Rational Design and Synthesis of Targeted Nanostructures in Organic Photovoltaics

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

0932666 Dadmun Intellectual Merit - Conjugated polymers (CPs) are a promising class of materials for use in the conversion of solar energy to electricity. For optimal performance in bulk heterojunction CPs, the morphology of the donor and acceptor materials must form percolating interpenetrating networks maximizing interfacial contacts w/ length scale of ~10 nm. Currently, we lack the fundamental understanding to guide the formation of bulk heterojunctions to these targeted nanoscale morphologies. In this collaborative proposal, an understanding of the fundamental driving forces that govern the nanoscale self-assembly and interfaces in conjugated block copolymer (BCP) thin films will be developed in order to enable the rational design and fabrication of the targeted bicontinuous nanoscale morphologies. This will be realized by completing an interdisciplinary research program that will detail the thermodynamic driving forces that control the formation of a bicontinuous interconnected percolated morphology in a thin film of conjugated BCP with controlled rigidity on a surface that is patterned incommensurately to the periodicity of the diblock copolymer as well as the synthesis and thin film structure of conjugated diblock polymers that exhibit traditional diblock morphologies. Therefore upon completion, we will attain an understanding of the thermodynamics that control the assembly of these systems in thin films; enabling the reproducible creation of the desired bicontinuous interconnected morphologies with this structure, providing a transformative method to rationally design, tailor and fabricate nanoscale morphologies with exquisite control of size and thickness for CP systems. The successful completion of these experiments will broaden the range of nanoscale thin film morphologies that can be targeted and rationally tuned in conjugated polymer thin films, and thus allow a systematic study of CP morphology on organic photovoltaics, a critical area in their optimization, yet a parameter that is not currently controllable experimentally. Broader Impact - This project is an integrated collaborative effort between Chemistry, Chemical Engineering, and Materials Science research groups at the University of Tennessee. The broader impacts of the proposed program are embodied in this interdisciplinary collaboration, as well as the educational experiences to which it will lead. In the course of this project, the PIs will continue their outreach programs and use their research to provide training experiences for undergraduate and high school students and K-12 teachers, as well as provide input to their own teaching and exciting areas for discussion at K-12 visits. The execution of this collaborative project will also develop an interdisciplinary system of instruction, via classroom and laboratory, for training graduate and undergraduate students in chemistry, materials science, and mathematics who will be equipped to tackle modern science and engineering challenges. This project will also further develop the sustainable research infrastructure in Tennessee, an EPSCOR state, and will be implemented to ensure the participation of underrepresented groups in this research.