A transferable visible-near infrared light absorber and a method for preparing the same

Abstract

The application provides a transferable visible-near-infrared light absorber and a preparation method thereof. The visible-near-infrared light absorber comprises, from bottom to top, a packaging layer, a substrate layer, a high-loss metal layer and a transfer layer; the substrate layer comprises a periodic array of single-layer microspheres, and the microspheres comprise at least one of polystyrene microspheres and silica microspheres; the substrate layer is prepared by colloidal self-assembly; the high-loss metal layer comprises a periodic array of high-loss metal columns, and the high-loss metal columns comprise at least one of chromium metal columns, titanium metal columns, tungsten metal columns, nickel metal columns, gold metal columns or silver metal columns; and the high-loss metal layer is obtained by magnetron direct-current sputtering of high-loss metal on the substrate layer. The visible-near-infrared light absorber can be prepared in a large area and quickly by colloidal self-assembly and magnetron direct-current sputtering, efficient absorption of light is realized in the frequency band of visible light-near-infrared light, and the absorber is transferred and packaged, so that the double-sided absorption performance can be applied.

Description

Technical Field

[0001] This invention belongs to the field of optical device technology, specifically relating to a transferable visible-near-infrared light absorber and its fabrication method. Background Technology

[0002] The sun's energy at the Earth's surface is primarily concentrated in the visible-near-infrared band. Therefore, electromagnetic absorbers with high absorption rates in this band can effectively absorb solar energy, playing a crucial role in solar photovoltaics, photoelectric detection, and stray light elimination. The physical properties of natural solid materials are mainly determined by the arrangement of their atoms and molecules, resulting in limited properties and making it difficult to efficiently absorb electromagnetic waves of arbitrary wavelengths. Metamaterials, on the other hand, are artificially processed composite materials with periodic or quasi-periodic structures. Their physical properties can be customized by designing the period, arrangement, and unit cell size of the structure. By adjusting the response between the structure and electromagnetic waves, metamaterials can achieve arbitrary control over electromagnetic waves, making them a promising candidate material for electromagnetic absorbers.

[0003] With the development of micro- and nano-fabrication technologies, metamaterial absorbers have made rapid progress in both absorption band and absorption bandwidth: the absorption band has expanded from the original microwave band to high-frequency bands such as the near-infrared band and the visible light band; the absorption band has evolved from the original single-band narrowband absorption to multi-band absorption and broadband absorption. By designing micro- and nano-structural units of metamaterial absorbers, efficient absorption of electromagnetic waves of any band can be achieved. Several types of metamaterial absorbers have been proposed for absorbing electromagnetic waves in the visible-near-infrared band, such as metamaterial absorbers with periodic nanodisc arrays (International Journal of Heat and Mass Transfer, Vol. 182, p. 122039) and metamaterial absorbers with periodic nanosquare disk arrays (Nanophotonics, Vol. 12, p. 2461). However, the fabrication of these metamaterial absorbers' micro / nano arrays is complex, typically relying on expensive top-down techniques such as focused ion beam, electron beam lithography, or high-resolution lithography. Furthermore, the substrate layer needs to be placed on a glass substrate, making it difficult to peel the substrate layer off. This inherently limits production area and device flexibility. The low yield and poor flexibility of the precise micro / nano structures of metamaterial absorbers restrict their production and application. Therefore, designing a visible-near-infrared metamaterial absorber that can be fabricated on a large area and flexibly transferred is of great practical significance and application value in solving the problems of high fabrication cost and difficult transfer and application of metamaterial absorbers. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a transferable visible-near-infrared light absorber that can be rapidly fabricated over a large area through colloidal self-assembly and magnetron DC sputtering. Thanks to the simple and separate structural units of the substrate layer and high-loss metal layer in the visible-near-infrared light absorber, the substrate layer and high-loss metal layer can be transferred using a transfer layer, making the visible-near-infrared light absorber easy to transfer. This allows the double-sided absorption performance of the visible-near-infrared light absorber to be used in various application scenarios, achieving broadband high absorption of light in the visible-near-infrared light band.

