We carry out research that is highly interdisciplinary, at the cross-section between materials science, chemistry, and biology. Below are some of the projects we are currently working on:

1. Nanoparticle Synthesis and Assembly

Predictable Nanoparticle Assembly A critical need in nanotechnology the development of new tools and methods to organize, connect, and integrate solid-state nanocomponents. We are developing new chemical and simulations tools for self-assembly – where components spontaneously organize themselves – to construct large-scale architectures using solid-state nanocrystal building blocks. We recently used this approach to construct metal-metal nanojunctions, using polymer grafts to tune non-specific nanocrystal interactions arising from van der Waals and steric forces. Our goal is to fabricate nanocrystal-based materials with chemical surfaces that possess complex energy landscapes.

Bio-inspired Nanomaterials. Bio-inspired synthetic routes have the potential for the development of low-cost, scalable, “green” manufacturing of inorganic materials. We are exploring biopolymer templates as fibrous scaffolds for metal oxide NPs, inspired by biomineralizing systems such as nacre, bone, and teeth where crystallization is facilitated at an inorganic-organic interface. These systems exhibit exquisite control over the formation of specific mineral phases, crystallographic orientations, and morphologies.

2. Nanoparticle Plasmonics & Metamaterials

Colloidal Metamaterials. We are utilising shape-controlled nanoparticles to fabricate metamaterials using a massively parallel bottom-up approach. Upon irradiation, metal nanoparticles with controlled shapes and sizes behave like optical antennae to facilitate large amplifications in the electromagnetic field near the metal surface. We are exploring how this field enhancement phenomenon can be tailored through the chemical synthesis and assembly of colloidal building blocks.

Biosensing. To improve signal-to-noise for in vivo sensing, we would like to collect optical readouts from small, localized volumes of interest within live cells or tissue. Surface Plasmon Resonance (SPR) sensing relies on the collection of scattered light from metal nanostructures that behave like optical antennae, concentrating electromagnetic fields down to sub-wavelength volumes. Our group studies free-standing, shape-controlled colloidal metal nanostructures that can be wholly integrated into fluids and biological environments. Because single nanoparticles can behave as independent plasmonic sensors, this sensing strategy has the potential for multiple-channel detection and nanoscale spatial resolution.

3. Nanoscale Composites

We are rationally designing nanoparticle (NP)-based materials for electronic and photonic devices. Organization and assembly of low-dimensional building blocks are major bottlenecks in device integration. We are addressesing the grand challenge of organizing nanostructures into hierarchical, macroscopic structures by utilizing NP-polymer composites, where self-assembly is facilitated by NP migration through the soft polymer matrix.

We are working on assembling semiconductor and metal NPs into NP-polymer composites for application as photovoltaic and plasmonic films, respectively. NP-biopolymer composites will also be explored for responsive, tunable optical materials that undergo reversible changes in spatial organization.

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