Large‐Scale Rapid Positioning of Hierarchical Assemblies of Conjugated Polymers via Meniscus‐Assisted Self‐Assembly

Abstract

Rapid and deliberate patterning of nanomaterials over a large area is desirable for device manufacturing. We report a method for meniscus‐assisted self‐assembly (MASA)‐enabled rapid positioning of hierarchically assembled dots and stripes composed of luminescent conjugated polymer over two length scales. Periodically arranged conjugated poly(9,9‐dioctylfluorene) (PFO) polymers, yield dots, punch‐holes and stripes at microscopic scale via MASA. Concurrent self‐assembly of PFOs into two‐dimensional lenticular crystals within each dot, punch‐hole and stripe is realized at nanoscopic scale. Hierarchical assembly is achieved by constraining the evaporation of the PFOs solution in two approximately parallel plates via a MASA process. The three‐phase contact line (TCL) of the liquid meniscus of the PFOs was printed using the upper plate, yielding an array of curved stripes. Rapid creation of hierarchical assemblies via MASA opens up possibilities for large‐scale organization of a wide range of soft matters and nanomaterials.

Full-Color Laser Displays Based on Optical Second-Harmonic Generation from the Thin Film Arrays of Selenium Nanowires

“… As shown in Figure g, the alignment angle distribution of the Se NWs was measured through the FFT analysis in the microfluidic channel. The result shows a narrow distribution of misalignments within the range of the ±30-degree range, similar to the aforementioned postulation and previous reports. , In the control experiment, a randomly oriented feature of the Se NWs was observed when the assembly process was performed without the guidance of the microfluidic geometry under the same condition. Interestingly, some regions were partially patterned by the Coffee-ring effect without any preferential alignment in the structure as shown in Figure S5. , …”

“…As reported previously, this unique geometric configuration has been recognized as a straightforward manner for positioning or assembly of colloidal nanomaterials or other small molecules, extending its capability to be a scale-up fabrication method. − As closely illustrated in Figure b, the prepatterned microfluidic channels guide the enabling of the dense filling of the Se NWs because the hydrophilic wetting regions were only exposed in the microfluidic channels (∼10 μm) at the regular intervals (∼2 μm) after the development of photoresists (i.e., alternating hydrophilic/hydrophobic surfaces). Hence, the evaporative flux could be balanced in the competition of the dragging force and surface tension of the meniscus at the three-phase contact line. , Figure c represents the measured SEM images in an aligned array of Se NWs on the patterned substrate. Notably, highly aligned configuration of Se NWs could be spontaneously tethered over the entire surface area (i.e., trench) without the residues in-between two adjacent regions (i.e., mesa).…”

3D Optical Heterostructure Patterning by Spatially Allocating Nanoblocks on a Printed Matrix

“…In nature, living organisms can synthesize various hierarchical structures through bottom-up self-assembly, which inspires people to construct functional materials via solution-based colloidal assembly. ,− The past decades have witnessed great advancements in assembly from colloidal nanoblocks and assembly mechanisms to properties and applications, , which also promotes the development of optical heterostructures via the assembly methods − including DNA direction, − grafted molecule integration, , and sequential dewetting. − In particular, the combination of nanoscale physical templates with evaporation-induced self-assembly boosts the accurate location and spatial arrangement of highly ordered heterogeneous superlattices. , But the high-resolution templates prepared by lithography are limited by complicated processing and high cost, unavoidably hindering the rapid and facile assembly of heterostructures. Recently, a coassembly strategy by soft liquid confinement has also been developed for the programmable patterning of binary heterostructures, , which provides the feasibility to precisely regulate the heterostructure morphology by manipulating the liquid property.…”