Design, Synthesis and Characterization of Novel, Functional pi-conjugated Materials for Diverse Applications

Organic semiconductors have become an attractive and useful alternative to inorganic systems in that they open possibilities to thinner and cheaper devices, such as transistors, light-emitting diodes and solar cells. Moreover, they benefit from their synthetic tunability, in terms of optical, electronic and physical properties. In the Bazan group, a great deal of research effort is directed towards understanding the role of molecular features and how they translate into the solid state. That knowledge is fed back into the lab in order to develop new, functional materials with tailored properties for a certain function.

Small Molecules as Donors for Bulk Heterojunction Solar Cells:

We have introduced a new class of small-molecule donor materials for solution processed organic photovoltaics (OPV). Before this work, small molecules seemed to be intrinsically inferior to polymers in their ability to generate useful bulk heterojunction solar cells. Using well-understood chemistry and organic materials, we developed a framework that can generally be described as containing a central electron-rich core flanked by relatively electron-poor units and terminated with pi-conjugated end-caps. This scaffold offers convenient synthetic entry to a broad class of materials with tailored optical, electronic and physical properties.

Graphical representation of molecular architecture (top) and example of small molecule donor (bottom).

This framework has supplied two of the highest performing small molecules for solution processed OPV and spawned new research efforts towards more environmentally friendly processing for organic semiconductors and even organic thermoelectric materials.