Our group researches various topics in solid state chemistry. We synthesise and characterise new functional materials, and develop new analytical methods. Below are some of the areas we are currently working on.
New directions in hybrid solar cell absorbers
Perovskite solar cells have attracted global attention for their high efficiencies and ease of processing. The most promising material is methyl ammonium lead iodide (MAPI). Despite its success, there are significant drawbacks to MAPI. We are developing new hybrid solar absorbers. By adapting the ionic radius concept to apply to heavier halides, we showed that few if any new hybrid halide perovskite materials will be stable (Chem. Sci. 2016). Therefore, by moving away from the perovskite structure, a huge compositional parameter space is opened up, allowing use of optically active organic groups in place of methyl ammonium (Inorg. Chem. 2016). We are currently researching new highly tuneable halide materials.
Tolerance factor and octahedral factor can predict halide perovskite stability, when revised ionic radii are used. Red crosses represent compositions that do not form perovskies, blue dots represent perovskites.
Complexes of lead and bismuth halides with optically active organic ligands offer a new design principle for hybrid solar absorber design
Structures of non-perovskite hybrid solar absorbers
Tuneable optical properties of ternary tin halide compounds
XPS Valence Band Analysis
We are pioneering new methods of structural analysis using X-ray photoelectron spectroscopy. The valence band spectrum contains structural information, which can be extracted quantitatively. We have developed methods for quantitative phase analysis of titania anatase / rutile mixtures (App. Surf. Sci. 2017)
Valence band analysis can be used to quantitatively measure surface phase fraction in anatase/rutile mixtures
XPS VB phase quantification correlates with photocatalytic activity
Vanadium dioxide as a thermochromic material
VO2 has long been studied as a thermochromic material for energy saving window coatings. A major barrier to commercialisation however is the high visible light absorption typically found in VO2. We study nanoparticles of VO2 embedded in a matrix,. We have improved the visible light absorption spectrum whilst maintaining the thermochromic properties. (J. Mater. Chem. C, 2018, 6, 11731-11739) (New J. Chem., 2017, 41, 9216-9222)
DIfferent morphologies of VO2 can be produced hydrothermally