[0005] This invention is achieved through the following technical solution:

[0006] A transferable visible-near-infrared light absorber includes, from bottom to top, an encapsulation layer, a substrate layer, a high-loss metal layer, and a transfer layer. The substrate layer comprises a periodically arranged monolayer microsphere array, which includes at least one of polystyrene microspheres and silica microspheres. The monolayer microsphere array is prepared by a colloidal self-assembly method, and there are gaps between the microspheres in the monolayer microsphere array. The high-loss metal layer comprises periodically arranged high-loss metal pillars, which include at least one of chromium, titanium, tungsten, nickel, gold, or silver pillars. The high-loss metal layer is obtained by magnetron DC sputtering of a high-loss metal onto the substrate layer. The transfer layer is attached to the side of the high-loss metal layer facing away from the substrate layer. The encapsulation layer is attached to one side of the substrate layer.

[0007] This invention provides a transferable visible-near-infrared (VNIIR) light absorber. A periodically arranged substrate layer is formed through colloidal self-assembly. High-loss metal pillars are then formed on the substrate layer using magnetron DC sputtering, enabling the fabrication of a large-area VNIIR light absorber. A transfer layer is attached to the high-loss metal layer, allowing the substrate layer and high-loss metal pillars to be transferred. An encapsulation layer is attached to one side of the substrate layer for device protection. The low-refractive-index substrate layer allows incident light to generate plasmon resonances and magnetic polarons with the periodic metal dome structure on the front side and the periodic metal bowl structure on the back side of the high-loss metal layer, respectively, enabling the high-loss metal layer to absorb visible and near-infrared light from both sides. The VNIIR light absorber provided by this invention achieves rapid, large-area fabrication through colloidal self-assembly and magnetron DC sputtering, achieving broadband high absorption of light in the visible-near-infrared frequency band. The absorber can be transferred and encapsulated using the transfer and encapsulation layers, allowing its double-sided absorption to be used in various applications.

[0008] Furthermore, the microspheres in the monolayer microsphere array are polystyrene microspheres, and the substrate layer is prepared by gas-liquid interface colloidal self-assembly.

[0009] Furthermore, the microspheres in the monolayer microsphere array are silica microspheres, and the substrate layer is prepared by spin coating.

[0010] Furthermore, in the monolayer microsphere array, each microsphere has a diameter of 400-600 nm. Controlling the diameter of the microspheres controls the size of the high-loss metal layer, thereby achieving efficient light absorption in the visible-near-infrared frequency band.

[0011] Furthermore, the period of the monolayer microsphere array is 405-640 nm, wherein the period of the monolayer microsphere array is larger than the diameter of the microspheres. The larger period of the monolayer microsphere array than the diameter of the microspheres indicates a non-dense distribution between the microspheres, which is beneficial for utilizing the gaps between the microspheres to form high-loss metal pillar units with gaps, thereby improving the absorption rate of incident light.

[0012] Furthermore, the height of the high-loss metal pillars is 300-700 nm. This height is limited to achieve efficient light absorption in the visible-near-infrared frequency band. The high-loss metal pillars are obtained by magnetron DC sputtering using a substrate as a template. Each high-loss metal pillar is located on a microsphere. Due to the gaps between the microspheres in the substrate, a non-dense distribution of high-loss metal pillars is formed, which is beneficial for utilizing the gaps between the high-loss metal pillars to improve the absorption rate of incident light.

[0013] Furthermore, the transfer layer is a PET tape layer. The transfer layer is used to adhere to the high-loss metal pillar, thereby transferring the visible-near-infrared light absorber. The PET tape has excellent properties such as good adhesion, acid and alkali resistance, and high temperature resistance, serving as an encapsulation and protection element. Simultaneously, using low-refractive-index PET tape in the transfer layer facilitates achieving the double-sided absorption performance of the visible-near-infrared light absorber.

[0014] Furthermore, the encapsulation layer is a PET tape layer. The encapsulation layer is used to adhere to the base layer. PET tape has excellent properties such as good adhesion, acid and alkali resistance, and high temperature resistance. The PET tape, in conjunction with the transfer layer, encapsulates the absorber, preventing direct contact between the visible-near-infrared light absorber and the external environment, thus playing a role in transferring, encapsulating, and protecting the absorber. Simultaneously, using low-refractive-index PET tape in the encapsulation layer helps achieve the double-sided absorption performance of the visible-near-infrared light absorber.

