A high-absorption ultra-wideband solar absorber

Abstract

This invention relates to the field of metal micro / nano optical device technology, and more particularly to a high-absorption ultra-wideband solar energy absorber, comprising several sets of nanocomposite structures, a titanium thin film, a one-dimensional PMMA grating structure, and a titanium substrate. The nanocomposite structures, titanium thin film, one-dimensional PMMA grating structure, and titanium substrate are arranged sequentially from top to bottom. By combining nanodisc structures and nanoelliptical disk structures, local surface plasmon resonance modes can be excited, thereby improving absorption in the short wavelength range. In addition, by introducing a one-dimensional PMMA grating structure, new and stronger local surface plasmon resonance modes can be excited at the one-dimensional PMMA grating structure, thereby improving absorption in the long wavelength range and achieving the effect of broadening the bandwidth.

Description

Technical Field

[0001] This invention relates to the field of metal micro-nano optical device technology, and in particular to a high-absorption ultra-wideband solar energy absorber. Background Technology

[0002] Broadband absorbers based on nanoscale structures have wide applications in research fields such as nanomaterials, nanophotonics, and energy utilization. Due to their light absorption over a wider wavelength range, they play a crucial role in various solar energy collection applications. A typical absorber employs a metal-dielectric-metal sandwich structure. The top layer consists of periodic metal micro / nanostructures based on various patterns, the middle layer is typically designed as a dielectric or insulating material of appropriate thickness, and the bottom layer is usually a metal material to prevent incident light transmission. By setting a suitable top-layer periodic metal micro / nanostructure and then adjusting appropriate structural parameters, localized surface plasmon resonance is achieved, thereby generating resonant absorption. This type of structure design can achieve good absorption at short wavelengths, but it also leads to limitations in its narrow bandwidth; its absorptivity and operating bandwidth still have considerable room for improvement.

[0003] Currently, most absorbers achieve high absorption by exciting localized surface plasmon resonance modes of periodic nanoparticles on a substrate. However, the high absorption band of this type of structure mainly operates in the wavelength range before 2500 nm. Although the solar energy radiation range is mainly concentrated before the wavelength of 2500 nm, the full solar spectrum range is 280–4000 nm, and there is also some solar energy in the 2500 nm–4000 nm range.

[0004] Therefore, in order to improve the absorption rate of the absorber and broaden its operating bandwidth to capture more solar energy, it is necessary to design a solar absorber with high absorption and wide bandwidth. Summary of the Invention

[0005] The purpose of this invention is to provide a high-absorption ultra-wideband solar energy absorber, which aims to solve the technical problems of low solar spectral weighted absorption efficiency and narrow absorption bandwidth in most existing solar energy absorbers.

[0006] To achieve the above objectives, the present invention provides a high-absorption ultra-wideband solar energy absorber, comprising several groups of nanocomposite structures, a titanium thin film, a one-dimensional PMMA grating structure, and a titanium substrate. The nanocomposite structures, the titanium thin film, the one-dimensional PMMA grating structure, and the titanium substrate are arranged sequentially from top to bottom. The several groups of nanocomposite structures are arranged in a periodic array along the horizontal direction, wherein the period in the X-axis direction is P1, the period in the Y-axis direction is P2, and the values ​​of P1 and P2 are both in the range of 450–550 nm.

[0007] Each group of nanocomposite structures includes two nanodisc structures and two nanoelliptical disk structures. The two nanodisc structures and the two nanoelliptical disk structures are arranged symmetrically about the central Z-axis of the nanocomposite structure. The projection of the nanodisc structure in the horizontal direction is circular, and the projection of the nanoelliptical disk structure in the horizontal direction is elliptical.

[0008] In the horizontal direction, the radius r of the nanodisc structure ranges from 50 to 100 nm, the distance d1 between the centers of the two circles ranges from 150 to 200 nm, the major semi-axis of the nanoelliptical disk structure is parallel to the X-axis, the major semi-axis a ranges from 50 to 120 nm, the minor semi-axis b ranges from 20 to 100 nm, and the distance d2 between the centers of symmetry of the two ellipses ranges from 200 to 250 nm.

