AgBr / BiOBr / ZnIn2S4 ternary heterojunction material, preparation method thereof and application thereof in PEC sensor

Abstract

The application discloses a kind of AgBr / BiOBr / ZnIn2S4 ternary heterojunction materials and preparation method and application in PEC sensor, belong to photoelectrochemistry sensing technical field.The application is with AgBr as electron donor, BiOBr as intermediate medium, ZnIn2S4 as electron acceptor, by in-situ precipitation method and hydrothermal method step-by-step construction formation ternary cascade heterojunction material, the material drop coating is coated on FTO conductive glass substrate surface, obtain AgBr / BiOBr / ZnIn2S4 / FTO electrode, again HER2 antibody, BSA, HER2 antigen drop coating on its surface, obtain photoelectrochemistry sensor for detecting HER2 tumor marker, the photoelectrochemistry sensor obtained detection sensitivity is high, with excellent selectivity and stability, has higher practical application value, can provide reliable technical support for the accurate detection of HER2 in clinical sample.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrochemical sensing technology, specifically relating to an AgBr / BiOBr / ZnIn2S4 ternary heterojunction material and its preparation method, as well as the application of this material in a photoelectrochemical (PEC) sensor for detecting human epidermal growth factor receptor 2 (HER2) tumor markers. Background Technology

[0002] Human epidermal growth factor receptor 2 (HER2) is a transmembrane tyrosine kinase receptor that plays a crucial role in the occurrence, development, and metastasis of malignant tumors such as breast cancer. In breast cancer patients, HER2 is not only significantly overexpressed, but its concentration is also dramatically elevated. Therefore, as an important biomarker for breast cancer, accurate detection of HER2 is of vital clinical significance for the early diagnosis, treatment planning, and prognostic assessment of breast cancer.

[0003] Currently, HER2 detection methods mainly include enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay, electrochemical sensing, and photoelectrochemical (PEC) sensing. Among these, photoelectrochemical sensors have received widespread attention in recent years due to their advantages such as high sensitivity, low background signal, ease of operation, and low cost. The detection principle of PEC sensors is based on the change in photocurrent caused by the specific interaction between the target analyte and the corresponding recognition probe. The photosensitive material and signal amplification strategy are the core elements determining the sensor's performance.

[0004] In the field of photosensitive materials, the construction of semiconductor heterojunctions is considered an effective strategy to improve the separation efficiency of photogenerated carriers and suppress electron-hole recombination. The double S-type heterojunction system is composed of three semiconductor materials with matched band structures. Each component interface forms an independent built-in electric field, enhancing the directional transport of photogenerated carriers. Compared to a single S-type heterojunction, this system exhibits three significant advantages: First, in terms of light harvesting capability, the synergistic effect of the three semiconductor components significantly enhances the absorption of light in the visible light region, effectively expanding the spectral response range. Second, at the charge separation level, the dual built-in electric fields and the cascaded band arrangement together construct two non-interfering carrier migration channels, significantly reducing the probability of electron-hole recombination. Third, in terms of redox performance, this structure achieves efficient carrier separation while still maintaining strong reduction and oxidation capabilities for the electrons and holes participating in the reaction, respectively. Therefore, the double S-shaped heterojunction design overcomes the performance bottleneck of a single S-shaped heterojunction and improves the sensitivity of PEC sensors through the synergistic effect of the built-in electric fields at multiple interfaces and the cascaded band structure.

[0005] Silver bromide (AgBr), a typical photosensitive material, possesses a narrow band gap (approximately 2.14 eV) and excellent visible light response, but its photogenerated electron-hole pairs are prone to recombination. Bismuth oxybromide (BiOBr), a layered p-type semiconductor, has a suitable band gap (approximately 2.59 eV) and good chemical stability, making it widely used in photocatalysis. Zinc indium sulfide (ZnIn2S4), a ternary sulfide semiconductor, exhibits visible light response characteristics and strong reducing ability. Designing these three materials into a ternary heterostructure through rational bandgap engineering holds promise for achieving cascaded separation and efficient transport of photogenerated carriers, thereby significantly improving photoelectrochemical performance.

[0006] In recent years, although photoelectrochemical sensors for HER2 detection have developed rapidly, their performance still has significant shortcomings. At the materials level, single photoelectrochemical materials suffer from low photogenerated carrier separation efficiency and high recombination rates, limiting their photoelectric conversion performance and making it difficult to meet the sensitivity requirements for trace detection. Simultaneously, non-specific adsorption in complex biological samples severely affects the selectivity of the sensors. Regarding the detection mechanism, traditional signal modalities still have considerable room for improvement in signal-to-noise ratio and detection limit. More importantly, most research remains under ideal laboratory conditions, lacking validation with real clinical samples, and the sensors are complex to fabricate and have poor reproducibility, leaving a significant gap between their clinical applicability and portability.

[0007] Currently, there are no reports on constructing ternary heterojunctions from AgBr / BiOBr / ZnIn2S4 ternary composite materials and applying them to the photoelectrochemical detection of HER2. Therefore, developing a high-performance photoelectrochemical immunosensor for HER2 detection based on AgBr / BiOBr / ZnIn2S4 ternary heterojunction materials has significant scientific and application value. Summary of the Invention

[0008] The purpose of this invention is to address the problems of insufficient photogenerated carrier separation efficiency, detection sensitivity, selectivity, and reproducibility of photosensitive materials in existing HER2 photoelectrochemical sensors. This invention provides an AgBr / BiOBr / ZnIn2S4 ternary heterojunction material and its preparation method, and applies it to the highly sensitive and selective photoelectrochemical detection of HER2 breast cancer markers.

[0009] This invention provides an AgBr / BiOBr / ZnIn2S4 ternary heterojunction material, using AgBr as the electron donor, BiOBr as the intermediate medium, and ZnIn2S4 as the electron acceptor. The ternary cascaded heterojunction material is constructed stepwise via in-situ precipitation and hydrothermal methods. This material can effectively promote the spatial separation and directional migration of photogenerated carriers through cascaded band arrangement: under visible light irradiation, photogenerated electrons on the AgBr conduction band are transported to the ZnIn2S4 conduction band via BiOBr, while photogenerated holes on the ZnIn2S4 conduction band are transported to the AgBr valence band via BiOBr, suppressing electron-hole recombination and exhibiting excellent photoelectrochemical activity.

[0010] This invention also provides a method for preparing AgBr / BiOBr / ZnIn2S4 ternary heterojunction materials, comprising the following steps: Step 1: Preparation of AgBr / BiOBr heterojunction powder Bi(NO3)3·5H2O was dissolved in ethylene glycol and stirred to form a transparent solution A. AgNO3 and KBr were dissolved in deionized water and ultrasonically dispersed to form solution B. Solution B was added dropwise to solution A under stirring, and it immediately turned into a pale yellow suspension. The suspension was transferred to a hydrothermal reactor, sealed, and placed in an oven to continue the reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, and the precipitate was collected by centrifugation. The precipitate was washed three times each with deionized water and anhydrous ethanol, dried, and ground to obtain AgBr / BiOBr heterojunction powder.

[0011] Step 2: Preparation of AgBr / BiOBr / ZnIn2S4 ternary heterojunction material AgBr / BiOBr heterojunction powder was dispersed in deionized water and sonicated. Zn(NO3)2·6H2O, InCl3·4H2O and thioacetamide (TAA) were added sequentially and stirred until homogeneous. The mixture was transferred to a hydrothermal reactor, sealed, and placed in an oven to continue the reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, centrifuged to collect the product, washed three times each with deionized water and ethanol, dried, and ground to obtain the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material.

