelectric conversion efficiency, the test of the embodiment itself uses GaS nanosheets with upright morphology. Such a shape increases the contact area between the light field and the photoelectric conversion layer. The gap between the nanosheets plays a local role in the light field. At the same time, the upright morphology of the GaS nanosheet carrier transfer provides more paths, making the photoelectric conversion efficiency higher, shortening the photoelectric conversion time, further reducing the delay, and improving the accuracy of signal transmission.

[0032] The utility model provides an optical communication system, such as Figure 1 and Figure 2As shown, the optical communication system includes an optical signal input module 10, a photoelectric conversion module 20, and an electrical signal output module 30; the photoelectric conversion module 20 is connected to the electrical signal output module 30. The optical signal input module 10 is used to generate modulated light, the modulated light carries communication information, the modulated light is irradiated on the photoelectric conversion module 20, the photoelectric conversion module 20 converts the optical signal into an electrical signal, and the modulated electrical signal output by the photoelectric conversion module 20 displays the communication signal through the electrical signal output module 30. The optical signal input module 10 includes a driving unit 11 and a light-emitting unit 12, the driving unit 11 is connected to the light-emitting unit 12, the driving unit 11 is used to send a driving signal to the light-emitting unit 12, and the driving signal carries information. The driving unit 11 can be a signal generator or a serial communication module, the serial communication module includes a serial communication board and a computer, the serial communication board is connected to the computer via a USB interface, and the computer is installed with serial communication software.

[0033] The light-emitting unit 12 includes a light-emitting element, and the light-emitting unit 12 is used to modulate the state of the light-emitting element according to the driving signal. The driving signal is generally a square wave, a sine wave, etc. In this embodiment, a square wave is used for convenience. A square wave is a non-sinusoidal waveform, which is usually used for electronic and signal processing. A square wave has a higher level and a lower level. Generally, "1" represents a higher value and "0" represents a lower value. The ratio of the time occupied by the high level in a waveform cycle is called the duty cycle. The duty cycle of the original square wave is 50%, that is, the high value and the low value occupy the same time. The modulated signal transmits information through the regularity of the occurrence of high and low levels, or called "intervals". Different information is expressed as different modulated waveforms with different high and low level distributions. The high level of the driving signal corresponds to the state of the light-emitting element as luminous, and the low level of the driving signal corresponds to the state of the light-emitting element as non-luminous. In this way, the state change of the light-emitting element is a communication signal. The light-emitting element is an LED lamp, and the LED lamp is a monochrome LED lamp or a multi-color integrated LED lamp, that is, the light-emitting element can emit light of different bands. The light-emitting unit 12 also includes a first circuit board and an adjustable power supply. The signal input end of the first circuit board is connected to the driving unit 11, the power supply end of the first circuit board is connected to the adjustable power supply, and the other end of the adjustable power supply is connected to 220V AC. The adjustable power supply is used to adjust the voltage at both ends of the LED lamp to achieve the regulation of the light field intensity. The load end of the first circuit board is connected to the positive and negative electrodes of the LED lamp, and the driving unit 11 is used to modulate the state of the LED lamp. More specifically, the circuit of the first circuit board is as follows: Figure 3As shown, it includes a diode, a triode (or MOS tube), a fuse, a resistor and a connector. The power input end is connected to the diode through a fuse, the signal input end is connected to the triode, the diode and the triode are connected through an external LED lamp, the diode is used to prevent the input from being connected in reverse, the triode plays the role of power amplification, the fuse is used to prevent the circuit from being burned out by excessive current, and the connector is used to connect the circuit board and the wire. The LED lamp, the first circuit board, the signal generator and the adjustable power supply form a loop.

[0034] The photoelectric conversion module 20 is the above-mentioned PEC type photodetector, and the light emitted by the LED lamp is irradiated onto the working electrode of the PEC type photodetector through the light-passing window. The photoelectric conversion layer faces the light-passing window, and the photoelectric conversion layer is used to convert the change of light into electrical change. The energy band gap of the semiconductor material is less than or equal to the photon energy of the light emitted by the LED lamp, so that the photon can excite the electron from the ground state to the excited state, forming photogenerated electrons, thereby converting the light signal into an electrical signal; the material of the reference electrode is Ag / AgCl, and the counter electrode is Pt wire. When in use, light irradiates the working electrode to generate electron-hole pairs. These excited electrons and holes increase the number of free carriers in the material, generate directional flow in the electrolyte, and form a photocurrent between the working electrode and the counter electrode, realizing the conversion of light signal to electrical signal. In multi-wavelength optical communication, multiple PEC type photodetectors can be used simultaneously. The energy band gaps of the photoelectric conversion layers on different PEC type photodetectors are different, corresponding to different band ranges, to obtain information.