[0009] In the vertical direction, the one-dimensional PMMA grating structure is disposed on the titanium substrate and is divided into two layers. The thickness of the first layer h1 ranges from 100 to 150 nm, and the thickness of the second layer h2 ranges from 50 to 100 nm. The titanium film covers the one-dimensional PMMA grating structure and has a thickness h3 range of 10 to 15 nm.

[0010] The width L of the first layer of the one-dimensional PMMA grating structure in the X-axis direction ranges from 100 to 200 nm, and the width in the Y-axis direction is consistent with the Y-axis period P2 of the nanocomposite structure. The size of the second layer of the one-dimensional PMMA grating structure is consistent with that of the nanocomposite structure.

[0011] In the vertical direction, both the nanodisc structure and the nanoelliptical disk structure have layers composed of different materials, and the thickness of the corresponding layers in the nanodisc structure and the nanoelliptical disk structure is consistent.

[0012] The nanodisc structure and the nanoelliptical disk structure have a total of four layers, arranged along the direction away from the titanium film. The thickness of the first layer, h4, ranges from 180 to 220 nm; the thickness of the second layer, h5, ranges from 35 to 45 nm; the thickness of the third layer, h6, ranges from 15 to 25 nm; and the thickness of the fourth layer is the same as that of the second layer.

[0013] This invention provides a high-absorption ultrawideband solar energy absorber, comprising several sets of nanocomposite structures, a titanium thin film, a one-dimensional PMMA grating structure, and a titanium substrate. The nanocomposite structures, titanium thin film, one-dimensional PMMA grating structure, and titanium substrate are arranged sequentially from top to bottom. By combining nanodisc structures and nanoelliptical disk structures, local surface plasmon resonance modes can be excited, thereby improving absorption in the short wavelength range. In addition, by introducing a one-dimensional PMMA grating structure, new and stronger local surface plasmon resonance modes can be excited at the one-dimensional PMMA grating structure, thereby improving absorption in the long wavelength range and achieving the effect of broadening the bandwidth. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a high-absorption ultra-wideband solar energy absorber according to the present invention.

[0016] Figure 2 This is a schematic diagram of the horizontal dimensions of a high-absorption ultra-wideband solar energy absorber according to the present invention.

[0017] Figure 3 This is a schematic diagram of the vertical dimensions of a high-absorption ultra-wideband solar energy absorber according to the present invention.

[0018] Figure 4 This is an absorption spectrum of a specific embodiment of the present invention.

[0019] 1-Nanocomposite structure, 11-Nano disk structure, 12-Nano elliptical disk structure, 2-Titanium thin film, 3-One-dimensional PMMA grating structure, 4-Titanium substrate. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] Please see Figures 1 to 3This invention proposes a high-absorption ultra-wideband solar energy absorber, comprising several groups of nanocomposite structures 1, titanium thin films 2, one-dimensional PMMA grating structures 3, and titanium substrates 4. The nanocomposite structures 1, titanium thin films 2, one-dimensional PMMA grating structures 3, and titanium substrates 4 are arranged sequentially from top to bottom. The several groups of nanocomposite structures 1 are arranged in a periodic array along the horizontal direction, wherein the period in the X-axis direction is P1, the period in the Y-axis direction is P2, and the values ​​of P1 and P2 are both in the range of 450 to 550 nm.

[0022] Each group of nanocomposite structures 1 includes two nanodisc structures 11 and two nanoelliptical disk structures 12. The two nanodisc structures 11 and the two nanoelliptical disk structures 12 are arranged symmetrically about the central Z-axis of the nanocomposite structure 1. The projection of the nanodisc structure 11 along the horizontal direction is circular, and the projection of the nanoelliptical disk structure 12 along the horizontal direction is elliptical.

[0023] In the horizontal direction, the radius r of the nanodisc structure 11 ranges from 50 to 100 nm, the distance d1 between the centers of the two circles ranges from 150 to 200 nm, the major semi-axis of the nanoelliptical disk structure 12 is parallel to the X-axis, the major semi-axis a ranges from 50 to 120 nm, the minor semi-axis b ranges from 20 to 100 nm, and the distance d2 between the centers of symmetry of the two ellipses ranges from 200 to 250 nm.

