Anti-Solvent Crystallization Strategies for Highly Efficient Perovskite Solar Cells

Abstract

Solution-processed organic-inorganic halide perovskites are currently established as the hottest area of interest in the world of photovoltaics, ensuring low manufacturing cost and high conversion efficiencies. Even though various fabrication/deposition approaches and device architectures have been tested, researchers quickly realized that the key for the excellent solar cell operation was the quality of the crystallization of the perovskite film, employed to assure efficient photogeneration of carriers, charge separation and transport of the separated carriers at the contacts. One of the most typical methods in chemistry to crystallize a material is anti-solvent precipitation. Indeed, this classical precipitation method worked really well for the growth of single crystals of perovskite. Fortunately, the method was also effective for the preparation of perovskite films by adopting an anti-solvent dripping technique during spin-coating the perovskite precursor solution on the substrate. With this, polycrystalline perovskite films with pure and stable crystal phases accompanied with excellent surface coverage were prepared, leading to highly reproducible efficiencies close to 22%. In this review, we discuss recent results on highly efficient solar cells, obtained by the anti-solvent dripping method, always in the presence of Lewis base adducts of lead(II) iodide. We present all the anti-solvents that can be used and what is the impact of them on device efficiencies. Finally, we analyze the critical challenges that currently limit the efficacy/reproducibility of this crystallization method and propose prospects for future directions.

Formamidinium‐Based Lead Halide Perovskites: Structure, Properties, and Fabrication Methodologies

“…The use of a second solvent (petroleum ether) makes this approach essentially an antisolvent treatment process, which is well known for MAPbI 3 devices, although chlorobenzene is more commonly used for both MAPbI 3 and FAPbI 3 . Antisolvent dripping to improve crystallization of the spin‐coated perovskite film is a common technique to prepare high‐efficiency perovskite devices, which has been recently reviewed . While antisolvent dripping has become a fairly common technique, it can be further modified, for example, to form graded heterojunctions with fullerene by adding fullerene to the antisolvent .…”

Μethylammonium Chloride: A Key Additive for Highly Efficient, Stable, and Up‐Scalable Perovskite Solar Cells

“…They fixed DMSO content so that a 1:1:1 PbI 2 :MAI:DMSO intermediate is formed. [69] In the case of MACl-excess crystallization, ethyl acetate was adopted as the anti-solvent. The role of DMSO in the MAI-PbI 2 -DMSO phase was to retard the rapid reaction between PbI 2 and MAI during the evaporation of solvent in the spin-coating process.…”

Highly Efficient and Stable MAPbI3 Perovskite Solar Cell Induced by Regulated Nucleation and Ostwald Recrystallization

“…Very recently, it was reported that antisolvent engineering was an effective means to boost the PCE of solar cells [14,15]. The non-polar antisolvent does not dissolve perovskite precursor (PbI 2 and CH 3 NH 3 I), but is quite miscible with DMF.…”