Snaith group

Abstract:

Relative populations of the four energy-lowest IPR (isolated-pentagon-rule) isomers of Er@C82 under the high-temperature synthetic conditions are computed using the Gibbs energy based on characteristics from the density functional theory calculations (B3LYP/6-31+G*∼SDD energetics, B3LYP/6-31G*∼SDD entropy). Two leading isomers are predicted - Er@ (Formula presented.) -C82 and Er@ (Formula presented.) -C82. The calculated equilibrium isomeric relative populations agree with available observations. As Er@C82 is one of the metallofullerenes recently used as dopants for improvement of efficiency and stability of perovskite solar cells, the calculations should help in finding rules for further selections of fullerene endohedrals for such new applications in photovoltaics.

Abstract:

Demand for energy in the context of climate change is driving rapid deployment of low-cost renewable energy and is accelerating efforts to deliver advanced photovoltaic (PV) technologies. In the past decade, the steeply rising solar-to-electrical power conversion efficiency of metal-halide perovskite solar cells (PSCs) make them a compelling candidate for next-generation PVs, with interesting applications envisaged beyond traditional solar plants. These include building integrated PVs, flexible solar-powered electronics, and solar vehicles and aircraft. Metal-halide perovskites benefit from the low formation energy for crystallization, a consequence of their ionic nature, which enables close to ambient-temperature solution or vapor-phase deposition and a thin-film crystallization process. However, the ease by which rapid crystallization occurs also introduces defects and local heterogeneities throughout the perovskite films and at internal interfaces, which limits their efficiency (1).