[0035] The electrical signal output module 30 includes an electrochemical workstation or an oscilloscope (including an IV conversion unit). Specifically, there are three access ports on the electrochemical workstation, which are respectively connected to the working electrode, reference electrode, and counter electrode of the PEC type photodetector. The electrochemical workstation also has an output interface, which is connected to a display, and the display displays the response waveform. The electrochemical workstation outputs the response waveform through the test software, and can also detect the long cycle stability, electrochemical impedance spectrum, Mott-Schottky curve, etc. corresponding to the optical communication system; when in use, the electrochemical workstation is connected to the computer monitor. The response waveform can also be displayed through the IV conversion unit and the oscilloscope. Specifically, the IV conversion unit is used to convert the detected current signal into a voltage signal recognizable by the oscilloscope, and read the response waveform through the oscilloscope. The IV conversion unit includes an IV conversion PCBA and a second circuit board. The main function of the second circuit board is to convert the mains power into a DC ±12V power supply; specifically, 220V AC power supplies the second circuit board, and the second circuit board supplies power to the IV conversion PCBA. The second circuit board contains a transformer, a bridge rectifier, a capacitor and a three-terminal voltage regulator IC. The transformer is used to change the voltage of the AC power, the bridge rectifier is used to rectify (convert AC power into DC power), the capacitor is used to improve the efficiency and smoothness of the DC output, and the three-terminal voltage regulator IC is used to convert the unstable input voltage into a stable output voltage. The circuit diagram of the IV conversion unit is shown in the figure below. Figure 4 As shown, the IV conversion PCBA is connected to the second circuit board, and the second circuit board supplies power to the IV conversion PCBA. The main functional component of the IV conversion PCBA is the transimpedance amplifier, which is equivalent to an operational amplifier plus a resistor (R f ), the resistance value of the resistor is used to set the IV conversion ratio. In summary, the main function of the IV conversion unit is to convert the photocurrent on the photoelectric conversion layer into a voltage signal according to the set ratio (V=-I×R f ), so that it can be read out by an oscilloscope. The two access ends of the IV conversion PCBA are respectively connected to the working electrode and the counter electrode of the PEC type photodetector, the positive electrode is connected to the working electrode, and the negative electrode is connected to the counter electrode. Then the IV conversion PCBA is connected to the second circuit board, and the output end of the second circuit board is connected to the oscilloscope. An electrical circuit is formed between the PEC type photodetector, the IV conversion unit, and the oscilloscope. The second circuit board supplies power to the devices on the IV conversion PCBA, and the oscilloscope is used to display the response waveform.

[0036] The photoelectric conversion module 20 is connected to the electrical signal output module 30. The modulated light emitted by the optical signal input module 10 is irradiated to the photoelectric conversion module 20. The photoelectric conversion module 20 converts the optical signal into an electrical signal, which is output through the electrical signal output module 30 to realize optical communication. Figure 5To connect the serial port tool to the computer, input the character "NWU" to be transmitted through the serial port debugging tool on the computer, and then give the signal to the LED light source. The detector detects the modulated light signal, and then converts it into a voltage signal that can be read by the oscilloscope through the IV conversion board. The output signal can be captured by the oscilloscope, and the binary waveform corresponding to the 3 letters is obtained; the optical communication system of this application can achieve good communication effects when using seawater and Na2SO4 solution as electrolytes, and can be used for underwater optical communication. When in use, the photoelectric conversion layer can be placed in a chemical battery as a working electrode, and the electrolyte immerses the effective surface of the material so that the material is in full contact with the electrolyte. The electrolyte is a solution containing conductive ions, which can be various acidic / inorganic solutions of any concentration, as well as real environment rivers, lakes and seawater. Therefore, the optical communication system of this application can realize communication functions in different solution environments. How to modulate and demodulate signals through serial communication belongs to the prior art, so it will not be repeated in this application.

[0037] Furthermore, an anti-static copper wire mesh can be arranged outside the optical communication system to shield electromagnetic interference in the environment. Specifically, the anti-static copper wire mesh is fixed on the optical platform by screws or support screws, for example, four support screws are used to fix it around to cover the optical communication system inside, the anti-static copper wire mesh is grounded, and the mesh of the anti-static copper wire mesh is greater than 200 meshes, effectively avoiding coupling interference of stray capacitance.

