The ACS Editors' Choice initiative highlights one article each day that is chosen from the entire American Chemical Society (ACS) portfolio. The article, written by Professor Jacqui Cole from ISIS, discusses the range of materials characterisation methods that can be used to study the structure of dye-sensitised solar cells (DSCs).
DSCs are one of a number of photovoltaic technologies that could improve the ability to harness solar energy. The fact they are transparent, flexible and can be produced cost effectively and with little environmental damage means that they could be suitable for applications such as solar-powered windows or wearable devices.
The working electrode of a DSC normally consists of a layer of mesoporous TiO2 nanoparticles, deposited onto fluorine-doped tin oxide glass, which have a monolayer of dye molecules adsorbed onto their surface. This is paired with a counter electrode and liquid electrolyte to complete the cell.
Although commercial DSC devices already exist, understanding the interaction between the dye and the TiO2 nanoparticles is key to understanding the process by which the device turns the light into electricity. The article, published in ACS Langmuir, focuses on the fundamental use of materials characterisation methods that directly determine structural information about the dye···TiO2 interface.
The review highlights examples of researchers using the techniques of ex-situ X-ray reflectometry (XRR), atomic force microscopy (AFM), grazing-incidence X-ray scattering (GIXS), pair-distribution function analysis of X-ray diffraction data (X-PDF), and in-situ neutron reflectometry (NR). These methods can be used to deliver specific structural information about one or more aspects of the dye···TiO2 interface. A previous paper from Professor Cole's group focusses on the NR experiment, and was the feature of a previous ISIS science highlight.
All the XRR, AFM, GIXS and X-PDF experiments were also undertaken at the Rutherford Appleton Laboratory (RAL), via Diamond Light Source or at the ISIS Materials Characterisation Laboratory. Samples were prepared at the Research Complex at Harwell. The review therefore represents the culmination of an extensive pan-RAL collaboration.
The information gained from materials characterisation experiments, such as those described in this article, is crucial for researchers to get a full picture of what is going on at this interface, to help them to use this to design better DSCs for the future.
The full paper can be found at DOI: 10.1021/acs.langmuir.1c02165