Introducing additives in the precursor solution is an effective way in realizing highly efficient perovskite solar cells. In this work, tetramethylene sulfone (TMS) is introduced into the perovskite precursor to improve perovskite film quality. The infrared spectroscopy proves that more than one PbI2 can interact with TMS by forming the intermediate phase PbI2-(TMS)(x). The two O-donor in one TMS link PbI2 molecules via strength of Pb-O bond, which results in decreasing density of charge recombination centers in perovskite films. As a results, the perovskite solar cells derive from MAI-PbI2-(TMS) x intermediate phase exhibits an elevated power conversion efficiency of 16.2% with high reproducibility. (C) 2018 Elsevier B.V. All rights reserved.