Rapid fabrication of a large-area 3D silica colloidal crystal thin film by a room temperature floating self-assembly method

We demonstrate the room temperature crystallization of colloidal silica particles dispersed in a mixture of ethanol and water at the air–liquid interface of the colloidal suspension spread on a glass substrate. By combining this approach with the dip-drawing technique, a room temperature floating self-assembly method has been developed. Applying this method, a three-dimensional silica colloidal crystal film of several square centimeters in area has been fabricated within 10 min without special facilities or heating of the suspension. SEM images and the normal incidence transmission spectrum of the sample show that the colloidal crystal film fabricated by this method had very high crystalline quality.