The Computational Materials Physics group of Shuxia Tao works on the understanding of the process-structure-property-performance relationship of materials for energy applications. To do this, we develop and use multiscale methods, combining quantum methods e.g. Density Functional Theory with classical methods e.g. Molecular Dynamics, to study the complex interplay of chemistry and physics of materials at the nanoscale.

Simulating materials one atom at a time

We use Density Functional Theory based multiscale computer simulations to design materials for energy application. Our main focus is perovskite solar cells. Perovskite solar cells have emerged as one of the most promising photovoltaic technologies because of their potentially higher efficiency and lower cost than Si ones. The one remaining challenge is the long-term stability. The state-of-the-art cells are only stable for hundreds of hours. Ion migration as well as chemical reactions are key processes causing degradation. All the above processes are triggered and accelerated by the presence of intrinsic defects in the perovskite and extrinsic device operation stress, such as, thermal stress, light excitation and electrical bias.

As highlights of our recent progress, we have understood the mechanisms of a major stability issue phase segregation and discovered an effective additive fluoride for effective defect passivation. Both have opened possibilities for designing new perovskite compositions for extended service life of perovskite solar cells. Our future challenges include the development of efficient multiscale methods for understanding several physical and chemical processes in the materials and devices at larger length and longer time scales. With these new tools, we will be able to gain thorough understanding of several instability problems and efficiently design materials solutions for ultimate stable solar cells.