The Journal of Physical Chemistry C is presenting a series of Feature Articles by key scientists about the fundamental properties of Hybrid Organic-Inorganic Halide Perovskites. Here is the first one.
Principles of Chemical Bonding and Band Gap Engineering in Hybrid Organic-Inorganic Halide Perovskites14 02 2015
J. Phys. Chem. C, Just Accepted Manuscript
The performance of solar cells based on hybrid halide perovskites has seen an unparalleled rate of increase, while our understanding of the underlying physical chemistry of these materials trails behind. Superficially, CH3NH3PbI3 is similar to other thin-film photovoltaic materials: a semiconductor with an optical band gap in the optimal region of the electromagnetic spectrum. Microscopically, the material is more unconventional. Progress in our understanding of the local and long-range chemical bonding of hybrid perovskites is discussed here, drawing from a series of computational studies involving electronic structure, molecular dynamic and Monte Carlo simulation techniques. The orientational freedom of the dipolar methylammonium ion gives rises to temperature dependant dielectric screening and the possibility for the formation of polar (ferroelectric) domains. The ability to independently substitute on the A, B and X lattice sites provides the means to tune the optoelectronic properties. Finally, ten critical challenges and opportunities for physical chemists are highlighted.