MS&E Seminar: Guillermo C. Bazan

Dr. Guillermo C. Bazan

Director- Center for Polymers and Organic Solids,

University of California, Santa Barbara

Emerging Guidelines for the Design of Novel Organic Semiconductors

This presentation will cover some emerging ideas in our laboratories for designing organic semiconductors with properties that make them relevant for established optoelectronic devices and that are opening up opportunities within the context of bioelectrochemical systems. The topics to discuss include the following: (a) Regioregular conjugated polymers. These materials are relevant with respect to high mobility organic field effect transistors and the fabrication of low energy loss, easy to fabricate transparent solar cells. We will examine complications of ambipolar charge carrier transport and how this property can be managed through either specific molecular design or the incorporation of hole- or electron-specific traps that direct the choice of transport channel. The relationship between energy loss in solar cells and the impact of a homogenous molecular structure under conditions of limited driving force for electron transfer will be also examined. (b) A relatively new class of anionic narrow bandgap conjugated polyelectrolytes (NBGCPE) that is interesting because the materials are easily doped in water. The choice of pendant ionic group and the ionization potential of the internal repeat units within the backbone are critical for favoring the doped state in aqueous media. These NBGCPEs are excellent dispersants for single walled carbon nanotubes (SWCNT). One finds that it is possible to obtain predominantly either n- or p-transport in the NBGCPE/SWCNT blends by the choice of the charged group in the pendant group, while keeping the backbone structure the same.   These blends can be therefore used to fabricate thermoelectric devices. Finally, because of their miscibility in aqueous media it is possible to integrate these materials into microbial fuel cells and demonstrate that they are capable of accepting electrons from exoelectrogenic bacteria under anaerobic conditions.

Biography:

This presentation will cover some emerging ideas in our laboratories for designing organic semiconductors with properties that make them relevant for established optoelectronic devices and that are opening up opportunities within the context of bioelectrochemical systems. The topics to discuss include the following: (a) Regioregular conjugated polymers. These materials are relevant with respect to high mobility organic field effect transistors and the fabrication of low energy loss, easy to fabricate transparent solar cells. We will examine complications of ambipolar charge carrier transport and how this property can be managed through either specific molecular design or the incorporation of hole- or electron-specific traps that direct the choice of transport channel. The relationship between energy loss in solar cells and the impact of a homogenous molecular structure under conditions of limited driving force for electron transfer will be also examined. (b) A relatively new class of anionic narrow bandgap conjugated polyelectrolytes (NBGCPE) that is interesting because the materials are easily doped in water. The choice of pendant ionic group and the ionization potential of the internal repeat units within the backbone are critical for favoring the doped state in aqueous media. These NBGCPEs are excellent dispersants for single walled carbon nanotubes (SWCNT). One finds that it is possible to obtain predominantly either n- or p-transport in the NBGCPE/SWCNT blends by the choice of the charged group in the pendant group, while keeping the backbone structure the same.   These blends can be therefore used to fabricate thermoelectric devices. Finally, because of their miscibility in aqueous media it is possible to integrate these materials into microbial fuel cells and demonstrate that they are capable of accepting electrons from exoelectrogenic bacteria under anaerobic conditions

 

Date/Time:
Date(s) - Jan 13, 2017
10:30 am - 12:00 pm

Location:
2101 Engineering V
420 Westwood Plaza Los Angeles CA 90095