Zn-doped CuInS2 (at) TiO2 material as well as preparation method and application thereof

Abstract

The invention discloses a Zn-doped CuInS2-coated TiO2 material as well as a preparation method and application thereof, and belongs to the technical field of materials. The preparation method of the Zn-doped CuInS2 (at) TiO2 material comprises the following steps: dissolving ZnxCuInS2 quantum dot powder in dichloromethane, then adding TiO2 nanoparticles, heating and stirring in a water bath environment at 40-45 DEG C, then adding dichloromethane, centrifuging, and then drying, thereby obtaining the Zn-doped CuInS2 (at) TiO2 material. In addition, the invention also provides a Zn-doped CuInS2 (at) TiO2 material which is prepared by the preparation method. In addition, the invention also provides an application of the Zn-doped CuInS2-coated TiO2 material prepared by the preparation method in preparation of a photoelectric detector device. The prepared Zn-doped CuInS2-coated TiO2 material is high in photoelectric conversion efficiency, and the response time of a photoelectric detector can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to a Zn-doped CuInS2@TiO2 material and a preparation method and application thereof. Background Art

[0002] Photodetectors are one of the important components of optoelectronic systems. They are key technical devices that convert optical signals into electrical signals. They play a vital role in modern science and technology. From missile guidance and infrared thermal imaging in the military field to industrial automatic control and photometry in the civilian field, to scientific research such as astronomy and spectroscopy, the application of photodetectors is extensive and far-reaching.

[0003] TiO2 semiconductors have been widely studied and applied in various fields due to their corrosion resistance, environmental friendliness, simple preparation and low cost. And with the development of nano-manufacturing technology, nano-TiO2 materials have shown more unique photoelectric properties. At present, nano-TiO2 semiconductors are widely used in ultraviolet detectors, solar cells, gas sensors, photocatalysis and coating protection. Due to the high electron-hole recombination rate inside a single TiO2, this greatly limits its application. Usually, its photoelectric performance is improved by semiconductor composite modification. Due to its heterojunction effect, controllable structure and morphology, simple preparation, low cost and other advantages, it has become an effective modification method to improve the photoelectric performance of TiO2. In addition, many types of composite semiconductors also provide more selectivity and diversity for the construction of heterostructure composite materials.

[0004] Traditional lead and cadmium quantum dot photodetectors have high photoelectric conversion efficiency, making them new high-performance photodetectors. However, the heavy metal elements in these quantum dot materials are potentially toxic, and their development is subject to certain restrictions. CuInS2 quantum dots have potential application prospects in the field of photodetectors due to their non-toxic and environmentally friendly properties. However, there is still a lack of new materials with high photoelectric conversion efficiency. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a Zn-doped CuInS2@TiO2 material and a preparation method and application thereof, and solve the technical problem of the lack of new materials with high photoelectric conversion efficiency in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention provides a method for preparing a Zn-doped CuInS2@TiO2 material, comprising the following steps: Zn xCuInS2 quantum dot powder is dissolved in dichloromethane, and then TiO2 nanoparticles are added and heated and stirred in a water bath environment at 40-45°C, and then dichloromethane is added and centrifuged, and then dried to obtain Zn-doped CuInS2@TiO2 material; wherein the value of x is 0.1-0.3.

[0007] In any embodiment, the Zn x CuInS2 quantum dot powder is prepared by the following steps: The Zn source precursor solution, In(OAc)3, CuI, oleylamine and octadecene are mixed, and then degassed, and then heated to 95-100°C in a nitrogen atmosphere, and then vacuumed, and then heated to 160-170°C in a nitrogen atmosphere and injected with S source precursor solution for reaction, and then centrifuged, washed and dried to obtain the Zn x CuInS2 quantum dot powder, wherein the value of x is 0.1-0.3.

[0008] In any embodiment, the temperature is raised to 160-170° C. under a nitrogen atmosphere and the S source precursor solution is injected to react for 15-20 minutes.

