Preparation method of InAs nanometer material and preparation method of photovoltaic solar cell

Abstract

The invention provides an InAs nano-material and a preparation method of a photovoltaic solar cell made of the InAs nano-material. High-performance nanometer materials such as InAs quantum dots and nanorods are prepared through the arsenic precursor which is low in price, easy to obtain, green and safe. The preparation process disclosed by the invention has the advantages of mild reaction conditions, simplicity and convenience in operation, good repeatability, low cost and the like; and the obtained InAs nano material has the characteristics of adjustable morphology, adjustable size, adjustable optical band gap and the like. The invention further provides a preparation method of a photovoltaic solar cell based on the InAs nano material, and the performance of a photoelectric device can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of III-V semiconductor fabrication methods and photovoltaic solar cells, and particularly to a method for preparing InAs nanomaterials and a method for preparing photovoltaic solar cells. Background Technology

[0002] III-V semiconductors have become important materials for novel photonic and nanoelectronic devices. Among these materials, indium arsenide has attracted much attention due to its high carrier mobility and narrow bandgap. However, in previous studies, most researchers have used techniques such as CVD and MBE to synthesize nanowires. These techniques involve high preparation temperatures, harsh experimental conditions, and long cycles. They also use highly dangerous and commercially unavailable arsenic precursors to synthesize quantum dots. Therefore, there is an urgent need for a preparation method that is simple to implement, has relatively mild conditions, is safe and reliable, and uses commercially available precursors.

[0003] In recent years, high-efficiency photovoltaic solar cells have received great attention due to their wide application in renewable energy power generation, building-integrated photovoltaics, off-grid power supply systems, space energy applications, power supply for portable electronic devices, and smart grids. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a method for preparing InAs nanoparticles. The preparation method provided by this invention can obtain InAs nanomaterials with tunable and controllable morphology, tunable and controllable size, and good photoelectric properties.

[0005] This invention provides a method for preparing InAs nanomaterials, comprising the following steps: Step 1: Mix trioctylphosphine, oleylamine and indium precursor, heat to obtain solution 1. Step 2: Mix benzoarsine and 1-octadecene, then add to solution 1 to obtain solution 2. Step 3: Inject diisobutylaluminum hydride into solution 2, heat, and react to obtain InAs nanomaterials.

[0006] Preferably, the ratio of trioctylphosphine to oleylamine is (10-40) mg: 1 mL.

[0007] Preferably, the indium precursor is one or more of indium fluoride, indium chloride, indium bromide, and indium iodide, and the arsenic precursor is one or more of 2-aminobenzoarsonic acid, 4-aminobenzoarsonic acid, 4-hydroxybenzoarsonic acid, and 3-nitro-4-hydroxybenzoarsonic acid.

[0008] Preferably, the mass ratio of the trioctylphosphine, indium precursor and arsenic precursor is 100:(10-30):(30-60).

[0009] Preferably, during the process of obtaining solution 1, the heating temperature is 80-120℃ and the reaction time is 20-40 min.

[0010] Preferably, in the step of obtaining InAs nanomaterials, the heating temperature is 150℃-400℃ and the reaction time is 2-30 min.

[0011] This invention also provides a method for preparing size-tunable InAs quantum dots, comprising the following steps: InAs quantum dots with a size of less than 2 nm are prepared by the preparation method described in claim 1. The InAs quantum dots are then added to solution 2 of the preparation method described in claim 1 to prepare large-sized InAs quantum dots.

[0012] Preferably, the size of the InAs quantum dots is 2-45 nm.

[0013] Preferably, the InAs nanomaterial is one or more of quantum dots, nanorods, nanowires, and nanosheets.

[0014] This invention also provides a method for preparing a photovoltaic solar cell, comprising the following steps: Substrate preparation: FTO-coated glass substrate (20×20mm) 2 The mixture was then subjected to ultrasonic treatment in deionized water, acetone, isopropanol and ethanol in sequence, and then dried. CdS layer deposition: A chemical bath deposition process is used, in which the substrate is immersed in an aqueous solution containing cadmium precursor and sulfur precursor, followed by annealing. Sb2Se3 electron transport layer synthesis: hydrothermal synthesis was carried out in a high-pressure reactor containing antimony precursor and selenium precursor, followed by annealing. Preparation of InAs hole transport layer: InAs nanomaterials were spin-coated onto a stacked Sb2Se3 / CdS / FTO layer and then annealed. Top contact layer: A 60nm Au electrode is thermally evaporated onto the InAs layer under high vacuum conditions.

