Solar absorbers based on gold nanoparticle arrays

Abstract

The present invention relates to a solar absorber based on a gold nanoarray, which belongs to the field of micro-nano optoelectronic technology. The solar absorber is composed of gold nanounits periodically arranged in an XOY plane. Sunlight is incident in the form of a plane wave. Each of the gold nanounits comprises, from bottom to top, a base layer, a distributed Bragg reflector layer, a two-dimensional material layer, and an antenna layer. The distributed Bragg reflector layer includes five layers of distributed Bragg reflectors (DBRs). The projections of the base layer, distributed Bragg reflector layer, and two-dimensional material layer on the XOY plane overlap and form a square. The projection of the antenna layer on the XOY plane is a circle, and the square and circle are concentric. The solar absorber has a simple structure, an average absorptivity of 80% in the visible light range of 400nm-700nm, is unaffected by the polarization of the light source, and exhibits good absorption effect within the incident angle range of 0° to 60°.

Description

Technical Field

[0001] The invention discloses a solar absorber based on a gold nanometer array and belongs to the technical field of micro-nano optoelectronics. Background Art

[0002] A metasurface is an artificially designed periodic structure. Because of its special electromagnetic properties, adjustable refractive index, asymmetric transmission and other characteristics, it is often used to prepare high-efficiency electromagnetic wave absorbers.

[0003] Nowadays, there are many technologies, such as photovoltaics, solar energy and thermal generators, which can convert solar energy into other forms of energy, such as light energy, heat energy or electricity, and apply them to other applications. Therefore, how to efficiently utilize solar energy has become a major research topic.

[0004] Currently, two-dimensional materials are widely used in advanced material detectors, metamaterial absorbers, and other modulators and optical devices due to their extraordinary electrical and optical properties and ability to enhance light absorption. A typical example is TMDCs. MoS2 is a representative TMDC material. It has the characteristics of high current cutoff ratio and tunability, and its single-layer structure has excellent optical properties and can be used in optoelectronic devices. However, this also raises a very difficult problem, that is, due to its ultra-thin thickness, the light absorption efficiency is very low. In recent years, in order to improve the low absorption efficiency of single-layer structures, researchers have adopted many methods to improve the absorption performance of solar absorbers. However, most absorbers still have some shortcomings, such as poor broadband performance, low absorptivity, or the absorption bandwidth cannot match the energy distribution of the solar spectrum, resulting in low absorption effect. Summary of the Invention

[0005] In order to efficiently utilize solar energy, the present invention designs a solar absorber based on a gold nanoarray. It has a simple structure and an average absorption rate of 80% in the visible light band of 400nm-700nm. It is not affected by the polarization of the light source and has a good absorption effect in the incident angle range of 0° to 60°.

[0006] The object of the present invention is achieved like this:

[0007] A solar absorber based on a gold nanoarray is composed of gold nanounits periodically arranged in an XOY plane. Sunlight is incident in the form of a plane wave. Each of the gold nanounits comprises, from bottom to top, a substrate layer, a distributed Bragg reflector layer, a two-dimensional material layer, and an antenna layer. The distributed Bragg reflector layer includes five layers of distributed Bragg reflectors (DBRs). The projections of the substrate layer, distributed Bragg reflector layer, and two-dimensional material layer on the XOY plane overlap and are square. The projection of the antenna layer on the XOY plane is circular, and the square and the circle are concentric.

[0008] The base layer is made of Si material, the distributed Bragg reflector DBR is composed of an Al2O3 material layer and a Si material layer from bottom to top, the two-dimensional material layer is a PtS2 two-dimensional material, and the antenna layer is made of Au material.

[0009] In the above-mentioned solar absorber based on gold nanoarray, the size of the base layer is 0.1μm×0.1μm×1μm; the size of the Al2O3 material layer is 0.1μm×0.1μm×0.09μm, the size of the Si material layer is 0.1μm×0.1μm×0.038μm; the size of the two-dimensional material layer is 0.1μm×0.1μm×0.65nm; the size of the antenna layer is 0.08μm×0.7μm in diameter.