[0038] The light-emitting unit 12 and the photoelectric conversion module 20 in the present application can be moved and have the same height. The light field is horizontally irradiated on the photoelectric conversion module 20. The distance between the light-emitting unit 12 and the photoelectric conversion module 20 is changed by moving to achieve the purpose of adjusting the light intensity irradiated on the photoelectric conversion module 20. When controlling variables, it is necessary to ensure that the light intensity irradiated on the photoelectric conversion module 20 is equal during the test. Generally, an optical power meter is used for detection, and the position of the preset optical power is detected, and then the photoelectric conversion module 20 is moved to the position, that is, the optical power meter is used to calibrate the placement position corresponding to the electrolytic cell under different power density illumination, so as to ensure the consistency of optical power; it can also be achieved by moving the light-emitting unit 12. The optical communication system of the present application can be used to test the response current, response time and bandwidth of the sample (photoelectrode) under different wavelengths, different frequencies and different illumination powers, and the transmission of character information can be realized through the serial communication module. The stability, response amplitude and response frequency of the optical communication system of the present application are detected, and the specific test results are shown below. The specific materials, parameters, etc. are only an example and are not limited to the scheme.

[0039] Figure 6The photocurrent density curves corresponding to incident light at different wavelengths in two different electrolytes (1M Na2SO4 and real seawater) are shown. Specifically, the photocurrent density is 2 mW / cm2 at different wavelengths of 365, 380, 400, 420, 440, 460, 480, 500, 520, 540, 560, 590, 600, 620 and 660 nm. 2 The photoresponse current was tested. The specific implementation process is to input a signal through a signal generator, the input signal is a square wave with a frequency of 100Hz, replace LED lights of different wavelengths, and use an optical power meter to calibrate the specific position of the PEC-type detector, and then obtain the output signal through an IV conversion unit combined with an oscilloscope. It can be seen that the obvious rising and falling edges in the figure indicate that the material has good photoresponse and can be used for optical communications. The response time of the photoelectric conversion layer in both electrolytes reaches the microsecond level. The rise and fall times in 1 M Na2SO4 solution are 12.1 microseconds and 12.9 microseconds, respectively, and the rise and fall times in seawater are 12.9 microseconds and 13 microseconds, respectively. In the wavelength range of 365-480nm, there is a more significant photoresponse current, corresponding to the better light absorption range of the photoelectric material. And there is a peak at 380nm, corresponding to the band gap of the photoelectric conversion layer. In addition, it exhibits a better light response in seawater. The acidity and alkalinity of seawater (PH=7.2) is different from that of Na2SO4 (PH=7) solution. The excellent performance of this optical communication system in seawater verifies its broad application scenarios.

[0040] Figure 7 To input square waves of different frequencies through the signal generator, Figure 3 and Figure 4 The test equipment is connected by the method of detecting the photocurrent signal at different frequencies, which can be converted into a voltage signal that can be read by an oscilloscope through an IV conversion unit, and the effective voltage value (V rms ), and then the frequency response curves in different electrolytes are plotted through formula conversion. We can estimate that the -3dB cutoff frequencies of the photodetector in seawater and Na2SO4 solution are approximately 55.3 kHz and 35.9 kHz, respectively. The high bandwidth cutoff frequency indicates the excellent communication capability of the photoelectric conversion layer.

[0041] Figure 8This is a long-term stability test of the sample to be tested (GaS) under 0 V bias and 380 nm light with an optical power of 2 mW. The stability test lasted for 2500 cycles, with the light turned on and off once per second (0.5 s on, 0.5 s off). The specific implementation process is that the signal generator inputs the signal, a 380 nm LED light is used, and the power of the LED light is adjusted to 2 mW through an adjustable power supply and an optical power meter, and then the PEC detector is placed in a suitable position, and finally the output signal is obtained through an electrochemical workstation combined with a computer. After 2500 cycles, the response current values ​​in seawater and Na2SO4 solution are still maintained at about 77.6% and 67.2% of the initial value, respectively. This phenomenon proves that the above-mentioned photoelectric conversion layer still has excellent stability in a solution environment, especially when working for a long time in seawater, and further confirms the reliability of the optical communication system.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photoelectric conversion device, characterized in that: The photoelectric conversion device is a PEC type photodetector, which includes an electrolytic cell, an electrolyte, a working electrode, a reference electrode, and a counter electrode. The electrolyte is arranged in the electrolytic cell, and the lower ends of the working electrode, the reference electrode, and the counter electrode are immersed in the electrolyte and do not contact the bottom of the electrolytic cell. The upper ends of the working electrode, the reference electrode, and the counter electrode are fixedly arranged on the top cover of the electrolytic cell, and the top cover is provided with a hole for fixing the working electrode, the reference electrode, and the counter electrode. The working electrode includes a transparent electrode and a photoelectric conversion layer fixedly arranged on one side of the transparent electrode, and the thickness of the photoelectric conversion layer is less than 40nm. The working electrode is arranged in the middle of the electrolytic cell, and one side of the photoelectric conversion layer of the working electrode is opposite to the light-transmitting window on the wall of the electrolytic cell, and the light field can be irradiated on the photoelectric conversion layer through the light-transmitting window, and the reference electrode and the counter electrode are arranged on both sides of the working electrode.

