Effects of methylammonium acetate on the perovskite film quality for the perovskite solar cell

An ionic-liquid additive of methylammonium acetate (MAAc) is introduced in the lead iodide (PbI2) precursor solution to enhance the morphology and photovoltaic performances of perovskite film through a two-step spin-coating method. The introduction of MAAc at the first step spin-coating process can produce a mixed perovskite of MAPbI(3-x)(Ac)x, which is capable of generating uniform perovskite film with enough thickness, large grain size, and suitable optical band gap at the second step spin-coating process as a function of crystal seed, resulting in highly efficient generation and transportation of electron for the perovskite solar cell (PSC). As a result, the PSC with 9% MAAc (molar ratio) yields efficiency of 17.07%, which is higher than that of the PSC without MAAc (14.54%). These effects of MAAc in the PbI2 precursor solution on the morphology and photovoltaic performances of perovskite film highlights the potential application of the methylamine compounds as the additives in the cost-effective PSC.