[0009] In any embodiment, the Zn source precursor solution is prepared by the following steps: Zinc acetate powder, octadecene and oleylamine are mixed, degassed, and then heated to 120-130°C for reaction.

[0010] In any embodiment, the S source precursor solution is prepared by the following steps: The S powder and oleylamine are mixed, and then degassed, and then the temperature is raised to 90-95° C. and the reaction is maintained to obtain the S source precursor solution.

[0011] In any embodiment, the heating time in a water bath environment at 40-45° C. is 2-3 hours.

[0012] In addition, the present invention also proposes a Zn-doped CuInS2@TiO2 material, which is prepared by the above preparation method.

[0013] In addition, the present invention also proposes a Zn-doped CuInS2@TiO2 material prepared by the above preparation method or an application of the above Zn-doped CuInS2@TiO2 material in the preparation of a photodetector device.

[0014] In any embodiment, the above application includes: The Zn-doped CuInS2@TiO2 material, α-pinene alcohol, ethyl cellulose and anhydrous ethanol are mixed, and then heated and stirred in a water bath environment at 40-45° C. to obtain a Zn-doped CuInS2@TiO2 slurry; The Zn-doped CuInS2@TiO2 slurry was spin-coated on the surface of conductive glass and then dried to obtain a photodetector device.

[0015] In any embodiment, the heating and stirring time in a water bath environment at 40-45° C. is 20-24 hours.

[0016] Compared with the prior art, the beneficial effects of the present invention include: x CuInS2 quantum dot powder is dissolved in dichloromethane, and then TiO2 nanoparticles are added and heated and stirred in a water bath environment at 40-45°C. Dichloromethane is then added and centrifuged, and then dried to obtain Zn-doped CuInS2@TiO2 material. The prepared Zn-doped CuInS2@TiO2 material has high photoelectric conversion efficiency and can significantly improve the response time of the photodetector. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the XRD diagram of CuInS2 quantum dot powder with different zinc doping ratios in Examples 1-5 of the present invention and Comparative Example 1.

[0018] Figure 2 The Zn obtained in Example 4 of the present invention 0.4 X-ray photoelectron spectrum of CuInS2 quantum dot powder.

[0019] Figure 3 The ZnO2 nanoparticles and quantum dots obtained in Example 4 of the present invention are combined. 0.4 TEM image of CuInS2@TiO2 material.

[0020] Figure 4 The current-time curve of the photodetector formed by combining quantum dots and TiO2 nanoparticles with different mass ratios in the application example.

[0021] Figure 5 The logarithmically processed (lg) current-voltage curves of the ZCIS / TiO2-2 sample photodetector prepared in Example 2 under 365 nm light source and dark conditions were compared. DETAILED DESCRIPTION

[0022] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0024] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0025] This specific embodiment provides a method for preparing a Zn-doped CuInS2@TiO2 material, comprising the following steps: The S powder and oleylamine are mixed, and then degassed, and then the temperature is raised to 90-95° C. and the reaction is maintained to obtain a S source precursor solution; Mix zinc acetate powder, octadecene and oleylamine, degas, and heat to 120-130°C to react and obtain a Zn source precursor solution; The Zn source precursor solution, In(OAc)3, CuI, oleylamine and octadecene are mixed, and then degassed, and then heated to 95-100°C in a nitrogen atmosphere, and then vacuumed, and then heated to 160-170°C in a nitrogen atmosphere and injected with S source precursor solution to react for 15-20 minutes, and then centrifuged, washed and dried to obtain the Zn x CuInS2 quantum dot powder, wherein the value of x is 0.1-0.3; Zn x CuInS2 quantum dot powder is dissolved in dichloromethane, and then TiO2 nanoparticles are added and heated in a water bath environment at 40-45°C for 2-3 hours with stirring. Then, dichloromethane is added and centrifuged, and then dried to obtain Zn-doped CuInS2@TiO2 material.

[0026] This specific embodiment also proposes a Zn-doped CuInS2@TiO2 material, which is prepared by the above preparation method.

