Effects of voltage operating strategy on electrophoretic self-assembly deposition of spherical SiO2 particles in water

• High quality of the photonic band gap (PBG) films was obtained within 5 min.
• The PBG films were fabricated by the electrophoretic deposition (EPD) process.
• Quality of the PBG film was affected by the applied voltage strategies.
• High quality of the PBG films was fabricated by the step-wise decreasing voltage strategy.

The quality of the photonic band gap (PBG) films composed of colloidal silica crystals was significantly improved by the electrophoretic self-assembly deposition process using a step-wise voltage operating strategy. The colloidal silica were synthesized by the sol–gel method and characterized as spherical particles with the size of 430 nm. The electrophoretic deposition (EPD) films were produced using the dispersed silica in water by different voltage operating strategies applied to the electrode of the EPD system. The produced EPD films were analyzed by UV–vis spectral data to evaluate the PBG quality based on the stop band intensity (SBI) of the films. Results show that the deposition patterns and the film thickness were greatly affected by the applied voltage strategies and the deposition time in the EPD system. High quality of the PBG films was fabricated by adopting the step-wise voltage operating strategy instead of the constant voltage setup for 5 min.

(a) UV–vis spectra of the photonic crystal films prepared under (b) different strategies of the step-wise decreasing voltage for the electrophoretic deposition (EPD) process. The best quality of the photonic crystal film was obtained for the sample #11.Figure optionsDownload as PowerPoint slide