Novel method for preparing organic-inorganic heterojunction structure and improving performance of pure material

Abstract

The invention provides a method for preparing a novel organic-inorganic heterojunction structure and improving the light detection performance of a pure material. According to the method, a Bi2O2S nanosheet and a conductive polymer polyaniline (PANI) are combined into an organic-inorganic hybrid structure by a dripping method according to the characteristics of an organic-inorganic heterostructure, and the performance of a bismuth-oxygen-sulfur self-powered photoelectrochemical (PEC) photoelectric detector is successfully constructed and improved. After optimization, the hybrid structure is excellent in optical detection performance, under the conditions of 0V and 350nm, the optical responsivity of the device can reach 29mA / W, the dark current density reaches 16nA / cm < 2 >, the switch ratio reaches 1812, the response time is only 0.1 s, the cycle test stability of the device is excellent, and the device can be compared favorably with commercial leading self-powered electronic products. Generally speaking, the invention has the advantages of low production cost, stable and simple combination mode and organic-inorganic hybrid structure p-n junction, shows excellent potential, and provides a good new choice for the industrial field.

Description

Technical Field

[0001] This invention belongs to the field of electronic devices, specifically relating to a method for preparing novel organic-inorganic heterojunction structures and improving the photodetection performance of pure material photodetectors. Background Technology

[0002] Photodetectors play a crucial role in infrared reconnaissance, infrared mapping, visible light communication, and ultraviolet detection. However, the need for an external power source to drive the photogenerated carriers in practical applications is cumbersome, severely limiting their application scope. Furthermore, the application of most detectors is limited by their long response times, weak light absorption, and small size. Self-powered photodetectors with strong built-in electron fields have attracted significant attention in nanorobotics, wearable electronics, and other electronic applications. Therefore, self-powered photodetectors based on heterostructures have emerged.

[0003] Self-powered photodetectors have wide applications in optical communication, optoelectronic instruments, optical measurement, optical imaging, and solar panels. Semiconductor heterostructures are attached to these devices and play an indispensable role. At the same time, the photoelectric properties of heterojunctions also have a significant impact on the performance of these electronic devices. Therefore, researching how to manufacture high-performance, low-cost heterojunctions is of great practical significance for the development and industrialization of the electronic device field.

[0004] This invention constructs a PEC-type photodetector with a Bi2O2S / PANI organic-inorganic hybrid structure using a drop-feed method. This photodetector exhibits commercially leading performance and, compared to a pure Bi2O2S device, demonstrates a significant improvement in photoresponse performance at 0V. Its photocurrent density is increased by 3 times, and its dark current density is reduced by 16 times, reaching 16 nA / cm². 2 Furthermore, it possesses excellent on / off ratio and optical response speed. The photodetector fabricated using this composite structure, while achieving equivalent performance, offers greater possibilities for the application and commercialization of heterojunction self-powered photodetectors due to its lower raw material and manufacturing costs. The finished product not only rivals commercially leading self-powered photodetectors but also boasts inexpensive materials, simple fabrication, and sufficiently low production costs. Moreover, it enables underwater detection, demonstrating broad application prospects. Therefore, this invention is a pioneering achievement with both research and application value. Summary of the Invention

[0005] To overcome the aforementioned shortcomings of existing technologies, this invention provides a novel method for preparing organic-inorganic heterostructures, enabling the fabrication of low-cost, high-performance industrial photodetectors and successfully masking the shortcomings of pure materials. To achieve the above objectives, this invention employs the following technical solution:

[0006] 1) Pour 101.5 mg of bismuth nitrate pentahydrate and 20 mL of deionized water into a 100 mL volumetric beaker A. Sonicate beaker A for a period of time until the solid is completely dissolved. Let beaker A stand for a period of time to confirm that no precipitate has formed.

[0007] 2) Mix 1 mL of hydrazine hydrate and 15.8 mg of thiourea and place them in beaker B. After sonication, continue sonicating until the solid is completely dissolved.

[0008] 3) Take the solution in beaker A obtained in step 1) and mix it with the solution in beaker B obtained in step 2). Quickly add 120 mg of potassium hydroxide and 320 mg of sodium hydroxide, and stir continuously for 30 minutes. Let it stand overnight. Then collect the precipitate, wash it three times with alcohol and deionized water respectively, and dry it in a vacuum drying oven for 12 hours at a drying temperature of 70℃. Collect the pure bismuth oxysulfur nanosheet powder.