2. The photoelectric conversion device according to claim 1, characterized in that The distance between the lower ends of the working electrode, the reference electrode and the counter electrode and the bottom of the electrolytic cell is greater than 1 cm; the distance between the reference electrode and the counter electrode and the working electrode in the middle is greater than 1.5 cm; the volume of the electrolyte is two-thirds to three-quarters of the volume of the electrolytic cell.

3. An optical communication system, comprising the photoelectric conversion device according to claim 1 or 2, characterized in that: The optical communication system comprises an optical signal input module, a photoelectric conversion module, and an electrical signal output module. The optical signal input module comprises a driving unit and a light-emitting unit. The driving unit is connected to the light-emitting unit. The driving unit is used to send a driving signal to the light-emitting unit. The driving signal carries information. The light-emitting unit comprises a light-emitting element. The light-emitting unit is used to modulate the state of the light-emitting element according to the driving signal. The photoelectric conversion module is the photoelectric conversion device. The light emitted by the light-emitting element is irradiated onto the photoelectric conversion layer of the working electrode through the light-transmitting window on the photoelectric conversion device. The working electrode and the counter electrode of the photoelectric conversion device are connected to the electrical signal output module to form an electrical circuit. The photoelectric conversion module is connected to the electrical signal output module. The modulated light emitted by the optical signal input module is irradiated onto the photoelectric conversion module. The photoelectric conversion module converts the optical signal into an electrical signal. The electrical signal is output through the electrical signal output module to realize optical communication.

4. The optical communication system according to claim 3, characterized in that: The driving unit is a signal generator or a serial communication module, the serial communication module includes a serial communication board and a computer, the serial communication board is connected to the computer via a USB interface, the computer is installed with serial communication software, the light emitting wavelength of the light emitting element is 300-1550nm; the driving signal is a square wave, the high level of the driving signal corresponds to the state of the light emitting element being luminous, and the low level of the driving signal corresponds to the state of the light emitting element being non-luminous.

5. The optical communication system according to claim 4, characterized in that: The light-emitting element is a multi-color integrated LED lamp; the light-emitting unit also includes a first circuit board and an adjustable power supply, the signal input end of the first circuit board is connected to the driving unit, the power end of the first circuit board is connected to the adjustable power supply, the other end of the adjustable power supply is connected to 220V AC, the load end of the first circuit board is connected to the positive and negative electrodes of the light-emitting element, the driving unit is used to modulate the state of the light-emitting element, and the adjustable power supply is used to adjust the voltage across the light-emitting element.

6. The optical communication system according to claim 5, characterized in that: The electrolyte is a solution containing conductive ions, the photoelectric conversion layer is a semiconductor material, the photoelectric conversion layer faces the light-transmitting window, the photoelectric conversion layer is used to convert changes in light into changes in electricity, and the energy band gap of the semiconductor material is less than or equal to the photon energy of the light emitted by the light-emitting element; the material of the reference electrode is Ag / AgCl, and the counter electrode is Pt wire.

7. The optical communication system according to claim 6, characterized in that: The electrical signal output module includes an electrochemical workstation, which has three connections, respectively connected to the working electrode, the reference electrode and the counter electrode of the PEC photoelectric detector. The electrochemical workstation also has an output interface, which is connected to a display, and the display displays the response waveform.

8. The optical communication system according to claim 7, characterized in that: The electrical signal output module includes an IV conversion unit and an oscilloscope. The IV conversion unit includes an IV conversion PCBA and a second circuit board, as well as a transformer, a bridge stack, a capacitor and a three-terminal voltage regulator IC integrated on the second circuit board. The two access ends of the IV conversion PCBA are respectively connected to the working electrode and the counter electrode of the PEC type photodetector. The IV conversion PCBA is connected to the second circuit board, and the output end of the second circuit board is connected to the oscilloscope. An electrical circuit is formed between the PEC type photodetector, the IV conversion unit and the oscilloscope, and the oscilloscope is used to display the response waveform.

9. The optical communication system according to claim 3, characterized in that: An antistatic copper wire mesh is arranged outside the optical communication system. The mesh opening of the antistatic copper wire mesh is larger than 200 meshes. The antistatic copper wire mesh covers the optical communication system and is grounded.

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