[0027] This specific embodiment also proposes an application of the Zn-doped CuInS2@TiO2 material prepared by the above preparation method or the above Zn-doped CuInS2@TiO2 material in preparing a photodetector device, including: The Zn-doped CuInS2@TiO2 material, α-pinene alcohol, ethyl cellulose and anhydrous ethanol are mixed, and then heated in a water bath environment at 40-45° C. for 20-24 hours and stirred to obtain a Zn-doped CuInS2@TiO2 slurry; The Zn-doped CuInS2@TiO2 slurry was spin-coated on the surface of conductive glass and then dried to obtain a photodetector device.

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0030] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0031] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0032] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0033] It should be noted that the cuprous iodide (CuI, 99.999%), zinc acetate (Zn (CH3COO)2, 99.999%), indium acetate (In(C2H3O2)3, 99.999%), sublimed sulfur (S, AR), oleylamine (C 18 H 37 N, 80-90%), octadecene (C 18 H 36 , 95%) were purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0034] This embodiment provides a Zn-doped CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 90 °C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L S source precursor solution. 0.22 g of zinc acetate powder (Zn(OAc)2), 8 ml of octadecene (ODE) and 2 ml of oleylamine (OAM) were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution; then, the temperature was raised to 130°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a Zn source precursor solution with a concentration of 0.1 mol / L. Take 0.2mL Zn source precursor solution, 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 100℃ in a nitrogen atmosphere and keep it at this temperature for 5 minutes to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, increase the temperature to 170℃ and quickly inject 1ml of S source precursor solution, then keep the reaction for 18 minutes. After the reaction is completed, cool it to room temperature, centrifuge, wash and dry it to finally obtain Zn 0.1 CuInS2 quantum dot powder; Take Zn 0.1 CuInS2 quantum dot powder was dissolved in 5 ml of dichloromethane, and P25 TiO2 nanoparticles were added and heated in a 40°C water bath and stirred for 2 hours to fully mix. Then 10 ml of dichloromethane was added and centrifuged to remove the unadsorbed quantum dots. Zn was obtained after drying. 0.1 CuInS2@TiO2 material (i.e., Zn-doped CuInS2@TiO2 material, abbreviated as ZCIS-TiO2-1).

[0035] This embodiment provides a Zn-doped CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 95°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L concentration of S source precursor solution. 0.22 g of zinc acetate powder (Zn(OAc)2), 8 ml of octadecene (ODE) and 2 ml of oleylamine (OAM) were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution; then, the temperature was raised to 120°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a Zn source precursor solution with a concentration of 0.1 mol / L; Take 0.4mL Zn source precursor solution, 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 95°C in a nitrogen atmosphere and keep it at this temperature for 5 minutes to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, raise the temperature to 160°C and quickly inject 1 ml of S source precursor solution, then keep the reaction for 15 minutes. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to finally obtain Zn 0.2 CuInS2 quantum dot powder; Take Zn 0.2 CuInS2 quantum dot powder was dissolved in 5 ml of dichloromethane, and P25 TiO2 nanoparticles were added and heated in a 40°C water bath and stirred for 2 hours to fully mix. Then 10 ml of dichloromethane was added and centrifuged to remove the unadsorbed quantum dots. Zn was obtained after drying. 0.2 CuInS2@TiO2 material (i.e., Zn-doped CuInS2@TiO2 material, abbreviated as ZCIS-TiO2-2).

[0036] This embodiment provides a Zn-doped CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 90 °C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L S source precursor solution. 0.22 g of zinc acetate powder (Zn(OAc)2), 8 ml of octadecene (ODE) and 2 ml of oleylamine (OAM) were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution; then, the temperature was raised to 130°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a Zn source precursor solution with a concentration of 0.1 mol / L. Take 0.6mL Zn source precursor solution, 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 100℃ in a nitrogen atmosphere and keep it at this temperature for 5 minutes to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, increase the temperature to 170℃ and quickly inject 1ml of S source precursor solution, then keep the reaction for 20 minutes. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to finally obtain Zn 0.3 CuInS2 quantum dot powder; Take Zn 0.3 CuInS2 quantum dot powder was dissolved in 5 ml of dichloromethane, and P25 TiO2 nanoparticles were added and heated in a 40°C water bath and stirred for 2 hours to fully mix. Then 10 ml of dichloromethane was added and centrifuged to remove the unadsorbed quantum dots. Zn was obtained after drying. 0.3 CuInS2@TiO2 material (i.e., Zn-doped CuInS2@TiO2 material, abbreviated as ZCIS-TiO2-3).

