The effect of phase purification on photovoltaic performance of perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have witnessed a rapid rising in power conversion efficiency (PCE) over the past few years; however, they still suffer from recombination loss via interface defects in perovskite films. In this study, we implement an efficient phase purification strategy by incorporating isopropyl alcohol (IPA) post-treatment of perovskite films that reduces defect states and improves charge transport. It is found that the DMSO-PbI2-MAI complex in the perovskite film is eliminated after IPA post-treatment. A suit of opto-electric characterizations demonstrates that the nonradiative recombination is greatly diminished, and charge extraction is effectively boosted in the modified perovskite films. The perovskite solar cells with phase-pure MAPbI3 achieve an impressively larger PCE of 18.78% than that of 17.1% for the control devices. Our work presents a facile and efficient path to performance improvement of PSCs.