[0015] This invention also provides a method for preparing the above-mentioned transferable visible-near-infrared absorber, comprising the following steps: preparing a periodically arranged monolayer microsphere array using a colloidal self-assembly method, such that there are gaps between the microspheres in the monolayer microsphere array to obtain a substrate layer; preparing a high-loss metal layer on the substrate layer by magnetron DC sputtering; attaching a transfer layer to the side of the high-loss metal layer opposite to the substrate layer; and attaching an encapsulation layer to the side of the substrate layer opposite to the high-loss metal layer to obtain the visible-near-infrared absorber.

[0016] The method for preparing a transferable visible-near-infrared absorber provided by this invention utilizes a colloidal self-assembly method to form a periodic monolayer microsphere array as a substrate layer. A columnar high-loss metal layer is formed on the substrate layer by magnetron DC sputtering, thereby achieving large-scale and rapid preparation of the visible-near-infrared absorber. The transfer layer is then attached to the high-loss metal layer to achieve the transfer of the visible-near-infrared absorber. Finally, an encapsulation layer is used in conjunction with the transfer layer to encapsulate the substrate layer and the high-loss metal layer.

[0017] Furthermore, in the step of preparing the substrate layer using the colloidal self-assembly method, a monolayer microsphere array is prepared by the gas-liquid interface colloidal self-assembly method or spin coating method; the monolayer microsphere array is transferred and dried to obtain the substrate layer; in the step of preparing a high-loss metal layer on the substrate layer by magnetron sputtering, the monolayer microsphere array is placed in a high-vacuum three-target magnetron sputtering coating machine and aligned with a high-loss metal target. Argon gas is pumped into the chamber, and the high-loss metal target is sputtered by DC radio frequency to form periodic high-loss metal pillars on the monolayer microsphere array.

[0018] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a structural model diagram of the visible-near-infrared light absorber in Example 2.

[0020] Figure 2 This is a simulated absorption spectrum of the visible-near-infrared light absorber in Example 2.

[0021] Figure 3 This is the absorption spectrum of the visible-near-infrared light absorber in Example 2.

[0022] Figure 4 This is a schematic diagram of the experimental procedure for the visible-near-infrared light absorber in Example 9.

[0023] Figure 5 This is a flowchart illustrating the fabrication process of the visible-near-infrared light absorber in Example 9.

[0024] Figure 6 This is a scanning electron microscope image of the chromium metal column from Example 10. Detailed Implementation

[0025] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the embodiments of the present invention, and not all structures.

[0026] Similarly, the terms "fixed" and "connected" are used in the specification and claims and should not be construed as limited to a direct connection. Therefore, the expression "device A is connected to device B" should not be limited to device A being directly connected to device B in a device or system; it means that there is a path between device A and device B, which can be a path that includes other devices or tools.

[0027] Example 1

[0028] This embodiment provides a transferable visible-near infrared light absorber, which includes an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2 and a transfer layer 3 arranged sequentially from bottom to top;

[0029] The substrate layer 1 includes a periodically arranged monolayer microsphere array, which includes at least one of polystyrene microspheres and silica microspheres; wherein the monolayer microsphere array is prepared by a colloidal self-assembly method, and there are gaps between the microspheres in the monolayer microsphere array;

[0030] The high-loss metal layer 2 includes periodically arranged high-loss metal pillars, which include at least one of chromium metal pillars, titanium metal pillars, tungsten metal pillars, nickel metal pillars, gold metal pillars, or silver metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1.

[0031] The transfer layer 3 is attached to the side of the high-loss metal layer 2 that is away from the substrate layer 1.

[0032] The encapsulation layer 4 is attached to the side of the substrate layer 1 that faces away from the high-loss metal layer 2.

[0033] In the transferable visible-near-infrared light absorber provided in this embodiment, a periodically arranged substrate layer 1 is formed through colloidal self-assembly. High-loss metal pillars are then formed on the substrate layer 1 by magnetron DC sputtering, achieving the fabrication of a large-area visible-near-infrared light absorber. A transfer layer 3 is attached to the high-loss metal layer 2, allowing the substrate layer 1 and the high-loss metal pillars to be transferred. The low-refractive-index substrate layer 1 allows incident light to generate plasmon resonances and magnetic polarons with the periodic metal dome structure on the front side and the periodic metal bowl structure on the back side of the high-loss metal layer, respectively, enabling absorption of visible and near-infrared light from both sides. The visible-near-infrared light absorber provided in this embodiment is rapidly fabricated over a large area using colloidal self-assembly and magnetron DC sputtering. The light-absorbing part of the absorber consists of a substrate layer 1 with a period of P and a high-loss metal pillar layer 2, achieving broadband high absorption of light in the visible-near-infrared frequency band, giving the absorber excellent double-sided absorption performance. Furthermore, the transfer layer 3 and the encapsulation layer 4 enable flexible transfer and encapsulation of the visible-near-infrared light absorber.