[0037] This embodiment provides a Zn-doped CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 90 °C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L S source precursor solution. 0.22 g of zinc acetate powder (Zn(OAc)2), 8 ml of octadecene (ODE) and 2 ml of oleylamine (OAM) were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution; then, the temperature was raised to 130°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a Zn source precursor solution with a concentration of 0.1 mol / L. Take 0.8mL Zn source precursor solution, 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 100°C in a nitrogen atmosphere and keep it at this temperature for 5 minutes to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, increase the temperature to 170°C and quickly inject 1 ml of S source precursor solution, then keep the reaction for 15 minutes. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to finally obtain Zn 0.4 CuInS2 quantum dot powder; Take Zn 0.4 CuInS2 quantum dot powder was dissolved in 5 ml of dichloromethane, and P25 TiO2 nanoparticles were added and heated in a 40°C water bath and stirred for 2 hours to fully mix. Then 10 ml of dichloromethane was added and centrifuged to remove the unadsorbed quantum dots. Zn was obtained after drying. 0.4 CuInS2@TiO2 material (i.e., Zn-doped CuInS2@TiO2 material, abbreviated as ZCIS-TiO2-4).

[0038] This embodiment provides a Zn-doped CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 90 °C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L S source precursor solution. 0.22 g of zinc acetate powder (Zn(OAc)2), 8 ml of octadecene (ODE) and 2 ml of oleylamine (OAM) were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution; then, the temperature was raised to 130°C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a Zn source precursor solution with a concentration of 0.1 mol / L. Take 1.0mL Zn source precursor solution, 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 100℃ in a nitrogen atmosphere and keep it at this temperature for 5 min to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, raise the temperature to 170℃ and quickly inject 1 ml of S source precursor solution, then keep the reaction for 15 min. After the reaction is completed, cool it to room temperature, centrifuge, wash and dry it to finally obtain Zn 0.5 CuInS2 quantum dot powder; Take Zn 0.5 CuInS2 quantum dot powder was dissolved in 5 ml of dichloromethane, and P25 TiO2 nanoparticles were added and heated in a 40°C water bath and stirred for 2 hours to fully mix. Then 10 ml of dichloromethane was added and centrifuged to remove the unadsorbed quantum dots. Zn was obtained after drying. 0.5 CuInS2@TiO2 material (i.e., Zn-doped CuInS2@TiO2 material).

[0039] Comparative Example 1 The difference between this comparative example and Example 4 is that no Zn is added, specifically: This comparative example proposes a CuInS2@TiO2 material, which is prepared by the following steps: 0.48 g of sulfur powder (S powder) and 10 ml of OAM were mixed in a three-necked flask and subjected to triple degassing to remove oxygen and other gas impurities in the solution. Subsequently, the temperature was raised to 90 °C and maintained for 5 min. After the timing was over, the mixture was naturally cooled to room temperature and sealed for storage to obtain a 1.25 mol / L S source precursor solution. Take 58.39mg In(OAc)3, 38mg CuI, 4ml oleylamine and 8ml octadecene and mix them in a three-necked flask. Degas the mixture three times to remove oxygen and other gas impurities in the solution. Heat to 100°C in a nitrogen atmosphere and keep it at this temperature for 5 min to ensure that the mixture is fully dissolved. Vacuum the reaction system again to remove possible impurities such as oxygen and water vapor. Under nitrogen atmosphere, raise the temperature to 170°C and quickly inject 1 ml of S source precursor solution, then keep the reaction for 15 min. After the reaction is completed, cool to room temperature, centrifuge, wash and dry to finally obtain CuInS2 quantum dot powder, i.e. Zn0CuInS2 quantum dot powder; Take CuInS2 quantum dot powder and dissolve it in 5 ml of dichloromethane. Add P25 TiO2 nanoparticles and heat and stir in a 40°C water bath for 2 hours to mix them thoroughly. Then add 10 ml of dichloromethane and centrifuge to remove the unadsorbed quantum dots. After drying, CuInS2@TiO2 material is obtained.

