In this communication, we demonstrate that chiral self-assembled monolayers can be used for polymorphism control of chiral crystals. We studied the crystallization of DL-glutamic acid on chiral self-assembled monolayers and showed that crystallization of DL-glutamic acid on the chiral SAMs resulted in stabilization of the metastable conglomerate form.

Considering the toxicity of lead ions, substituting Pb with nontoxic elements in halide perovskites, HaPs, has become one of the most significant challenges associated with these materials. Here, we report on replacing Pb with Sn and Ge, focusing on an all-inorganic HaP, CsSn x Ge1–x Br3, and using a multihead spray deposition setup for thin-film formation to overcome the low solubility of the precursors and improve film coverage. We find that, in this way, we can form CsSn x Ge1–x Br3 films up to high x values as homogeneous solid solutions; i.e., we obtain a range of compositions with one crystal structure (rather than clusters of two phases). The cubic structure of pure CsSnBr3 is maintained up to 77 atom % Ge, with the lattice spacing decreasing with increasing Ge concentration. The optical band gap is tunable between 1.8 and 2.5 eV, from pure Sn to pure Ge HaP. Most importantly, the perovskite structural stability increases with increasing concentration of Ge, with less oxidation of both Ge and Sn to the +4 state, which can be ascribed to less octahedral tilting and stronger bonding. Electrical and electronic transport measurements show the potential of these materials as Pb-free absorbers for solar cells, particularly, given their band gap range as the top cell of a tandem photovoltaic device.

A detailed investigation is presented for the solvent-free mechanochemical synthesis of zinc oxide nanoparticles from ε-Zn(OH)2 crystals by high-energy ball milling. Only a few works have ever explored the dry synthetic route from ε-Zn(OH)2 to ZnO. The milling process of ε-Zn(OH)2 was done in ambient conditions with a 1:100 powder/ball mass ratio, and it produced uniform ZnO nanoparticles with sizes of 10–30 nm, based on the milling duration. The process was carefully monitored and the effect of the milling duration on the powder composition, nanoparticle size and strain, optical properties, aggregate size, and material activity was examined using XRD, TEM, DLS, UV-Vis, and FTIR. The mechanism for the transformation of ε-Zn(OH)2 to ZnO was studied by TGA and XPS analysis. The study gave proof for a reaction mechanism starting with a phase transition of crystalline ε-Zn(OH)2 to amorphous Zn(OH)2, followed by decomposition to ZnO and water. To the best of our knowledge, this mechanochemical approach for synthesizing ZnO from ε-Zn(OH)2 is completely novel. ε-Zn(OH)2 crystals are very easy to obtain, and the milling process is done in ambient conditions; therefore, this work provides a simple, cheap, and solvent-free way to produce ZnO nanoparticles in dry conditions. We believe that this study could help to shed some light on the solvent-free transition from ε-Zn(OH)2 to ZnO and that it could offer a new synthetic route for synthesizing ZnO nanoparticles.

The origin of crystalline complex superstructures of biomaterials and the unique selfassembly mechanisms of their formations have attracted a great deal of attention recently. In this paper the crystallization of cystine hierarchical structures by a crystallization procedure that mimics the slow oxidation chemistry of L-cysteine to L-cystine is studied. The crystalline superstructures of cystine are identified by X-ray diffraction (XRD), micro Raman spectroscopy, and scanning electron microscopy (SEM). It is found that the formation of unique spherical or hexagonal shaped cystine hierarchical structures depends on the initial concentration of L-cysteine. A possible mechanism based on the self-assembly process of cystine crystals is proposed. Overall our study suggests that it is possible to control morphogenesis and the formation of cystine crystalline superstructures by a simple chemical method that mimics biomineralization.

Na‐ion batteries have recently emerged as a promising alternative to Li‐based batteries, driven by an ever‐growing demand for electricity storage systems. In the present work, we propose a cobalt‐free high‐capacity cathode for Na‐ion batteries, synthesized using a high‐entropy approach. The high‐entropy approach entails mixing more than five elements in a single phase; hence, obtaining the desired properties is a challenge since this involves the interplay between different elements. Here, instead of oxide, oxyfluoride is chosen to suppress oxygen loss during long‐term cycling. Supplement to this, Li was introduced in the composition to obtain high configurational entropy and Na vacant sites, thus stabilizing the crystal structure, accelerating the kinetics of intercalation/deintercalation, and improving the air stability of the material. With the optimization of the cathode composition, a reversible capacity of 109 mAh g−1 (2‐4 V) and 144 mAh g−1 (2‐4.3 V) is observed in the first few cycles, along with a significant improvement in stability during prolonged cycling. Furthermore, in‐situ and ex‐situ diffraction studies during charging/discharging reveal that the high‐entropy strategy is successful in suppressing the complex phase transition. The impressive outcomes of the present work strongly motivate the pursuit of the high‐entropy approach to develop efficient cathodes for Na‐ion batteries.This article is protected by copyright. All rights reserved