[0034] Compared with existing technologies, the transferable visible-near-infrared light absorber provided by this invention utilizes colloidal self-assembly to prepare a substrate layer 1, and then prepares a high-loss metal pillar layer 2 on the substrate layer 1 by magnetron DC sputtering, forming a bottom-up visible-near-infrared light absorber. Since colloidal self-assembly and magnetron sputtering have the advantages of high yield and low cost, the visible-near-infrared light absorber can overcome the difficulties of low yield and high cost faced by most current metamaterial absorbers. This visible-near-infrared light absorber can also be flexibly transferred and encapsulated by a transfer layer 3 and an encapsulation layer 4, improving the flexibility and stability of the device.

[0035] In this embodiment, the microspheres in the monolayer microsphere array are polystyrene microspheres, and the substrate layer is prepared by gas-liquid interface colloidal self-assembly. The gas-liquid interface colloidal self-assembly is used to prepare periodically arranged monolayer polystyrene microspheres with certain gaps between them, so as to form gaps between the high-loss metal pillars disposed on the polystyrene microspheres, thereby enhancing the absorption of incident light.

[0036] In another embodiment, the microspheres in the monolayer microsphere array are silica microspheres, and the substrate layer is prepared by spin coating. The spin coating method is used to prepare periodically arranged monolayer silica microspheres with certain gaps between them, so as to form gaps between the high-loss metal pillars disposed on the silica microspheres, thereby enhancing the absorption of incident light.

[0037] In this embodiment, in the monolayer microsphere array, the diameter D of each microsphere is 400-600 nm. Controlling the diameter D of the microspheres controls the size L of the high-loss metal layer, thereby achieving efficient absorption of light in the visible-near-infrared frequency band.

[0038] In this embodiment, the period P of the monolayer microsphere array is 405-640 nm, wherein the period P of the monolayer microsphere array is greater than the diameter D of the microspheres. The period P of the monolayer microsphere array being greater than the diameter D indicates that the microspheres are not densely distributed, which is beneficial for forming high-loss metal pillar units with gaps, thereby improving the light absorption rate by utilizing the gaps between the microspheres.

[0039] In this embodiment, the height H of the high-loss metal pillars is 300-700 nm. Limiting the height H of the high-loss metal pillars enables efficient absorption of light in the visible-near-infrared frequency band. Since the high-loss metal pillar layer 2 is obtained by magnetron DC sputtering using the substrate layer 1 as a template, the high-loss metal pillars are located on each microsphere. Due to the gaps between the microspheres in the substrate layer 1, a non-densely distributed high-loss metal pillar layer 2 is formed, which is beneficial for utilizing the gaps between the high-loss metal pillars to improve the absorption rate of incident light.

[0040] In this embodiment, transfer layer 3 is a PET tape layer used to adhere to the high-loss metal pillar layer 2, thereby transferring the visible-near-infrared light absorber. PET tape possesses excellent properties such as good adhesion, acid and alkali resistance, and high temperature resistance, serving as an encapsulation and protection element. Simultaneously, using low-refractive-index PET tape in transfer layer 3 facilitates achieving the double-sided absorption performance of the visible-near-infrared light absorber.

[0041] In this embodiment, the visible-near-infrared light absorber also includes an encapsulation layer 4, which is disposed on the base layer 1. The PET tape has excellent properties such as good adhesion, acid and alkali resistance, and high temperature resistance. The PET tape works in conjunction with the transfer layer 3 to encapsulate the absorber, preventing direct contact between the visible-near-infrared light absorber and the external environment, thus playing a role in transferring, encapsulating, and protecting the absorber. Simultaneously, the use of low-refractive-index PET tape in the encapsulation layer 4 facilitates the achievement of double-sided absorption performance of the visible-near-infrared light absorber.

[0042] Example 2

[0043] This embodiment provides a transferable visible-near-infrared light absorber, comprising an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3 arranged sequentially from bottom to top; the substrate layer 1 includes a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is polystyrene microspheres; the substrate layer 1 is prepared by gas-liquid interface colloidal self-assembly;

[0044] The high-loss metal layer 2 includes periodically arranged high-loss metal pillars, which include chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1.

