Temperature-modified photonic bandgap in colloidal photonic crystals fabricated by vinyl functionalized silica spheres

A thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals was described. The colloidal photonic crystals were assembled from monodisperse vinyl functionalized silica spheres by a gravity sedimentation process. The samples diffract light following Bragg's law combined with Snell's law. By annealing the sample at temperatures in the range of 60–600 °C, the position of its stop band shifted from 943 to 706 nm. It had more than 25% blue shift. In addition, the annealing temperature and the Bragg peak values have a linear relationship in the 120–440 °C range. Fourier transform infrared (FT-IR) spectra and thermo-gravimetric analysis (TGA) curves of vinyl functionalized silica spheres confirmed the above results. The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals.

A thermal annealing procedure was described for fine modifying the photonic bandgap properties of colloidal photonic crystals, which were self-assembled from vinyl-functionalized silica spheres by a gravity sedimentation process.Figure optionsDownload as PowerPoint slideHighlights
► We described a thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals.
► The position of its stop band had more than 25% blue shift by annealing the sample from 60 to 600 ̊C.
► The annealing temperature and the Bragg peak values have a linear relationship in the 120-440 ̊C range.
► The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals.