This NER proposal seeks to develop a new method for controlling the performance thin-film polymer photovoltaic devices. This will be accomplished by using nanopatterned surface templates to chemically induce phase separation in semiconducting polymer blends on the 10-100 nm length scale and by showing that such templates can be used to optimize photovoltaic device performance. This project will advance the societal goal of developing renewable energy sources while it advances the scientific goal of enhancing understanding of the relationship between nanoscale phase separation and the optoelectronic properties in conjugated polymer blends. To achieve these objectives, we will use Dip-Pen Nanolithography (DPN) to generate monolayer-thick nanoscale patterns on electrode surfaces onto which blends of conjugated polymers will be spin-coated from solution. The proposal will determine the effects of the template chemistry on phase-separation in the polymer blend films. After identifying conditions that allow control over the morphology on the appropriate length scale, we will correlate the performance and photophysical properties of the blends with their morphology. The 10-100 nm length scale of interest is well-matched to the resolution of DPN. This proposal will provide us with a new means to systematically probe the relationship between nanoscale morphology and optoelectronic properties in blends of organic semiconductors by using DPN as a 'rapid prototyping' tool.
Broader Impacts Meeting the energy needs of the world's growing population in an environmentally sustainable fashion is a fundamental challenge facing society today. The surface templates developed through this proposal could be adapted to high-throughput contact printing procedures and could thereby lead to the development of low-cost, high-efficiency photovoltaic cells using polymeric semiconductors. Furthermore, this project will provide interdisciplinary research training to graduate and undergraduate students and this proposal will support training in a lab that is presently ~50% female, and 25% undergraduate.
