Effects of influential factors on sedimentation self-assembly processing of photonic band gap crystals by relative humidity-controlled environments

The quality of the produced photonic band gap (PBG) films from colloidal silica in different sedimentation conditions was investigated according to the stop band intensity of the films. The PBG films were fabricated using the solution of monodispersed silica colloids with different alcohol-content solvents for a sedimentation self-assembly process under a relative humidity (RH)-controlled environment. The produced PBG films were analyzed by SEM images for the morphology of the crystal structures and by spectrometer measurements for their stop band intensities. Results show that the quality of the produced films was significantly influenced by the solvent evaporation rates in different sedimentation environments. Higher quality of the PBG films was produced at low evaporation rates by adopting a high RH-controlled conditions or a low alcohol-content solvent.