2D ceramics nanopatterning and 3D particle assembly

2D ceramics nano/micropatteming and 3D particle assembly were realized using self-assembly processes. Site-selective deposition of UV- and visible-light-emitting ZnO crystals was successfully achieved in an aqueous solution at low temperature. Molecular recognition was effectively utilized for patterning of ZnO crystals on self-assembled monolayers. Crystalline ZnO was further controlled to have different morphologies such as cylindrical hexagonal rods, ellipse or multi-needle shape by changing the solution conditions to improve the photoluminescence properties. All of the morphologies emitted strong photoluminescence in UV and visible regions with different emission spectra. The novel process shows the high ability of solution processes for fabricating nano/micro-devices constructed from crystalline materials for visible-light-emitting devices. We further proposed a novel process to fabricate micropatterns of spherical particle assemblies. Hydrophilic regions of a patterned self-assembled monolayer were covered with methanol solution containing SiO2 particles and immersed in decalin to control the shape of droplets and gradually dissolve the methanol into decalin. Particles were assembled to form spherical shapes on hydrophilic regions of an SAM and consequently, micropatterns of spherical particle assemblies were successfully fabricated through self-assembly. This patterned two-solution process has the advantages of both a drying process having meniscus force and a static solution process having high controllability.