Photoelectric detector based on aluminum-doped copper-indium-sulfur quantum dots and preparation method thereof

Abstract

The invention relates to a photoelectric detector based on aluminum-doped copper-indium-sulfur quantum dots and a preparation method thereof, and belongs to the technical field of quantum dot material optical communication, and the preparation method comprises the following steps: (1) depositing bismuth oxyiodide (BiOI) nanosheets on clean conductive glass through an electro-deposition method, after the bismuth oxyiodide (BiOI) nanosheets are cleaned and dried, dropwise adding a vanadium source, and carrying out high-temperature calcination and cleaning to obtain a bismuth vanadate film; (2) synthesizing a high-quality copper-indium-sulfur quantum dot by adopting a co-heating method, and doping an aluminum element after nucleation is finished, so as to obtain the aluminum-doped copper-indium-sulfur quantum dot with excellent photoelectric property; and (3) vertically immersing the porous bismuth vanadate into the purified quantum dot / toluene solvent, depositing quantum dots into the bismuth vanadate by using an electrophoretic deposition method, washing redundant quantum dots on the surface by using toluene, and drying to obtain the quantum dot sensitized bismuth vanadate film photoelectrochemical photoelectric detector. The beneficial effects of the invention are that the response speed of the PEC-type photoelectric detector is improved by improving the photoelectric performance of the aluminum-doped copper indium sulfur quantum dots.

Description

Technical Field

[0001] The present invention belongs to the technical field of quantum dot material optical communication, and in particular relates to a photoelectric detector based on aluminum-doped copper indium sulfide quantum dots and a preparation method thereof. Background Art

[0002] Underwater optical communication (UOC) uses light waves as information carriers, transmitting information through underwater channels. It has applications in marine resource exploration, underwater environmental monitoring, oceanographic surveys, and military reconnaissance. Photodetectors are essential components of optical communication systems and must be sensitive, safe, portable, and energy-efficient for efficient system operation. Emerging photoelectrochemical (PEC) photodetectors utilize the energy barrier at the semiconductor / electrolyte interface to facilitate the efficient separation of photogenerated electron-hole pairs, which then complete the circuit through electron transfer to the electrolyte. These photodetectors have attracted significant attention in UOC systems due to their competitive advantages. First, PEC-type photodetectors can operate directly in aqueous solutions without the need for complex waterproof packaging. Second, due to band bending at the solid-liquid interface, they exhibit self-powered behavior. Third, they exhibit remarkable efficiency and sensitivity across light intensity and wavelength, regardless of operating at low or no driving voltage. Finally, PEC-type photodetectors feature a simple fabrication process and utilize cost-effective components, further enhancing their appeal in UOC applications. Despite continuous technological advances, achieving highly responsive PEC-type photodetectors remains a significant challenge, primarily because conventional materials have poor light absorption properties and suffer from rapid electron-hole pair recombination rates.

[0003] Colloidal quantum dots (QDs) possess unique size-tunable absorption / emission properties due to the quantum confinement effect, making them highly promising for PEC applications. Among the numerous quantum dots, copper indium sulfide (CIS) stands out for its small direct band gap (1.45 eV). Due to its inherent advantages of non-toxicity, low-cost production, and high absorption coefficient, it has become one of the most promising candidate materials for various applications, including photodetection, solar energy conversion, and light-emitting diodes. However, CIS QDs still face key challenges, including a high density of surface defects / traps and poor stability, which limit the performance of their associated devices. Therefore, the rational design and preparation of efficient and stable photodetectors based on CIS QDs plays an important role.

[0004] Current quantum dot-based PEC photodetectors exhibit low responsivity or slow response speed due to their slow separation / transfer of photogenerated excitons during the reaction. Summary of the Invention

[0005] The present invention provides a photoelectric detector based on aluminum-doped copper indium sulfide quantum dots and a preparation method thereof, which are used to solve the technical problem that PEC-type photoelectric detectors in the prior art have low responsiveness or slow response speed. By improving the photoelectric performance of aluminum-doped copper indium sulfide quantum dots, the response speed of the PEC-type photoelectric detector is improved.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] A method for preparing a photoelectric detector based on aluminum-doped copper indium sulfide quantum dots is characterized by comprising the following steps:

