Method for in-situ preparation of photoresponsive and tunable titanium dioxide heterojunction thin films

Abstract

The invention discloses a method for preparing a titanium dioxide heterojunction film with adjustable light response in situ, and the specific implementation method is as follows: first the substrate is cleaned, then pickling annealing pretreatment is performed, the substrate after treatment is cleaned again and dried for standby use; titanium source, salt, acid and ultrapure water are mixed and stirred evenly, and reaction precursor liquid is prepared for standby use; the substrate and reaction precursor liquid are transferred to a stainless steel autoclave, and hydrothermal reaction is carried out in an electric heating blast drying oven, and cooling and taking out after the reaction is completed, ultrasonic cleaning is performed with ultrapure water, and a titanium dioxide crystal face heterojunction film is obtained on the substrate surface. The film prepared by the present invention can be grown in situ on the substrate, uniform and dense, and has good bonding strength. By adjusting the ratio of different crystal forms and different crystal faces of titanium dioxide film and the construction of nanostructures, the light response regulation of different windows in the near-infrared light region (I zone: 650-1000nm, II zone: 1000-1350nm) can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for in-situ preparation of a titanium dioxide heterojunction film with adjustable light response. Background Art

[0002] Titanium and titanium alloys are widely used in the field of medical implant materials due to their excellent mechanical properties, corrosion resistance and biocompatibility. However, medical implants often cause inflammation and affect bone integration due to bacterial infection after surgery, usually requiring large amounts of antibiotics or even a second operation.

[0003] In order to improve the antibacterial properties of the titanium surface, antibacterial coatings are constructed by coating the titanium surface with antibiotics, loading metal ions such as silver and zinc, or antimicrobial peptides. Large-scale use of antibiotics will produce drug resistance and damage cells. Silver ion loading has good antibacterial effects, but the price is high and biocompatibility cannot be guaranteed. Antimicrobial peptides have obvious bactericidal effects but are costly and have a complex synthesis process, so they cannot be used on a large scale.

[0004] In recent years, remote light-controlled therapy has received increasing attention in the biomedical field due to its advantages such as non-invasiveness, tissue penetration, and compatibility. Titanium dioxide has good absorption in the ultraviolet region and can produce a large number of highly active photogenerated electrons, holes, and reactive oxygen species, but ultraviolet light is very harmful to human tissue. It is necessary to modify the titanium surface so that the absorption region is red-shifted from the initial ultraviolet region to the visible and near-infrared regions to overcome the damage caused by ultraviolet light excitation to human tissue. Common modification methods include: element doping, nanostructure engineering, crystal surface engineering, and construction of heterojunctions. Summary of the invention

[0005] To solve the above problems, the purpose of the present invention is to propose a method for in-situ preparation of titanium dioxide heterojunction thin films with adjustable photoresponse, combining crystal plane engineering with heterojunction and nanostructure, modifying the surface of the substrate, and realizing photoresponse regulation in different windows in the near-infrared light region (region I: 650-1000nm, region II: 1000-1350nm).

[0006] In order to achieve the above objectives, the following technical solutions are proposed:

[0007] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film comprises the following steps:

[0008] 1) First clean the substrate, then perform pickling and annealing pretreatment, and then clean the treated substrate again and dry it for later use;

[0009] 2) Evenly mix the titanium source, salt, acid and ultrapure water and stir them thoroughly to prepare a reaction precursor solution for use;

[0010] 3) The substrate and the reaction precursor solution are transferred to a stainless steel high-pressure reactor, and a hydrothermal reaction is carried out in an electric heated blast drying oven. After the reaction is completed, the substrate is cooled and taken out, and ultrasonically cleaned with ultrapure water to obtain a substrate with a titanium dioxide heterojunction film on the surface.

[0011] The present application mainly regulates the near-infrared light response window of titanium dioxide thin films by regulating the titanium dioxide crystal form, crystal plane ratio and nanostructure, constructing different crystal plane heterojunctions, changing the band gap.

[0012] Furthermore, the substrate in step 1) is at least one of titanium and titanium alloy.

[0013] Furthermore, in step 2), the titanium source in the reaction precursor solution is at least one of titanium sulfate and titanium trichloride.

[0014] Furthermore, in step 2), the salt in the reaction precursor solution is at least one of sulfate, chloride, nitrate, oxalate, acetate, titanous sulfate and titanium trichloride.