[0024] In the vertical direction, the one-dimensional PMMA grating structure 3 is disposed on the titanium substrate 4 and is divided into two layers. The thickness of the first layer h1 ranges from 100 to 150 nm, and the thickness of the second layer h2 ranges from 50 to 100 nm. The titanium film 2 covers the one-dimensional PMMA grating structure 3 and has a thickness h3 range of 10 to 15 nm.

[0025] The width L of the first layer of the one-dimensional PMMA grating structure 3 in the X-axis direction ranges from 100 to 200 nm, and the width in the Y-axis direction is consistent with the Y-axis period P2 of the nanocomposite structure 1. The second layer of the one-dimensional PMMA grating structure 3 is consistent with the size of the nanocomposite structure 1.

[0026] In the vertical direction, both the nanodisc structure 11 and the nanoelliptical disk structure 12 are provided with layers composed of different materials, and the thickness of the corresponding layers of the nanodisc structure 11 and the nanoelliptical disk structure 12 is consistent.

[0027] Specifically, the first layer is titanium (Ti), the second layer is aluminum oxide (Al2O3), the third layer is titanium (Ti), and the fourth layer is aluminum oxide (Al2O3).

[0028] The nanodisc structure 11 and the nanoelliptical disk structure 12 have a total of four layers, arranged along the direction away from the titanium thin film 2. The thickness h4 of the first layer ranges from 180 to 220 nm, the thickness h5 of the second layer ranges from 35 to 45 nm, the thickness h6 of the third layer ranges from 15 to 25 nm, and the thickness of the fourth layer is the same as that of the second layer.

[0029] In this embodiment, the design of the nanodisc structure 11 and the nanoelliptical disk structure 12 can excite local surface plasmon resonance modes, thereby improving absorption in the short wavelength range. In addition, based on the periodic nanocomposite structure, a one-dimensional PMMA grating structure 3 is introduced, and a new and stronger local surface plasmon resonance mode can be excited at the one-dimensional PMMA grating structure 3, thereby improving absorption in the long wavelength range and achieving the effect of broadening the bandwidth.

[0030] This invention also provides a specific embodiment and simulation experiments for illustration:

[0031] The incident light source is a TM-polarized plane wave, perpendicularly incident on the surface of the periodic nanocomposite structure 1. Periodic boundary conditions are applied in the x and y directions; a perfectly matched layer (PML) boundary condition is applied in the z direction. Specifically, the transverse period of nanocomposite structure 1 is P1 = 480 nm, and the longitudinal period is P2 = 500 nm. The thicknesses of the first layer of nanodisk structure 11 and nanoelliptical disk structure 12 are h4 = 200 nm, h5 = 40 nm, h6 = 20 nm, and the fourth layer has the same thickness as the second layer. The radius of the periodic nanodisk structure 11 is r = 75 nm, the distance between the centers of the two nanodisks is d1 = 190 nm, the semi-major axis of the nanoelliptical disk structure 12 is a = 100 nm, the semi-minor axis is b = 40 nm, and the distance between the centers of symmetry of the two nanoelliptical disk structures is d2 = 240 nm. The thickness of the metal thin film between the periodic nanodisk particles and the grating is h3 = 10 nm. The first layer of the one-dimensional PMMA grating structure 3 has a thickness h1 = 120 nm and a lateral width L = 160 nm, while the second layer has a thickness h2 = 70 nm. The materials chosen for the nanodisk structure 11 and the nanoelliptical disk structure 12 are as follows: the first layer is titanium (Ti), the second layer is aluminum oxide (Al2O3), the third layer is titanium (Ti), and the fourth layer is aluminum oxide (Al2O3). The filling material for the one-dimensional PMMA grating structure 3 is polymethyl methacrylate (PMMA), the substrate material is titanium, and the thin film material between the one-dimensional PMMA grating structure 3 and the nanodisk particles is titanium. The dielectric constants of titanium and aluminum oxide are determined using the model in the Palik handbook, and the refractive index of PMMA is a constant 1.47.

