Ningbo Institute of Materials Research and Development of New Plasmon Structural Color Materials and Preparation Technology

[ Instrument R&D of Instrument Network ] In the sub-wavelength micro-nano structure, surface plasmon resonance (SPR) absorbs (or radiates) visible light in a specific frequency band, producing plasmon structural color. Compared with traditional chemical pigments and dyes, the plasmon structure color originates from the interaction between the micro-nano structure of the material and the photon, so it can overcome the complex chemical color components, environmental pollution and difficult recovery, mechanical properties and aging resistance. Problems such as poor, are widely used in the fields of ultra-high resolution display, optical student sensing, anti-counterfeiting encryption, optical information storage and other fields. Carrying out research on plasmon structural color materials, preparation technology and color development mechanism has important scientific research significance and practical application significance.

Artificial metal micro-nano structures are physical carriers that produce plasmon structural colors. At present, the research and development of plasmon structure color based on template method or micro-nano processing (lithography, laser direct writing, ion beam etching or nano-imprinting, etc.) encounters bottlenecks, mainly due to small sample preparation area and vertical integration Poor compatibility, the application value of the material does not match the value of the equipment required to prepare the material, etc., the development of new technologies is imperative. Among them, using the direct growth method to construct the plasmon structure color is a promising new-generation technology, which can realize large-area preparation and vertical integration growth of materials. The direct growth method is completely free of the template method and the micro-nano processing technology. It can be fully inorganic and has a high interface quality. It is compatible with CMOS technology and material system selection. It is easy to be active during integration and is a dynamic response of plasmon. Provide the underlying support.

The research team of Cao Hongtao, a researcher at Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, used metal and ceramic co-sputtering growth technology to prepare metal nanowire array/ceramic composite metamaterial thin films. The characteristic geometric dimensions of nanowire arrays can be customized as needed, and the process can be customized. Controllable and repeatable, as shown in Figure 1. Due to the large number of precious metal/dielectric interfaces, a plasmon effect is induced (the electromagnetic wave at the metal/dielectric interface couples with free electrons to generate resonance); it is different from traditional open structures (such as nanopores, pillars, and cones prepared by micro-nano processing Etc.), the precious metal/dielectric interface is not in contact with air, and is a closed plasmon micro-nano structure, which objectively provides structural guarantee for color rendering stability and durability. On this basis, with the composite metamaterial film layer as the basic element (Building block), a transparent substrate / Building block layer / ultra-thin dielectric gap layer / metal mirror layer plasmon structure color film structure, such as Figure 1. Through the adjustment of the microstructure of the material under the influence of the preparation parameters, the basic colors of blue green, yellow and magenta are realized in the CMYK color coordinate. Similarly, in the RGB color coordinates, rich colors other than the three primary colors of red, green, and blue are realized (Figures 1 and 2). The color gamut is wide and the colors are full. The reflective color rendering is not sensitive to angle, and even super black can be constructed. absorb. After the prepared sample was placed in the atmospheric environment for one year, both the color appearance and the color rendering spectrum remained stable, highlighting the advantages of the closed plasmon micro-nano structure. In order to improve the color saturation of red and green, the research team proposed an improved film structure. Through optical theory simulation combined with high-throughput sample preparation and parameter extraction, the results show that the color development of the new plasmon structure originates from the formation of multi-mode and multi-order standing waves in the nano-microcavity. The electromagnetic coupling between the parameters and the transverse plasmon resonance mode forms frequency-selective absorption in the visible light band and produces reflective color development. The structural color film constructed in this study was deposited layer by layer in a magnetron sputtering chamber and at room temperature. The substrate has a high degree of freedom in selection (it can be flexible, conductive, and insulating). Figure 2 shows the laboratory equipment Under the conditions of 10cm×10cm, the magnetron sputtering deposition equipment is a mature device commonly used in the semiconductor and optical film industries. The preparation technology developed is expected to be industrially amplified, which is conducive to accelerating the application and development of plasmon materials process.

The research was carried out in cooperation with Ningbo University and Shanghai Synchrotron Radiation Light Source, and related research results were published in Advanced Functional Materials. The research work was supported by the leading talents of science and technology innovation of Zhejiang Province Ten Thousand Plan, Zhejiang Natural Science Foundation and Ningbo Science and Technology Innovation Team Plan.