Review of Two‐Step Method for Lead Halide Perovskite Solar Cells

Abstract

The quality of the perovskite film is crucial to the technological breakthrough of perovskite solar cells (PSCs). The two‐step method can facilitate the formation of a perovskite film with high quality and reproducibility. Many milestones have been made in the development of hybrid lead halide PSCs by using the two‐step method, which has a significant impact on their practical application. Herein, the reaction mechanism of the two‐step method including two‐step immersion method and two‐step spin coating method is summarized. The strategies such as component engineering, solvent engineering, and additive engineering of the two‐step method in preparing high‐quality films are introduced systematically and in detail. In addition, current issues of the two‐step method and its applications in lead‐free PSCs, all‐inorganic PSCs, large areas, and tandems are introduced and some suggestions are put forward for future research.

0D–3D mixed-dimensional perovskite Cs4Pb(BrCl)6–CsPbBr2−xCl1+x films for stable and sensitive self-powered, high-temperature photodetectors

“…In terms of perovskite film formation by a two-step solution reaction, a porous lead halide film with a flat surface makes the reaction occur more easily and leads to the formation of a pure-phase and compact film. 40,41 Therefore, we speculate that the 0.10 M CsCl additive seems to be the best choice for preparing the target sample. As shown in Fig.…”

Simultaneous Surface Modification and Defect Passivation on Tin Oxide–Perovskite Interfaces using Pseudohalide Salt of Sodium Tetrafluoroborate

“…In most cases, a spun‐cast lead iodide (PbI 2 ) layer was prepared first, followed by the thermally diffused organic salt ions. [ 28 ] We found that the formation of an incomplete perovskite phase during the crystal growth process after annealing leaves an unreacted PbI 2 component that causes low crystallinity, pinholes, and irregular grains in the resulting perovskite film, eventually negatively affects optoelectronic properties, i.e., electronic disorders and/or a shunt device. Figure 1c shows a top‐view SEM image of the spun‐cast PbI 2 –CsI layer.…”

2D Material and Perovskite Heterostructure for Optoelectronic Applications

“…However, bulk perovskites are unstable under ambient atmosphere and irradiation, which triggers studies on their more stable reduceddimensional counterparts, namely 0D quantum dots, 2D, and quasi-2D. Comprehensive reviews on the synthesis of perovskites can be found in [5][6][7][8][9]62,63], and therefore we summarize the synthesis methods of perovskites with different dimensions for optoelectronic applications in this review.…”

“…Alternatively, the organic salt solution is spin-coated on the inorganic layer to form the desired 3D LHPs (Figure 3a). For the two-step sequential deposition methods, it is important to control parameters to obtain the high-quality film, such as the morphology of the inorganic layer at the first step, the concentration of the organic salt solution, and the speed of the spincoating [62]. Although the two-step method offers good reproducibility and compact films, it often encounters an issue of incomplete conversion.…”