Unveiling the Relationship between the Perovskite Precursor Solution and the Resulting Device Performance

Abstract

For the fabrication of perovskite solar cells (PSCs) using a solution process, it is essential to understand the characteristics of the perovskite precursor solution to achieve high performance and reproducibility. The colloids (iodoplumbates) in the perovskite precursors under various conditions were investigated by UV–visible absorption, dynamic light scattering, photoluminescence, and total internal reflection fluorescence microscopy techniques. Their local structure was examined by in situ X-ray absorption fine structure studies. Perovskite thin films on a substrate with precursor solutions were characterized by transmission electron microscopy, X-ray diffraction analysis, space-charge-limited current, and Kelvin probe force microscopy. The colloidal properties of the perovskite precursor solutions were found to be directly correlated with the defect concentration and crystallinity of the perovskite film. This work provides guidelines for controlling perovskite films by varying the precursor solution, making it possible to use colloid-engineered lead halide perovskite layers to fabricate efficient PSCs.

Organic N‐Type Molecule: Managing the Electronic States of Bulk Perovskite for High‐Performance Photovoltaics

“…The obtained colloids consisting of HVI could promote perovskite crystals growth toward high crystallinity and uniform grains. [ 46–47 ] Because considering the bottom‐up‐growth process of the two‐step‐deposition perovskite films, we assume that the gradient‐distribution dopants may serve as heterogeneous nucleation centers. These centers could provide a significantly lower nucleation barrier than that associated with homogeneous nucleation, due to the decreased Gibbs free energy.…”

Small-angle scattering to reveal the colloidal nature of halide perovskite precursor solutions

“…One approach to gain further knowledge that has received considerable attention is to study the chemical organization in the precursor solution used to synthesize the perovskite thin film. 5,6 As the crystalline thin film is growing directly from solution, a detailed understanding of the crystallization mechanism is critical to enable control of the perovskite formation. In this regard, the colloidal chemistry of perovskite precursor solutions contributes significantly to the crystallization process and thus to the perovskite morphology, which is known to have a direct impact on the performance of PSCs.…”

“…In this regard, the colloidal chemistry of perovskite precursor solutions contributes significantly to the crystallization process and thus to the perovskite morphology, which is known to have a direct impact on the performance of PSCs. 5,7,8 In a theoretical study, Radicchi et al 9 present the iodoplumbate complexes [PbI m X n ] 2−m that can be expected in a certain solvent, being X N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), lead as the central atom. The role of solvents and coordination chemistry of the central atom Pb is one of the key topics in the field of solution chemistry for perovskite precursors.…”

“…13 Methods preferably used for solution characterization, like dynamic light scattering (DLS), UV-vis spectroscopy or cryogenic transmission electron microscopy (cryo-TEM) should be used with caution, as often the nature of the regarded system slightly differs, or crucial properties are only indirectly determined. 5,7,[14][15][16] Considering the origin of biochemical solutions (e.g. micelle formation), DLS is particularly suitable to detect larger nanostructures in the range of 5 to 1000 nm.…”

Crystal Reorientation and Amorphization Induced by Stressing Efficient and Stable P–I–N Vacuum‐Processed MAPbI3 Perovskite Solar Cells

“…[14,15] Recently, however, Holzhey et al, demonstrated that solution-processed MAPbI 3 -based solar cells exhibited operational stability in excess of 500 h under illumination when kept at 65 C. [16] It has been found that the residual solvent in the perovskite layer, [17] crystal structure, [18] grain size, [19] defect density, [20,21] and compactness of the film [22] affect the degradation of the perovskite layer. [23] Therefore, the preparation method is an important factor in obtaining stable perovskite films. Perovskite films have been fabricated by several methods, such as spin coating, [24] spray deposition, [25] dip coating, [26] doctor blading, [27] and vacuum deposition.…”