[0045] The transfer layer 3 is PET tape, which is adhered to the side of the high-loss metal layer 2 that is away from the base layer 1.

[0046] The encapsulation layer 4 is PET tape, which is attached to the side of the base layer 1 that is away from the high-loss metal layer 2.

[0047] In this embodiment, low-refractive-index polystyrene microspheres facilitate the achievement of double-sided absorption in the visible-near-infrared light absorber. Furthermore, they exhibit excellent single-sidedness during the gas-liquid interface colloidal self-assembly process, allowing for single-sided arrangement of polystyrene microspheres, which is beneficial for large-scale rapid production. The polystyrene microspheres possess good heat resistance, the chromium metal pillars have a high extinction coefficient and melting point, and the selected PET tape has advantages such as low refractive index, high transparency, good adhesion, and good heat resistance. Both the encapsulation layer 4 and the transfer layer 3 are PET tapes; the low-refractive-index PET tape is beneficial for achieving double-sided absorption of visible-near-infrared light. The visible-near-infrared light absorber provided in this embodiment is easy to prepare, easy to transfer, and has good heat resistance.

[0048] In this embodiment, the diameter D of the polystyrene microspheres is 500 nm, and the period P of the polystyrene monolayer microsphere array is 520 nm. The polystyrene monolayer microsphere array prepared by gas-liquid interface colloidal self-assembly is non-densely distributed, with gaps between the polystyrene microspheres. This allows for the formation of a non-dense, high-loss metal layer 2 via magnetron DC sputtering, thereby improving the light absorption rate.

[0049] In this embodiment, the height H of the high-loss metal pillars is 500 nm, and the side length L is 290 nm. The high-loss metal pillars are obtained by magnetron DC sputtering, forming periodically arranged hexagonal columnar chromium metal pillars. The high-loss metal pillars are non-densely distributed, which is beneficial for improving the light absorption rate by utilizing the gaps between the high-loss metal pillars.

[0050] Figure 1 This is a structural model diagram of a visible-near-infrared light absorber. Figure 2 This is a simulated absorption spectrum of a visible-near-infrared absorber. Please refer to [link / reference]. Figure 1-2 In the visible-near-infrared light absorber provided in this embodiment, light in the visible-near-infrared range is incident sequentially towards the chromium metal pillar (i.e., the front direction of the visible-near-infrared light absorber) and towards the substrate 1 (i.e., the back direction of the visible-near-infrared light absorber). In the 400-2500nm wavelength band, the simulated average absorption rates of the visible-near-infrared light absorber on the front and back sides are 89% and 91%, respectively.

[0051] The reflectance spectrum of the front side and the transmission spectrum of the back side of the visible-near-infrared absorber were measured using a spectrophotometer. The absorption spectrum was obtained according to A = 1 - TR. Figure 3 This is an absorption spectrum; please refer to [link / reference]. Figure 3 In the 400-2500nm wavelength range, the average absorption rates of the front and back sides of the visible-near-infrared light absorber reached 84% and 91%, respectively, achieving efficient absorption of visible-near-infrared electromagnetic waves.

[0052] Example 3

[0053] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is silica microspheres; the substrate layer 1 is prepared by spin coating; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, including chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1; the transfer layer 3 is attached to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer 4 is attached to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0054] In this embodiment, the diameter D of the silica microspheres is 400 nm and the period P is 405 nm.

[0055] In this embodiment, the height H of the chromium metal column is 300 nm and the side length L is 220 nm.

[0056] Example 4

[0057] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is silica microspheres; the substrate layer 1 is prepared by spin coating; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, including chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal onto the substrate layer 1; the transfer layer 3 is PET tape, adhered to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer 4 is PET tape, adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0058] In this embodiment, the diameter D of the silica microspheres is 400 nm and the period P is 420 nm.

[0059] In this embodiment, the height H of the chromium metal column is 300 nm and the side length L is 220 nm.

[0060] Example 5

[0061] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is polystyrene microspheres; the substrate layer 1 is prepared by gas-liquid interface colloidal self-assembly; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, including chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1; the transfer layer 3 is PET tape, adhered to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer is PET tape, adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0062] In this embodiment, the polystyrene microspheres have a diameter D of 600 nm and a period P of 640 nm.

[0063] In this embodiment, the height H of the chromium metal column is 700 nm and the side length L is 340 nm.

