Transferable Crack‐Free Colloidal Crystals on an Elastomeric Matrix with Surface Relief

Abstract

Crack-free three-dimensional (3D) colloidal silica crystals are fabricated on an elastomeric polydimethylsiloxane (PDMS) stamp via the lift-up method. A surface relief structure is fabricated on the PDMS substrate to enable the formation of colloidal crystal assemblies that cannot be achieved on a plane PDMS substrate owing to the hydrophobic nature of its surface. Four samples of uniform silica particles having different sizes are prepared for colloidal crystal assembly on PDMS substrates with various relief patterns. This strategy not only provides a means for the assembly of crack-free colloidal crystals on a soft hydrophobic surface via the lift-up method but enables the transfer of the crack-free colloidal crystals onto a curved surface.

Self-Patterned Nanoparticle Layers for Vertical Interconnects: Application in Tandem Solar Cells

“…In recent years, nanoparticle (NP) layers have found application in electronic and optoelectronic devices, in an effort to reduce cost and improve performance. For example, NP layers have been utilized as quantum emitters and absorbers, photonic crystals, and charge-transport layers, for plasmonic and photonic light trapping and for NP-assisted texturing. − Nanoparticle single- and multilayers can readily be deposited by solution-processing methods, such as dip coating, Langmuir–Blodgett deposition, capillarity-assisted particle assembly, and spin coating. − When solution-processed, the deposition of NP layers is governed mainly by the dynamics of the receding liquid contact line during the drying of the NP dispersion film. , Therefore, NP deposition can be influenced by modifying the drying of the liquid film. − Well-controlled, densely packed NP layers have been obtained by texturing the surface with nano- or microstructures that pin the receding liquid contact line. − Interestingly, NP layers deposited on such textured surfaces typically do not cover the top of sharp surface features. , These properties inspired us to realize vertical interconnects in thin-film electronic devices using self-patterned electrically insulating NP layers with local openings.…”

“…Then, the liquid volume is reduced due to droplet ejection by centrifugal forces and solvent evaporation, which becomes the dominating mechanism once the liquid film is sufficiently thin . When the liquid film thickness becomes comparable to the height of the surface features, the sharp tips of the pyramids act as nucleation points, which initiate the rupture and dewetting of the liquid film. , Once the liquid film has dewetted from the pyramid tips, they can also act as pinning points for the liquid contact line, enhancing the planarization of the liquid film. , The combination of dewetting and planarization directs the NPs toward the bottom of the valleys, which leads to a smoothening of the NP layer surface and the formation of openings around the peaks of the surface features. Liquid film rupture and dewetting at sharp surface features have also been reported for polymer solutions on corrugated Si wafers, albeit on a much smaller length scale than demonstrated here for SiO 2 NPs …”

“…19−23 Interestingly, NP layers deposited on such textured surfaces typically do not cover the top of sharp surface features. 22,23 These properties inspired us to realize vertical interconnects in thin-film electronic devices using self-patterned electrically insulating NP layers with local openings.…”

Insights into Lithium Surface: Stable Cycling by Controlled 10 μm Deep Surface Relief, Reinterpreting the Natural Surface Defect on Lithium Metal Anode

“…Furthermore, the effect of the shape of patterns is yet unexplored. Soft lithography is suggested to overcome the problems of photolithography in semiconductor fabrication, and it also enables the manufacture of various small micrometer-scale patterns on the substrate . Here, we adopted this method and used a metallic master instead of rubbery stamps for Li patterning.…”

Coordination-bond-driven fabrication of crack-free photonic crystals

“…24,25 In a typical fabrication process, with the evaporation of solvent, the three phase contact line begins to retract and latex spheres aggregate together driven by the weak interactions. 27,28 Besides, Johnson's group also proposed a template-assisted growth method to avoid cracks, in which latex spheres were directed to grow in a non-close-packed structure in the (100) plane. To obtain crack-free PCs, many methods have been developed.…”