[0008] Step S1, preparing BiOI nanosheets on conductive glass by electrodeposition, and after the BiOI nanosheets are dried, adding a vanadium source dropwise onto the BiOI nanosheets, annealing at high temperature in a muffle furnace, and washing with a sodium hydroxide solution to obtain a yellow bismuth vanadate film;

[0009] Step S2: synthesizing high-quality copper indium sulfide quantum dots by a co-thermal method, and after high-temperature growth, lowering the reaction temperature and then performing aluminum doping to obtain aluminum-doped copper indium sulfide quantum dots with excellent photoelectric properties;

[0010] Step S3, vertically immersing the porous bismuth vanadate in a quantum dot / toluene solvent, and depositing quantum dots into the bismuth vanadate using electrophoretic deposition, then rinsing excess quantum dots on the surface of the bismuth vanadate with toluene, and drying to obtain a quantum dot-sensitized bismuth vanadate film to obtain a photoelectrochemical photodetector;

[0011] Step S4: Using the quantum dot-sensitized bismuth vanadate film as a working electrode, assembling the working electrode, a Pt sheet counter electrode, and an Ag / AgCl reference electrode into a three-electrode test system.

[0012] Optionally, in step S1, BiOI nanosheets are deposited on the clean FTO conductive glass substrate by cyclic voltammetry electrodeposition, and a vanadium source is added dropwise after the BiOI nanosheets are cleaned and dried, followed by high-temperature calcination to obtain a bismuth vanadate film.

[0013] Optionally, the voltage conditions of the cyclic voltammetry electrodeposition method are a scan rate of 5 mV / s, a potential range of -0.13 V to 0 V, a time of 260 s, a drying temperature of 60 ° C, and a vanadium source drop of 100~150 μl / cm 2 , the high temperature calcination temperature is 450℃ and the time is 2h.

[0014] Optionally, in step S2, high-quality copper indium sulfur quantum dots are synthesized by a co-thermal method, which is as follows: a copper source, an indium source and a solvent are added to a 50 mL three-necked flask in sequence, and after the copper source, indium source and solvent are mixed, they are degassed at room temperature, and then heated to 220-230°C under nitrogen protection. After the reaction temperature stabilizes, it is kept warm for 5-10 minutes, and quenched in a water bath to obtain copper indium sulfur quantum dots. After the growth of copper indium sulfur is completed, the temperature is lowered to 150-200°C, and then an aluminum precursor solution is injected, kept warm for 30-50 minutes, and quenched in a water bath to obtain aluminum-doped copper indium sulfur quantum dots.

[0015] Optionally, the copper source, indium source and solvent used for aluminum-doped copper indium sulfur quantum dots are copper iodide, indium acetate and n-dodecyl mercaptan, respectively, and the amounts of copper iodide, indium acetate and n-dodecyl mercaptan are 0.1 mmol, 0.1 mmol and 5 mL, respectively. n-dodecyl mercaptan serves as a sulfur source, the elemental aluminum precursor is 0.1 mmol aluminum isopropoxide, and the solvent is 1 mL of n-dodecyl mercaptan.

[0016] Optionally, in step S3, the porous bismuth vanadate film is vertically immersed in the purified and redispersed quantum dot / toluene solution, and quantum dots are electrophoretically deposited in the porous bismuth vanadate film under a DC bias voltage of 100~200V for a deposition time of 1~2h to obtain a quantum dot-sensitized bismuth vanadate film photoelectrochemical photodetector.

[0017] Optionally, in step S4, the photoelectrochemical photodetector is encapsulated with epoxy resin, and the reserved area after encapsulation is 0.1 cm 2 .

[0018] The invention relates to a photoelectric detector based on aluminum-doped copper indium sulfide quantum dots, which is prepared by a preparation method of a photoelectric detector based on aluminum-doped copper indium sulfide quantum dots.

[0019] Furthermore, the photodetector based on aluminum-doped copper indium sulfide quantum dots includes: a bismuth vanadate working electrode sensitized by aluminum-doped copper indium sulfide quantum dots, a Pt counter electrode, an Ag / AgCl reference electrode, an electrolyte of a mixed aqueous solution of potassium borate / sodium sulfite, and a monochromatic light source with a light intensity of 0.14-0.69 mW / cm 2 .

[0020] Beneficial effects of the present invention:

[0021] 1. The present invention synthesized copper indium sulfide quantum dots and, by doping the copper indium sulfide quantum dots with aluminum, improved the photogenerated carrier separation / transfer efficiency and exciton lifetime while maintaining the quantum dots' own efficient light absorption / emission.