[0010] Beneficial effects:

[0011] First, the solar absorber based on the gold nanoarray of the present invention has only four layers: a substrate layer, a distributed Bragg reflector layer, a two-dimensional material layer, and an antenna layer. Its shapes are only square and cylindrical, making it simple in structure and easy to process, which helps to reduce costs.

[0012] Second, the solar absorber based on the gold nanoarray of the present invention has an average absorptivity of 80% in a broadband range of 400nm-700nm, which is high;

[0013] Third, the solar absorber based on the gold nanoarray of the present invention is not affected by the polarization of the light source and has a good absorption effect within the incident angle range of 0° to 60°. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the three-dimensional structure of the solar absorber based on the gold nanoarray of the present invention.

[0015] Figure 2 Schematic diagram of the three-dimensional structure of a single gold nanounit.

[0016] Figure 3 Schematic diagram of the relative positions of the substrate layer, distributed Bragg reflector layer, two-dimensional material layer and antenna layer.

[0017] Figure 4 This is a screenshot of the simulation software interface of the present invention.

[0018] Figure 5 for Figure 4 Absorption effect curve in .

[0019] Figure 6 This is the curve showing the effect of the height change of the gold nanoarray on the absorption rate.

[0020] Figure 7This is the curve showing the effect of the change in the radius of the gold nanoarray on the absorption rate.

[0021] Figure 8 This is the curve showing the effect of changes in the incident angle of sunlight on the absorptivity.

[0022] Figure 9 This is the curve of the influence of the change of sunlight polarization angle on the absorption rate.

[0023] In the figure: 1 substrate layer, 2 distributed Bragg reflector layer, 2-1Al2O3 material layer, 2-2Si material layer, 3 two-dimensional material layer, 4 antenna layer. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in further detail below with reference to the accompanying drawings. Specific implementation method 1

[0026] The solar absorber based on gold nanoarray in this embodiment has a three-dimensional structural diagram as shown in FIG. Figure 1 As shown, it is composed of gold nano-units arranged periodically in the XOY plane. Sunlight is incident in the form of plane waves. Each of the gold nano-units is composed of a base layer 1, a distributed Bragg reflector layer 2, a two-dimensional material layer 3 and an antenna layer 4 from bottom to top. The three-dimensional structure diagram is shown as follows Figure 2 As shown; the distributed Bragg reflector layer 2 includes five layers of distributed Bragg reflectors DBR; the projections of the substrate layer 1, the distributed Bragg reflector layer 2 and the two-dimensional material layer 3 on the XOY plane coincide with each other and are square, the projection of the antenna layer 4 on the XOY plane is a circle, the square and the circle are concentric, and the relative positions of the substrate layer 1, the distributed Bragg reflector layer 2, the two-dimensional material layer 3 and the antenna layer 4 are shown in the figure. Figure 3 As shown;

[0027] The base layer 1 is made of Si material, the distributed Bragg reflector DBR is composed of an Al2O3 material layer 2-1 and a Si material layer 2-2 from bottom to top, the two-dimensional material layer 3 is a PtS2 two-dimensional material, and the antenna layer 4 is made of Au material.

[0028] In the above-mentioned solar absorber based on gold nanoarray, the size of the base layer 1 is 0.1μm×0.1μm×1μm; the size of the Al2O3 material layer 2-1 is 0.1μm×0.1μm×0.09μm, and the size of the Si material layer 2-2 is 0.1μm×0.1μm×0.038μm; the size of the two-dimensional material layer 3 is 0.1μm×0.1μm×0.65nm; the size of the antenna layer 4 is r0.05-0.09μm×0.7μm. Specific implementation method 2

[0030] In this embodiment, the solar absorber based on the gold nanoarray is simulated and tested on the effect of the height change of the antenna layer 4 on the absorption rate based on the embodiment 1 using FDTD-Solutions software. The simulation interface is as follows: Figure 4 As shown, Figure 4 The absorption effect curve in Figure 5 As shown, and using:

[0031]

[0032] Where A is the average absorptivity of the absorber, A is the absorptivity of the absorber, which is a function of the wavelength λ of the incident light, λ is the wavelength of the incident light, and λ max is the maximum value within the wavelength range of the incident light, λ min It is the minimum value within the wavelength range of the incident light;

[0033] The average absorption rate can be calculated as 80% through the above formula;