[0040] The XRD (X-ray diffraction) patterns of the CuInS2 quantum dot powders with different zinc doping ratios prepared in Examples 1-5 and Comparative Example 1 are as follows: Figure 1 It should be noted that Zn0CuInS2 represents the CuInS2 quantum dot powder prepared in Comparative Example 1; Zn 0.1 CuInS2 represents the Zn obtained in Example 1 0.1 CuInS2 quantum dot powder; Zn 0.2 CuInS2 represents Zn obtained in Example 2 0.2 CuInS2 quantum dot powder; Zn 0.3 CuInS2 represents Zn obtained in Example 3 0.3 CuInS2 quantum dot powder; Zn 0.4 CuInS2 represents Zn obtained in Example 4 0.4 CuInS2 quantum dot powder; Zn 0.5 CuInS2 represents Zn obtained in Example 5 0.5 CuInS2 quantum dot powder; after fitting and comparison with the standard card (JCPDS No.027-0159), the positions of each diffraction peak correspond to the (112), (220) / (204) and (312) / (116) crystal planes of the chalcopyrite structure, and the diffraction peaks of all samples did not shift significantly, which indicates that the introduced Zn atoms did not change the crystal structure of the quantum dots and still maintained the original single chalcopyrite structure.

[0041] Figure 2 The Zn prepared in Example 4 0.4 X-ray photoelectron spectroscopy (XPS) test results of CuInS2 quantum dot powder, which provides chemical state and composition information of the elements on the surface of the material. Figure 2 (a) Zn 0.4 The full spectrum of CuInS2 quantum dot powder, after correction of the C1s standard peak, shows the characteristic peaks of four elements: Zn, Cu, In and S. These peaks represent the binding energy of photoelectrons released after the core energy level electrons of the elements are excited. Figure 2(b) is the XPS spectrum of Zn, showing the characteristic photoelectron peak of Zn 2p, the Zn 2p3 / 2 and Zn 2p1 / 2 peaks are located at binding energies of 1021.46 eV and 1044.41 eV, respectively, and there is an obvious energy difference of 22.95 eV between the two peaks. This energy splitting and specific binding energy position prove that zinc exists in the sample in the form of +2 valence. Figure 2 (c) is the XPS spectrum of Cu, in which the Cu 2p core energy level region of Cu shows two main photoelectron peaks, namely the Cu 2p3 / 2 and Cu 2p1 / 2 peaks. The energy level of Cu is split into two orbits, Cu 2p3 / 2 and Cu 2p1 / 2, with binding energies at 951.58 eV and 931.82 eV, respectively. At the same time, the energy difference between the two peaks is usually very fixed, about 20 eV. The calculated test results show that the difference between the two peaks is 19.76 eV. What is more characteristic is that copper in the +1 valence state shows very weak satellite peaks near the Cu 2p3 / 2 and Cu 2p1 / 2 peaks, which is different from the characteristics of higher valence copper ions (such as +2 valence), where the satellite peaks are more obvious. Therefore, through the peak position of Cu 2p and the presence or absence of satellite peaks, it can be determined that the valence state of copper in the XPS spectrum is +1. Figure 2 In (d), the In 3d electron orbit of In shows two obvious characteristic peaks, and the orbital binding energies in the spectrum are located at 452.18 eV and 444.64 eV, corresponding to the sub-energy levels of In 3d5 / 2 and In 3d3 / 2, respectively. The peak shape of the In 3d peak shows a sharp and symmetrical morphology, and is not accompanied by obvious satellite peaks, which is different from the performance of low-valence or metallic In in the XPS spectrum. There is a typical energy splitting between the two peaks, and the calculated difference in the figure is 7.548 eV. Through these spectral features, combined with the peak position and energy splitting, it can be confirmed that In is mainly presented in the +3 valence state in the sample. Figure 2 (e) shows the energy spectrum peak of S 2p, showing two main photoelectron peaks, corresponding to the sub-energy levels of S 2p3 / 2 and S 2p1 / 2 respectively. After peak separation, it can be seen that the positions of the two orbital binding energies are 162.77 eV and 161.56 eV, with a difference of 1.21 eV (this energy splitting is about 1.18 eV). By combining the binding energy range, double peak structure and energy splitting, the chemical environment of sulfur in the -2 valence state can be determined in the XPS spectrum. It is worth noting that Figure 2 The green peak of Cu in (c) should be caused by Zn doping, which once again proves that Zn ions enter the CuInS2 quantum dots by doping, and as the reaction proceeds, dynamic equilibrium is finally reached to form a stable quantum dot structure. 0.4The chemical composition of each element of CuInS2 quantum dots and their corresponding chemical valence states.

