Conductive Supramolecular Assemblies with High Charge Mobility
Nanoscale Material Development
As more strain is placed on current energy supplies, due to increasing demand, solar energy will become an indispensable addition to available energy resources. The most promising candidate for large-scale economical power generation is the organic photovoltaic device (OPV), due to the low cost of materials, and fabrication methods with the same theoretical efficiency as conventional semiconductor devices. Research conducted in different groups has provided clear evidence that the progress of the OPVs technology is driven by the improvement in materialsÕ optoelectronic properties, such as light-harvesting, morphology and charge transport. Head-to-tail regioregular poly(3-alkylthiophenes) (rrPATs) have been widely used in OPVs due to their superior charge mobility. Studies of the relationship between the rrPAT films morphology and their charge mobility clearly suggested that the more ordered structures led to higher charge mobility. Although rrPAT can form ordered crystalline structures in the short range, long range ordered crystalline structures are critical in improving OPV efficiency, since the shorter diffusion path associated with longer range crystalline structures will reduce the recombination of electrons and holes, increasing the OPV efficiency. While various approaches have been employed to improve the ordering of rrPAT self-assembly structures, little is known about how the orientation can be optimized to obtain higher charge mobility.
Figure 1. Highly ordered rrPAT nanowires can be fabricated using ending group functionalization.
For More Information
Dr. Lei Zhai
NanoScience Technology Center
University of Central Florida
Orlando, FL 32826