[0064] Example 6

[0065] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer 4, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is polystyrene microspheres; the substrate layer 1 is prepared by gas-liquid interface colloidal self-assembly; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, wherein the high-loss metal pillars are tungsten metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1; the transfer layer 3 is PET tape, which is adhered to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer is PET tape, which is adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0066] In this embodiment, the polystyrene microspheres have a diameter D of 600 nm and a period P of 620 nm.

[0067] In this embodiment, the height H of the tungsten metal column is 700 nm and the side length L is 360 nm.

[0068] Example 7

[0069] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is polystyrene microspheres; the substrate layer 1 is prepared by gas-liquid interface colloidal self-assembly; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, including chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1; the transfer layer 3 is PET tape, adhered to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer is PET tape, adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0070] In this embodiment, the polystyrene microspheres have a diameter D of 500 nm and a single-layer microsphere array period PP of 530 nm.

[0071] In this embodiment, the height H of the chromium metal column is 700 nm and the side length L is 300 nm.

[0072] Example 8

[0073] This embodiment provides a transferable visible-near-infrared light absorber, comprising, from bottom to top, an encapsulation layer, a substrate layer 1, a high-loss metal layer 2, and a transfer layer 3; the substrate layer 1 comprises a periodically arranged monolayer microsphere array, wherein the monolayer microsphere array is polystyrene microspheres; the substrate layer 1 is prepared by gas-liquid interface colloidal self-assembly; the high-loss metal layer 2 comprises periodically arranged high-loss metal pillars, including chromium metal pillars; the high-loss metal layer 2 is obtained by magnetron DC sputtering of high-loss metal on the substrate layer 1; the transfer layer 3 is PET tape, adhered to the side of the high-loss metal layer 2 facing away from the substrate layer 1; the encapsulation layer is PET tape, adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0074] In this embodiment, the polystyrene microspheres have a diameter D of 500 nm and a single-layer microsphere array period PP of 510 nm.

[0075] In this embodiment, the height H of the chromium metal column is 700 nm and the side length L is 280 nm.

[0076] Example 9

[0077] This embodiment provides a method for preparing the transferable visible-near-infrared light absorber of Example 1. Figure 4 This is a schematic diagram of the experimental procedure for a visible-near-infrared light absorber. Figure 5 This is a flowchart of the fabrication process for a visible-near-infrared light absorber. Please refer to [link / reference]. Figure 4-5 The method for preparing a visible-near-infrared light absorber includes the following steps:

[0078] Step S1: A monolayer microsphere array with a period of P is formed using a colloidal self-assembly method as the substrate layer 1. Specifically, the monolayer microsphere array is prepared using a gas-liquid interface colloidal self-assembly method or spin coating; the monolayer microsphere array is then transferred and dried to obtain the substrate layer 1.

[0079] Step S2: A high-loss metal layer 2 is prepared on the substrate layer 1 by magnetron sputtering. Specifically, the monolayer microsphere array is placed in a high-vacuum three-target magnetron sputtering coating machine and aligned with a high-loss metal target. Argon gas is pumped into the chamber, and the high-loss metal target is sputtered by DC radio frequency to form a high-loss metal column with a period of P on the monolayer microsphere array.

[0080] Step S3: Adhere the transfer layer 3 to the side of the high-loss metal layer 2 facing away from the substrate layer 1. Specifically, use PET tape as the transfer layer 3 and adhere it to the side of the high-loss metal layer 2 facing away from the substrate layer 1 to achieve the transfer.

[0081] Step S4: Adhere the encapsulation layer 4 to the side of the substrate layer 1 facing away from the high-loss metal layer 2 to complete the encapsulation, resulting in a visible-near-infrared light absorber that is easy to transfer and can absorb light from both sides. Specifically, PET tape is used as the encapsulation layer 4 and adhered to the side of the substrate layer 1 facing away from the high-loss metal layer 2.

[0082] Before fabricating the visible-near-infrared light absorber, a model diagram of the metamaterial absorber can be constructed using the finite-difference time-domain method (FDTD). The simulated absorption spectrum of the metamaterial absorber can be calculated, and the parameters can be optimized through simulation. Finally, the parameters such as the period P of the substrate layer 1, the diameter D of the microspheres, and the height H of the high-loss metal column can be determined.

