For practical applications, the crystal quality of perovskites should be controlled in high reproducibility. However, current reports of solution-processed perovskite single crystals always meet with large fluctuations. For example, the resistivity of Pb-based perovskite SCs exhibits a wide fluctuation range from 10 7 to 10 9 Ω cm. [16][17][18] Moreover, the crystal surface is often troubled with terraces, which bring many undesired grain boundaries in the surface and negatively influence the properties. [1] These fluctuations all render the synthesis process inefficient, wasting a lot of time and raw materials.Above issues have also been observed in our recent work of Cs 2 AgBiBr 6 SC-based X-ray detectors. Due to the high average atomic number, high µτ product, and high resistivity, Cs 2 AgBiBr 6 is a potential material for direct X-ray conversion. Nevertheless, in a normal synthesis, Cs 2 AgBiBr 6 SCs are confronted with a wide resistivity range from 10 9 to 10 11 Ω cm [9] and hexagonal terraces are often seen on the surface. The wide resistivity range of Cs 2 AgBiBr 6 makes the dark current of the device with a high fluctuation range. We thus focus on the reproducible synthesis of stacking-free, high-quality Cs 2 AgBiBr 6 SCs for X-ray detectors.For solution synthesis of single crystals, there are successful theories to direct the growth process, which have been studied a lot in other materials like KH 2 PO 4 . [19,20] Principally, LaMer's [21] theories describe the crystal growth process as that the solution enters the nucleation stage upon the concentration of the precursor reaches the critical level for nucleation, and then the gradual consumption of the solute decreases the concentration into growth region where crystal nuclei could keep growing while no new nucleus could form. Further decreasing the concentration may lead to the dissolution of the products. Thereby, the nucleation and growth concentration are two key factors toward precise control over reproducibility and crystal quality. For perovskite crystal growth, such information is rarely reported, except some studies disclosed the value of solubility, [22][23][24][25] which is not enough for guiding the whole nucleation and crystal growth process.Herein, we measured the solubility and supersolubility curve to direct the growth process of Cs 2 AgBiBr 6 SCs. The supersolubility is defined as the solute concentration when nucleation starts in precursor solution, and the solubility is the Cs 2 AgBiBr 6 double perovskite recently emerges as a promising semiconductor for ionization detections because of the low detection limit and nontoxic composition. However, it suffers from unsatisfactory reproducibility and wide fluctuation of electrical properties, as also in other halide perovskite systems. Here, solubility and supersolubility are employed as quantitative indicators to direct the growth of Cs 2 AgBiBr 6 single crystals. The optimized Cs 2 AgBiBr 6 crystals exhibit smooth surface as well as high resistivity with narrow distribution from 6.10 × 10 ...

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Both of O-glycosides and nucleosides are important biomolecules with crucial rules in numerous biological processes. Chemical synthesis is an efficient and scalable method to produce well-defined and pure carbohydrate-containing molecules for deciphering their functions and developing therapeutic agents. However, the development of glycosylation methods for efficient synthesis of both O-glycosides and nucleosides is one of the longstanding challenges in chemistry. Here, we report a highly efficient and versatile glycosylation method for efficient synthesis of both O-glycosides and nucleosides, which uses glycosyl ortho-(1-phenylvinyl)benzoates as donors. This glycosylation protocol enjoys the various features, including readily prepared and stable donors, cheap and readily available promoters, mild reaction conditions, good to excellent yields, and broad substrate scopes. In particular, the applications of the current glycosylation protocol are demonstrated by one-pot synthesis of several bioactive oligosaccharides and highly efficient synthesis of nucleosides drugs capecitabine, galocitabine and doxifluridine.

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As readily accessible strained carbocycles, cyclopropenes show a diverse range of reactivities, and a lot of novel and useful transformations have been developed.

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