(521f) Manipulating Organic Photovoltaic Thin Film Morphology through Interface Modification and Additives
AIChE Annual Meeting
2015
2015 AIChE Annual Meeting Proceedings
Materials Engineering and Sciences Division
Conjugated Polymers
Wednesday, November 11, 2015 - 2:00pm to 2:15pm
The conversion of sunlight to energy using organic photovoltaic devices (OPVs) is viewed as a promising route to sustainable energy generation. The drive to improve the power conversion efficiency (PCE) of OPVs has rightfully attracted a great deal of attention; however, overcoming the shortfall in PCE remains a significant challenge. While various factors such as inadequate hole transport mobility of donor-type conjugated polymers, limited solubility and miscibility with fullerene acceptors, and inefficient light harvesting are obstacles, controlling the morphology of the bulk heterojunction (BHJ) active layer remains a particularly thorny multi-dimensional problem. In this presentation, efforts to address this through the use of well-defined, end-functional poly(3-hexylthiophene)s (P3HTs) that allow interfacial layers that straddle the anode-BHJ interface will be described. Neutron reflectivity studies, which enable the laterally averaged depth profile of P3HT donor and PCBM acceptors in BHJ-like thin films to be measured, show that the interfacial “P3HT brush” layer impacts morphology, leading to a more uniform composition profile through the film. Coupled with various annealing strategies and the use of additives, these studies point to possibilities for tuning BHJ morphology and optimizing performance.