[0083] Example 10

[0084] This embodiment provides a method for preparing the transferable visible-near-infrared light absorber of Example 2, comprising the following steps:

[0085] Step S1: A single-layer microsphere array with a period of P is formed using the gas-liquid interface colloidal self-assembly method as the substrate layer 1.

[0086] Specifically, 400 mL of deionized water was placed in a glass container, and 20 μL of 10 wt% SDS (sodium dodecyl sulfate) solution was added dropwise to reduce the surface tension gradient of the liquid; a glass plate was placed at an angle at the gas-liquid interface; a polystyrene microsphere solution with a mass fraction of 5 wt% and a single particle diameter D of 500 nm was selected, and the polystyrene microsphere solution and anhydrous ethanol were mixed at a volume ratio of 1:2 to obtain a mixed microsphere solution;

[0087] A mixed microsphere solution was slowly injected into the gas-liquid interface of a glass plate using a point injection method. The polystyrene microspheres self-assembled at the gas-liquid interface to form a large-area, monolayer, ordered array with a period of P. The polystyrene monolayer microsphere array was then transferred using a 3cm × 3cm square silicon wafer and allowed to air dry naturally at room temperature.

[0088] Step S2: A high-loss metal layer 2 is prepared on the substrate layer 1 by magnetron sputtering.

[0089] Specifically, the prepared polystyrene monolayer microsphere array was placed as a template into a high-vacuum three-target magnetron sputtering coating machine and aligned with a metallic chromium target. Argon gas was pumped into the chamber, and the sputtering mode was set to DC radio frequency. Metallic chromium was sputtered onto the polystyrene monolayer microsphere array. The chamber vacuum level was 7 × 10⁻⁶. -2 Pa, argon flow rate is 20 cm⁻¹ 3 The sputtering rate was approximately 8.3 nm / min, with a sputtering power of 50 W. Sputtering at these parameters for 60 min resulted in the formation of 500 nm high chromium pillars on a polystyrene monolayer microsphere array. Figure 6 This is a scanning electron microscope image of a chromium metal column. Please refer to [link / reference]. Figure 6 Chromium metal pillars were formed on substrate 1 by magnetron DC sputtering. The periodicity of the chromium metal pillars was well maintained, and the actual parameters were consistent with the simulation parameters.

[0090] When preparing polystyrene microsphere solutions, a solution of a certain concentration can be prepared according to the selected polystyrene microsphere diameter D to form a monolayer polystyrene microsphere array with a suitable period P. If the polystyrene solution concentration is too low, it will be difficult to form a periodically arranged microsphere array; if the polystyrene solution concentration is too high, it may cause the polystyrene microspheres to accumulate, forming a multilayer disordered structure.

[0091] Step S3: Adhere the transfer layer 3 to the side of the high-loss metal layer 2 that is away from the substrate layer 1. Specifically, use PET tape as the transfer layer 3 and adhere it to the side of the high-loss metal layer 2 that is away from the substrate layer 1 to achieve the transfer.

[0092] Step S4: Adhere the encapsulation layer 4 to the side of the base layer 1 facing away from the high-loss metal layer 2. Specifically, use PET tape as the encapsulation layer 4 and adhere it to the side of the base layer 1 facing away from the high-loss metal layer 2 to complete the encapsulation, thus obtaining a visible-near-infrared light absorber that is easy to transfer and can absorb light from both sides.

[0093] Example 11

[0094] This embodiment provides a method for preparing the transferable visible-near-infrared light absorber of Example 3, comprising the following steps:

[0095] Step S1: Use spin coating to form a single-layer microsphere array with a period of P as the substrate layer 1.

[0096] Specifically, the silica microsphere solution is mixed and diluted with anhydrous ethanol in a certain proportion to obtain a mixed microsphere solution; the silicon substrate is placed on a spin coater, the spin coater is started to rotate at high speed, and the mixed microsphere solution is dropped onto the silicon substrate. Under the action of centrifugal force, the solution is evenly spread on the silicon wafer; the spin coater is turned off, and after the solvent evaporates, a monolayer array of silica microspheres is formed on the silicon substrate.

[0097] When preparing colloidal crystals, spin coating can utilize the self-assembly mechanism of colloids to form an ordered array of particles. A mixed microsphere solution of a certain concentration can be selected according to the preset diameter of silica microspheres, and a periodically arranged array of silica monolayer microspheres with a certain spacing can be formed by spin coating.