[0022] 2. The present invention obtains a quantum dot-sensitized bismuth vanadate photodetector through the synthesized aluminum-doped copper indium sulfide quantum dots, and achieves good underwater optical communication applications.

[0023] 3. Based on the above aluminum-doped copper indium sulfide quantum dots, the PEC photodetector has excellent responsivity (0.14mW / cm 2 The device has a high power consumption of 707mA / W under high light intensity (1000W), a fast response time (tr=32ms, td=27ms), and has achieved good underwater optical communication applications. It provides new improvements for low-cost, efficient and stable quantum dot-based PEC photodetector systems, and promotes practical applications in the field of underwater optical communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a scanning electron microscope image of the morphology of Al-doped copper indium sulfide quantum dots of the present invention;

[0026] Figure 2 This is a graph showing the ultraviolet absorption of Al-doped copper indium sulfide quantum dots of the present invention;

[0027] Figure 3 The steady-state fluorescence spectrum and transient fluorescence lifetime diagram of the Al-doped copper indium sulfide quantum dots of the present invention;

[0028] Figure 4 This is a detection performance diagram of the Al-doped copper indium sulfide quantum dot-sensitized bismuth vanadate thin film photodetector of the present invention;

[0029] Figure 5 This is a response speed diagram of the Al-doped copper indium sulfide quantum dot-sensitized bismuth vanadate thin film photodetector of the present invention;

[0030] Figure 6 This is a demonstration diagram of the application of the Al-doped copper indium sulfide quantum dot-sensitized bismuth vanadate thin film photodetector of the present invention in underwater optical communications. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0032] Example 1

[0033] This embodiment provides a photodetector based on aluminum-doped copper indium sulfide quantum dots. The working electrode is a bismuth vanadate thin film sensitized by aluminum-doped copper indium sulfide quantum dots, the counter electrode is a Pt sheet, the reference electrode is Ag / AgCl, the electrolyte is a mixed aqueous solution of potassium borate / sodium sulfite (pH approximately 9.5), and the light source is a xenon lamp modulated into monochromatic light by a monochromator. The test wavelengths are 450, 470, 490, and 520 nm, and the light intensity is 0.14-0.69 mW / cm 2 .

[0034] Example 2

[0035] Based on Example 1, this embodiment provides a method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots, comprising the following steps:

[0036] Step S1, preparing (bismuth iodide) BiOI nanosheets on conductive glass by electrodeposition, and after the BiOI nanosheets are dried, adding a vanadium source dropwise onto the BiOI nanosheets, annealing at high temperature in a muffle furnace, and washing with a sodium hydroxide solution to obtain a yellow bismuth vanadate film;

[0037] Conventional electrodeposition refers to the electrochemical deposition of metals or alloys from aqueous or non-aqueous solutions of their compounds, or from molten salts. It forms the basis of metal electrolytic smelting, electrorefining, electroplating, and electroforming. These processes are carried out under specific electrolytes and operating conditions. The difficulty of metal electrodeposition and the morphology of the deposit are related to the properties of the deposited metal, as well as factors such as the electrolyte composition, pH, temperature, and current density.

[0038] Specifically, FTO conductive glass is used as the working electrode, Pt is used as the counter electrode, and Ag / AgCl is used as the reference electrode. They are placed in a precursor solution containing iodine and bismuth, and BiOI nanosheets are electrodeposited using cyclic voltammetry. After the BiOI nanosheets are rinsed and dried, vanadium solution is added dropwise, and the mixture is calcined at 450°C in a muffle furnace for 2 hours with a heating rate of 2°C / min. After the calcination, it is washed with a sodium hydroxide aqueous solution and dried to obtain a porous bismuth vanadate film.

[0039] In the precursor solutions of iodine and bismuth, the iodine source and bismuth source are potassium iodide and bismuth nitrate pentahydrate, respectively. The voltage conditions of the cyclic voltammetry electrodeposition method are a scan rate of 5 mV / s, a potential range of -0.13 V to 0 V, and an electrodeposition time of 260 s. The vanadium source is a dimethyl sulfoxide solution of VO(acac)2, and the concentration of the sodium hydroxide aqueous solution is 1 mol / L.

