Controlled growth of CH3NH3PbI3 films towards efficient perovskite solar cells by varied-stoichiometric intermediate adduct

摘要

Lewis acid-base adduct approach with anti-solvent (diethyl ether) has been one of the efficient strategies to prepare high-quality perovskite films for top-performing perovskite solar cells. Conventionally, the molar ratio of CH3NH3I:PbI2:DMSO in the precursor solution is 1:1:1, however, DMSO will be volatile alongside the extraction of DMF due to its miscibility with DMF solvent during the process of anti-solvent washing, which introduces a non-stoichiometric intermediate adduct CH3NH3I center dot PbI2 center dot xDMSO (x < 1). In this work, we increased the DMSO content in the Lewis acid-base adduct approach to enhance the conversion efficiency of perovskite solar cells. More complete intermediate adduct CH3NH3I center dot PbI2 center dot DMSO and wider window period of washing process ensure high-quality perovskite films and high reproducibility with raised content of DMSO. Furthermore, the devices prepared by the precursor solution of CH3NH3I center dot PbI2 center dot xDMSO (x = 2.0) exhibit high reproducibility and the best efficiency of perovskite solar cells is 17.84% under one-sun illumination. (C) 2017 Elsevier B.V. All rights reserved.