[0012] Furthermore, in step one, the amount of ethylene glycol used is 10mL-20mL; the stirring time is 30min-40min; the amount of deionized water used in solution B is 10mL-15mL; the reaction temperature is 150℃-170℃, the reaction time is 9h-11h; the drying temperature is 50℃-70℃, and the drying time is 5h-7h.

[0013] Furthermore, in step two, the amount of deionized water used is 30mL-50mL; the ultrasonic time is 30min-40min; the stirring time is 2h-3h; the reaction temperature is 150℃-170℃, and the reaction time is 5h-7h; the drying temperature is 50℃-70℃, and the drying time is 5h-7h; the molar ratio of AgBr, BiOBr, and ZnIn2S4 is 0.33:1.00:0.1.

[0014] This invention also provides the application of AgBr / BiOBr / ZnIn2S4 ternary heterojunction material, which is used as a photosensitive material to prepare a photoelectrochemical sensor for detecting HER2 tumor markers.

[0015] Furthermore, a method for preparing a photoelectrochemical sensor for detecting HER2 tumor markers using AgBr / BiOBr / ZnIn2S4 ternary heterojunction material as a photosensitive material includes the following steps: Step 1: Preparation of AgBr / BiOBr / ZnIn2S4 / FTO electrode The AgBr / BiOBr / ZnIn2S4 ternary heterojunction material was dispersed in an ethanol solution and ultrasonicated to form a uniform suspension. The suspension was then drop-coated onto the surface of an FTO conductive glass substrate that had been ultrasonically cleaned and dried with acetone, anhydrous ethanol and deionized water. After drying, a photoelectric active film was formed on the surface, thus obtaining the AgBr / BiOBr / ZnIn2S4 / FTO electrode. Step 2: Construction of a photoelectrochemical sensor for detecting HER2 tumor markers HER2 antibody (Ab) was drop-coated onto an AgBr / BiOBr / ZnIn2S4 / FTO electrode and incubated. After natural drying, the Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode was washed with PBS. Subsequently, BSA was drop-coated to block non-specific binding sites, and finally HER2 antigen (Ag) was drop-coated to obtain the Ag / BSA / Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode, which is the photoelectrochemical sensor for detecting HER2 tumor markers.

[0016] Furthermore, in step one, the time for sonication to suspend the slurry is 30-40 min; the drying temperature is 60℃-80℃ and the drying time is 10-20 min; the drying temperature is 60℃-80℃ and the drying time is 5-15 min; the concentration of PBS is 0.1 mol / L and the pH value is 7.4.

[0017] Furthermore, the method for detecting HER2 tumor markers using a photoelectrochemical sensor includes the following steps: A three-electrode system was adopted, with the Ag / BSA / Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode of the photoelectrochemical sensor as the working electrode, a platinum wire as the counter electrode, a saturated Ag / AgCl electrode as the reference electrode, a phosphate buffer solution containing ascorbic acid as the electrolyte, and a xenon lamp as the excitation source.

[0018] Furthermore, the photoelectrochemical sensor can generate a stable photocurrent signal under visible light irradiation, and can realize the quantitative detection of HER2 tumor markers based on changes in photocurrent intensity.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention first constructed a ternary heterojunction material of AgBr / BiOBr / ZnIn2S4. Through the cascade coupling of the two heterojunctions AgBr / BiOBr and BiOBr / ZnIn2S4, the dual separation and directional transport of photogenerated carriers were realized, thereby improving the photoelectric conversion efficiency.

[0020] (2) The present invention uses in-situ precipitation-hydrothermal method to construct ternary heterojunctions stepwise. The process is simple, convenient to operate, the raw materials are readily available, the cost is low, and it is easy to scale up production.

