Stitching triple cation perovskite by a mixed anti-solvent process for high performance perovskite solar cells

By using solvent-solvent extraction process, different amounts of weak coordination solvent IPA were added to the anti-solvent. IPA can take away residual CB rapidly in the film and reduce the density of grain boundaries of perovskite films. We propose a new “stitching effect” based on this mixed anti-solvent process, which results in a smooth surface morphology of perovskite with large grains. Solar cells fabricated using the anti-solvent process exhibit a best efficiency of 19.2%.231