[0015] Preferably, the electron transport layer is one or more of Sb2Se3, Sb2S3, or Sb2(S,Se) with different Se / S ratios.

[0016] Preferably, the hole transport layer is one or more InAs nanomaterials, and the thickness of the InAs nanomaterials is 80-120 nm.

[0017] This invention provides a method for preparing InAs nanomaterials. The method involves mixing trioctylphosphine, an indium precursor, and oleylamine, heating the mixture to obtain a liquid solution, then mixing an arsenic precursor and 1-octadecene with the above liquid solution to obtain a final mixture. Finally, diisobutylaluminum hydride is injected and reacted to obtain the InAs nanomaterials. This invention utilizes an oil-phase reflux method to prepare InAs nanomaterials with monodispersity, tunable morphology and size. The materials used in this synthesis method are inexpensive and readily available, the synthesis method is safe and controllable, and the yield is high. The prepared InAs nanomaterials are applied to photovoltaic solar cells, exhibiting good photoelectric conversion efficiency in the visible and infrared bands, providing a solid foundation for the application of InAs nanomaterials. The preparation method of InAs nanomaterials provided by this invention is expected to break through foreign restrictions on arsenic precursors, enabling basic research and large-scale application research of InAs nanomaterials in China. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the preparation and application of InAs nanomaterials;

[0019] Figure 2 The X-ray diffraction (XRD) patterns of InAs nanomaterials synthesized at different temperatures;

[0020] Figure 3 These are transmission electron micrographs (TEM) of InAs nanomaterials synthesized at different temperatures;

[0021] Figure 4 This is a particle size distribution diagram of InAs nanomaterials synthesized at different temperatures;

[0022] Figure 5 These are transmission electron microscope (TEM) images of InAs quantum dots synthesized at 350℃ and 400℃ using the seed injection method via oil phase reflux.

[0023] Figure 6 The particle size distribution diagrams are for InAs quantum dots synthesized at 350℃ and 400℃ using the seed injection method via oil phase reflux.

[0024] Figure 7 The X-ray photoelectron spectroscopy (XPS) full spectrum of InAs nanomaterials synthesized by oil-phase reflux method at 300℃ is shown in (a), and the high-resolution energy spectrum of element In3d and element As3d is shown in (b).

[0025] Figure 8 These are high-resolution transmission electron microscope images and high-angle annular dark-field scanning transmission electron microscope images of InAs nanomaterials synthesized by oil phase reflux at 300℃.

[0026] Figure 9This is the UV-Vis-NIR absorption spectrum of InAs nanomaterials synthesized by the oil-phase reflux method;

[0027] Figure 10 This is the Fourier transform infrared spectrum of InAs nanomaterials synthesized at 300℃ using the oil-phase reflux method;

[0028] Figure 11 This is a photograph of InAs nanomaterials undergoing surface treatment and phase transfer from the oil phase to the aqueous phase.

[0029] Figure 12 These are the ultraviolet photoelectron spectroscopy (UPS) and solid-state ultraviolet spectrum (DRUVS) diagrams of InAs nanomaterials;

[0030] Figure 13 This is a schematic diagram of the structure and energy level matching diagram for fabricating photovoltaic solar cells;

[0031] Figure 14 This is the JV curve for preparing photovoltaic solar cells. Detailed Implementation

[0032] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0033] In view of the preparation problems and application requirements of indium arsenide (InAs) materials, this invention provides a synthesis process for InAs nanomaterials. This process uses different indium and arsenic sources as reaction precursors and employs an oil-phase reflux method to obtain InAs nanomaterials with tunable morphology and size. The prepared InAs nanomaterials are then used to fabricate photovoltaic solar cells with good photovoltaic performance. Specifically, this invention discloses a method for preparing InAs nanomaterials, including the following steps: Trioctylphosphine, oleylamine and indium precursor were mixed, heated and reacted to obtain solution 1; After mixing the arsenic precursor and 1-octadecene, the mixture was added to solution 1 to obtain solution 2; Diisobutylaluminum hydride was added to solution 2, heated, and reacted to obtain InAs nanomaterials.

