Computational characterisation of donor-acceptor polymer properties for solar cell applications

Organic solar cells based on polymers have attracted great attention. They are mechanically flexible, light, and cost-efficient (see Fig. 1). Polymers that comprise both electron donor and acceptor moieties are specifically interesting as energy harvesting materials as they contain a large number of light-absorption and charge-separation centres in one macromolecule and enable versatile synthesis with a variety of molecular building blocks. However, a major remaining challenge is the molecular-level characterisation of the structure and the optoelectronic properties of this type of materials, both in solution and inside a photovoltaic thin-film where the polymer is in contact with a conductive charge extraction layer (see Fig. 2). First-principles computational modelling has the ability to predict the structure and optoelectronic properties of molecules in photovoltaic devices and, in synergy with controlled polymer synthesis and atomic-resolution characterization experiments, can provide a bottom-up route to the rational design of polymer-based organic solar cells. This is the goal of this project.

The successful applicant will use ab-initio simulation based on Density Functional Theory and the highly-efficient Density-Functional Tight-Binding method to predict the charge donor and acceptor properties of polymers as a function of their structure. This will guide experimental development of new polymeric solar cell materials. The student will work in tight collaboration with experimental and our industrial project partner Merck Chemicals Ltd. to elucidate the structure and optoelectronic properties of organic polymers in bulk and in contact with metallic electrodes.

This PhD project will be embedded in a unique experiment-theory collaboration that encompasses polymer synthesis, experimental on-surface characterisation and sequencing of single polymer molecules, and quantum theoretic simulation of structural and optoelectronic properties of polymers in solvent and when adsorbed on metallic electrodes. Based on the experience of the supervisor on modelling complex organic materials [2] and hybrid organic-metallic interfaces [3], the student will be trained in state-of-the-art computational materials modelling techniques and in scientific computing on national-scale high-performance computing infrastructure.

The student will employ state-of-the-art electronic structure theory, will perform computations on national and international-scale high-performance computing facilities, and enhanced data analysis and visualization. The candidate will have an opportunity to visit the industrial project partners and will be in constant contact with the experimental collaborators at the University of Warwick.

This project is suitable for a student with a background in the physical sciences and the successful applicant will have a minimum of a 2:1 first degree in a relevant discipline/subject area. The start date is the 1st of October 2018.

For further details please contact Dr. Reinhard J. Maurer: [Email Address Removed]

Group webpage: warwick.ac.uk/maurergroup

References:
[1] Lichttechnisches Institut, Karlsruhe Institute of Technology. https://www.lti.kit.edu/7003.php
[2] Mortazavi et al., J. Phys. Chem. Lett. 9, 399-405 (2018)
[3] Maurer et al., Progr. Surf. Sci. 91, 72-100 (2016)