A Ga2O3@Pt quantum dot with a core-shell structure, a preparation method and application thereof

Abstract

The application provides a GaN nanowire Ga2O3@Pt quantum dot core-shell structure, which is modified by a two-step method of immersion reduction and photodeposition. Ga2O3 is coated on the surface of Pt, and can effectively inhibit the negative influence caused by a side reaction. The Ga2O3 layer in the heterostructure formed on the surface under the Pt metal particles can be used as a hole blocking layer, and can effectively improve the separation efficiency of photo-generated carriers. In addition, by using a plasma-assisted molecular beam epitaxy (MBE) technology, the GaN nanowire array can be grown on a Si substrate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoelectric detectors, and particularly relates to a Ga2O3@Pt quantum dot with a core-shell structure of GaN nanowires and a preparation method and application thereof. BACKGROUND

[0002] A photoelectric detector is a device that can convert optical signals into electrical signals, and is widely used in optical communication, photography, spectral analysis, remote sensing and other fields. Among them, the ultraviolet photoelectric detector is a photoelectric detector specially designed for detecting ultraviolet light radiation. They use photosensitive materials to convert ultraviolet light into electrical signals, thereby realizing the detection of ultraviolet light. These detectors play a key role in many fields, including environmental monitoring, medical applications, communication systems, etc.

[0003] The ultraviolet photoelectric detector plays a key role in many fields because of its fast response, high quantum efficiency and high sensitivity to ultraviolet light. Its high sensitivity and fast response speed make it an indispensable component in various applications. Controlling the transport behavior of carriers is one of the important means to improve the performance of ultraviolet photoelectrochemical detectors. However, the photo-excited carriers are difficult to directly reach the reaction site, which greatly limits the response of the photoelectrochemical detector. SUMMARY

[0004] This section aims to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0005] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0006] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art and provide a Ga2O3@Pt quantum dot with a core-shell structure of GaN nanowires.

[0007] To solve the above technical problems, the present application provides the following technical solutions: the core-shell structure takes Pt as the core, and the outer layer is coated with Ga2O3.

[0008] Among them, the upper layer of Ga2O3 acts as a molecular sieve, and the lower layer acts as a hole blocking layer.

[0009] The purpose of the present application is to overcome the deficiencies in the prior art and provide a preparation method of a Ga2O3@Pt quantum dot with a core-shell structure of GaN nanowires.

[0010] To solve the above technical problems, the application provides the following technical scheme: a noble metal Pt is modified by a two-step method of impregnation reduction and photodeposition, comprising,

[0011] Impregnation reduction: the GaN nanowire sample is immersed in a precursor solution A, taken out after heating, dried by blowing N2, and then annealed;

[0012] Photodeposition: the nanowire sample is immersed in a precursor solution B, Pt is deposited by photodeposition, washed with ethanol and deionized water, and finally dried with N2 gas, so that the GaN nanowire Ga2O3@Pt quantum dot core-shell structure is obtained.

[0013] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the precursor solution A is a mixed solution of H2PtCl6 aqueous solution and deionized water, wherein the volume ratio of H2PtCl6 solution to deionized water is 1:250.

[0014] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the heating, wherein the heating temperature is 160-200℃, and the heating time is 35-45min.

[0015] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the annealing temperature is 550-650℃, and the annealing time is 35-45min.

[0016] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the precursor solution B is a mixed solution of H2PtCl6 aqueous solution, methanol and deionized water, wherein the volume ratio of H2PtCl6 aqueous solution, methanol and deionized water is 3:200:8000.

[0017] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the concentration of the H2PtCl6 solution is 25-30mg / ml.

[0018] As a preferred scheme of the preparation method of the GaN nanowire Ga2O3@Pt quantum dot with core-shell structure, the H2PtCl6 aqueous solution in the precursor solution A is 40μL, and the H2PtCl6 aqueous solution in the precursor solution B is 5μL.

[0019] As a preferred scheme of the preparation method of the Ga2O3@Pt quantum dot with the core-shell structure of GaN nanowire according to the application, the photodeposition process is carried out under the irradiation of a mercury lamp for 20-30 min.