[0009] 4) Weigh 1 mg of Bi2O2S nanosheets and add 1 mL of anhydrous ethanol. After ultrasonic homogenization, drop-cast the homogenized 1 mg / mL Bi2O2S solution onto the conductive side of the ITO surface and keep it in a drying oven at 60°C for 12 hours.

[0010] 5) Weigh 1 mg of the purchased polyaniline powder, add 1 mL of NMP solution to prepare a homogeneous solution of 1 mg / mL; then drop it onto the dried ITO surface to form a dense film. After it is completely dried, continue to drop it three times (with an interval of about 8 hours) to form a polyaniline film of a certain thickness on the surface. Then place it at room temperature for a period of time.

[0011] 6) The photoelectric performance of the photodetector obtained in step 5) is tested. The test system is an electrochemical workstation (CHI760D, Chenhua, China) with a three-electrode system consisting of a working electrode, a counter electrode (platinum electrode), and a reference electrode (mercury oxide electrode).

[0012] 7) Repeat the electrochemical test performed in step 6) by changing the parameters to explore its optimal working environment.

[0013] 8) Set the optimal parameters found in step 7), and perform cyclic testing on the sample for 800 seconds and 10 days to observe the changes in its performance.

[0014] According to a preferred embodiment of the present invention, in step 1), the ultrasonic treatment time is 2 hours and the placement time is 30 minutes.

[0015] According to a preferred embodiment of the present invention, in step 2), the mass of thiourea is 15.8 mg, the volume of hydrazine hydrate is 1 mL, and the ultrasonic time is 2 h.

[0016] According to a preferred embodiment of the present invention, in step 3), the settling time is 12 hours, the washing method is centrifugal washing, the centrifugal speed is 8000 rad / s, the vacuum drying time is 12 hours, and the temperature is 70°C.

[0017] According to a preferred embodiment of the present invention, in step 4), 1 mg of Bi2O2S and 1 mL of anhydrous ethanol are used, and the drying oven is used for 12 hours at a temperature of 60°C.

[0018] According to a preferred embodiment of the present invention, in step 5), the polyaniline is 1 mg, the NMP solution volume is 1 mL, the ultrasonic treatment time is 2 h, the drying time is 12 h, the drying temperature is 60 °C, the drip interval is 8 h, the number of drips is 3, and the room temperature environment is 4 h.

[0019] According to a preferred embodiment of the present invention, in step 6), the device used for electrochemical testing is a three-electrode system, and the testing environment is a PEC environment.

[0020] According to a preferred embodiment of the present invention, in step 7), the modified working environment parameters selected during the test are electrolyte solution concentration, light source wavelength, and light source intensity.

[0021] All equipment and raw materials used in the method of this invention are commercially available products. Based on the above technical solution, this invention has the following advantages:

[0022] (1) The optoelectronic device of the present invention exhibits significantly improved performance. Compared with a simple Bi2O2S device, this device shows a substantial improvement in photoresponse performance at 0V. Its photocurrent density is increased by 3 times, and its dark current density is reduced by 16 times, reaching 16 nA / cm². 2 It also boasts excellent on / off ratio and optical response speed.

[0023] (2) The preparation process of this invention is simple, the cost is low, the application range is wider, and it is easy to prepare on a large scale and realize commercialization.

[0024] (3) The composite structure in this invention is more stable and durable than the simple Bi2O2S device.

[0025] (4) The heterojunction self-powered photodetector manufactured by this invention has a wide range of applications. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below:

[0027] Figure 1 This is a flowchart of the fabrication process of the hybrid structure photoanode in Example 1.

[0028] Figure 2This is the IV curve of the composite structure detector in this invention.

[0029] Figure 3 The photocurrent density of the hybrid structure in Example 2 at different KOH electrolyte concentrations is (0.2, 0.3, 0.4, 0.5 mol / L).

[0030] Figure 4 The images show the EIS spectra of the hybrid structure in Example 2 at different KOH electrolyte concentrations (0.2, 0.3, 0.4, 0.5 mol / L).

[0031] Figure 5 The photoresponse time of the device in Example 2 in different KOH electrolyte solutions (0.2, 0.3, 0.4, 0.5 mol / L).

[0032] Figure 6 The photocurrent densities of the hybrid structure in Example 3 at different wavelengths are (350, 365, 546, 630, 660, 700, 760 nm).

[0033] Figure 7 This is a schematic diagram showing the change in photocurrent density of the hybrid structure in Example 4 at different power densities (90, 100, 110, 120, 130 μW / cm²). 2 ).

