Our research covers material science and engineering on a broad scale, from single molecules to molecular assemblies, i.e., from angstroms to nanometers to micrometers. The central topics of basic science include the control and optimization of electron transfer, charge separation, charge transport, and long-range diffusion of electron-hole pairs. These topics remain unclear and are hotly debated in the organic semiconductor community. Studying these properties helps improve the function and performance of organic materials and the devices they comprise, such as solar cells, light-emitting diodes (LEDs), transistors, lasers and sensor systems. The long-term goal of our research is to reveal the structure-property-function relationship of organic semiconductors when fabricated into nanostructures, which often demonstrate unique properties and unprecedented performance compared to the traditional bulk-phase materials. The uniqueness of our research lies in the flexibility of our materials, where the optoelectronic properties can be modulated and optimized through "bottom-up" molecular design and engineering. Students involved are trained in various cross-disciplinary areas, including chemical synthesis, physical characterization, materials science, as well as nanoscale engineering and processing.
The outcomes of our research bring significant impact to the fields of nanomaterials and optoelectronic device systems in various ways, ranging from novel molecular design and synthesis, to exquisite supramolecular assembly, to novel devices, and to advanced spectroscopic and microscopic characterization methods. The materials synthesized are uniquely multifunctional, combining the properties of strong fluorescence emission, self-waveguiding, 1D enhanced exciton migration and charge transport. This combination of properties enables a range of important technological applications that demand tightly coupled interaction between matter, light, and electrons. Our research program also helps break down the traditional science and engineering barriers by training a generation of students to think about and understand the broad spectrum of research activities that are important to the general field of nanotechnology.
Beyond fundamental research, we also strive to explore the commercialization potential of the materials and techniques we develop, with the goal of achieving real applications in areas relevant to national security, renewable energy, and the environment. Such transformation of laboratory innovations into marketable products is a key element of USTAR's long-term strategy. Two University of Utah spinoff companies have been incorporated from our work, MetalloSensors, Inc. and Vaporosens, LLC; these businesses focus on trace detection of hazardous metals and explosives, respectively. Our recently developed photovoltaic materials are currently being incorporated into a new solar cell business, USolar, in association with the USTAR program. The R&D along the directions of metal detection and solar cells are also part of the recently established US-China (Utah-Qinghai) EcoPartnerships.
The current research effort in our lab is portioned into four major directions:
- One-Dimensional Nanomaterials of Organic Semiconductors and Optoelectronic Sensing
- One-dimensional self-assembly vs. molecular structure/conformation.
- One-dimensional confinement of optoelectronic properties (linear polarization, waveguide, lasing, etc.).
- Amplified optical sensing with nanofibers.
- Electrical sensing based on conductivity modulation of nanowires.
- Multimode sensing with integrated nanodevices with nanowires as active channels.
Molecular Engineering for Enhanced Photoconductivity
- Long-range charge transport vs. molecular arrangement.
- Molecular self-assembly vs. device configuration.
- Molecular design and synthesis for optimized self-assembly and spectral response.
Single-Molecule Imaging and Molecular Probing
- Selective probing or sensing of bio-related metal ions, e.g., Zn2+.
- Detection of environmentally relevant hazardous metals, e.g., mercury.
- Single-molecule imaging of dynamic structure and adaptable function of proteins and living cells.
- Single-molecule charge transfer vs. molecular structure/configuration.
- Single-molecule FET: sensor, switch, etc.
- Photoinduced electron transfer kinetics vs. electrical conductivity.