Relationship between the size of SiO2 nanospheres and the structure colour

According to the emerging requirement in the nanofabrication field of obtaining the quantitative relationship between the nanostructure and the colour exhibited, a sphere-size colour model has been proposed and proved by experiments. The photonic crystal structures of SiO₂ nanospheres with different diameters are fabricated on glass substrate by the self-assembly method. Simulation is carried out by thin film principle using the plane segmentation method, and a model is fitted to express the relationship between the peak wavelength and the diameter of the nanospheres. The result shows good agreement with that by the improved Bragg equation, and matched the experimental results quite well. Thus, the characteristics of its colour can be determined by the spectra obtained and the colorimetric principle. Finally, according to the model, the linear relationship between the sphere size and the peak wavelength, namely the colour of the sample, has been built.