Two‐Step Sequential Deposition of Organometal Halide Perovskite for Photovoltaic Application

Abstract

simply divided into two kinds, one-step and two-step methods. The one-step method has been adopted in pioneering works. [3,11,21] However, the naturally crystallized perovskite often exhibited an anisotropic growth, leading to low uniformity and poor coverage. [22,23] This phenomenon limited the PV performance, which should be solved by the following anti-solvent strategy. [8,12,24] For the two-step method, PbI 2 layer was first deposited, followed by the conversion to perovskite in MAI solution. [25,26] Since the deposition processes and the control strategy of PbI 2 layer are versatile and flexible, uniform and full coverage PbI 2 layer could be easily obtained, which tends to improve the quality of the perovskite layer.The first successful work on the two-step method for PSCs was reported by Burschka et al. in 2013, which obtained a record PCE of 15% at that time. [26] Soon after, tremendous following works have been conducted on the two-step method due to its high operability and good performance reproducibility. Most importantly, the great progress on the reaction/ growth mechanism of the two-step method resulted in more modified processes, which well improved perovskite quality and enhanced device performance. Typically, by combining the second spin-coating step with the optimization on MAI concentration, perovskite grain size was optimized to absorb most of visible light with the minimum recombination loss, which promoted the PCE to over 16%. [7] Then, a novel interdiffusion strategy based on two spin-coating step process further improved the perovskite quality and promoted the PCE to about 19%. [27] Recently, by applying a new Pb-I precursor of PbI 2 (DMSO), high-quality FAPbI 3 /MAPbBr 3 perovskite was obtained through intramolecular exchange between FA/MA with DMSO, which boosted the PCE to over 20%. [4] Therefore, the two-step method has been well proved to be an effective approach to synthesize high-quality perovskite for high-performance PSCs.Herein, we made a thorough review on the recent progresses on the two-step deposition of perovskite for the application in PSCs. Firstly, we will review the reaction principle at the second step, converting lead-based precursor to perovskite. Then, the researches on the deposition technique, structure, and composition of lead-based precursors will be collected and discussed, followed by a summary on the conversion technique, conversion atmosphere, and growth of large crystals at the second step. Finally, the issues on the two-step method will be stated, accompanied with proposed solutions.Organometal halide perovskite materials have become a superstar in the photovoltaic (PV) field because of their advantageous properties, which boost the power conversion efficiency (PCE) of perovskite solar cells (PSCs) from about 3.8% to above 22% in just seven years. Most importantly, such promising achievement is mainly based on its low-cost and solution-processed fabrication technique. One of the most promising and famous approaches to fabricating perovskite is a two-step s...

The Impact of a Dynamic Two‐Step Solution Process on Film Formation of Cs0.15(MA0.7FA0.3)0.85PbI3 Perovskite and Solar Cell Performance

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Iodine Induced PbI2 Porous Morphology Manipulation for High‐Performance Planar Perovskite Solar Cells

“…Except for the phase purity of perovskite, the morphology of perovskite is also quite important for the device performance. In general, perovskite film with a large grain size and smooth surface can improve the charge transport and reduce the charge recombination, which are favorable for the high PCE . So it is quite desirable to simultaneously manipulate the phase purity and morphology of perovskite film with the sequential deposition.…”

Sequential deposition method fabricating carbonbased fully-inorganic perovskite solar cells

“…Stability is still a challenge for the hybrid PSCs [27]. Herein the stability test of the devices based on D-40 films were conducted under ambient air without any encapsulation.…”