Disruptive technologies powered by nanoscale materials and devices will define our future life in the same way that microtechnology has done over the past several decades. Our current research centers on the discovery of new chemistry, physics, and materials science associated with nanocrystals--a novel class of materials with feature sizes smaller than 100 nm, as well as the development of innovative technologies enabled by nanocrystals.

1. The Chemistry, Physics, and Materials Science of Nanocrystals

This research thrust focuses on a long-standing problem in chemistry and physics--understanding and control of the nucleation and growth involved in a synthesis of nanocrystals with controlled size, shape, and other properties. We aim to bring revolutionary advances to this field  by developing new tools capable of capturing, identifying, and quantifying the nuclei (small clusters) and seeds that bridge atomic species and nanocrystals. This research requires the integration of chemical synthesis, theoretical modeling, cluster speciation using mass spectrometry and electron microscopic analysis. It will provide an atomistic picture of the evolution pathway from atoms to clusters and nanocrystals, as well as the design rules for synthesizing metal and semiconductor nanocrystals with controlled electronic, magnetic, catalytic, and optical properties. The ultimate goal of this work is to build a scientific base for the large-scale production of nanocrystals with the specific properties sought for applications in areas such as electronics, photonics, catalysis, information storage, optical sensing, biomedical research.

2. Putting Nanocrystals to Work for Biomedical Research

Because of their small sizes and unique properties, nanocrystals are finding widespread use in studying complex biological systems. This work aims to advance biomedical research by developing new tools and methods based on functional nanocrystals. Our current efforts include development of gold nanocages as contrast agents for optical imaging modalities (e.g., optical coherence tomography, photoacoustic tomography, and multi-photon luminescence), and as photothermal agents for therapeutic treatment. We are exploring the use of gold nanocages and other metal nanocrystals as substrates for SERS- and LSPR-based detection. We are developing nanoscale capsules by integrating gold nanocages with smart polymers and/or phase-change materials for targeted delivery and controlled release with superb spatial/temporal resolutions. We are applying electrospun nanofibers to neural tissue engineering, drug release, stem cell, and tendon-to-bone insertion site repair. We are also designing new colloidal particles with superparamagnetic features for separation, detection, manipulation, and  tracking of biological species and cellular events. All these research activities will contribute to the emerging fields of nanomedicine and regenerative medicine.

3. Nanocrystals and Environmental Research

Nanocrystals also hold the key to the continuous progress towards a cleaner environment and sustainability. We aim to demonstrate the fabrication of functional nanocrystals with optimized properties for  a range of related applications. For example, we are exploring the use of nanocrystals for improving the performance of  solar cells, fuel cells, catalytic converters, and water-splitting devices. This research requires a superb understanding of structure-property relationships that guide the design and synthesis of novel nanocrystals with well-controlled sizes and shapes for specific applications.