[0020] Another object of the application is to provide an application of the Ga2O3@Pt quantum dot with the core-shell structure of GaN nanowire in PEC light detection.

[0021] The application has the following beneficial effects:

[0022] The application provides a GaN nanowire Ga2O3@Pt quantum dot core-shell structure, and a noble metal Pt is modified by using a two-step method of immersion reduction and photodeposition. Ga2O3 is coated on the Pt as a surface layer, and can effectively inhibit the negative influence caused by a side reaction. The Ga2O3 layer in the heterostructure formed on the surface under the Pt metal particles can be used as a hole blocking layer, and can effectively improve the separation efficiency of photo-generated carriers.

[0023] The application can grow GaN nanowire arrays on a Si substrate by using a plasma-assisted molecular beam epitaxy (MBE) technology, and can deposit Pt. The structure can effectively improve the response speed and external quantum efficiency of a device. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort. Among them:

[0025] Figure 1 The flow chart of the photocatalytic structure prepared in the embodiment 1 of the application.

[0026] Figure 2 The TEM diagram of the photocatalytic structure prepared in the embodiment 1 of the application. DETAILED DESCRIPTION

[0027] In order to make the above objects, characteristics and advantages of the application more apparent, the following will make a detailed description of the specific implementation of the application by combining the embodiment of the specification.

[0028] In the following description, many specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the application, therefore, the application is not limited to the specific embodiments disclosed below.

[0029] Second, the term "one embodiment" or "an embodiment" as may appear in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments.

[0030] The raw materials used in the present application are all commercially available.

[0031] The material prepared in the embodiments of the present application is tested for performance as follows: an electrochemical workstation 760e is used to test the current, voltage and other performances of the sample.

[0032] Example 1

[0033] This embodiment provides a preparation method of a photocatalytic structure, as shown in Figure 1 Specifically, the method comprises the following steps:

[0034] Step 1: Preparation of Ga2O3-Pt / GaN nanowires: immerse the nanowire sample in a precursor solution containing 40 μL of 25 mg / mL H2PtCl6 solution and 10 mL of deionized water without adjusting the pH. Then heat the sample on a hot stage at 160℃ for 35 min, blow dry with N2, and then put it into a tube furnace and anneal at 550℃ for 35 min.

[0035] Step 2: Photodeposition of Pt nanoparticles: immerse the nanowire sample in a precursor solution containing 30 μL of 25 mg / mL H2PtCl6 solution, 2 mL of methanol and 80 mL of deionized water, and perform Pt deposition under mercury lamp irradiation for 20 min to obtain the sample. Wash the sample with ethanol and deionized water for 4 times, and finally dry it with N2 to obtain the photocatalytic structure.

[0036] Figure 1 The flow chart of the photocatalytic structure prepared in Example 1 of the present application, as shown in the figure, is formed by heating on a hot stage and then annealing, which includes loaded Pt nanoparticles, a Ga2O3 hole blocking layer and a cladding layer.

[0037] Figure 2 The TEM image of the photocatalytic structure prepared in Example 1 of the present application, as shown in the figure, can directly see from the TEM image that the Pt nanoparticles (NPs) obtained by IMP (immersion reduction) are covered by an oxide layer, and there is also an oxide layer between the contact with GaN. This oxide layer is the designed Ga2O3.

[0038] Comparative Example 1

[0039] The difference between this embodiment and embodiment 1 is that the IMP solution is adjusted to 30 μL, and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0040] Comparative Example 2

[0041] The difference between this embodiment and embodiment 1 is that the IMP solution is adjusted to 30 μL and does not contain PD (photodeposition), and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0042] Comparative Example 3

[0043] The difference between this embodiment and embodiment 1 is that the IMP solution is adjusted to 40 μL and does not contain PD (photodeposition), and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0044] Comparative Example 4

[0045] The difference between this embodiment and embodiment 1 is that the IMP solution is adjusted to 50 μL and does not contain PD (photodeposition), and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0046] Comparative Example 5

[0047] The difference between this embodiment and embodiment 1 is that only PD (photodeposition) is contained without IMP (immersion reduction), and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0048] Comparative Example 6

[0049] The difference between this comparative example and embodiment 1 is that the structure is adjusted to Bare / GaN, and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0050] Comparative Example 7

[0051] The difference between this comparative example and embodiment 1 is that the structure is adjusted to PD / GaN, and the rest of the preparation process is the same as that of embodiment 1, and a photocatalytic structure is prepared.

