Quantum Defects, Tube^2, E=mC^2 & Beyond

The Wang research group focuses on Materials innovation, Chemical manipulation, Carbon nanotechnology and beyond (E=mC^2 & beyond). We synthetically create new materials with exciting new properties from low-dimensional carbon materials. New chemistries and tools are being developed in our laboratory to directly tailor nanostructures at the electronic and optical levels. In so doing, we have been able to open new research directions and develop technology platforms for discovering new phenomena and properties at both the very small length scale and nanostructured interfaces that may allow extending nano to the very large length scale. Examples of our current research include creating molecularly tunable fluorescent quantum defects to understand and control the coupling of electrons, excitons, phonons, and spin with defects in reduced dimensions, establishing the molecular science of carbon, elucidating the fundamental principles that govern the assembly and collective properties of nanostructured solids and networks, and developing novel devices, instrumentation and methodologies to tackle some of the most fundamental problems in energy, nanofabrication, quantum science, electronics, and biomedicine.

1. Molecularly Tunable Fluorescent Quantum Defects.

Defects can rule the properties of a crystal. This effect is particularly intriguing in atom-thick materials such as single-walled carbon nanotubes (SWCNTs) and graphene, where new chemistry and physics may arise due to strong coupling of electrons, excitons, phonons, and spins with defects in reduced dimensions. Our lab has synthetically created an entirely new class of defects that we call molecularly tunable fluorescent quantum defects, or quantum defects for short. We are exploring these chemically tailored, fluorescent quantum defects as a new toolkit for materials engineering, for brightening dark excitons, for creating near-infrared quantum emitters and single photon sources, and for probing chemical events that could be otherwise difficult to capture.

2. Tube^2.

Atom-thick materials such as SWCNTs and graphene are prone to chemical attack because all of the constituent atoms are exposed. To overcome this materials limitation, my research group has synthesized a tube-in-a-tube (Tube^2) semiconductor that is equivalent to a SWCNT hermetically sealed by a chemically tailored outer wall, created from double-walled carbon nanotubes through outer wall-selective covalent chemistry. This concept allows us to address a series of fundamental questions central to nanomaterials chemistry. For example, how are the electronic properties of a semiconducting nanostructure affected by its chemical environment? What if the environmental effects could be controlled or completely eliminated by protecting the inner-tube with the outer wall? Will electrical transport in such a “double wall” structure become immune to chemical perturbations by oxygen and water? Will it fluoresce brightly?

3. Nanoelectrode Networks for Energy Storage and Harvesting.

Owing to their high conductivity and current-carrying capacity, carbon nanotubes may vastly improve energy harvest, transport, and storage. The projects in our lab currently focus on studying electrical transport through nanotube interfaces, with a goal of harnessing the collective properties of nanostructures, and synthesizing heterogeneous nanostructures that are electrochemically reversible as the anode of lithium ion batteries. The remarkable electron accepting capabilities and charge transport properties of SWCNTs have also suggested new possibilities for overcoming the efficiency bottleneck currently facing several next-generation solar cells.

4. Question Y.

The researchers in the Wang group like to ask impossible questions, and we are always seeking the wow moments. Stay tuned.