Printable perovskite solar cells employ a device structure for which the organic-inorganic perovskite absorber is hosted by an inorganic mesoporous scaffold. Its advantages include simple fabrication process, low material cost and relatively high stability. However, it is challenging to homogeneously deposit high-quality perovskite crystals on the mesoporous scaffold. Herein, by incorporating lead acetate (Pb(Ac)₂) in the typical perovskite precursor, methylamine lead iodine (MAPbI₃), the crystal growth and pore-filling of the perovskite crystals in the mesoporous scaffold is improved by facilitating the crystal nucleation. Meanwhile, Ac^- and MA⁺ form MAAc which releases during thermal annealing process, resulting in excess PbI₂ in the perovskite layer which passivates the grain boundaries. By incorporating 1% molar ratio of Pb(Ac)₂ in the perovskite precursor, a power conversion efficiency of 15.42% is obtained for printable perovskite solar cells. This indicates that it is feasible to enhance the performance of printable perovskite solar cells by employing additives to tune the crystallization of the perovskite absorbers.