[0015] Furthermore, in step 2), the acid in the reaction precursor solution is at least one of sulfuric acid, hydrochloric acid, nitric acid, acetic acid and oxalic acid.

[0016] Furthermore, in step 2), the concentration of titanium ions in the reaction precursor solution is 2-3.5 mM.

[0017] Furthermore, in step 2), the molar ratio of the titanium source to the acid is 1:1000-1:300.

[0018] Furthermore, the pickling annealing treatment used in step 1) is to subject the substrate to ultrasonic etching treatment with a mixed solution of hydrofluoric acid and nitric acid for 5-20 seconds at a temperature of 250-750° C. for 0.5-2 hours.

[0019] Furthermore, in step 3), the time of the hydrothermal reaction is 1-5 hours, the temperature of the hydrothermal reaction is 140-180° C., and the cooling method after the hydrothermal reaction is water cooling.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a method for preparing a titanium dioxide heterojunction film with adjustable light response in situ on a substrate by constructing a nanostructure containing a titanium dioxide crystal face heterojunction. The present invention has low operation difficulty, simple instrument requirements, and low cost. The titanium dioxide heterojunction film with adjustable light response prepared by the present invention can achieve good light response in different near-infrared windows according to application requirements, and has good photothermal effect and photothermal conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1The field emission scanning electron microscope image and X-ray diffraction analysis spectrum of the titanium dioxide film prepared in Example 1;

[0023] Figure 2 The titanium dioxide film prepared in Example 1 is 2 ) Heating curve after laser irradiation for 15 minutes;

[0024] Figure 3 The field emission scanning electron microscope image and X-ray diffraction analysis spectrum of the titanium dioxide film prepared in Example 2;

[0025] Figure 4 The titanium dioxide film prepared in Example 2 is 808nm (0.6 W / cm 2 ) Heating curve after laser irradiation for 15 minutes;

[0026] Figure 5 The field emission scanning electron microscope image and X-ray diffraction analysis spectrum of the titanium dioxide film prepared in Example 3;

[0027] Figure 6 The titanium dioxide film prepared in Example 3 is 2 ) Heating curve after laser irradiation for 15 minutes;

[0028] Figure 7 The field emission scanning electron microscope image and X-ray diffraction analysis spectrum of the titanium dioxide film prepared in Example 4;

[0029] Figure 8 The titanium dioxide film prepared in Example 4 is 2 ) Heating curve after laser irradiation for 15 minutes. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the examples and drawings of the specification, but the scope of protection of the present invention is not limited thereto. For example, the reaction equipment, reaction temperature, reaction time, and the type and concentration of the reaction precursor are not limited to those given in the examples. The present invention uses pure titanium, titanium alloy, etc. as a substrate for in-situ growth of titanium dioxide thin films, which is suitable for medical implants. Implants include but are not limited to implants into the human body as human body substitutes or supports, implants into animals as bone substitutes, etc. Implant substitutes for the human body include but are not limited to dental implants, bone substitutes, steel nails, steel plates, and other implants that support or connect bones, etc. The present invention studies the photothermal performance of the method, but is not limited to photothermal performance, as well as other performances.

[0031] Example 1

[0032] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0033] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0034] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, and the concentration of hydrochloric acid is 1.5 M;

[0035] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0036] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 685 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0037] like Figure 1-2 As shown, in Example 1, a needle-shaped nanostructured titanium dioxide film containing a rutile (110)-(101) crystal plane heterojunction was prepared, which showed a good photothermal effect under a 685nm laser, and the temperature reached 56.2°C in 15 minutes.

[0038] Example 2

[0039] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0040] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0041] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, and the concentration of sulfuric acid is 0.5 M;

[0042] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0043] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with an 808 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0044] like Figure 3-4 As shown, Example 2 prepared a block cluster nanostructured titanium dioxide film containing rutile (110)-(101) crystal plane heterojunction and anatase (101)-(001) crystal plane heterojunction, which showed a good photothermal effect under an 808nm laser, and the temperature reached 53.9°C in 15 minutes.

