It has been a busy year in terms of university and network activities, but chemistry comes first. The first third of the year has been a mix of code developments, research reviews and new science.
- “Introducing k-Point Parallelism into VASP” A. Maniopoulou, E. R. M. Davidson, R. Grau-Crespo, A. Walsh, I. J. Bush, C. R. A. Catlow and S. M. Woodley, Computer Physics Communications 183, 1696 (2012).
VASP is the most used electronic structure code on the national supercomputer, but it cannot take full advantage of the thousands of available processors. This paper is the result of a collaboration between the HPC Materials Chemistry Consortium and NAG to add a new mode of parallelism into the code. It works, and will hopefully be adopted into the mainstream version of VASP soon. The approach makes hybrid density functional theory calculations less painful to run!
- “Structural and electronic properties of CuSbS2 and CuBiS2: potential absorber materials for thin-film solar cells” J. T. R. Dufton, A. Walsh, P. M. Panchmatia, L. M. Peter, D. Colombara and M. S. Islam, Physical Chemistry Chemical Physics 14, 7729 (2012).
Solar cells work, but to enable widespread adoption of thin-film technologies, new absorber materials need to be developed that are made from earth abundant elements. Copper based compounds are the current hot topic, and this work presents a theoretical understanding of the structure and bonding in two candidate materials that have recently been synthesised in the Department of Chemistry at Bath.
- “Kesterite Thin-Film Solar Cells: Advances in Materials Modelling of Cu2ZnSnS4” A. Walsh, S. Chen, S.-H. Wei and X. G. Gong, Advanced Energy Materials 4, 400 (2012).
People are excited about CZTS solar cells, and with good reason. While the elements are abundant and low cost, the challenge is in the complex solid-state chemistry associated with a four-component system. This paper reviews our work performed over the past five years exploring the materials chemistry and physics of the kesterite system.
- “Synthesis, Characterization, and Calculated Electronic Structure of the Crystalline Metal–Organic Polymers [Hg(SC6H4S)(en)]n and [Pb(SC6H4S)(dien)]n” D. L. Turner, K. H. Stone, P. W. Stephens, A. Walsh, M. P. Singh, and T. P. Vaid, Inorganic Chemistry 51, 370 (2012).
The development of semiconducting metal-organic frameworks is the primary subject of my recently funded European grant. To complement our predominately theoretical research, we are collaborating with the group of Tom Vaid at the University of Alabama. Novel lead and mercury sulfide networks that show some real promise were synthesized and characterised.
- “Surface structure of In2O3(111) (1×1) determined by density functional theory calculations and low energy electron diffraction” K. Pussi, A. Matilainen, V. R. Dhanak, A. Walsh, R. G. Egdell, K. H. L. Zhang, Surface Science 606, 1 (2012).
It may be increasingly rare and expensive, but indium makes my favourite oxide material. So simple yet so complex. Last year we predicted the surface structure of In2O3 based on my calculations, and this year we managed to get experimental validation by one of the largest LEED studies performed to date.