[0034] In this invention, trioctylphosphine and oleylamine are first mixed and heated to obtain solution 1. The ratio of trioctylphosphine to oleylamine is (10-40) mg: 1 mL; in a specific embodiment, the ratio of trioctylphosphine oxide to octadecene is 10 mg: 1 mL. The heating temperature is 80-120°C, and the time is 20-40 min.

[0035] In this invention, 2-aminobenzoarsonic acid (4-aminobenzoarsonic acid, 4-hydroxybenzoarsonic acid, or 3-nitro-4-hydroxybenzoarsonic acid) is mixed with 1-octadecene, and then mixed with the above mixture to obtain solution 2; in this process, the mixing temperature with the mixture is 150-400°C. Octadecene, as a non-ligand solvent and surfactant, has a boiling point comparable to the temperature required for the reaction system. In this invention, the mass ratio of trioctylphosphine, indium precursor, and arsenic precursor is 100:(10-30):(30-60).

[0036] According to the present invention, diisobutylaluminum hydride is then added to the mixture obtained above, and the reaction is carried out to obtain InAs nanomaterials. During the above reaction, the solution system appears slightly yellow. This process belongs to the activation and monomer release process. Under high temperature conditions, the indium precursor and arsenic precursor are reduced by diisobutylaluminum hydride, releasing indium and arsenic atoms. The two atoms combine to form InAs nanomaterials, and the solution system gradually turns black. The reaction time is 2-30 min.

[0037] This invention also provides a method for preparing size-tunable InAs quantum dots, comprising the following steps: InAs quantum dots with a size of less than 2 nm are prepared by the preparation method described in claim 1. The InAs quantum dots are then added to solution 2 of the preparation method described in claim 1 to prepare large-sized InAs quantum dots.

[0038] Preferably, the size of the InAs quantum dots is 2-45 nm.

[0039] This invention also provides a method for preparing a photovoltaic solar cell, comprising the following steps: Substrate preparation: FTO-coated glass substrate (20×20mm) was prepared. 2 Clean and dry. CdS layer deposition: A chemical bath deposition process is used, in which the substrate is immersed in an aqueous solution containing cadmium precursor and sulfur precursor, followed by annealing. Electron transport layer synthesis: Sb2Se3 electron transport layer was prepared by hydrothermal synthesis in a high-pressure reactor containing antimony precursor and selenium precursor solution, followed by annealing. Preparation of hole transport layer: InAs nanomaterials were spin-coated onto the electron transport layer and then annealed to prepare the InAs hole transport layer. Top layer: A 60nm gold electrode is thermally evaporated onto an InAs layer under high vacuum conditions to prepare a gold layer.

[0040] In the method for preparing the photovoltaic solar cell of the present invention, preferably, the electron transport layer is one or more of Sb₂Se₃, Sb₂S₃, or Sb₂(S,Se) with different Se / S ratios. Preferably, the hole transport layer is one or more of InAs nanomaterials, and the thickness of the InAs nanomaterials is 80-120 nm.

[0041] This invention proposes a simple, mild, and repeatable liquid-phase reflux method for preparing III-V group InAs nanomaterials. The nanomaterials obtained by this method exhibit advantages such as good monodispersity, controllable morphology and size, small optical band gap, and low cost. This invention also proposes a method for constructing a photovoltaic solar cell with a vertical structure based on indium arsenide nanomaterials, demonstrating high photoelectric conversion efficiency.

