| Conjugated polymer solar cells have steadily grown in efficiency, from less than 1% to over 10% in less than two decades. They have the potential to be the next major energy source due to lightweight, flexible and inexpensive materials. However, the main stumbling block to full scale adoption of polymer solar cells is the still relatively low power conversion efficiency. Researchers are currently addressing this issue by designing new materials and device structures that can improve solar cell performance.;In this report, we focused on designing and characterizing new polymers and device structures for polymer solar cells. We focus specifically on the recent discovery of effects of substituents on the conjugated backbone and how it affects not only photovoltaic response, but also charge recombination and device morphology. Further collaborations with experts of complementary expertise in the field have allowed us to zero in on specific effects fluorine substituents have on polymer stacking, domain organization with PCBM, and polymer/PCBM miscibility. Our findings have helped us to understand the influence these substituents play on photovoltaic polymers and will help us to design new higher performance materials in the near future.;Charge recombination and charge transport have been a serious issue that has plagued polymer solar cells since their inception. We are addressing this issue by fabricating a new high porosity transparent nanoparticle electrode that can not only suppress geminate recombination but also aid in hole transport. Initial studies have yielded robust oxide films that can be easily loaded with both conjugated polymer and PCBM. Through future optimization of film coverage, these nanoparticle films should be the next stepping stone in achieving 15% efficiency with polymer solar cells. |
