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Two-dimensional (2D) layered materials have many features suitable for optoelectronic devices, but poor quality substrates can degrade optical properties. By encapsulating a monolayer semiconductor in layers of atomically-thin hexagonal boron nitride, a nearly pristine environment can be achieved free from surface roughness and defects of typical substrates.

Princeton researchers alter a sequence of random copolymers and provide the first experimental observations of thermoreversible crew-cut micelles, and thermotropic micro- and macrophase separation in a nonaqueous polymer solution.

Recent advances in gold nanoparticle synthesis combined with functionalization with DNA linkers has enabled the self-assembly of stacks of gold nanodisks in which the optical spectra can be tuned and modulated by controlling the stack structure (e.g., particle spacing, arrangement, and stack length). The figure shows three possible arrangements of the particles, and the corresponding spectra that are associated with the plasmon resonance excitation in the stack.

  MRSEC outreach activities coordinate with Utah Core Curriculum Standards. These sixth-graders are studying the properties of light in their classroom. The Adelante program seeks to increase the expectation of university attendance and success among Hispanic students at Jackson Elementary. Participants:

The nanoscale structural and compositional features of molecular beam epitaxy (MBE)-grown GaAs1−yBiy films have been successfully characterized with unprecedented precision by researchers of the Wisconsin MRSEC using high-resolution x-ray diffractometry and high-resolution high-angle annular dark field (HAADF or “Z-contrast”) imaging in a scanning transmission electron microscope. The spots on the left side of the paired bright spots in the image below are identified as the Ga

NIPS is a non-equilibrium liquid-liquid phase separation phenomenon used to make polymer membranes through solvent-nonsolvent exchange. Newly developed phase-field simulations allow investigation of coupled mass transfer, flow and thermodynamic instability during processing and the corresponding microstructures that result from variations in film composition and thickness. These simulation tools provide critical insight into the nonequilibrium processing of complex fluids to make architectured, resilient solids and soft materials.

Cytoplasmic flows, bacterial colonies, and algal blooms are ubiquitous examples of active suspensions assembled from self-propelled particles, which internally inject energy into their suspending medium and, at sufficient concentrations, can produce large-scale flows. Linking macroscale material properties of active suspension to their underlying microscopic dynamics is a key challenge to describing these materials.

Objective: Use plasmon-enhanced photochemical reactions to map the polarization-dependent near fields of optical antennas. Approach: Use the anisotropic nano-crescent structure and SU-8 photo-resist. SU-8 exposure accomplished through plasmon-enhanced multi-photon absorption by 800 nm light.  Approach: Use the anisotropic nano-crescent structure and SU-8 photo-resist. SU-8 exposure accomplished through plasmon-enhanced multi-photon absorption by 800 nm light.