Sulfonium‐Cations‐Assisted Intermediate Engineering for Quasi‐2D Perovskite Solar Cells

Abstract

Quasi‐2D Ruddlesden–Popper (RP) perovskites with superior stability are admirable candidates for perovskite solar cells (PSCs) toward commercialization. However, the device performance remains unsatisfactory due to the disordered crystallization of perovskites. In this work, the effects of sulfonium cations on the evolution of intermediates and photovoltaic properties of 2D RP perovskites are investigated. The introduction of sulfonium cations leads to preferred intermediate transformation and improved film quality of perovskites. The resulting devices deliver a champion efficiency of 19.08% at room temperature and 20.52% at 180 K, due to reduced recombination and enhanced charge transport. More importantly, the unencapsulated device maintains 84% of the initial efficiency under maximum power point (MPP) tracking at 40 °C for 1000 h. This work helps to gain a comprehensive understanding of the crystallization process of quasi‐2D perovskites and provides a simple strategy to modulate the intermediates of perovskites.

Fabrication strategies for high quality halide perovskite films in solar cells

“…For the low-dimension perovskite, Wang et al developed an intermediate engineering method for quasi-2D Ruddlesden-Popper (RP) perovskites, (BDA)(MA) 4 Pb 5 I 16 , by introducing the sulfonium cations into the precursor solution. 57 In the control precursor solution without sulfonium cation, it is easy for the PbI 2 and MAI to react with DMF/DMSO to form [(MA + ) 2 -(PbI 3 ) 2 ÁS 2 ] (S = DMSO/DMF) and (PbI 2 ) 2 ÁS 2 intermediates. The (MA + ) 2 (PbI 3 ) 2 ÁS 2 can easily transform to the perovskite fiber (MAPbI 3 ) by losing the solvent.…”

Surface Reconstruction with Aprotic Trimethylsulfonium Iodide for Efficient and Stable Perovskite Solar Cells

“…44,45 The organosulfur compounds can strongly interact with uncoordinated Pb 2+ ions in 3D perovskites to passivate the surface defects. 46,47 Gao et al constructed 2D/3D heterojunction PSCs by using organosulfur amine [thienylmethylamine iodide (TMAI)] and its counterpart organic amine (PEAI) salts and showed that the perovskite film passivated by TMAI has lower trap state density, longer carrier lifetime, and higher overall stability, along with a PCE improvement of 5.1% compared to the PEAI-treated Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 PSC. 48 In another report, Gultekin et al used 2-thiophenecarboxylic acid (2TiCOOH) through post-treatment without forming 1D or 2D perovskites and passivated the uncoordinated Pb 2+ ions in Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 perovskite.…”

“…Organic sulfonium-based materials are an interesting class of aprotic compounds with higher hydrophobicity and chemical stability than their ammonium-based counterparts. − Recently, we reported 1D trimethylsulfonium lead iodide (TMSPbI 3 ) and trimethylsulfoxonium lead iodide perovskites-based on aprotic trimethyl sulfonium iodide (TMSI) and trimethyl sulfoxonium iodide, even though these perovskites exhibit low PCE, but their significantly higher moisture stability suggests the possibility to employ them as promising surface passivation layers for the development of stable and high-performance PSCs. , The organosulfur compounds can strongly interact with uncoordinated Pb 2+ ions in 3D perovskites to passivate the surface defects. , Gao et al constructed 2D/3D heterojunction PSCs by using organosulfur amine [thienylmethylamine iodide (TMAI)] and its counterpart organic amine (PEAI) salts and showed that the perovskite film passivated by TMAI has lower trap state density, longer carrier lifetime, and higher overall stability, along with a PCE improvement of 5.1% compared to the PEAI-treated Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb­(I 0.83 Br 0.17 ) 3 PSC . In another report, Gultekin et al.…”

Modulation of Colloidal Assembly Behavior Enables Printable Low‐Dimensional Perovskite Photovoltaics

“…Specifically, strategies such as component engineering, additive engineering, process optimization, and ligand engineering are utilized to optimize the complicated crystallization processes through thermodynamic and crystallization kinetic perspectives. [10][11][12][13] Nevertheless, the majority of optimization strategies are verified during spin-coating process, and further investigation in large-area devices under upscaling printing process remains elusive. It should be noted that the optimization strategy for the spin-coating process is hardly compatible with the printing process due to the film formation variability.…”