[0034] Figure 8 This is a schematic diagram comparing the performance of the hybrid structure device in Examples 5 and 6, the simple bismuth-oxy-sulfur device, and the simple polyaniline device.

[0035] Figure 9 This invention compares the self-powered performance of PEC devices based on different structures.

[0036] Figure 10 This is a schematic diagram illustrating the stability of the hybrid structure device in Example 1 during continuous operation.

[0037] Figure 11 This is a schematic diagram of the time stability of the hybrid structure device in Example 1. Detailed Implementation

[0038] Example 1

[0039] 1) Pour 101.5 mg of bismuth nitrate pentahydrate and 20 mL of deionized water into a 100 mL volumetric beaker A. Sonicate beaker A for a period of time until the solid is completely dissolved. Let beaker A stand for a period of time to confirm that no precipitate has formed.

[0040] 2) Mix 1 mL of hydrazine hydrate and 15.8 mg of thiourea and place them in beaker B. After sonication, continue sonicating until the solid is completely dissolved.

[0041] 3) Take the solution in beaker A obtained in step 1) and mix it with the solution in beaker B obtained in step 2). Quickly add 120 mg of potassium hydroxide and 320 mg of sodium hydroxide, and stir continuously for 30 minutes. Let it stand overnight. Then collect the precipitate, wash it three times with alcohol and deionized water respectively, and dry it in a vacuum drying oven for 12 hours at a drying temperature of 70℃. Collect the pure bismuth oxysulfur nanosheet powder.

[0042] 4) Weigh 1 mg of Bi2O2S nanosheets and add 1 mL of anhydrous ethanol. After ultrasonic homogenization, drop-cast the homogenized 1 mg / mL Bi2O2S solution onto the conductive side of the ITO surface and keep it in a drying oven at 60°C for 12 hours.

[0043] 5) Weigh 1 mg of the purchased polyaniline powder, add 1 mL of NMP solution to prepare a homogeneous solution of 1 mg / mL; then drop it onto the dried ITO surface to form a dense film. After it is completely dried, continue to drop it three times (with an interval of about 8 hours) to form a polyaniline film of a certain thickness on the surface. Then place it at room temperature for a period of time.

[0044] 6) The photoelectric performance of the photodetector obtained in step 5) is tested. The test system is an electrochemical workstation (CHI760D, Chenhua, China) with a three-electrode system consisting of a working electrode, a counter electrode (platinum electrode), and a reference electrode (mercury oxide electrode).

[0045] 7) Repeat the electrochemical test performed in step 6) by changing the parameters to explore its optimal working environment.

[0046] 8) Set the optimal parameters found in step 7), and perform cyclic testing on the sample for 800 seconds and 10 days to observe the changes in its performance.

[0047] Example 2

[0048] The method for constructing a self-powered photodetector with significantly improved performance, as described in Example 1, differs in that different concentrations of electrolyte are used in the electrochemical test in step 7). KOH solutions with concentrations of 0.2, 0.3, 0.4, and 0.5 mol / L were selected for the test.

[0049] Figure 3 The photocurrent density of the hybrid structure in Example 2 at different KOH electrolyte concentrations is (0.2, 0.3, 0.4, 0.5 mol / L).

[0050] Figure 4 The images show the EIS spectra of the hybrid structure in Example 2 at different KOH electrolyte concentrations (0.2, 0.3, 0.4, 0.5 mol / L).

[0051] Figure 5 The photoresponse time of the device in Example 2 in different KOH electrolyte solutions (0.2, 0.3, 0.4, 0.5 mol / L).

[0052] Example 3

[0053] The method for constructing a self-powered photodetector with significantly improved performance, as described in Example 1, differs in that different wavelengths of light sources are used in the electrochemical testing in step 7). The wavelength range is 350–760 nm.

[0054] Figure 6 The photocurrent densities of the hybrid structure in Example 3 at different wavelengths are (350, 365, 546, 630, 660, 700, 760 nm).

[0055] Example 4

[0056] The method for constructing a self-powered photodetector with significantly improved performance, as described in Example 1, differs in that different power densities of light sources are used in the electrochemical testing in step 7). The power densities of the light sources during testing are 90, 100, 110, 120, and 130 μW / cm². 2 .

[0057] Figure 7 This is a schematic diagram showing the change in photocurrent density of the hybrid structure in Example 4 under different power densities.