[0045] Example 3

[0046] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0047] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0048] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, and the concentration of sulfuric acid is 0.75 M;

[0049] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0050] Photothermal test: Cut 10×10mm 2The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 1064 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0051] like Figure 5-6 As shown, Example 3 prepared a bulk granular nanostructured titanium dioxide film containing a small amount of rutile (110)-(101) crystal plane heterojunction and anatase (101)-(001) crystal plane heterojunction, which showed good photothermal effect under a 1064nm laser, and the temperature reached 52.1°C in 15 minutes.

[0052] Example 4

[0053] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0054] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0055] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of sulfuric acid is 0.5 M, and the concentration of sodium sulfate is 0.25 M;

[0056] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0057] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 1064 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0058] like Figure 7-8As shown, Example 4 prepared a clustered nanostructured titanium dioxide film containing rutile (110)-(101) crystal plane heterojunction and anatase (101)-(001) crystal plane heterojunction, which showed good photothermal effect under a 1064nm laser, and the temperature reached 52.6°C in 15 minutes.

[0059] Example 5

[0060] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0061] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0062] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of sulfuric acid is 0.5 M, and the concentration of oxalic acid is 0.25 M;

[0063] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0064] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with an 808 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0065] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 53.6°C after 15 minutes.

[0066] Example 6

[0067] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0068] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0069] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of hydrochloric acid is 1 M, the concentration of nitric acid is 0.5 M, and the concentration of sodium chloride is 0.5 M;

[0070] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0071] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 685 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0072] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 53°C after 15 minutes.

[0073] Example 7

[0074] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0075] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0076] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of sulfuric acid is 0.75 M, and the concentration of sodium acetate is 0.5 M;

[0077] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 160 °C for 2 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0078] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 1064 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0079] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 51.2°C after 15 minutes.

[0080] Example 8

[0081] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0082] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0083] 2) Prepare 50 mL of reaction precursor solution, using titanium trichloride as the titanium source, the concentration of titanium trichloride is 3 mM, the concentration of sulfuric acid is 0.5 M, and the concentration of potassium oxalate is 0.5 M;

[0084] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated blast drying oven at a temperature of 160 °C for 3 h. After water cooling, take out the sample, ultrasonically clean it in ultrapure water, and dry it at room temperature.

[0085] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with a 1064 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0086] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 53°C after 15 minutes.

[0087] Example 9

[0088] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0089] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0090] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of hydrochloric acid is 1 M, and the concentration of acetic acid is 0.5 M;

[0091] 3) Put the precursor solution and titanium sheet into a stainless steel high-pressure reactor at the same time, and carry out hydrothermal reaction in an electric heated air drying oven at a temperature of 150 °C for 2 h. After water cooling, take out the sample, clean it ultrasonically in ultrapure water, and dry it at room temperature.

[0092] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with an 808 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0093] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 54.3°C after 15 minutes.

[0094] Example 10

[0095] The method for in-situ preparation of a light-responsive and controllable titanium dioxide heterojunction film provided in this embodiment comprises the following steps:

[0096] 1) Pickling and annealing pretreatment of titanium substrate: cut 10*25mm 2 The titanium alloy sheet was cleaned alternately with acetone and ethanol for 3 times, each time for 5 minutes, and then cleaned with ultrapure water for 3 times. The substrate was ultrasonically etched with a mixed solution of hydrofluoric acid and nitric acid for 5 seconds, cleaned with ultrapure water three times, and after drying, the titanium sheet was annealed at 450°C in a muffle furnace for 90 minutes, and then cleaned with acetone, ethanol, and ultrapure water in the same way, and dried at room temperature for use;

[0097] 2) Prepare 50 mL of reaction precursor solution, using titanous sulfate as the titanium source, the concentration of titanous sulfate is 1.5 mM, the concentration of hydrochloric acid is 0.5 M, the concentration of sulfuric acid is 0.5 M, and the concentration of sodium nitrate is 0.5 M;

[0098] 3) The precursor solution and titanium alloy sheet were placed in a stainless steel high-pressure reactor at the same time, and a hydrothermal reaction was carried out in an electric heated blast drying oven at a temperature of 160 °C for 2 h. After water cooling, the sample was taken out, ultrasonically cleaned in ultrapure water, and dried at room temperature;

[0099] Photothermal test: Cut 10×10mm 2 The hydrothermal samples were placed in a 24-well plate containing 1 ml of phosphate buffer and irradiated with an 808 nm laser for 15 minutes at a power of 0.6 W / cm 2 , and record the temperature every 1 minute using an infrared thermal imager.

