Effect of H2O on the Optical Properties of Silicone Materials : a hybrid first principle calculation and molecular dynamic simulation study

In this paper, molecular dynamics simulation method was used to simulate the change in optical properties of organic silicon materials after adsorption H₂O by using Materials Studio simulation software. The results show that after the H₂O are adsorbed by the silicone material, the main chain of the silicone material molecules breaks and the silicone material molecules react with the H₂O to form new chemical bonds. After the water molecules are adsorbed, the reflectance of the material to visible light increases and the transmittance decreases. The more H₂O are adsorbed, the smaller light transmittance of the silicon material. In addition, the diffusion characteristics of H₂O at different temperatures of silicon materials with different concentrations of water molecules were analyzed. The results show that the molecular thermal motion is aggravated by the increase of temperature, the activity of molecular chains increases in the silicon material model, and the diffusion coefficient of H₂O increases with the increasing temperature. At the same temperature, the diffusion coefficient of H₂O is determined by the concentration of H₂O in the silicone material. This study content is of great significance for analyzing the aging mechanism of silica gel and improving LED reliability.