[0034] When the height of the antenna layer 4 changes from 0.05 μm to 0.09 μm, the absorption rate curve is as follows Figure 6 As shown, the simulation results show that with the increase of height, the absorption peak moves from 402nm to 551nm, and a new high absorption rate part appears in the absorption rate at long wavelengths, indicating that when the antenna height of the absorber changes, the absorption bandwidth of the absorber will not be consistent with the band where the energy of solar energy is more concentrated, resulting in a decrease in the absorption effect of the absorber, further proving the rationality of the parameters of the solar absorber based on gold nanoarrays in the present invention. Specific implementation method three

[0036] In this embodiment, the solar absorber based on the gold nanostructure array is simulated and tested on the effect of the radius change of the cylindrical structure in the antenna layer 4 on the absorptivity based on the embodiment 1. When the diameter changes from 0.05 μm to 0.09 μm, the absorptivity curve is as follows: Figure 7 As shown, the simulation results show that as the radius increases, the absorption peak gradually moves to the long wavelength, and the absorption effect of the absorber is the best when the diameter is 0.08μm. When light is irradiated on the surface of the structure, the metal nanoparticles generate surface charges. These particles generate repulsive forces inside the nanoparticles, while there is attraction between adjacent particles, which is determined by the distribution of positive and negative charges. As the radius of the gold nanostructure increases, the repulsive force inside the particles increases, resulting in a red shift of the absorption peak. This movement will change the overall absorption effect of the absorber to a certain extent, further proving the rationality of the parameters of the solar absorber based on the gold nanoarray of the present invention. Specific implementation method four

[0038] The solar absorber based on gold nanoarray in this embodiment is based on the embodiment 1, and the effect of the angle change of sunlight incident on the absorption rate is simulated and tested at the incident angles of 0°, 15°, 30°, 45°, 60° and 75°, as shown in FIG. Figure 8 As shown, the simulation results show that when the incident angle is less than 60°, the absorption rate curve at the short wavelength does not change significantly, and the absorption rate at the long wavelength decreases slightly; when the incident angle is greater than 60°, the absorption peak begins to show a decrease in absorption rate, which indicates that the solar absorber based on gold nanoarrays of the present invention has good wide-angle absorption performance. Specific implementation method five

[0040] The solar absorber based on gold nanoarray in this embodiment is based on the first embodiment. The effect of the change of the polarization angle of sunlight on the absorption rate is simulated and tested at the polarization angles of 0°, 15°, 30°, 45°, 90°, 75° and 90°, respectively. Figure 9 As shown in the figure, the simulation results show that the absorptivity curve of the absorber does not change when the polarization angle of the light source is changed, and the overall performance is polarization insensitive.

Claims

1. A solar absorber based on a gold nanoarray, which is composed of gold nanounits arranged periodically in an XOY plane, and incident sunlight in the form of a plane wave, is characterized by: Each of the gold nanometer units comprises, from bottom to top, a base layer (1), a distributed Bragg reflector layer (2), a two-dimensional material layer (3), and an antenna layer (4); the distributed Bragg reflector layer (2) comprises five layers of distributed Bragg reflectors (DBRs); the projections of the base layer (1), the distributed Bragg reflector layer (2), and the two-dimensional material layer (3) on the XOY plane overlap and are square; the projection of the antenna layer (4) on the XOY plane is circular, and the square and the circle are concentric; The base layer (1) is made of Si material, the distributed Bragg reflector DBR is composed of an Al2O3 material layer (2-1) and a Si material layer (2-2) from bottom to top, the two-dimensional material layer (3) is a PtS2 two-dimensional material, and the antenna layer (4) is made of Au material; the size of the antenna layer (4) is a diameter of 0.08 μm×0.7 μm.

2. The solar absorber based on gold nanoarray according to claim 1, characterized in that: The size of the base layer (1) is 0.1 μm×0.1 μm×1 μm; the size of the Al2O3 material layer (2-1) is 0.1 μm×0.1 μm×0.09 μm, the size of the Si material layer (2-2) is 0.1 μm×0.1 μm×0.038 μm; the size of the two-dimensional material layer (3) is 0.1 μm×0.1 μm×0.65 nm.

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