[0040] The basic principle of conventional cyclic voltammetry electrodeposition is to apply a triangular waveform pulse voltage to change the potential at the interface between the working electrode and the electrolyte. This change causes the active substance on the working electrode to undergo oxidation or reduction reactions. The system records the changes in electrode potential and response current to generate a current-voltage curve. When the voltage is swept from low to high, an oxidation peak appears; when the voltage is swept in the reverse direction, a reduction peak appears. By analyzing these peaks, the potential and mechanism of the redox reaction can be determined.

[0041] Step S2: synthesizing high-quality copper indium sulfide quantum dots by a co-thermal method, and after high-temperature growth, lowering the reaction temperature and then performing aluminum doping to obtain aluminum-doped copper indium sulfide quantum dots with excellent photoelectric properties;

[0042] The aluminum-doped copper indium sulfide quantum dots were prepared by the following steps: A copper source, an indium source, and a solvent were sequentially added to a 50 mL three-necked flask. After mixing, the mixture was degassed at room temperature. The mixture was then rapidly heated to 220-230°C under nitrogen. After the reaction temperature stabilized, the mixture was held at this temperature for 5-10 minutes and then quenched in a water bath to yield the copper indium sulfide quantum dots. After the copper indium sulfide quantum dots had grown, the temperature was lowered to 150-200°C. An aluminum precursor solution was then added, the mixture was held at this temperature for 30-50 minutes, and the mixture was quenched in a water bath to yield the aluminum-doped copper indium sulfide quantum dots.

[0043] The copper source, indium source, and solvent used in the aluminum-doped copper indium sulfur quantum dots are copper iodide, indium acetate, and n-dodecyl mercaptan, respectively. The amounts of copper iodide, indium acetate, and n-dodecyl mercaptan are 0.1 mmol, 0.1 mmol, and 5 mL, respectively. Among them, n-dodecyl mercaptan also serves as a sulfur source. The elemental aluminum precursor is 0.1 mmol aluminum isopropoxide, the solvent is 1 mL n-dodecyl mercaptan, and the injection volume is 0.1 mL~0.5 mL.

[0044] Step S3, vertically immersing the porous bismuth vanadate in a quantum dot / toluene solvent, and depositing quantum dots into the bismuth vanadate using electrophoretic deposition, then rinsing excess quantum dots on the surface of the bismuth vanadate with toluene, and drying to obtain a quantum dot-sensitized bismuth vanadate film to obtain a photoelectrochemical photodetector;

[0045] Electrophoretic deposition is a process in which colloidal particles are deposited into a material in a stable suspension through the action of a DC electric field. For example, when a DC voltage is applied to an electrophoretic coating, the charged coating particles migrate to the cathode and react with the alkaline solution generated on the cathode surface to form insoluble particles that are deposited on the work surface.

[0046] Specifically, a quantitative 1-2 mL of the synthesized aluminum-doped copper indium sulfur quantum dot stock solution was taken, 6 mL of toluene solution was added, shaken and centrifuged at a speed of 3000 rpm for 2-3 min. The upper clear liquid was evenly divided into two tubes and ethanol solution was added to 12 mL respectively, followed by a second centrifugation at a speed of 12000 rpm for 3-5 min. The quantum dots were then redispersed in the toluene solution.

[0047] The porous bismuth vanadate film was vertically immersed in a redispersed quantum dot / toluene solution. Under a DC bias voltage of 100-200 V, quantum dots were electrophoretically deposited on the porous bismuth vanadate film for 1-2 hours to obtain a quantum dot-sensitized bismuth vanadate film photodetector.

[0048] Step S4: Using the quantum dot-sensitized bismuth vanadate film as a working electrode, assembling the working electrode, a Pt sheet counter electrode, and an Ag / AgCl reference electrode into a three-electrode test system.

[0049] The quantum dot-sensitized bismuth vanadate film was encapsulated with epoxy resin for photodetector to retain a thickness of about 0.1 cm 2 working area.

[0050] Example 3

[0051] Based on Example 2, the specific steps of the preparation method of the photodetector based on aluminum-doped copper indium sulfide quantum dots are as follows:

[0052] (1) BiOI nanosheets were electrodeposited on FTO conductive glass substrates using cyclic voltammetry. After the BiOI nanosheets dried, 100-150 μl of vanadium source was added dropwise. The nanosheets were then calcined at 450 °C in a muffle furnace for 2 h. After removal, the excess vanadium pentoxide on the surface was washed with a 1 mol / L sodium hydroxide aqueous solution to obtain a yellow bismuth vanadate film.

