Formamidine and cesium-based quasi-two-dimensional perovskites as photovoltaic absorbers

Formamidine (FA) and cesium (Cs) cations were introduced into quasi-two-dimensional (2D) perovskites as B site cations. The unique crystalline growth of the resulting (n-C₆H₁₃NH₃)₂FAPb₂I₇, which promotes charge transport in photovoltaic solar cells, was confirmed, as was the stability of this material. The photovoltaic properties of (n-C₆H₁₃NH₃)₂FAPb₂I₇ were found to be superior to those of other homologous quasi-2D perovskite compounds.