Source: Amorphous China
Metal-based color filters have received widespread attention in optical and other functional applications due to their non-fading, good color persistence and high saturation. In recent years, the method of surface coloring using the optical interference effect in planar thin film structures has been widely used in various practical applications. For example, optical display equipment, structural color printing, household electronics, photodetectors, solar cells, auto parts and so on. However, conventional reflective metal-based filter diaphragms require complex multiple deposits due to their multilayer dielectric films, and due to the difference in the coefficient of thermal expansion between their material layers, the application area and mechanical properties of reflective color filters, such as binding force and wear resistance, are limited. How to regulate the composition and process of optical films so that they have extremely high color saturation and good mechanical properties and can be applied in large areas is a key and urgent problem to be solved.
Recently, the research group of Professor Lu Jian (corresponding author) of the City University of Hong Kong proposed to use a one-step magnetron sputter deposition method to successfully obtain a full-color magnesium-based reflective filter diaphragm that can be applied in a large area on the basis of the preparation of high-strength magnesium-based supernatural films (2017 nature cover article, doi: 10.1038/nature21691). This is another new progress in amorphous nanocrystalline biphasic materials following the aluminum-based amorphous nanocrystalline biphasic materials published last month in nature communication, further expanding the application of supernatural biphasic work in other fields. It has extremely high color saturation and excellent mechanical properties.
In this paper, the new magnesium-based reflective color filter size is 2cm×2cm, to achieve a full visible light spectrum color, and has a high hardness of 9.12gpa, the new magnesium-based color filter has an optical constant controllable absorption layer and has a magnesium fund genus glass reflective layer. You can control the saturation and color of the rendered color by adjusting the optical constant and thickness of the absorbing layer. In addition, because the metal glass reflective layer and the absorber layer come from the same material target, the filter has a high film-based binding force, and the overall hardness of the reflective filter is also improved with the support of the excellent mechanical properties of the magnesium glass reflective layer. The new magnesium-based reflective filter provides broad application prospects for the manufacture of large-area color filter devices. The results were published in Advanced Optical Materials, doi: 10.1002/adom.201901626, the first author of the article was Bu Yu (PhD candidate, City University of Hong Kong).
Figure 1, a) Magnesium-based reflective filter corresponding to the visible spectrum color, b) magnesium-based thin film cross-section high-resolution transmission electron microscopy analysis and high-resolution projected electron microscopy analysis corresponding to the absorption layer (upper right) and reflective layer (lower right).
Figure 2, Magnesium-based reflective filter angle dependence analysis