[0053] (2) Aluminum-doped copper indium sulfide quantum dots were synthesized by a co-thermal method, mainly by the following steps: 0.1mmolCuI, 0.1mmolIn(Ac)3, and 5mL of n-dodecyl mercaptan were added to a 50mL three-necked flask in sequence, mixed evenly, and degassed at room temperature. Finally, the temperature was rapidly raised to 230℃ under nitrogen protection, kept warm for 5min, and then the temperature was lowered to 200℃. 0.1mL of elemental aluminum precursor solution (0.1mmol aluminum isopropoxide dissolved in 1mL of n-dodecyl mercaptan) was injected, and then kept warm at 200℃ for 30min and quenched in a water bath.

[0054] (3) Take a certain amount of 1 mL of the synthesized aluminum-doped copper indium sulfide quantum dot stock solution, add 6 mL of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 min. Take the upper clear liquid and divide it into two tubes equally. Add ethanol solution to 12 mL respectively and centrifuge it twice at a speed of 12000 rpm for 3 min. Then, redisperse the quantum dots into 8 mL of toluene solution.

[0055] (4) The prepared porous bismuth vanadate film was vertically immersed in the purified and redispersed quantum dot / toluene solution, and quantum dots were electrophoretically deposited in the porous bismuth vanadate film at a DC bias voltage of 200 V for 1 hour to obtain a quantum dot-sensitized bismuth vanadate film photodetector.

[0056] (5) The prepared quantum dot-sensitized bismuth vanadate photodetector was encapsulated with epoxy resin to retain a thickness of about 0.1 cm 2 working area.

[0057] Example 4

[0058] Based on Example 2, the specific steps of the preparation method of the photodetector based on aluminum-doped copper indium sulfide quantum dots are as follows:

[0059] (1) BiOI nanosheets were electrodeposited on FTO conductive glass substrates using cyclic voltammetry. After drying, 100-150 μl of vanadium source was added dropwise. The nanosheets were then calcined at 450 °C in a muffle furnace for 2 h. After removal, the excess vanadium pentoxide on the surface was washed with a 1 mol / L sodium hydroxide aqueous solution to obtain a yellow bismuth vanadate film.

[0060] (2) Aluminum-doped copper indium sulfide quantum dots were synthesized by a one-pot thermal method, mainly by the following steps: 0.1mmolCuI, 0.1mmolIn(Ac)3, and 5mL of n-dodecanethiol were added to a 50mL three-necked flask in sequence, mixed evenly, and degassed at room temperature. Finally, the temperature was rapidly raised to 230℃ under nitrogen protection and kept warm for 5min. The temperature was then lowered to 200℃, and 0.2mL of elemental aluminum precursor solution (0.1mmol aluminum isopropoxide dissolved in 1mL of n-dodecanethiol) was injected. The mixture was then kept warm at 200℃ for 30min and quenched in a water bath.

[0061] (3) Take a certain amount of 1 mL of the synthesized aluminum-doped copper indium sulfide quantum dot stock solution, add 6 mL of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 min. Take the upper clear liquid and divide it into two tubes equally. Add ethanol solution to 12 mL respectively and centrifuge it twice at a speed of 12000 rpm for 3 min. Then, redisperse the quantum dots into 8 mL of toluene solution.

[0062] (4) The prepared porous bismuth vanadate film was vertically immersed in the purified and redispersed quantum dot / toluene solution, and quantum dots were electrophoretically deposited in the porous bismuth vanadate film at a DC bias voltage of 200 V for 1 hour to obtain a quantum dot-sensitized bismuth vanadate film photodetector.

[0063] (5) The prepared quantum dot-sensitized bismuth vanadate photodetector was encapsulated with epoxy resin to retain a thickness of about 0.1 cm 2 working area.

[0064] Example 5

[0065] Based on Example 2, the specific steps of the preparation method of the photodetector based on aluminum-doped copper indium sulfide quantum dots are as follows:

[0066] (1) BiOI nanosheets were deposited on FTO conductive glass substrates by cyclic voltammetry. After drying, 100-150 μl of vanadium source was added dropwise. The nanosheets were then calcined at 450 °C in a muffle furnace for 2 h. After removal, the excess vanadium pentoxide on the surface was washed with a 1 mol / L sodium hydroxide aqueous solution to obtain a yellow bismuth vanadate thin film photodetector.