[0042] Example 4: TiO2 nanoparticles and Zn quantum dots combined 0.4 TEM images of CuInS2@TiO2 materials are shown in Figure 3 As shown below, at a resolution of 100nm, the TEM image clearly shows that a large number of quantum dots are evenly distributed and attached to the surface of the TiO2 nanoparticles. As the magnification increases to 50nm, the quantum dots can be seen attached to the surface of the TiO2 nanoparticles, and the morphology and size of the quantum dots can be observed. At the zoom level of 10nm, it can be observed that the quantum dots with extremely high resolution are directly distributed on the surface of the TiO2 particles. Further zooming in to a resolution of 5nm, not only the individual particles of the quantum dots are clearly visible, but also the lattice structure of their surface is revealed, which allows the lattice spacing of the quantum dots to be accurately measured. Through systematic image analysis, two different lattice fringes can be observed. The lattice fringes spacing is measured to be 0.3541 nm. Compared with the standard PDF card (JCPDS No.021-1272), the corresponding crystal plane of the TiO2 anatase structure is obtained. The other lattice fringes spacing is measured to be 0.3209 nm. Compared with the standard PDF card, it is obtained that it corresponds to the (101) crystal plane of CuInS2.

[0043] Application Examples The Zn-doped CuInS2@TiO2 material prepared in Examples 1-4 and the single P25 TiO2 nanoparticles were respectively mixed with 1.025 g of α-pinene alcohol, 0.13 g of ethyl cellulose and 3 ml of anhydrous ethanol, and heated and stirred in a 40°C water bath for 24 hours to volatilize the excess anhydrous ethanol, finally obtaining the Zn-doped CuInS2@TiO2 slurry and the single P25 TiO2 nanoparticle slurry corresponding to Examples 1-4; The Zn-doped CuInS2@TiO2 slurry corresponding to Examples 1-4 or the single P25 TiO2 nanoparticle slurry was spin-coated on the surface of conductive glass (20*10 mm, square resistance <7Ω, channel size of 1*10 mm) at a speed of 3000 r / min. The coating thickness was 3 μm, and then dried in a drying oven at 50°C to obtain the Zn-doped CuInS2@TiO2 photodetector device. The sample corresponding to the single P25TiO2 nanoparticle slurry is abbreviated as ZCIS-TiO2-0.