[0032] In this practical example, a substrate is first prepared using PECVD deposition technology; then, a one-dimensional PMMA grating structure 3 is prepared on a titanium substrate 4 using photolithography, and the PMMA material is filled by spin coating to prepare the one-dimensional PMMA grating structure 3; then, a titanium thin film 2 is prepared using PECVD deposition technology; then, a four-layer thin film structure of titanium (Ti)-aluminum oxide (Al2O3)-titanium (Ti)-aluminum oxide (Al2O3) is prepared using PECVD deposition technology, and then periodic nanoelliptical disk structure 12 and periodic nanodisk structure 11 are prepared using photolithography and etching technology.

[0033] Based on the absorption spectrum obtained from numerical simulation, such as Figure 4 As shown, this invention yielded two absorption peaks at wavelengths of 434 nm and 631 nm, both with absorbance exceeding 99%. The average absorbance in the 300–4000 nm wavelength range can be calculated to be 94.10%, and the solar spectral weighted absorption efficiency is 98.35%.

[0034] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A high-absorption ultra-wideband solar absorber, characterized in that, comprising a plurality of groups of nano-composite structures, a metal titanium film, a one-dimensional PMMA grating structure and a metal titanium substrate, the nano-composite structures, the metal titanium film, the one-dimensional PMMA grating structure and the metal titanium substrate are sequentially arranged from top to bottom, and the plurality of groups of nano-composite structures are arranged in a periodic array along the horizontal direction, wherein the period in the X-axis direction is P1 and the period in the Y-axis direction is P2, and the values of P1 and P2 are both in the range of 450-550 nm; each group of nano-composite structures comprises two nano-disc structures and two nano-elliptical disc structures, the two nano-disc structures and the two nano-elliptical disc structures are symmetrically arranged with the center Z-axis of the nano-composite structure as the axis, the projection of the nano-disc structure along the horizontal direction is circular, and the projection of the nano-elliptical disc structure along the horizontal direction is elliptical. In the vertical direction, the one-dimensional PMMA grating structure is arranged on the metal titanium substrate and is divided into two layers, the thickness h1 of the first layer is in the range of 100-150 nm, the thickness h2 of the second layer is in the range of 50-100 nm, the metal titanium film is arranged above the one-dimensional PMMA grating structure, the thickness h3 of the metal titanium film is in the range of 10-15 nm, and the refractive index of PMMA is a constant value of 1.

47. 2.The high-absorption ultra-wideband solar absorber of claim 1, characterized in that, in the horizontal direction, the radius r of the circular nano-disc structure is in the range of 50-100 nm, the distance d1 between the centers of the two circles is in the range of 150-200 nm, the long semi-axis a of the nano-elliptical disc structure is in the range of 50-120 nm, the short semi-axis b is in the range of 20-100 nm, and the distance d2 between the centers of the two elliptical discs is in the range of 200-250 nm. 3.The high-absorption ultra-wideband solar absorber of claim 2, characterized in that, the width L of the first layer of the one-dimensional PMMA grating structure in the X-axis direction is in the range of 100-200 nm, the width in the Y-axis direction is consistent with the Y-axis period P2 of the nano-composite structure, and the second layer of the one-dimensional PMMA grating structure is consistent with the size of the nano-composite structure. 4.The high-absorption ultra-wideband solar absorber of claim 3, characterized in that, in the vertical direction, the nano-disc structure and the nano-elliptical disc structure are both provided with a layered structure composed of different materials, and the thickness of the corresponding layered structures of the nano-disc structure and the nano-elliptical disc structure is consistent. 5.The high-absorption ultra-wideband solar absorber of claim 4, characterized in that, the layered structures of the nano-disc structure and the nano-elliptical disc structure have four layers, which are arranged away from the metal titanium film, the thickness h4 of the first layer is in the range of 180-220 nm, the thickness h5 of the second layer is in the range of 35-45 nm, the thickness h6 of the third layer is in the range of 15-25 nm, and the thickness of the fourth layer is the same as the thickness h5 of the second layer.

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