Polymer-Mediated Particle Coarsening within Hollow Silica Shell Nanoreactors

Abstract

Inspired by the scanning probe block copolymer lithography process, hollow silica shells were loaded with polymermetal ink mixtures and investigated as solution-based nanoreactors for the synthesis of gold nanoparticles. The incorporation of poly(ethylene oxide) (PEO) into these hollow silica nanoreactors (approximately 40 nm in size) and the use of a two-step reductive annealing process (first at 200 °C and then at 600 °C) results in a high yield (76%) of larger (∼6 nm) single nanoparticles; when the polymer is not used, smaller (∼3 nm) particles dominate, and the yield of single particles is only 6%. It was determined that particle coarsening mostly occurs in the temperature range where the polymer is present and not degraded (i.e., <400 °C for PEO), as indicted by correlative in situ scanning/transmission electron microscopy in a reductive gas-phase environment. Thus, polymer incorporation in this nanoreactor system, which is amenable to scale up, drives the complete conversion of nanoreactor contents without excessive metal loss, highlighting the impact of nanoreactor composition and structural design on particle synthesis.

From Heterostructures to Solid‐Solutions: Structural Tunability in Mixed Halide Perovskites

“…Nanoreactors of the ink was formed on the substrate after retraction of the pen array, and these droplets were allowed to evaporate under atmospheric conditions to form individual halide perovskite nanocrystals, in line with previous nanoreactor approaches. [23] To achieve patterning at high-temperature, a home-built microheater, which was made up of Pt-wires 0.2 mm in diameter, was attached below the substrate. Consistent heat was applied to the substrate during the patterning.…”

“…Nanoreactors of the ink was formed on the substrate after retraction of the pen array, and these droplets were allowed to evaporate under atmospheric conditions to form individual halide perovskite nanocrystals, in line with previous nanoreactor approaches. [ 23 ]…”

Arrays of Colloidal Single Crystals Engineered with DNA in Lithographically Defined Microwells

“…For example, biomineralization often relies on insoluble organic matrices to serve as templates to produce highly ordered hierarchical structures. − Indeed, by studying crystallization in confinement, one can glean a fundamental understanding and insights that can be used to engineer systems. Confinement can alter crystal morphology in atomic systems, where complex porous morphologies can be attained with templates, − and it has been used to control crystal lattice and habit orientation, position, and size in molecular, polymer, and colloidal systems. − Finally, template geometry can be used to stabilize different polymorphs. , …”