[0044] Figure 4The current-time curve of the photodetector formed by combining quantum dots with different mass ratios and TiO2 nanoparticles in the application example is shown. It is found that the mass ratio of different quantum dots has a significant effect on its performance. The photodetector corresponding to Example 2 shows a faster current rise response and a larger peak current under illumination conditions than other ratios. This result shows that the device can quickly and effectively generate and collect photogenerated electrons under light activation, which is one of the key indicators for measuring the performance of photodetectors. Although photodetectors with other mass ratios also show an upward trend in light response, they are inferior to the samples in Example 2 in terms of rapid current response and peak current. When the proportion of quantum dots continues to increase, the photocurrent decreases, indicating that the negative effect of adding carrier recombination of quantum dots is greater than the gain brought by absorbing more light energy. When the photodetector device corresponding to the quantum dots of Example 2 reaches the optimal value in dynamic balance, the photoelectric performance at this time is better than that of other ratios. In further testing the IV curve, it was found that among the new photodetectors with quantum dots of different mass ratios, the detector corresponding to the quantum dots of Example 2 showed the optimal current curve value. In a certain voltage range (-5V~5V), the current density (i.e., current divided by device area) of the quantum dot sample of Example 2 reaches the highest, indicating that it has higher photoresponsivity and photoelectric conversion efficiency. For the best performing ZCIS / TiO2-2 sample, under the same applied voltage, the current value is higher than that of samples with other mass ratios.

[0045] Figure 5 Comparing the logarithmic (lg) current-voltage curves of the ZCIS / TiO2-2 sample photodetector under 365 nm light source and dark conditions, the effect of illumination on the photocurrent gain becomes very obvious. The IV curve under dark conditions shows a lower current value because there are only thermally activated carriers in the absence of light, resulting in a lower current. Under 365 nm illumination, the current value rises sharply. This increase is due to the large generation of carriers after absorbing photons, resulting in an increase in photogenerated current. Logarithmic processing can make this effect more significant because it amplifies the change in current value, allowing the current change to be presented linearly on the graph for easy identification and comparison.

[0046] When analyzing the new photodetector with the best performance of ZCIS / TiO2-2 quantum dots separately, the focus is on its response time and recovery time, two key dynamic performance parameters. The response time of this detector is 2.92 seconds, indicating that it takes 2.92 seconds to reach a stable current response peak after the start of light. The response recovery time is 1.45 seconds, which means that after the light is removed, the detector takes 1.45 seconds to recover to a dark current level close to the initial level. Such response and recovery times indicate that the device has a faster rate in detecting optical signals and outputting electrical signals, and is suitable for occasions that do not require extremely fast response. However, compared to some applications, these times still have room for optimization, especially in applications such as fast optical communications or real-time light detection, which may require faster response and recovery speeds.

[0047] Table 1 Detailed photoelectric performance parameters of the photodetectors corresponding to the Zn-doped CuInS2@TiO2 materials and the single P25 TiO2 nanoparticles prepared in Examples 1-4 Sample ZCIS / TiO2-0 ZCIS / TiO2-1 ZCIS / TiO2-2 ZCIS / TiO2-3 ZCIS / TiO2-4 Photocurrent(A) 1.50×10-9 2.32×10-8 2.60×10-7 1.29×10-8 5.42×10-9 Dark current(A) 8.15×10-14 9.57×10-12 1.20×10-11 7.10×10-12 1.13×10-11 Effective area (cm2) 0.75 0.6525 0.725 0.725 0.6525 Responsivity (A / W) 1.63×10-7 2.90×10-6 2.93×10-5 1.45×10-6 6.77×10-7 Detection rate (Jones) 8.76×108 1.34×109 1.27×1010 8.21×108 2.88×108 Light-to-dark current ratio 1.84×104 2.42×109 2.17×104 1.82×103 4.80×102 Table 1 summarizes the values ​​of various device performance parameters of new photodetectors with different mass ratios of quantum dots. These parameters reflect the photoelectric performance of each device under specific conditions, including photoresponsivity, detection rate, etc., as well as the maximum photocurrent value at a specific voltage (1V). The key performance indicators of new photodetectors with different mass ratios of quantum dots are clearly represented in the table, which is convenient for intuitive comparison and evaluation.