[0021] (3) The photoelectrochemical sensor constructed in this invention has high sensitivity for HER2 detection, as well as excellent selectivity and stability, and exhibits good linearity (R0) in the concentration range of 0.0001 ng / mL to 100 ng / mL. 2 Six parallel experiments (n=6) were conducted on actual human serum samples. The spiked recovery rate of this sensor reached 96.7%-99.3%, and the relative standard deviation (RSD) was less than 6%, which verified that the detection method has excellent accuracy and precision, has high practical application value, and can provide reliable technical support for the accurate detection of HER2 in clinical samples. Attached Figure Description

[0022] Figure 1 This is a flowchart of the fabrication method for a photoelectrochemical sensor.

[0023] Figure 2 X-ray diffraction (XRD) patterns of AgBr / BiOBr / ZnIn2S4 ternary heterojunction material and single-component materials.

[0024] Figure 3 This is a scanning electron microscope (SEM) image of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material.

[0025] Figure 4 Photocurrent response curves of photoelectrochemical sensors at different modification stages.

[0026] Figure 5 Photocurrent response curves for detecting different concentrations of HER2 using a photoelectrochemical sensor.

[0027] Figure 6 This is a graph showing the logarithmic linear relationship between the photocurrent signal intensity of the photoelectrochemical sensor and different HER2 concentrations.

[0028] Figure 7 The results are from the selective test of the photoelectrochemical sensor.

[0029] Figure 8 These are the stability test results for the photoelectrochemical sensor.

[0030] Figure 9 This is a standard operating curve of the photoelectrochemical sensor for different concentrations of HER2.

[0031] Figure 10 The graph shows the relationship between the relative standard deviation (RSD) and the concentration of the analyte when using a photoelectrochemical sensor to detect HER2. Detailed Implementation

[0032] Example 1: Preparation of AgBr / BiOBr heterojunction powder Step 1: Preparation of AgBr / BiOBr heterojunction. 1.0 mmol Bi(NO3)3·5H2O (0.485 g) was weighed and dissolved in 20 mL ethylene glycol. The solution was magnetically stirred at room temperature for 30 min to form a transparent solution A. Simultaneously, 0.33 mmol AgNO3 (0.056 g) and 1.33 mmol KBr (0.158 g) were weighed and dissolved in 10 mL deionized water, and ultrasonically dispersed to form solution B. Under stirring, solution B was slowly added dropwise to solution A, and the solution immediately turned into a pale yellow suspension. After stirring for another 30 min, the mixture was transferred to a 50 mL PTFE-lined stainless steel hydrothermal reactor, sealed, and placed in an oven at 160 °C for 10 h. After the reactor cooled naturally to room temperature, the precipitate was collected by centrifugation, washed three times each with deionized water and anhydrous ethanol, and finally dried in a vacuum drying oven at 60 °C for 6 h. The dried product was ground into a fine powder to obtain AgBr / BiOBr heterojunction powder (AB), which was stored away from light for later use. Figure 1 As shown.

[0033] Step 2: Preparation of AgBr / BiOBr / ZnIn2S4 ternary heterojunction material Weigh 40 mg of the AgBr / BiOBr heterojunction powder prepared above, disperse it in 40 mL of deionized water, and sonicate for 30 min to ensure uniform dispersion. Add 0.1 mmol Zn(NO3)2·6H2O (0.030 g), 0.2 mmol InCl3·4H2O (0.0586 g), and 0.8 mmol thioacetamide (TAA, 0.06 g) sequentially, and magnetically stir at room temperature for 2 h to ensure uniform mixing. Transfer the mixture to a 50 mL polytetrafluoroethylene-lined stainless steel hydrothermal reactor, seal it, and place it in an oven at 160 °C for 6 h. After the reactor cools naturally to room temperature, collect the product by centrifugation, wash it three times each with deionized water and anhydrous ethanol, and finally dry it in a vacuum drying oven at 60 °C for 6 h. Grind the dried product into a fine powder to obtain the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material (ABZ). Figure 1 As shown.

