Fabrication of High-Quality Opal Films with Controllable Thickness

Abstract

A dipping method was developed to fabricate three-dimensional colloidal crystal films. The thickness of the films fabricated by this method can be precisely controlled from one layer to several tens of layers by controlling the particle concentration and the film formation speed. Experimental results showed that the spheres form a face-centered cubic structure and that single crystals in the film can extend to centimeter dimensions.

Colloidal Lithography

“…Vertical deposition may allow formation of large-area crack-free colloidal crystals provided the suspensions of colloidal particles wet well supporting substrates, there is no interaction between the particles and the substrates, the suspensions are sufficiently stable and the solvent evaporation is well controlled [9]. Dip-coating is a fast and dip-coater assisted variant of vertical deposition [11]. Besides, a number of techniques have been developed to improve the efficiency and quality of colloidal crystallization via vertical deposition, such as variable-flow deposition [12], isothermal heating evaporation-induced self-assembly [13], two-substrate deposition [14], reduction of the humidity fluctuation [15], adjustment of the meniscus shape [16], temperature-induced convective flow [17] and vertical deposition with a tilted angle [18].…”

Tunable structural color in organisms and photonic materials for design of bioinspired materials

“…On the other hand, crystal planes oriented on the substrate induce monochromatic structural color in colloidal crystal films. Simple preparation techniques based on convective self-assembly have been developed and are widely used in this research field [64][65][66]. Figure 4(C) shows a scanning electron microscopy (SEM) image of close-packed polystyrene (PS) colloids on a silicon wafer.…”

High Frequency Acoustics in Colloid-Based Meso- and Nanostructures by Spontaneous Brillouin Light Scattering

“…The assembly of colloids into well defined coherent structures commonly occurs under the influence of external fields, e.g., gravitational sedimentation, [13] electrophoretic deposition, [14] or vertical deposition either by evaporation [15] or lifting the substrate [16] (Fig. 3.1).…”

“…[12] Another already mentioned advantage is the possibility to realize well ordered single or multi-component systems by self-assembly (colloidal crystals). In Fig.3.1 several techniques to achieve colloidal crystals will be presented, including sedimentation, [13] electrodeposition, [14] centrifugation, filtering, vertical deposition, [15,16] and compression molding. [17] Especially the last two techniques play a role in this thesis and will be introduced in more detail in the sections 3.1 and 3.2.…”