[0058] Example 5

[0059] The method for constructing a self-powered photodetector with significantly improved performance, as described in Example 1, differs in that: after completing step 4), the polyaniline layer is no longer dripped in step 5), but the electrochemical test is directly performed in step 6).

[0060] Figure 8 This is a performance comparison chart of the hybrid structure device and the simple bismuth-oxy-sulfur device in Example 5.

[0061] Example 6

[0062] The difference between this method and the one described in Example 1 for constructing a self-powered photodetector with significantly improved performance is that: after completing the dripping of the polyaniline layer in step 5), the process proceeds directly to the electrochemical testing in step 6).

[0063] Figure 8 This is a performance comparison chart of the hybrid structure device and the simple polyaniline device in Example 6.

Claims

1. A novel method for preparing organic-inorganic heterojunction structures and improving the properties of pure materials, characterized in that: Includes the following steps: 1) Pour 101.5 mg of bismuth nitrate pentahydrate and 20 mL of deionized water into a 100 mL volumetric beaker A. Sonicate beaker A for a period of time until the solid is completely dissolved. Let beaker A stand for a period of time to confirm that no precipitate has formed. 2) Mix 1 mL of hydrazine hydrate and 15.8 mg of thiourea and place them in beaker B. After sonication, continue sonicating until the solid is completely dissolved. 3) Take the solution in beaker A obtained in step 1) and mix it with the solution in beaker B obtained in step 2). Quickly add 120 mg of potassium hydroxide and 320 mg of sodium hydroxide, and stir continuously for 30 minutes. Let it stand overnight. Then collect the precipitate, wash it three times with alcohol and deionized water respectively, and dry it in a vacuum drying oven for 12 hours at a drying temperature of 70℃. Collect the pure bismuth oxysulfur nanosheet powder. 4) Weigh 1 mg of Bi2O2S nanosheets and add 1 mL of anhydrous ethanol. After ultrasonic homogenization, drop-cast the homogenized 1 mg / mL Bi2O2S solution onto the conductive side of the ITO surface and keep it in a drying oven at 60°C for 12 hours. 5) Weigh 1 mg of the purchased polyaniline powder, add 1 mL of NMP solution to prepare a homogeneous solution of 1 mg / mL; then drop it onto the dried ITO surface to form a dense film. After it is completely dried, continue to drop it three times (with an interval of about 8 hours) to form a polyaniline film of a certain thickness on the surface. Then place it at room temperature for a period of time. 6) The photoelectric performance of the photodetector obtained in step 5) is tested. The test system is an electrochemical workstation (CHI760D, Chenhua, China) with a three-electrode system consisting of a working electrode, a counter electrode (platinum electrode), and a reference electrode (mercury oxide electrode). 7) Repeat the electrochemical test performed in step 6) by changing the parameters to explore its optimal working environment. 8) Set the optimal parameters found in step 7), and perform cyclic testing on the sample for 800 seconds and 10 days to observe the changes in its performance.

2. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 1), the mass of bismuth nitrate pentahydrate is 101.5 mg, and the volume of deionized water is 20 mL. The ultrasonic treatment time is 2 h.

3. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 2), the ultrasonic treatment time is 2 hours. The mass of thiourea is 15.8 mg, and the volume of hydrazine hydrate is 1 mL.

4. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 3), the mass of potassium hydroxide is 120 mg and the mass of sodium hydroxide is 320 mg. The washing method is centrifugal washing at a speed of 8000 rad / s. The drying temperature is 70℃. The vacuum drying time is 12 h.

5. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 4), the mass of Bi2O2S used is 1 mg, the volume of anhydrous ethanol is 1 mL, the drying temperature is 60℃, and the drying time is 12 h.

6. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 5), the mass of polyaniline used is 1 mg, and the volume of NMP is 1 mL. The drying temperature is 60℃, and the drying time is 12 h. The number of drips is 3, the drip interval is 8 h, and the time at room temperature is 4 h.

7. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 6), a three-electrode electrochemical workstation was used for the test, and the test environment was a PEC environment.

8. The novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 7), the parameters selected for the electrochemical test are electrolyte concentration, light source wavelength, and light intensity. The electrolyte solution used for the test is KOH solution, with concentrations of 0.2, 0.3, 0.4, and 0.5 mol / L. The wavelength range of the light source during the test is 350–760 nm, and the light intensity is selected as 90, 100, 110, 120, and 130 μW / cm². 2 .

9. A novel method for preparing organic-inorganic heterostructures and improving the properties of pure materials according to claim 1, characterized in that, In step 8), the loop test time is 800s and 10 days.

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