[0067] (2) Aluminum-doped copper indium sulfide quantum dots were synthesized by a one-pot thermal method, mainly by the following steps: 0.1mmolCuI, 0.1mmolIn(Ac)3, and 5mL of n-dodecanethiol were added to a 50mL three-necked flask in sequence, mixed evenly, and degassed at room temperature. Finally, the temperature was rapidly raised to 230℃ under nitrogen protection and kept warm for 5min. The temperature was then lowered to 200℃, and 0.3mL of elemental aluminum precursor solution (0.1mmol aluminum isopropoxide dissolved in 1mL of n-dodecanethiol) was injected. The mixture was then kept warm at 200℃ for 30min and quenched in a water bath.

[0068] (3) Take a certain amount of 1 mL of the synthesized aluminum-doped copper indium sulfide quantum dot stock solution, add 6 mL of toluene solution, shake well and centrifuge roughly at a speed of 3000 rpm for 3 min. Take the upper clear liquid and divide it into two tubes equally. Add ethanol solution to 12 mL respectively and centrifuge it twice at a speed of 12000 rpm for 3 min. Then, redisperse the quantum dots into 8 mL of toluene solution.

[0069] (4) The prepared porous bismuth vanadate film was vertically immersed in the purified and redispersed quantum dot / toluene solution, and quantum dots were electrophoretically deposited in the porous bismuth vanadate film at a DC bias voltage of 200 V for 1 hour to obtain a quantum dot-sensitized bismuth vanadate film photodetector.

[0070] (5) The prepared quantum dot-sensitized bismuth vanadate photodetector was encapsulated with epoxy resin to retain a thickness of about 0.1 cm 2working area.

[0071] Example 6

[0072] The phase and morphology of the aluminum-doped copper indium sulfide quantum dots prepared in Example 3 were analyzed, and the transmission electron microscope analysis and X-ray diffraction pattern were shown in FIG. Figure 1 and Figure 2 The UV-visible absorption spectrum, steady-state fluorescence photoluminescence spectrum and transient fluorescence photoluminescence lifetime of aluminum-doped copper indium sulfide quantum dots in toluene were analyzed. Figure 3 、 Figure 4 It can be seen that the aluminum-doped copper indium sulfide quantum dots of the present invention improve the exciton fluorescence lifetime while maintaining the efficient light absorption / emission of the quantum dots themselves.

[0073] Figure 5 The response speed of the copper indium sulfide quantum dot-sensitized bismuth vanadate thin film photodetector was demonstrated, with a rise time tr=32ms and a fall time td=27ms. This fast response speed is crucial in the field of optical communications. Compared with traditional photodetectors, it can respond more quickly to changes in underwater optical signals, achieve high-speed data transmission and processing, and greatly improve the real-time performance and efficiency of the system.

[0074] Figure 6 It demonstrates the ability to work effectively in underwater environments. Underwater optical communications face many challenges, such as light absorption and scattering by water. The detector of the present invention has been successfully applied underwater, providing a new technical means for communications in the fields of marine resource exploration, underwater environmental monitoring, and military reconnaissance, and expanding the application scope of quantum dot-based photoelectric detectors.

[0075] A PEC-type photodetector test system was constructed based on the photodetector obtained in Example 3. The specific parameters were as follows: an aluminum-doped copper indium sulfide quantum dot-sensitized bismuth vanadate film was used as the working electrode, a Pt sheet was used as the counter electrode, an Ag / AgCl reference electrode was used, the electrolyte was a mixed aqueous solution of potassium borate / sodium sulfite (pH approximately 9.5), and the light source was a xenon lamp modulated into monochromatic light by a monochromator. The test wavelengths were 450, 470, 490, and 520 nm, and the intensity was 0.14–0.69 mW / cm 2 . The PEC photodetector performance test was carried out, and the photocurrent density was 205uAcm -2 , the responsivity can reach 707mA / W, with a response speed of tr=32ms, td=27ms, and has realized underwater optical communication applications. ‌