[0042] To further understand the present invention, the preparation method and application of InAs nanomaterials provided by the present invention will be described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0043] Example

[0044] InAs nanomaterials were synthesized using a two-step hot-injection method: Oleylamine, indium bromide, and trioctylphosphine were added to a three-necked flask at room temperature. The mixture was first heated to 100°C under a nitrogen stream and magnetic stirring, and held for 30 minutes to remove water and other low-boiling-point impurities. The arsenic precursor was dissolved in 1-octadecene and injected into the three-necked flask at 150-400°C. Then, diisobutylaluminum hydride was injected into the mixture, and the reaction was allowed to proceed for 2-30 minutes. Finally, the solution was allowed to cool naturally to room temperature, the reaction solution was removed, and toluene was added for washing. The product was InAs nanomaterials.

[0045] Photovoltaic solar cell manufacturing method: The treated glass substrate was immersed in a precursor solution containing cadmium nitrate and thiourea and reacted for 10 min, followed by air annealing to obtain a dense and uniform CdS film. An Sb₂Se₃ layer was prepared using a hydrothermal method. The substrate with the deposited CdS layer was placed in a polytetrafluoroethylene liner, and a precursor solution composed of potassium antimony tartrate, thiourea, and sodium selenite was added. The reaction was carried out hydrothermally at 100°C. The sample was transferred to a glove box and annealed for 10 min to obtain a highly crystalline Sb₂Se₃ film. InAs nanorods were then uniformly coated onto the surface of the Sb₂Se₃ film and annealed in air at 100°C to achieve good interfacial contact. Finally, gold electrodes were deposited on the InAs nanorod film surface to complete the device fabrication.

[0046] Figure 2The XRD patterns of the InAs nanomaterials prepared in this embodiment at different reaction temperatures of 150-400℃ are shown. All diffraction peaks in the figure correspond to the (111), (200), (220), (311), (400), (331) and (422) crystal planes of InAs. The positions of the diffraction peaks are consistent with the standard card JCPDS: PDF#15-0869, indicating that its space group is F-43m and its structure is face-centered cubic.

[0047] from Figure 3 The TEM images show that indium arsenide nanomaterials with controllable size and morphology can be prepared by adjusting the reaction temperature.

[0048] Figure 4 This is a particle size distribution diagram of InAs nanomaterials generated at different reaction temperatures.

[0049] Figure 5 These are TEM images showing the regeneration of InAs nanoclusters into large-sized InAs quantum dots via a seed growth method and continuous injection at reaction temperatures of 350℃ and 400℃.

[0050] Figure 6 This is a particle size distribution diagram of InAs nanoclusters being regrowed into large-size InAs quantum dots via a seed growth method and continuous injection at reaction temperatures of 350℃ and 400℃.

[0051] In addition, to further analyze the elemental composition and state of the prepared samples, the XPS spectra of the InAs nanorods generated at a reaction temperature of 300℃ were studied. Figure 7 The full spectrum confirmed the presence of five elements—In, As, C, N, and O—in the prepared sample, with no other impurities. The C, N, and O elements originated from surface oxidation in the air and surfactants. The 3d high-resolution spectrum of In (…) Figure 7 b) Two strong peaks are observed at binding energies of 451.79 eV and 444.30 eV, respectively, with a spin energy separation of 7.49 eV, indicating that there is only one valence state on the sample surface, namely In. 3+ ; Figure 7 The abscissa range of 45eV-35eV is the fine spectrum of As3d, with two distinct peaks at binding energies of 40.78eV and 41.40eV, respectively, proving that the valence state of arsenic is -3. Therefore, the XPS results are in high agreement with the XRD pattern, confirming the successful synthesis of InAs.

[0052] Figure 8 These are high-resolution transmission electron microscope (TEM) images and high-angle annular dark-field scanning transmission electron microscope (STEM) images. The two-dimensional lattice is clearly visible in each image, and the interplanar spacing of the two-dimensional crystal planes is obtained through measurement. It can be well matched to the (111) crystal plane of indium arsenide. The EDS mapping diagram shows that the elements arsenic and indium are uniformly distributed within the nanocrystal range. All the above characterizations prove the successful synthesis of indium arsenide nanomaterials.

[0053] The UV-Vis-NIR absorption spectrum of the product prepared at a reaction temperature of 300℃ in this experimental example is as follows: Figure 9 The nanorods absorb throughout the ultraviolet-near infrared spectrum, with the first exciton absorption peak located at approximately 515 nm.

