Research

The complicated microstructure of polymers can have a large impact on the electrical performance of organic optoelectronic devices. The effect of polymer dynamics on performance, however, is less well understood. Neutron spectroscopy (at the Institut Laue-Langevin in Grenoble, France) and computational simulations are used in the group to investigate the dynamics present in such polymer materials. This combination of techniques allow for the study of motions with a wide range of energies, from carbon-carbon vibrations to molecular diffusion.

Computational calculations of the motion of polymers is studied in the group using molecular dynamics. This technique gives atomic resolution and aids in the interpretation of experimental data.

Our group is also working on simulation and characterisation of charge and ion transport in perovskite semiconductors in collaboration with the group of Dr. Piers Barnes. Driftfusion, a home-brewed drift-diffusion simulation tool, was developed by Dr. Phil Calado for modelling solar cells with mixed ionic-electronic conducting absorber layers. The software allows for investigation of how mobile ionic charge alters the interpretation of data obtained from optoelectronic measurements of perovskite solar cells. Simulation can play a large role in furthering our understanding of the physics of optoelectronic devices.

Organic photovoltaic (OPV) cells are traditionally based on fullerene n-type semiconductors. Our research group is purifying bis-P[60]CBM mixtures into isolated isomers for use in OPV devices. Devices with purified isomers have lower energetic and structural disorder, leading to improved performance. These isomers will additionally promote the study of the fundamental materials properties that determine OPV device degradation.

See the news release for our research on a non-toxic salt water battery prototype using polymer electrodes.

Photocatalytic fuel generation involves using a light-absorbing material to generate charges that can drive chemical reactions, such as water photolysis into hydrogen and oxygen. Molecular semiconductors are extremely interesting for this application due to their tuneable, sharp and strong light absorption, low impact fabrication, and controllabe surface area. 

Our group is exploring the relationship between chemical structure, physical environment and photocatalytic activity of polymer based photocatalysts. Transient optical spectroscopy in collaboration with the group of Prof. James Durrant is used as a tool to probe the photoinduced charge transfer in different conditions. Nanostructured materials and heterojunction structures based on hybrid organic – metal oxide heterojunctions are being explored.