The field of photovoltaics is undergoing a surge of interest following the recent discovery of the lead hybrid perovskites as a remarkably efficient class of solar absorber. Of these, methylammonium lead iodide (MAPI) has garnered significant attention due to its record breaking efficiencies, however, there are growing concerns surrounding its long-term stability and toxicity. Compounding these problems is a more fundamental limitation: the hybrid perovskite structure shows a severe lack of compositional tunability. Beyond minor changes to the halide and A site composition it has not been possible to significantly supersede the original MAPI formulation, because the hybrid perovskite structure is not accommodating to significant changes to composition of the A or B sites. Many of the excellent properties seen in hybrid perovskites are thought to derive from the 6s2 electronic configuration of lead, a configuration found in a range of post-transition metal compounds. In this presentation I will outline our computational and experimental efforts to unearth new earth abundant absorbers containing ns2 cations. Our results highlight the importance of electronic and geometric connectivity of the lone pair cations for achieving suitable electronic structures for PV applications, and we computationally pinpoint some new compounds with high efficiency.

Looking beyond methylammonium lead iodide for next generation solar absorbers

255th National Meeting (2018)

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