[0054] The Fourier transform infrared spectrum of the product prepared at a reaction temperature of 300℃ in this experimental example is as follows: Figure 10 As shown, a long-chain oleylamine ligand is coated on the surface of the nanorods, affecting the photoelectric properties of InAs nanorods, such as electron transport.

[0055] In this experimental example, the ultraviolet photoelectron spectroscopy (UPS) was performed as follows: Figure 12 (a), (b) and solid-state ultraviolet spectra (DRUVS) Figure 12 (c) Calculate the band gap width and the positions of the conduction band and valence band of the InAs nanorods.

[0056] In this experimental example, a schematic diagram and energy level matching diagram of a photovoltaic solar cell fabricated using a material with energy level matching with InAs nanorods are shown below. Figure 13 As shown.

[0057] The photovoltaic solar cell prepared in this experimental example has good photoelectric conversion efficiency, as shown in the JV curve. Figure 14 As shown.

Claims

1. A method for preparing InAs nanomaterials, comprising the following steps: Trioctylphosphine, oleylamine and indium precursor were mixed, heated and reacted to obtain solution 1; After mixing the arsenic precursor and 1-octadecene, the mixture was added to solution 1 to obtain solution 2; Diisobutylaluminum hydride was added to solution 2, heated, and reacted to obtain InAs nanomaterials.

2. The preparation method according to claim 1, characterized in that, The indium precursor is one or more of indium fluoride, indium chloride, indium bromide, and indium iodide, and the arsenic precursor is one or more of 2-aminobenzoarsonic acid, 4-aminobenzoarsonic acid, 4-hydroxybenzoarsonic acid, and 3-nitro-4-hydroxybenzoarsonic acid.

3. The preparation method according to claim 1, characterized in that, The ratio of trioctylphosphine to oleylamine is (10-40) mg: 1 mL, and the mass ratio of trioctylphosphine, indium precursor and arsenic precursor is 100: (10-30): (30-60).

4. The preparation method according to claim 1, characterized in that, During the process of obtaining solution 1, the heating temperature is 80-120℃ and the reaction time is 20-40 min.

5. The preparation method according to claim 1, characterized in that, In the step of obtaining InAs nanomaterials, the heating temperature is 150℃-400℃ and the reaction time is 2-30min.

6. A method for preparing size-tunable InAs quantum dots, comprising the following steps: InAs quantum dots with a size of less than 2 nm are prepared by the preparation method described in claim 1. The InAs quantum dots are then added to solution 2 of the preparation method described in claim 1 to prepare large-sized InAs quantum dots.

7. The preparation method according to claim 6, characterized in that, InAs quantum dots have sizes ranging from 2 to 45 nm.

8. An InAs nanomaterial, characterized in that, The nanomaterial is one or more of quantum dots, nanorods, nanowires, and nanosheets.

9. A method for preparing a photovoltaic solar cell, comprising the following steps: Substrate preparation: The FTO-coated glass substrate is cleaned and dried. CdS layer deposition: A chemical bath deposition process is used, in which the substrate is immersed in an aqueous solution containing cadmium precursor and sulfur precursor, followed by annealing. Electron transport layer synthesis: Sb2Se3 electron transport layer was prepared by hydrothermal synthesis in a high-pressure reactor containing antimony precursor and selenium precursor solution, followed by annealing. Preparation of hole transport layer: InAs nanomaterials were spin-coated onto the electron transport layer and then annealed to prepare the InAs hole transport layer. Top layer: A 60nm gold electrode is thermally evaporated onto an InAs layer under high vacuum conditions to prepare a gold layer.

10. The preparation method according to claim 7, characterized in that, The electron transport layer is one or more of Sb2Se3, Sb2S3, or Sb2(S,Se) with different Se / S ratios.

11. The preparation method according to claim 7, characterized in that, The hole transport layer is one or more of InAs nanomaterials.

12. The preparation method according to claim 7, characterized in that, The thickness of InAs nanomaterials is 80-120 nm.

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