Shenzhen Advanced Institute Successfully Prepared High-Quality Zinc Sulfide Photonic Crystals

The research group of Li Jia, an associate researcher at 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 achieves nearly 100% high reflectivity, but also saturation, contrast, brightness and other structures Color performance has been significantly improved.
 
"Colloidal photonic crystals refer to an ordered periodic structure composed of monodispersed 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 the structural color research based on colloidal photonic crystals, the colloidal particle materials currently used have a low refractive index, causing them to face 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 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 the 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 adopts physical mixing method, but this method easily leads to agglomeration of black materials and uneven distribution in the photonic crystal.

 
 Therefore, it is necessary to develop a simple and effective method to mix the black material into the photonic crystal uniformly without affecting the long-range ordered periodic structure of the photonic crystal.
 
In this work, in view of the above research goals, researchers have successfully prepared uniform zinc sulfide nanoparticles with an adjustable size of 40-200 nm, and further dispersed the material through the method of silica coating to protect the calcination and partial etching Degree, surface charge and crystallinity. At the same time, the organic structure directing agent added in the material synthesis can generate in situ carbon-based materials that can effectively absorb scattered light and evenly distribute them in the colloidal particles after calcination. After self-assembly, a periodic arrangement structure with long-range order and structural color significantly enhanced is obtained. The maximum reflectivity of the obtained self-assembled colloidal photonic crystal can reach 98%, and its reflectance 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 improving the quality of colloidal photonic crystals, and promoting the wide application of photonic crystal technology.