All-inorganic CsPbX3 (X = Cl, Br or I) perovskite nanocrystals have attracted extensive interest recently due to their exceptional optoelectronic properties. In an effort to improve the charge separation and transfer following efficient exciton generation in such nanocrystals, novel functional nanocomposites were synthesized by the in situ growth of CsPbBr3 perovskite nanocrystals on two-dimensional MXene nanosheets. Efficient excited state charge transfer occurs between CsPbBr3 NCs and MXene nanosheets, as indicated by significant photoluminescence (PL) quenching and much shorter PL decay lifetimes compared with pure CsPbBr3 NCs. The as-obtained CsPbBr3/MXene nanocomposites demonstrated increased photocurrent generation in response to visible light and X-ray illumination, attesting to the potential application of these heterostructure nanocomposites for photoelectric detection. The efficient charge transfer also renders the CsPbBr3/MXene nanocomposite an active photocatalyst for the reduction of CO2 to CO and CH4. This work provides a guide for exploration of perovskite materials in next-generation optoelectronics, such as photoelectric detectors or photocatalyst.

Homogeneous gold catalysis has received growing attention over the past few years, enabling the replacement of consolidated organic reactions with more simple, selective, and chemically sustainable alternatives. The fine-tunability of the electronic as well as steric properties of gold catalysts contributed substantially to the popularity of the research field, with robust applications in total synthesis and asymmetric catalysis. In this context, the metal counterions proved of pivotal importance in impacting both kinetics and selectivity of gold-assisted transformations. Despite the intrinsic difficulties in properly rationalizing and predicting the role of anions in complex reaction machineries, nowadays, some general trends are available. This review aims at presenting some leading examples of counterion-controlled gold catalysis, with particular emphasis on their structure–activity relationship.

Metal carbenes usually possess versatile reactivities that are controlled by the presence of both the metals and the ligands. Diazo compounds are commonly used for the generation of such species through elimination of nitrogen. However, they are often unstable, explosive, and toxic, which limits their applications in large-scale syntheses. Thus, identifying sustainable and safe surrogates for the generation of metal carbenes has attracted great attention. In this Review, we summarize some of the most important breakthroughs in the generation, catalytic reactions, and selectivity control of metal carbenes from non-diazo starting compounds.

The potential optoelectronic applications of perovskite nanocrystals (NCs) are primarily limited by major material instability arising from the ionic nature of the NC lattice. Herein, we introduce a facile and effective strategy to prepare extremely stable CsPbX3 NC-polymer composites. NC surfaces are passivated with reactive methacrylic acid (MA) ligands, resulting in the formation of homogenous nanocubes (abbreviated as MA-NCs) with a size of 14-17 nm and a photoluminescence quantum yield (PLQY) above 80%. The free double bonds on the surface then serve as chemically addressable synthetic handles, enabling UV-induced radical polymerization. Critically, a bromide-rich environment is developed to prevent NC sintering. The composites obtained from copolymerizing MA-NCs with hydrophobic methyl methacrylate (MMA) and methacrylisobutyl polyhedral oligomeric silsesquioxane (MA-POSS) monomers exhibit enhanced properties compared to previously reported encapsulated NCs, including higher QYs, remarkable chemical stability towards water, and much enhanced thermal stability. The good solubility of the composite in organic solvent further enables its use as a solution processable luminescent ink, used here for fabrication of white light-emitting diodes (WLED) with high luminous effciency and excellent color rendering index. The resulting fluorescent and stable NC ink opens the door to potential scalable and robust optoelectronic applications.

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