[0098] Step S2: A high-loss metal layer 2 is prepared on the substrate layer 1 by magnetron sputtering.

[0099] Specifically, the prepared silica monolayer microsphere array is placed as a template into a high-vacuum three-target magnetron sputtering coating machine and aligned with a metallic chromium target. Argon gas is pumped into the chamber, the sputtering mode is set to DC radio frequency, and metallic chromium is sputtered onto the polystyrene monolayer microsphere array.

[0100] Step S3: Adhere the transfer layer 3 to the side of the high-loss metal layer 2 that is away from the substrate layer 1. Specifically, use PET tape as the transfer layer 3 and adhere it to the side of the high-loss metal layer 2 that is away from the substrate layer 1 to achieve the transfer.

[0101] Step S4: Adhere the encapsulation layer 4 to the side of the base layer 1 facing away from the high-loss metal layer 2. Specifically, use PET tape as the encapsulation layer 4 and adhere it to the side of the base layer 1 facing away from the high-loss metal layer 2 to complete the encapsulation, thus obtaining a visible-near-infrared light absorber that is easy to transfer and can absorb light from both sides.

[0102] This invention is not limited to the above-described embodiments. If any modifications or variations to this invention do not depart from the spirit and scope of this invention, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this invention, then this invention also intends to include such modifications and variations.

Claims

1. A transferable visible-near-infrared light absorber, characterized in that: It includes, from bottom to top, an encapsulation layer, a substrate layer, a high-loss metal layer, and a transfer layer; The substrate layer includes a periodically arranged monolayer microsphere array, which includes at least one of polystyrene microspheres and silica microspheres. The monolayer microsphere array is prepared by a colloidal self-assembly method, and there are gaps between the microspheres in the monolayer microsphere array. The high-loss metal layer includes periodically arranged high-loss metal pillars, which include at least one of chromium metal pillars, titanium metal pillars, tungsten metal pillars, nickel metal pillars, gold metal pillars, or silver metal pillars; the high-loss metal layer is obtained by magnetron DC sputtering of high-loss metal on a substrate layer. The transfer layer is adhered to the side of the high-loss metal layer that is opposite to the substrate layer; The encapsulation layer is adhered to one side of the base layer; In the monolayer microsphere array, the diameter of each microsphere is 400-600 nm; the period of the monolayer microsphere array is 405-640 nm, wherein the period of the monolayer microsphere array is greater than the diameter of the microsphere. The height of the high-loss metal column is 300-700 nm.

2. The transferable visible-near-infrared light absorber according to claim 1, characterized in that: The microspheres in the monolayer microsphere array are polystyrene microspheres, and the substrate layer is prepared by gas-liquid interface colloidal self-assembly.

3. The transferable visible-near-infrared light absorber according to claim 1, characterized in that: The microspheres in the monolayer microsphere array are silica microspheres, and the substrate layer is prepared by spin coating.

4. The transferable visible-near-infrared light absorber according to claim 1, characterized in that: The transfer layer is a PET tape layer.

5. The transferable visible-near-infrared light absorber according to claim 1, characterized in that: The encapsulation layer is a PET tape layer.

6. A method for preparing a transferable visible-near-infrared light absorber according to any one of claims 1-5, characterized in that, Includes the following steps: A periodically arranged monolayer microsphere array was prepared using a colloidal self-assembly method, resulting in a base layer by creating gaps between the microspheres in the monolayer microsphere array. A high-loss metal layer was prepared on a substrate by magnetron DC sputtering. The transfer layer is attached to the side of the high-loss metal layer that is away from the substrate. By attaching the encapsulation layer to the side of the substrate layer that faces away from the high-loss metal layer, a visible-near-infrared light absorber is obtained.

7. The method for preparing a transferable visible-near-infrared absorber according to claim 6, characterized in that: In the step of preparing the substrate layer using the colloidal self-assembly method, a monolayer microsphere array is prepared by the gas-liquid interface colloidal self-assembly method or spin coating method, and the monolayer microsphere array is transferred and dried to obtain the substrate layer. In the step of preparing a high-loss metal layer on a substrate by magnetron sputtering, a monolayer microsphere array is placed in a high-vacuum three-target magnetron sputtering coating machine and aligned with a high-loss metal target. Argon gas is pumped into the chamber, and the high-loss metal target is sputtered by DC radio frequency to form periodic high-loss metal pillars on the monolayer microsphere array.

Images