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    Shenzhen Advanced Institute successfully prepared high-quality zinc sulfide photonic crystals
    Hits:   Date:2020-06-10  
    Li Jia, associate researcher of the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, has made new progress in the field of photonic crystals and successfully prepared high-quality zinc sulfide photonic crystals, which not only obtain high reflectance of nearly 100%, but also have structures such as saturation, contrast, brightness Color performance has been significantly improved.
    Colloidal photonic crystal refers to an ordered periodic structure composed of monodisperse micron or nanometer-sized colloidal particles. In recent years, colloidal photonic crystals have been widely used in optical displays and biochemical sensors. Although some excellent results have been achieved in structural color research based on colloidal photonic crystals, the currently used colloidal particle materials have a low refractive index, which leads to many problems in display brightness, contrast, and visibility. Great improvement and promotion. Therefore, the use of high refractive index materials to prepare photonic crystals to achieve a wider photonic band gap has become the research focus and difficulty of obtaining high-quality colloidal photonic crystals. On the other hand, it has been reported that adding a black light-absorbing material to a photonic crystal can absorb scattered light and significantly enhance the color of the photonic crystal structure.
    At present, the common method of combining black materials into colloidal photonic crystals mainly uses the physical mixing method. However, this method is easy to cause the agglomeration of black materials and uneven distribution within the photonic crystals. Therefore, it is necessary to develop a simple and effective method to uniformly mix black materials into the photonic crystal without affecting the long-range ordered periodic structure arrangement of the photonic crystal.
    In this work, in response to the above research goals, researchers have successfully prepared uniform ZnS nanoparticles with adjustable sizes of 40-200 nm, and further disperse the materials by silica coating to protect the calcination and partial etching methods Degree, surface charge and crystallinity are adjusted. At the same time, the organic structure guiding agent added in the material synthesis can generate in-situ carbon-based materials that can effectively absorb scattered light after calcination and are evenly distributed in the colloidal particles. After self-assembly, a long-range ordered structure with significantly enhanced structural colors is obtained. The maximum reflectivity of the obtained self-assembled colloidal photonic crystal can reach 98%, and its reflection spectrum can also be flexibly adjusted by the particle size. This work provides new design ideas and methods for obtaining high-quality photonic crystals, effectively improves the quality of colloidal photonic crystals, and facilitates the widespread application of photonic crystal technology.