[0100] The prepared titanium dioxide heterojunction thin film sample was subjected to photothermal testing, and the temperature reached 53.7°C after 15 minutes.

[0101] The method proposed in the present invention is to prepare in situ titanium dioxide heterojunction films with adjustable light response, which forms different nanostructures (needle-shaped, clustered, blocky, granular and cross-complex structures) at the same time by adjusting the titanium dioxide crystal form (anatase type, rutile type) and crystal plane orientation, constructs different crystal plane heterojunctions and nanostructures to work together, and shows good photothermal effects in different near-infrared regions.

[0102] Since titanium dioxide is mainly absorbed in the ultraviolet region, the present invention uses lasers of different wavelengths of 685, 808, and 1064 nm to perform photothermal tests, proving that the titanium dioxide heterojunction film prepared by hydrothermal treatment has good light response in different near-infrared windows.

[0103] The present invention can be implemented in the absence of any one or more elements, one or more restrictions, where such restrictions are not specifically stated. For example, the terms "comprising", "consisting essentially of" and "consisting of" in each example here can be replaced by the other two terms of either. The terms and expressions used here are descriptive and not limited thereto, and there is no intention to indicate that the terms and explanations described in this book exclude any equivalent features, but it can be understood that any appropriate changes or modifications can be made within the scope of the present invention and the claims. It can be understood that the embodiments described in the present invention are some preferred embodiments and features, and any person of ordinary skill in the art can make some changes and variations based on the essence of the description of the present invention, and these changes and variations are also considered to be within the scope of the present invention and the scope limited by the independent claims and the appended claims.

Claims

1. A method for in-situ preparation of a photoresponsive and controllable titanium dioxide heterojunction film, characterized in that: The steps include: 1) Matrix cleaning: First clean the matrix, then perform pickling and annealing pretreatment, and then clean the treated matrix again and dry it for later use; 2) Preparation of reaction precursor solution: uniformly mix the titanium source, salt, acid and ultrapure water and stir them thoroughly to prepare a reaction precursor solution for use; 3) Hydrothermal reaction: The substrate and the reaction precursor solution are transferred to a stainless steel high-pressure reactor, and the hydrothermal reaction is carried out in an electric heating blast drying oven. After the reaction is completed, the substrate is cooled and taken out, and ultrasonically cleaned with ultrapure water to obtain a substrate with a titanium dioxide heterojunction film on the surface; The salt in the reaction precursor solution in step 2) is at least one of sulfate, chloride, nitrate, oxalate, acetate, titanous sulfate, and titanium trichloride; the titanium ion concentration in the reaction precursor solution in step 2) is 2-3.5 mM; the molar ratio of the titanium source to the acid in step 2) is 1:1000-1:300; The pickling annealing treatment used in step 1) is to subject the substrate to ultrasonic etching treatment with a mixed solution of hydrofluoric acid and nitric acid, the volume ratio of hydrofluoric acid, nitric acid and ultrapure water is 1:3:6, the ultrasonic time is 5-20s, the annealing temperature is 200-700°C, and the heat preservation is 0.5h-2h; The titanium dioxide heterojunction film with adjustable in-situ photoresponse obtained by the above method regulates the titanium dioxide near-infrared photoresponse window by constructing titanium dioxide crystal surface heterojunction and nanostructure.

2. The method for in-situ preparation of a titanium dioxide heterojunction thin film with adjustable light response according to claim 1, characterized in that: The substrate in step 1) is at least one of titanium and titanium alloy.

3. The method for in-situ preparation of a titanium dioxide heterojunction thin film with adjustable light response according to claim 1, characterized in that: In step 2), the titanium source in the reaction precursor solution is at least one of titanium sulfate and titanium trichloride.

4. The method for in-situ preparation of a titanium dioxide heterojunction thin film with adjustable light response according to claim 1, characterized in that: In step 2), the acid in the reaction precursor solution is at least one of sulfuric acid, hydrochloric acid, nitric acid, acetic acid and oxalic acid.

5. The method for in-situ preparation of a titanium dioxide heterojunction thin film with adjustable light response according to claim 1, characterized in that: In step 3), the time of the hydrothermal reaction is 1-5 hours, the temperature of the hydrothermal reaction is 140° C.-180° C., and the cooling method after the hydrothermal reaction is water cooling.

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