A novel, sequential method of dip-coating a ZnO covered mesoporous TiO₂ electrode was performed using a non-halide lead precursor in an aqueous system to form a nanoscale perovskite film. The introduction of a ZnO interfacial layer induced significant adsorption in the non-halide lead precursor system. An efficient successive solid-state ion exchange and reaction process improved the morphology, crystallinity, and stability of perovskite solar cells. Improved surface coverage was achieved using successive ionic layer adsorption and reaction processes. When all sequential dipping conditions were controlled, a notable power conversion efficiency of 12.41% under standard conditions (AM 1.5, 100 mW·cm⁻²) was achieved for the perovskite solar cells fabricated from an aqueous non-halide lead precursor solution without spin-casting, which is an environmentally benign and low-cost manufacturing processes.

High-performance PHJ MAPbI₃ perovskite films fabricated using efficient and low-cost dip-coating deposition approach over ZnO/TiO₂ bilayered ETL system from an aqueous non-halide Pb(NO₃)₂.

Sequential all-dip-coating deposition of (CH₃)₃NPbI_3−xCl_x perovskite materials was conducted in an aqueous nonhalide lead precursor solution, which was followed by that in a (CH₃)₃NI and (CH₃)₃NCl mixed solution as part of a facile, cost-effective, and environmentally benign manufacturing process for high-efficiency perovskite solar cells. The (CH₃)₃NPbI_3−xCl_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 (CH₃)₃NPbI₃ perovskite lattice. The amount of Cl inserted was readily modulated by varying the (CH₃)₃NCl concentration in the (CH₃)₃NI/(CH₃)₃NCl 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 (CH₃)₃NPbI₃ fabricated under the same conditions. The perovskite solar cell devices with these (CH₃)₃NPbI_3−xCl_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 (CH₃)₃NPbI_3−xCl_x perovskite material with an aqueous nonhalide lead precursor is more efficient than conventional spin-casting approach with detrimental organic solvents.