[0034] The molar amount of AgBr is 0.33 mmol, the molar amount of BiOBr is 1.0 mmol, and the ZnIn2S4 precursor contains Zn 2+ In 3 + The molar ratio of TAA to TAA is 1:2:8.

[0035] Example 2: Characterization Analysis of Materials The crystal structure of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material prepared in Example 1 was analyzed using X-ray diffraction. Figure 2 As shown, the characteristic diffraction peaks of AgBr, BiOBr and ZnIn2S4 appeared simultaneously in the XRD pattern, indicating the successful preparation of the ternary composite material and that each component maintained a good crystal phase structure.

[0036] The microstructure of the material was observed using a scanning electron microscope. For example... Figure 3 As shown in the SEM images, the AgBr / BiOBr / ZnIn2S4 composite material exhibits a typical flower-like microsphere structure with a rough surface, which is beneficial for increasing the specific surface area and providing more active sites.

[0037] Example 3: Construction of photoelectrochemical sensor and HER2 detection Step 1: Preparation of AgBr / BiOBr / ZnIn2S4 / FTO electrode Fluorine-doped tin dioxide (FTO) conductive glass was cut into 1cm × 2cm pieces and ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 min each. After drying at 60°C, it was ready for use. 5 mg of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material prepared in Example 1 was weighed and dispersed in 1 mL of anhydrous ethanol, and ultrasonicated for 30 min to form a uniform suspension. 20 μL of the suspension was drop-coated onto the surface of the FTO conductive glass using a pipette, air-dried at room temperature, and then dried at 60°C for 10 min to obtain the AgBr / BiOBr / ZnIn2S4 / FTO electrode.

[0038] Step 2: Construction of a photoelectrochemical sensor for detecting HER2 tumor markers HER2 antibody (Ab) was drop-coated onto an AgBr / BiOBr / ZnIn2S4 / FTO electrode and incubated at 4°C for 90 min. After air drying, the obtained Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode was washed with 0.1 mol / L phosphate-buffered saline (PBS, pH=7.4). Bovine serum albumin (BSA) was then drop-coated and incubated at 4°C for 90 min to block non-specific binding sites. Finally, HER2 antigen (Ag) was drop-coated, and the Ag / BSA / Ab / AgBr / BiOBr / ZnIn2S4 / FTO-based PEC immunosensor was successfully constructed.

[0039] Step 3: Quantitative detection of HER2 A three-electrode system was used, with FTO (a biomaterial modified stepwise) as the working electrode, platinum wire as the counter electrode, and a saturated Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1 mol / L phosphate-buffered saline (PBS, pH 7.4) containing ascorbic acid (AA). A xenon lamp was used as the excitation source, with a lamp on-off cycle of 20 s and an applied potential of +0.3 V.

[0040] like Figure 4 As shown, the working electrodes all generate a rapid and stable photocurrent response upon illumination, and the photocurrent intensity decreases stepwise with increasing modification steps. The bare electrode (i) exhibits the strongest photocurrent due to its efficient electron transport capability; antibody (Ab) immobilization (ii) and BSA blocking (iii) result in photocurrent attenuation due to the insulating effect of biomolecules; when the electrode captures the HER2 antigen (iv), the photocurrent further decreases due to the increased interfacial steric hindrance caused by the antigen-antibody immune complex. These results indicate that the sensor has been successfully constructed and can be used for the quantitative detection of HER2.

[0041] Different concentrations of HER2 standard solutions (0.0001 ng / mL, 0.001 ng / mL, 0.01 ng / mL, 0.1 ng / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL) were drop-coated onto the surface of the working electrode. After incubation at 4°C for 90 min, the electrode surface was rinsed with PBS to remove unbound HER2, followed by photoelectrochemical testing. Figure 5 As shown, the photocurrent intensity gradually decreases with the increase of HER2 concentration. This is because HER2 specifically binds to the electrode surface, affecting the interfacial charge transport.

