Spectral study of colloidal photonic crystals

The spectroscopic and microscopic investigation in polystyrene photonic crystals was performed. Colloidal crystalline layers were deposited on glass and quartz by vertical evaporation deposition. Emission, excitation and up-converted emission were studied on both polystyrene powders and polystyrene photonic crystals. The results indicated that spectral features were strongly dependent on the particle properties of size, shape, and arrangement. Blue emission at 420 nm was also found by using a 532-nm excitation due to multiphoton process and a dynamic model was proposed to explain the mechanism of the up-converted emission.