Facile all-dip-coating deposition of highly efficient (CH 3 ) 3 NPbI 3- x Cl x perovskite materials from aqueous non-halide lead precursor.

Sequential all-dip-coating deposition of (CH 3 ) 3 NPbI 3- x Cl x perovskite materials was conducted in an aqueous nonhalide lead precursor solution, which was followed by that in a (CH 3 ) 3 NI and (CH 3 ) 3 NCl mixed solution as part of a facile, cost-effective, and environmentally benign manufacturing process for high-efficiency perovskite solar cells. The (CH 3 ) 3 NPbI 3- x Cl x perovskite layers deposited via the proposed process were constructed with a Cl/I ratio below ∼3%, indicating the partial insertion of Cl into the (CH 3 ) 3 NPbI 3 perovskite lattice. The amount of Cl inserted was readily modulated by varying the (CH 3 ) 3 NCl concentration in the (CH 3 ) 3 NI/(CH 3 ) 3 NCl mixed solution. Incorporating a small amount of Cl led to significant improvements in the surface morphology and crystallinity of the perovskite layer as compared to (CH 3 ) 3 NPbI 3 fabricated under the same conditions. The perovskite solar cell devices with these (CH 3 ) 3 NPbI 3- x Cl x perovskite films exhibited superior device performances and stabilities, resulting in an outstanding power conversion efficiency of ∼15.3%. Results show that the fabrication of (CH 3 ) 3 NPbI 3- x Cl x perovskite material with an aqueous nonhalide lead precursor is more efficient than conventional spin-casting approach with detrimental organic solvents.