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots, characterized in that: The steps include: Step S1, preparing BiOI nanosheets on conductive glass by electrodeposition, and after the BiOI nanosheets are dried, adding a vanadium source dropwise onto the BiOI nanosheets, annealing at high temperature in a muffle furnace, and washing with a sodium hydroxide solution to obtain a yellow bismuth vanadate film; Step S2: synthesizing high-quality copper indium sulfide quantum dots by a co-thermal method, and after high-temperature growth, lowering the reaction temperature and then performing aluminum doping to obtain aluminum-doped copper indium sulfide quantum dots with excellent photoelectric properties; Step S3, vertically immersing the porous bismuth vanadate in a quantum dot / toluene solvent, and depositing quantum dots into the bismuth vanadate using electrophoretic deposition, then rinsing excess quantum dots on the surface of the bismuth vanadate with toluene, and drying to obtain a quantum dot-sensitized bismuth vanadate film to obtain a photoelectrochemical photodetector; Step S4: Using the quantum dot-sensitized bismuth vanadate film as a working electrode, assembling the working electrode, a Pt sheet counter electrode, and an Ag / AgCl reference electrode into a three-electrode test system.

2. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 1, characterized in that: In the step S1, the BiOI nanosheets are deposited on the clean FTO conductive glass substrate by cyclic voltammetry electrodeposition. After the BiOI nanosheets are cleaned and dried, the vanadium source is added dropwise, and the bismuth vanadate film is obtained after high-temperature calcination.

3. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 2, characterized in that: The voltage conditions of the cyclic voltammetry electrodeposition method are a scan rate of 5 mV / s, a potential range of -0.13 V to 0 V, a time of 260 s, a drying temperature of 60 ° C, and a dropwise addition of the vanadium source of 100-150 μl / cm 2 , the high temperature calcination temperature is 450℃ and the time is 2h.

4. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 1, characterized in that: In step S2, the co-thermal method for synthesizing high-quality copper indium sulfur quantum dots is as follows: a copper source, an indium source, and a solvent are sequentially added to a 50 mL three-necked flask, and after the copper source, the indium source, and the solvent are mixed, they are degassed at room temperature, and then heated to 220-230° C. under nitrogen protection, and after the reaction temperature stabilizes, the reaction is kept warm for 5-10 minutes, and the reaction is quenched in a water bath to obtain copper indium sulfur quantum dots. After the growth of copper indium sulfur is completed, the temperature is lowered to 150-200° C., and then an aluminum precursor solution is injected, the reaction is kept warm for 30-50 minutes, and the reaction is quenched in a water bath to obtain aluminum-doped copper indium sulfur quantum dots.

5. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 4, characterized in that: The copper source, indium source and solvent used in the aluminum-doped copper indium sulfur quantum dots are copper iodide, indium acetate and n-dodecyl mercaptan, respectively. The amounts of the copper iodide, the indium acetate and the n-dodecyl mercaptan are 0.1 mmol, 0.1 mmol and 5 mL, respectively. n-dodecyl mercaptan serves as a sulfur source, the elemental aluminum precursor is 0.1 mmol aluminum isopropoxide, and the solvent is 1 mL of the n-dodecyl mercaptan.

6. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 1, characterized in that: In step S3, the porous bismuth vanadate film is vertically immersed in the purified and redispersed quantum dot / toluene solution, and quantum dots are electrophoretically deposited in the porous bismuth vanadate film under a DC bias voltage of 100~200V for a deposition time of 1~2h to obtain a quantum dot-sensitized bismuth vanadate film photoelectrochemical photodetector.

7. The method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 1, characterized in that: In step S4, the photoelectrochemical photodetector is encapsulated with epoxy resin, and the reserved area after encapsulation is 0.1 cm 2 .

8. A photodetector based on aluminum-doped copper indium sulfide quantum dots, prepared according to the method for preparing a photodetector based on aluminum-doped copper indium sulfide quantum dots according to any one of claims 1 to 7.

9. The photodetector based on aluminum-doped copper indium sulfide quantum dots according to claim 8, characterized in that: include: The working electrode is a bismuth vanadate sensitized by aluminum-doped copper indium sulfide quantum dots, the counter electrode is a Pt sheet, the reference electrode is Ag / AgCl, the electrolyte is a mixed aqueous solution of potassium borate / sodium sulfite, and the light source is monochromatic light with a light intensity of 0.14~0.69mW / cm 2 .

Images