[0042] like Figure 6 As shown, the linear regression equation is y = 12.44896 - 5.04537x (R²). 2 =0.99819), where y is the photocurrent intensity (nA) and x is the logarithm of the HER2 concentration (lgC, where C is ng / mL). It can be seen that the change in photocurrent intensity (ΔI) has a good linear relationship with the logarithm of the HER2 concentration. The detection range is 0.0001 ng / mL-100 ng / mL, and the detection limit is 0.81 pg / mL. It has a wide detection range and a low detection limit for HER2 detection, and has high sensitivity for HER2 detection.

[0043] Example 4: Sensor Selectivity and Stability Test To examine the selectivity of the sensor, carcinoembryonic antigen (CEA), prostate-specific antigen (PSA), and squamous cell carcinoma antigen (SCCA), which may coexist with HER2, were selected as interfering agents. Figure 7 As shown, under the same concentration conditions, when the applied voltage is +0.3V, the sensor's response signal to HER2 is higher than that of the aforementioned interfering substance. The signal change caused by the interfering substance is not significantly different from that of the blank sample, indicating that the sensor has good specific recognition ability for HER2.

[0044] To examine the stability of the sensor, the same working electrode was subjected to a 10-minute continuous switching test with the lamp on and off under an applied voltage of +0.3V. Figure 8 As shown, the photocurrent response remains basically stable, indicating that the AgBr / BiOBr / ZnIn2S4 double S-type heterojunction material has good photochemical stability, and the constructed sensor has an acceptable reusable lifespan.

[0045] Example 5: Evaluation of Sensor Accuracy and Precision To evaluate the accuracy of the sensor, the standard addition method was used to detect HER2 in actual human serum samples. HER2 standard solution at concentrations of 0 ng / mL, 0.0005 ng / mL, 0.01 ng / mL, and 5 ng / mL was added to blank serum samples, with six parallel determinations per group (n=6). Figure 9 As shown, a standard working curve was plotted with the added concentration on the x-axis and the detected concentration on the y-axis. Within the concentration range of 0.0005 ng / mL to 0.01 ng / mL, the detected value showed a good linear relationship with the theoretical added value, indicating that the method has good accuracy and the measurement results are in high agreement with the true values.

[0046] To evaluate the precision of the sensor, the relative standard deviation (RSD) of the sensor under different HER2 concentrations was further investigated. Figure 10 As shown, within the concentration range of 0.0005 ng / mL to 0.01 ng / mL, the RSD values ​​ranged from 2.92% to 5.01%. Specifically, the RSD was 2.92% in the low concentration region (0.0005 ng / mL) and 3.39% in the high concentration region (0.01 ng / mL). All RSD values ​​were less than 6%, indicating that the sensor exhibits good precision and repeatability at different concentration levels. In summary, this sensor can meet the requirements for quantitative detection of HER2 in clinical samples and has promising prospects for practical application.

Claims

1. A ternary heterojunction material of AgBr / BiOBr / ZnIn2S4, characterized in that, Using AgBr as an electron donor, BiOBr as an intermediate medium, and ZnIn2S4 as an electron acceptor, a ternary cascade heterojunction material was constructed stepwise by in-situ precipitation and hydrothermal methods.

2. A method for preparing the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material according to claim 1, characterized in that, Includes the following steps: Step 1: Preparation of AgBr / BiOBr heterojunction powder Bi(NO3)3·5H2O was dissolved in ethylene glycol and stirred to form a transparent solution A. AgNO3 and KBr were dissolved in deionized water and ultrasonically dispersed to form solution B. Solution B was added dropwise to solution A under stirring, and it immediately turned into a pale yellow suspension. The suspension was transferred to a hydrothermal reactor, sealed, and placed in an oven to continue the reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, and the precipitate was collected by centrifugation. The precipitate was washed three times each with deionized water and anhydrous ethanol, dried, and ground to obtain AgBr / BiOBr heterojunction powder. Step 2: Preparation of AgBr / BiOBr / ZnIn2S4 ternary heterojunction material AgBr / BiOBr heterojunction powder was dispersed in deionized water and sonicated. Zn(NO3)2·6H2O, InCl3·4H2O and thioacetamide were added sequentially and stirred until homogeneous. The mixture was transferred to a hydrothermal reactor, sealed, and placed in an oven to continue the reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, centrifuged to collect the product, washed three times each with deionized water and ethanol, dried, and ground to obtain AgBr / BiOBr / ZnIn2S4 ternary heterojunction material.

