Solvent-Additive Coordination Effect on Lead-Iodide Precursor for Enlarging Grain Size of Perovskite Film

A uniform and large grain perovskite helps directly enhance the device performance. Solvent additives can be introduced to obtain a uniform and large grain perovskite. To investigate the effect of solvent additives on the perovskite grain growth and photovoltaic performance, we fabricated perovskite films and solar cells prepared with solvent additives in terms of the Gutmann's donor number (DN). The perovskite solar cell with dimethyl sulfide, which has the highest DN, exhibited a power conversion efficiency of 21.2% with a short-circuit current density of 24.0 mA/cm2, an open-circuit voltage of 1.1 V, and a fill factor of 80.2%.