Highly emissive isotropic CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals are typically observed in a six-faceted cube shape. When a unique approach is adopted and the reaction medium is enriched with halides, arm growth on all six facets was carried out and reported. Analysis suggested that these armed nanostructures were obtained from intermediate polyhedron shaped structures having 26 facets, and these were formed under halide-deficient conditions. Surface energy calculations further supported the possible existence of all facets for both of these structures under different halide composition environments. The entire study was first explored for CsPbBr3 and then extended to CsPbCl3; however, for CsPbI3 nanocrystals, Sr­(II) dopant was used for obtaining stable emission. Arm lengths could also be tuned with a function of reaction temperature for CsPbBr3. Formation of stable facets in polyhedron shaped nanostructures and their transformation to respective hexapods under halide-deficient and halide-rich conditions add new fundamental concepts for these nanostructures and their shape evolutions.

Organic-inorganic metal-halide materials (OIMMs) with zero-dimensional (0D) structures offer useful optical properties with a wide range of applications. However, successful examples of 0D structural OIMMs with well-defined optical performance at the micro-/nanometer scale are limited. We prepared one-dimensional (1D) (DTA) 2 SbCl 5 •DTAC (DTAC = dodecyl trimethyl ammonium chloride) single-crystal microrods and 2D microplates with a 0D structure in which individual (SbCl 5 ) 2À quadrangular units are completely isolated and surrounded by the organic cation DTA + . The organic molecular unit with a long alkyl chain (C 12 ) and three methyl groups enables microrod and -plate formation. The singlecrystal microrods/-plates exhibit a broadband orange emission peak at 610 nm with a photoluminescence quantum yield (PLQY) of ca. 90 % and a large Stokes shift of 260 nm under photoexcitation. The broad emission originates from selftrapping excitons. Spatially resolved PL spectra confirm that these microrods exhibit an optical waveguide effect with a low loss coefficient (0.0019 dB mm À1 ) during propagation, and linear polarized photoemission with a polarization contrast (0.57).Organic-inorganic metal-halide materials (OIMMs), a bulk crystal with 0D structure at the molecular level, have attracted tremendous attentions due to their potential optoelectronic applications as light-emitting materials. [1] These materials though in bulk; but can have bright emission and also retain as high as near unity photoluminescence quantum yield (PLQY). [2] Among different applications these could also serve as a potential optical materials in micro-/ nanosized optical waveguides. [3] To date, research on optical

Low-cost and eco-friendly metal hybrid materials with zero dimensional (0D) structure have recently attracted increasing attention owing to their excellent optical properties and widely applications. However, successful examples of 0D...

The conversion of metal halides to lead halide perovskites with B-site metal ion diffusion has remained a convenient approach for obtaining shape-modulated perovskite nanocrystals. These transformations are typically observed for materials having a common A-site Cs-sublattice platform. However, due to the fast reactions, trapping the interconversion process has been difficult. In an exploration of the tetragonal phase of Cs7Cd3Br13 platelets as the parent material, herein, a slower diffusion of Pb­(II) leading to facet-modulated CsPbBr3 platelets is reported. This was expected due to the presence of Cd­(II) halide octahedra along with Cd­(II) halide tetrahedra in the parent material. This helped in microscopically monitoring their phase transformation via an epitaxially related core/shell intermediate heterostructure. The transformation was also derived and predicted by density functional theory calculations. Further, when the reaction chemistry was tuned, core/shell platelets were transformed to different facet-modulated and hollow CsPbBr3 platelet nanostructures. These platelets having different facets were also explored for catalytic CO2 reduction, and their catalytic rates were compared.

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