Facet-induced coordination competition for highly ordered CsPbBr_(3) nanoplatelets with strong polarized emission

Controllable anisotropic growth of perovskite nanocrystals(NCs)is challenging since it is difficult to separate the nucleation and growth processes.Here,a two-step nucleation strategy is proposed to control the binding interaction between surface ligands and NCs,resulting in facet-induced coordination competition.Oleic acid as surface activated ligand leads to the formation of defective lead bromine octahedron,and the binding interaction between 4-dodecylbenzenesulfonic acid and lead atoms promotes the formation of two kinds of binding interactions.Based on this strategy,the anisotropic growth of CsPbBr_(3) nanoplatelet(NPLs)with adjusted length from 11.4 to 24 nm,and the evolution of NPLs from stacked to tongue-shaped have been realized.Elemental line scan reveals the sulfur atoms mainly distribute at the edge of NPLs.Furthermore,binding energy calculation and experimental results illustrate the coordination competition of different binding interaction on specific facets induces the anisotropic growth of NPLs.Importantly,strong emission anisotropy of highly ordered NPLs with polarization ratio up to 0.58 is illustrated.This work not only deepens our understanding of the controllable synthesis of perovskite NCs,but also provides a reference for the regulation of light emitting diode and soler cells.

Chain-to-Chain Competition Under Demand Uncertainty

In this paper,we aim to study the structure choice of supply chains under competitive environment with uncertain demand.We consider two competing supply chains,each of which chooses to either vertically integrate or decentralize with coordinating contracts.We first analyze firms’strategic behavior under given supply chain structures:two integrated chains(II),two decentralized chains(DD),and a mixed structure with one decentralized chain and one integrated chain.We then compare different supply chain structures and examine the equilibrium structure choice.We find that the equilibrium structure depends on the product characteristics.For substitutable products,DD is the equilibrium supply chain structure choice,whereas for complementary products,II is the equilibrium structure.Furthermore,a high demand uncertainty strengthens these equilibrium choices.

Highly efficient Hg2+ removal via a competitive strategy using a Co-based metal organic framework ZIF-67

The stronger coordination ability of mercury ions with organic ligands than the metal ions in metal organic framework(MOFs) provides an accessible way to separate mercury ions from solution using specific MOFs. In this study, a Co-based MOF(ZIF-67, Co(mIM)) was synthesized. It did not introduce specific functional groups, such as-SH and-NH, into its structure through complicated steps. It separate Hgfrom wastewater with a new strategy, which utilized the stronger coordination ability of Hgwith the nitrogen atom on the imidazole ring of the organic ligand than the Coions. Hgreplaced Conodes from ZIF-67 and formed a more stable precipitate with m IM. The experimental results showed that this new strategy was efficient. ZIF-67 exhibited Hgadsorption capacity of 1740 mg/g, much higher than the known MOFs sorbents. m IMs is the reaction center and ZIF-67 can improve its utilization. The sample color faded from purple to white due to the loss of cobalt ion. It is a great feature of ZIF-67 that allows users to judge whether the sorbent is deactivated intuitively. ZIF-67 can be sustainable recycled by adding organic ligands to the solution after treatment due to its simple synthesis method at room temperature. It’s a high-efficient and sustainable sorbent for Hgseparation from wastewater.