Additive Engineering in Antisolvent for Widening the Processing Window and Promoting Perovskite Seed Formation in Perovskite Solar Cells

Abstract

The chlorobenzene (CB) antisolvent is widely used to fabricate high-efficiency perovskite solar cells (PSCs). However, the narrow processing window and the strict volume ratio of a binary mixed solvent limit the fabrication of large-area and high-quality perovskite films. In this work, by systematic investigation of additives with the CB antisolvent, a universal guideline is achieved wherein a small amount of additive with a donor number between 9.0 and 27.0 kcal/mol can significantly widen the antisolvent treating time slot from 2 to 40 s while simultaneously enlarging the processor binary mixed solvent (dimethylformamide/dimethyl sulfoxide) from 7:3 to 0:10. Moreover, this process facilitates the formation of perovskite seeds as templates for perovskite crystal growth, effectively reducing the bulk defects in perovskite films. Finally, the obtained PSCs show remarkable power conversion efficiencies (PCEs) of 22.22 and 19.74% for rigid and flexible devices, respectively.

Seeding Agents in Metal Halide Perovskite Solar Cells: From Material to Mechanism

“…Reproduced with permission. [73] Copyright 2022, American Chemical Society. and reduced strain, thus the photovoltaic device performance and long-term stability during operation.…”

“…Recently, Feng et al. used a small amount of polar solvent in chlorobenzene to facilitates the formation of perovskite seeds [73] . They found the major factor influencing the formation is the donor number (DN) of the solvent, which present the intermolecular interaction between solvents and cations.…”

Molecular design for perovskite solar cells

“…Replacing DMSO with N‐methyl‐2‐pyrrolidone (NMP, C5H9NO) leads to the formation of a stable intermediate adduct that is ascribed to the stronger interaction between NMP with NH 2 CH=NH 2 I (FA) (Figure 2J), 127 while the complex molecule‐mediated film growth process is elucidated when FAI, MAI and PbI 2 (DMSO) x are considered in DMSO and diethyl ether 128 . In addition, various anti‐solvent molecules have been proposed, which are often related to the formation of the intermolecular hydrogen bonds that affect the perovskite film growth 129‐131 . (4) Solvent combination is another feasible approach to further modify the intermediates and the perovskite crystallization process 132,133 .…”

Introduction of cadmium chloride additive to improve the performance and stability of perovskite solar cells

“…16,17 To date, several ways of controlling perovskite morphology have been explored, involving manipulating the deposition method, additive engineering, interfacial engineering, and compositional engineering. [18][19][20][21][22] Additive engineering has been shown to be effective in improving the quality of the perovskite layer since it is a more simple and reproducible approach. Some agents, including copper chloride, N,1-diiodoformamidine, potassium hexauorophosphate, formamidine acetate salt, etc., can form an intermediate phase with perovskite precursors, which could regulate the dynamic process of crystal formation and thereby minimize GBs.…”