Greener and Easily Available Solvent Assisted Preparation of High Efficiency Perovskite Solar Cells

To replace or reduce toxic solvents in perovskite solar cell manufacturing. 2‐Methyltetrahydrofolate (2‐MTHF), as an important raw material for organic synthesis and excellent solvent, is incorporated in perovskite solar cells as additive co‐soluble precursor to fabricate photolayer (FAPbI 3 ) for the first time. It is investigated that this is not only an toxicity‐reducing strategy, but an effective defect passivation method for manufacturing perovskite solar cells. The introduction of 2‐MTHF in a stoichiometric precursor solution is capable of induce precursor film to generate perovskite films through a simple one‐step spin‐coating process, more than 15% of toxic solvents can be reduced. The perovskite trap state is decreased by passivated perovskite crystal surface thus improve carrier lifetime, extraction rate and photovoltaic performance. The maximum power conversion efficiency (PCE) of the solar cell when the 2‐MTHF volume fraction was optimized at 15% was improved to 23.58%, up from 7% in the control. Meanwhile, the notorious J‐V hysteresis was much suppressed. Hence, it is expected that novel 2‐MTHF will find their applications in perovskite solar cells and optoelectronic devices. This article is protected by copyright. All rights reserved.