[0048] Table 2 Response time of the novel photodetector corresponding to the Zn-doped CuInS2@TiO2 material prepared in Examples 1-4 and the single P25 TiO2 nanoparticles Sample ZCIS / TiO2-0 ZCIS / TiO2-1 ZCIS / TiO2-2 ZCIS / TiO2-3 ZCIS / TiO2-4 Rise time Tr (s) 6.28 3.8 2.92 6.74 8.20 Fall time Td (s) 1.65 1.53 1.45 2.71 2.41 The response time of each sample is calculated and listed in Table 2, and the speed of response can be seen. The new photodetector of ZCIS / TiO2-2 quantum dots has the fastest response speed and the shortest response recovery time, which provides the photodetector with faster light signal processing capability. This is related to the fact that quantum dots have the best surface state, energy level matching or photogenerated carrier dynamics at this ratio, thereby effectively reducing the trap capture and release time of carriers.

[0049] By changing the mass ratio between TiO2 nanoparticles and quantum dots to adjust the performance of the photodetector, a new type of photodetector with ZCIS / TiO2-2 quantum dots with optimal photodetection performance was prepared. By adjusting the ratios, the stability and repeatability of the device were significantly improved. The device exhibited excellent photoelectric performance. Under the irradiation of a 365 nm light source, it was able to quickly and effectively generate and collect photogenerated electrons. At this time, the device had a responsivity of 2.93×10-5 A / W and a detection rate of 1.27×1010 Jones. It also had a fast response rise time of 2.92 seconds and a response recovery time of 1.45 seconds. This series of performance improvements can be attributed to a more efficient photogenerated carrier separation process and the good light absorption characteristics of the quantum dots themselves.

[0050] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a Zn-doped CuInS2@TiO2 material, characterized in that: The following steps are involved: Zn x CuInS2 quantum dot powder is dissolved in dichloromethane, and then TiO2 nanoparticles are added and heated and stirred in a water bath environment at 40-45°C, and then dichloromethane is added and centrifuged, and then dried to obtain Zn-doped CuInS2@TiO2 material; wherein the value of x is 0.1-0.

3.

2. The method for preparing the Zn-doped CuInS2@TiO2 material according to claim 1, characterized in that: The Zn x CuInS2 quantum dot powder is prepared by the following steps: The Zn source precursor solution, In(OAc)3, CuI, oleylamine and octadecene are mixed, and then degassed, and then heated to 95-100°C in a nitrogen atmosphere, and then vacuumed, and then heated to 160-170°C in a nitrogen atmosphere and injected with S source precursor solution for reaction, and then centrifuged, washed and dried to obtain the Zn x CuInS2 quantum dot powder.

3. The method for preparing the Zn-doped CuInS2@TiO2 material according to claim 2, characterized in that: In a nitrogen atmosphere, the temperature was raised to 160-170°C and the S source precursor solution was injected to react for 15-20 minutes.

4. The method for preparing the Zn-doped CuInS2@TiO2 material according to claim 2, characterized in that: The Zn source precursor solution is prepared by the following steps: Zinc acetate powder, octadecene and oleylamine are mixed, degassed, and then heated to 120-130°C for reaction.

5. The method for preparing the Zn-doped CuInS2@TiO2 material according to claim 2, characterized in that: The S source precursor solution is prepared by the following steps: The S powder and oleylamine are mixed, and then degassed, and then the temperature is raised to 90-95° C. and the reaction is maintained to obtain the S source precursor solution.

6. The method for preparing the Zn-doped CuInS2@TiO2 material according to claim 1, characterized in that: The heating time in a water bath at 40-45°C is 2-3 hours.

7. A Zn-doped CuInS2@TiO2 material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the Zn-doped CuInS2@TiO2 material prepared by the preparation method according to any one of claims 1 to 6 or the Zn-doped CuInS2@TiO2 material according to claim 7 in the preparation of photodetector devices.

9. The use according to claim 8, characterized in that: include: The Zn-doped CuInS2@TiO2 material, α-pinene alcohol, ethyl cellulose and anhydrous ethanol are mixed, and then heated and stirred in a water bath environment at 40-45° C. to obtain a Zn-doped CuInS2@TiO2 slurry; The Zn-doped CuInS2@TiO2 slurry was spin-coated on the surface of conductive glass and then dried to obtain a photodetector device.

10. The use according to claim 9, characterized in that: The mixture is heated and stirred in a water bath at 40-45°C for 20-24 hours.

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