Tin-based halide perovskite materials have been successfully employed in lead-free perovskite solar cells,b ut the overall power conversion efficiencies (PCEs) have been limited by the high carrier concentration from the facile oxidation of Sn 2+ to Sn 4+ .N ow ac hemical route is developed for fabrication of high-quality methylammonium tin iodide perovskite (MASnI 3 )f ilms:h ydrazinium tin iodide (HASnI 3 ) perovskite film is first solution-deposited using presursors hydrazinium iodide (HAI) and tin iodide (SnI 2 ), and then transformed into MASnI 3 via acation displacement approach. With the two-step process,adense and uniform MASnI 3 film is obtained with large grain sizes and high crystallization. Detrimental oxidation is suppressed by the hydrazine released from the film during the transformation. With the MASnI 3 as light harvester,m esoporous perovskite solar cells were prepared, and amaximum power conversion efficiency (PCE) of 7.13 %i sdelivered with good reproducibility.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Presented herein is an intriguing effect of fluorine, and it allows difluoroenol silyl ethers to couple with aryliodanes in ar edox-neutral manner to affordo rtho-iodo difluoroalkylated arenes.T he remaining iodide group provides av ersatile platform for converting the products into various valuable difluoroalkylated arenes.T he reaction shows excellent functional-group compatibility and broad substrate scope. AD FT mechanistic study suggests that the fluorine effect facilitates as ubtle nucleophilic attacko ft he oxygen atom of enol silyl ethers onto aryliodanes,t herefore leading to ar earrangement.Scheme 1. Backgrounda nd initial results. TMS = trimethylsilyl.

A DFT comparative mechanistic study unveils that the TBD-catalyzed reactions of amines with CO2 and hydrosilanes may either undergo a neutral mechanism or a mechanism involving free ions, depending on the polarity of the solvent. The nucleophilicity of the amines is an important factor to determine the chemoselectivities of the reactions to give formamide or aminal/N-methylated amine.

Methylammonium iodide (MAI) and lead iodide (PbI ) have been extensively employed as precursors for solution-processed MAPbI perovskite solar cells (PSCs). However, the MAPbI perovskite films directly deposited from the precursor solutions, usually suffer from poor surface coverage due to uncontrolled nucleation and crystal growth of the perovskite during the film formation, resulting in low photovoltaic conversion efficiency and poor reproducibility. Herein, propylammonium iodide and PbI are employed as precursors for solution deposition of propylammonium lead iodide (PAPbI ) perovskite film. It is found that the precursors have good film formability, enabling the deposition of a large-area and homogeneous PAPbI perovskite film by a scalable dip-coating technique. The dip-coated PAPbI film is then subjected to an organic-cation displacement reaction, resulting in MAPbI film with high surface coverage and crystallinity. With the MAPbI film as the light absorber, planar PSCs are fabricated, and stabilized power conversion efficiencies of 19.27% and 15.68% can be achieved for the devices with active areas of 0.09 and 5.02 cm , respectively. The technology reported here provides a robust and efficient approach to fabricate large-area and high-efficiency perovskite cells for practical application.

A simple high-performance liquid chromatographic (HPLC) assay using the internal standard method is developed for the simultaneous determination of eight polyphenols. The analyzed compounds isolated from the leaves of Crataegus pinnatifida Bge. var. major include chlorogenic acid, vitexin-4"-O-glucoside, vitexin-2"-O-rhamnoside, vitexin, rutin, hyperoside, isoquercitrin, and quercetin. HPLC analysis is performed on a Diamonsil C18 analytical column (150 x 4.6 mm, i.d., 5-microm) using solvent (A) acetonitrile-tetrahydrofuran (95:5, v/v) and (B) 1% aqueous phosphoric acid as the mobile phase with UV absorption at 270 nm. The calibration curves of the eight polyphenols are linear (r(2) > 0.9992) over the concentration range of 0.0894-120.0 microg/mL. The mean recoveries are 95.4% to 98.1%. The results indicate that the HPLC method developed can easily be applied to the determination of eight polyphenols in the leaves of Crataegus pinnatifida Bge. var. major.