Self-assembled free-standing colloidal crystals

Abstract

We propose a novel technique to fabricate a free-standing three-dimensional colloidal crystal by self-assembling the colloidal microspheres with controllable thickness from the air–liquid interface. Highly ordered three-dimensional colloidal crystals are formed by polymethylmethacrylate or polystyrene monodisperse microspheres. We also demonstrate the fabrication technique of the free-standing inversed opals by removing the microspheres using calcination. The free-standing colloidal crystal structures can be used for nano-photonic circuits, white-light LEDs or as a photocatalyst.

Light harvesting analysis of a nano‐cylinder structure on crystalline silicon using the Mie scattering model

“…Diameter controlled SiO 2 nanospheres were prepared using the modified Stöber process in the alcohol-rich phase [10,11]. Purified water, ammonium hydroxide, and pure alcohol were added to a sealed bottle, purged with nitrogen and stirred to ensure full mixing.…”

Mass production of ZnxCd1−xS nanoparticles with enhanced visible light photocatalytic activity

“…Therefore, Zn x Cd 1-x S, as a visible light-driven photocatalyst, has been intensively explored. Up to date, several synthetic routes have been developed to prepare Zn x Cd 1-x S, such as co-precipitation [16], successive ionic layer adsorption and reaction [17], H 2 S gas thermal treatment [18], hydrothermal method [19] and chemical reduction route [20]. However, the application of Zn x Cd 1-x S in photocatalysis is largely limited owing to the high cost of large-scale production.…”

Rapid self-assembly of submicrospheres at liquid surface by controlling evaporation and its mechanism

“…Well-ordered spheres with single layer at the liquid surface were obtained by Wickman and Korley [11], Kempa et al [12], Wang et al [13], but this method cannot produce three-dimensional lattice, which is important for photonic crystal. Im et al [14,15], Chan et al [16] obtained well ordered spheres in three dimensions at the water-air interface by elevating the temperature of suspension. Liu et al [17] introduced self-assembling of polymer spheres on the surface of ethylene glycol through the slow evaporation of the solvent.…”

“…High quality synthetic opals were produced at air-liquid interface for avoiding the influence of substrate [14][15][16][17][18]. But, while a solid layer is formed at the surface of suspension, many problems, such as that there is no meniscus for un-arrayed spheres immersed in solvent, arise in this method.…”