CsPb Br is a ternary halogen-plumbate material with close characteristics to the well-reported halide perovskites. Owing to its unconventional two-dimensional structure, CsPb Br is being looked at broadly for potential applications in optoelectronics. CsPb Br investigations are currently limited to nanostructures and powder forms of the material, which present unclear and conflicting optical properties. In this study, we present the synthesis and characterization of CsPb Br bulk single crystals, which enabled us to finally clarify the material's optical features. Our CsPb Br crystal has a two-dimensional structure with Pb Br layers spaced by Cs cations, and exhibits approximately 3.1 eV indirect band gap with no emission in the visible spectrum.

Here, we demonstrate an approach to synthesizing and structurally characterizing three atomically precise anion-templated silver thiolate nanoclusters, two of which form one-and two-dimensional structural frameworks composed of bipyridine-linked nanocluster nodes (referred to as nanocluster-based frameworks, NCFs). We describe the critical role of the chloride (Cl − ) template in controlling the nanocluster's nuclearity with atomic precision and the effect of a single Ag atom difference in the nanocluster's size in controlling the NCF dimensionality, modulating the optical properties, and improving the thermal stability. With atomically precise assembly and size control, nanoclusters could be widely adopted as building blocks for the construction of tunable cluster-based framework materials.

Copper-based nanomaterials have attracted tremendous interest due to their unique properties in the fields of photoluminescence and catalysis. As a result, studies on the correlation between their molecular structure and their properties are of great importance. Copper nanoclusters are a new class of nanomaterials that can provide an atomic-level view of the crystal structure of copper nanoparticles. Herein, a high-nuclearity copper nanocluster with 81 copper atoms, formulated as [Cu81(PhS)46( t BuNH2)10(H)32]3+ (Cu 81 ), was successfully synthesized and fully studied by X-ray crystallography, X-ray photoelectron spectroscopy, hydrogen evolution experiments, electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and density functional theory calculations. Cu 81 exhibits extraordinary structural characteristics, including (i) three types of novel epitaxial surface-protecting motifs; (ii) an unusual planar Cu17 core; (iii) a hemispherical shell, comprised of a curved surface layer and a planar surface layer; and (iv) two distinct, self-organized arrangements of protective ligands on the curved and planar surfaces. The present study sheds light on structurally unexplored copper nanomaterials and paves the way for the synthesis of high-nuclearity copper nanoclusters.

Metal-halide perovskite materials are highly attractive materials for optoelectronic applications. However, the instability of perovskite materials caused by moisture and heatinduced degradation impairs future prospects of using these materials. Here we employ water to directly transform films of the three-dimensional (3D) perovskite CsPbBr 3 to stable twodimensional (2D) perovskite-related CsPb 2 Br 5. A sequential dissolution-recrystallization process governs this water induced transformation under PbBr 2 rich condition. We find that these postsynthesized 2D perovskite-related material films exhibit excellent stability against humidity and high photoluminescence quantum yield. We believe that our results provide a new synthetic method to generate stable 2D perovskite-related materials that could be applicable for light emitting device applications.