3. The preparation method of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material according to claim 2, characterized in that, In step one, the amount of ethylene glycol used is 10mL-20mL; the stirring time is 30min-40min; the amount of deionized water used in solution B is 10mL-15mL; the reaction temperature is 150℃-170℃, and the reaction time is 9h-11h; the drying temperature is 50℃-70℃, and the drying time is 5h-7h.

4. The preparation method of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material according to claim 2, characterized in that, In step two, the amount of deionized water used is 30mL-50mL; the ultrasonic time is 30min-40min; the stirring time is 2h-3h; the reaction temperature is 150℃-170℃ and the reaction time is 5h-7h; the drying temperature is 50℃-70℃ and the drying time is 5h-7h; the molar ratio of AgBr, BiOBr, and ZnIn2S4 is 0.33:1.00:0.

1.

5. The application of the AgBr / BiOBr / ZnIn2S4 ternary heterojunction material according to claim 1, characterized in that, The AgBr / BiOBr / ZnIn2S4 ternary heterojunction material is used as a photosensitive material to prepare a photoelectrochemical sensor for detecting HER2 tumor markers.

6. The application according to claim 5, characterized in that, Includes the following steps: Step 1: Preparation of AgBr / BiOBr / ZnIn2S4 / FTO electrode The AgBr / BiOBr / ZnIn2S4 ternary heterojunction material was dispersed in an ethanol solution and ultrasonicated to form a uniform suspension. The suspension was then drop-coated onto the surface of a fluorine-doped tin dioxide conductive glass substrate that had been ultrasonically cleaned and dried with acetone, anhydrous ethanol and deionized water. After drying, an opto-active thin film was formed on the surface, resulting in the AgBr / BiOBr / ZnIn2S4 / FTO electrode. Step 2: Construction of a photoelectrochemical sensor for detecting HER2 tumor markers HER2 antibody was drop-coated onto an AgBr / BiOBr / ZnIn2S4 / FTO electrode and incubated. After natural drying, the resulting Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode was washed with phosphate buffer. Subsequently, bovine serum albumin was drop-coated to block non-specific binding sites. Finally, HER2 antigen was drop-coated to obtain the Ag / BSA / Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode, which is the photoelectrochemical sensor for detecting HER2 tumor markers.

7. The application according to claim 6, characterized in that, In step one, the time for sonication to suspend the solution is 30-40 minutes; the drying temperature is 60℃-80℃ and the drying time is 10-20 minutes; the drying temperature is 60℃-80℃ and the drying time is 5-15 minutes; the concentration of the phosphate buffer is 0.1 mol / L and the pH value is 7.

4.

8. The application according to claim 5, characterized in that, Includes the following steps: A three-electrode system was adopted, with the Ag / BSA / Ab / AgBr / BiOBr / ZnIn2S4 / FTO electrode of the photoelectrochemical sensor as the working electrode, a platinum wire as the counter electrode, a saturated Ag / AgCl electrode as the reference electrode, a phosphate buffer solution containing ascorbic acid as the electrolyte, and a xenon lamp as the excitation source.

9. The application according to claim 5, characterized in that, The photoelectrochemical sensor can generate a stable photocurrent signal under visible light irradiation, and realize the quantitative detection of HER2 tumor markers based on the change in photocurrent intensity.

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