The innovation engine for new materials

Laura Neumann

Laura Neumann, Chemical Engineering, Eindhoven University of Technology


Eindhoven University of Technology


Chemical Engineering


Johannes Sprafke

Faculty Sponsor(s): 

Craig Hawker

Faculty Sponsor's Department: 

Materials Research Laboratory

Project Title: 


Project Description: 

In the past two decades, organic photovoltaic solar cells (OPVC) have been of great interest for both industry and academia, because they combine mechanical flexibility and light weight, and can be easily produced by solution processing. In this study, we focus on polymer solar cells with a bulk-hetero-junction (BHJ) in which the active layer commonly consists of a conjugated donor polymer and fullerene acceptor. To date, the most widely used fullerene derivative is 6,6-phenyl-C61-butyric acid methyl ester (PCBM) which gives good results in combination with poly(3-hexylthiophene) (P3HT) as the donor polymer. However, PCBM may not be the best choice in terms of miscibility and energy level alignment when other polymers, especially the newly developed low bandgap polymers, are used. Here, we apply a one-pot synthesis that allows easy access to a variety of novel C60 derivatives enabling the creation of a library of functionalized fullerenes. Preliminary test devices have shown efficiencies comparable to the PCBM-P3HT system, indicating that further exploration of this novel system is promising. We have shown that the solubility of these novel derivatives can be readily tuned; however, the energy levels of these compounds are all very similar, even between mono- and bis adducts. This unusual behavior should allow for the synthetic optimization of the miscibility with only little effect on the energy level alignment. Extensive device testing and optimization may lead to BHJ solar cells with unprecedented efficiencies.