We have applied steady-state and time resolved photoluminescence (PL) to study the influence of monovalent and divalent metal additives on the electronic structure and charge carrier dynamics in CH3NH3PbI3 (MAPbI3) perovskite films fabricated on a layer of compact TiO2 deposited onto FTO-coated glass substrate. Monovalent metals Li + , Na + , K + and Cs + have a detrimental effect on perovskite crystal grain growth and charge carrier dynamics. In contrast, the divalent additives Zn + , Cd + and Hg + facilitate larger grain growth in MAPbI 3 perovskite film. Enlarged grain size, reduced trap state density, and the longest photogenerated carrier life time have been observed for the case of Cd incorporated into MAPbI 3 perovskite films.