[0052] The performance test is performed on the materials prepared in the above comparative examples, and the comparison results with embodiment 1 are shown in Table 1.

[0053] Table 1

[0054] External quantum efficiency (%) Response speed (ms) Example 1 41.58 34 Comparative Example 1 - - Comparative Example 2 3.25 - Comparative Example 3 6.84 - Comparative Example 4 9.9 - Comparative Example 5 0.36 - Comparative Example 6 0.067 720 Comparative Example 7 2.52 650

[0055] Note: “-” indicates that the photocatalytic structure preparation fails, and there is no related data at present.

[0056] As can be seen from Table 1, adjusting IMP and PD has a significant effect on the performance of the photocatalytic structure, because both of them play an important role in the preparation of the photocatalytic structure, and the noble metal Pt is modified by using the two-step method of impregnation reduction and photodeposition. Pt strengthens the surface kinetics, Ga2O3 is coated on the surface of Pt as a surface layer, which can effectively inhibit the negative effects caused by side reactions, and the Ga2O3 layer in the heterostructure formed by the surface under the Pt metal particles can be used as a hole blocking layer, which can effectively improve the separation efficiency of photo-generated carriers. Except for Example 1, changing any preparation condition will cause the failure of the photocatalytic structure.

[0057] The present application uses the two-step method of impregnation reduction (IMP) and photodeposition (PD) to modify the noble metal Pt to obtain Ga2O3@Pt quantum dot core-shell structure of GaN nanowires. For the preparation of Ga2O3-Pt / GaN nanowires, the growth of Ga2O3 and the preliminary deposition of Pt nanoparticles on the GaN nanowires are completed by using the impregnation reduction method. For the photodeposition of Pt nanoparticles, in-situ selective photodeposition method is used to deposit Pt nanoparticles on the surface of GaN at room temperature.

[0058] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A GaN nanowire Ga2O3@Pt quantum dot with a core-shell structure, characterized in that: The shell-core structure has a Pt core and is coated with Ga2O3 on the outside. In this design, the upper surface layer of Ga2O3 serves as a molecular sieve, and the lower surface layer serves as a hole-blocking layer. The Pt was modified using a two-step method of impregnation reduction and photodeposition, including: Impregnation and reduction: GaN nanowire samples were immersed in precursor solution A, heated, removed, dried with N2, and then annealed. Photodeposition: The nanowire sample is immersed in precursor solution B, Pt is photodeposited, washed with ethanol and deionized water, and finally dried with N2 gas to obtain GaN nanowire Ga2O3@Pt quantum dot core-shell structure. The precursor solution A is a mixed solution of H2PtCl6 aqueous solution and deionized water, wherein the volume ratio of H2PtCl6 solution to deionized water is 1:

250. The precursor solution B is a mixed solution of H2PtCl6 aqueous solution, methanol and deionized water, wherein the volume ratio of H2PtCl6 aqueous solution, methanol and deionized water is 3:200:8000.

2. The GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in claim 1, characterized in that: The heating process involves a heating temperature of 160–200°C and a heating time of 35–45 minutes.

3. The GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in claim 1, characterized in that: The annealing process involves an annealing temperature of 550–650°C and an annealing time of 35–45 minutes.

4. The GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in claim 1, characterized in that: The concentration of the H2PtCl6 solution is 25–30 mg / ml.

5. The GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in claim 1, characterized in that: The precursor solution A contains 40 μL of H2PtCl6 aqueous solution, and the precursor solution B contains 5 μL of H2PtCl6 aqueous solution.

6. The GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in claim 1, characterized in that: The photodeposition process was carried out under mercury lamp irradiation for 20–30 minutes.

7. An application of GaN nanowires with a core-shell structure and Ga2O3@Pt quantum dots as described in any one of claims 1 to 6 in PEC photodetector.

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