Research Briefing

Charge-selective contacts have a key role in increasing the efficiency of perovskite solar cells (PSCs). A hole-transport material (HTM) is designed based on a symmetric aromatic molecule that facilitates long-range ordered π–π stacking on substrates. This HTM shows enhanced charge-transport properties, and when incorporated into PSCs, helps to deliver good efficiency and stability.

Selective functionalization of methylene C−H bonds at distal positions remains a challenge. Now, through ligand design, the Pd-catalysed activation of distal methylene C(sp³)–H groups in free carboxylic acids for the assembly of γ,δ-benzocyclobutene (BCB) acids is demonstrated. This approach enables the preparation of diverse BCBs from simple starting materials.

Two-dimensional (2D) perovskite passivation layers can enhance the performance of perovskite solar cells but controlling their phase purity remains a challenge. Now, a non-invasive surface reaction (NSR) strategy enables the formation of phase-pure 2D perovskite passivation layers with controlled dimensions. Devices based on NSR-treated perovskites show good efficiency and operational stability.

Asymmetric migratory cross-couplings that proceed through heteroatom-based group migration are challenging. Now, a nickel-catalysed cross-coupling reaction of amino alcohol-derived sulfonates with various carbon-based electrophiles, enabled by a radical 1,2-amino migration process, is reported. Using chiral biimidazoline ligands, diverse β-arylethylamines can be accessed with high stereoselectivity and reactivity.

Controlling the synthesis of semiconductor nanoclusters — or artificial atoms — is a challenge. Now, a programmable method is introduced to create a series of precisely defined semiconductor clusters, Zn₁₄Se₁₃, Cd₁₄Se₁₃ and Hg₁₄Se₁₃, which exhibit atom-like electronic structures and distinct doublet absorptions.

A method for the synthesis of oligosulfonimidates with control of the monomer sequence and the stereogenicity at each of the S(VI) atoms is demonstrated. This approach hinges on the use of robust and enantiospecific sulfur–fluoride and sulfur–phenolate exchange reactions and also allows for the efficient synthesis of chiral sequence-controlled polymers.

Stereochemical integrity is preserved in an intramolecular Friedel–Crafts alkylation, enabling the synthesis of axially chiral spirocarbons. Leveraging this stereoretentive alkylation, an iterative synthetic approach is developed for constructing enantiopure multispirocarbon-bridged carbocycles through a one-shot stereospecific conversion of chiral tertiary alcohol units, in a ‘zipping-up’ process.

The synthesis of fully π-conjugated carbon nanobelts has been a long-standing challenge. Now, through the introduction of pentagonal rings, fully π-conjugated non-alternant carbon nanobelts are realized. These nanobelts exhibit smaller band gaps and more effective π-conjugation than all-benzenoid counterparts.

Nanocrystals are increasingly used in high-tech applications and consumer products, but water-stable variants for life science and healthcare applications have production bottlenecks owing to complex syntheses. Now, water-stable nanocrystals are made in a single step by replacing ‘oily’ reagents with oxygen-rich alkoxy ligands and solvents, endowing the nanocrystals with broad solvent dispersibility.

Dendralenes, polyene structures with extensive cross-conjugation, have long fascinated organic chemists. Now, the streamlined synthesis of long dendralene skeletons is realized through the copper-mediated chain-growth polymerization of strained [3]cumulenes. The resultant polymers enable two-photon lithography in the visible range.

A tricoordinate antimony(III) dication with multiple coordination sites has been isolated that can bind two different substrates in proximity and promote a reaction. The lowest unoccupied molecular orbital (LUMO) and the 5s lone pair on the antimony centre interact with diphenylamine and styrene, respectively, to facilitate intermolecular hydroamination.

Homogeneous two-dimensional multicomponent materials are difficult to synthesize using current methods. Now, a strategy — termed space-confined chemical vapour transport — is developed for the synthesis of transition metal phosphorous chalcogenides and their high-entropy alloys with precise control of the composition and without phase separation.

Superconductivity in infinite-layer nickelates has been restricted to epitaxial thin films, limiting experimental exploration. The constraints of substrate-bound geometries have now been overcome by using a technique that integrates a water-soluble sacrificial layer into superconducting (Nd,Sr)NiO₂/SrTiO₃ heterostructures, enabling the release of the infinite-layer nickelate in a freestanding form.

Control of the lattice alignment within perovskite films is crucial to achieving stable and efficient devices. Now, the sublimation of volatile species from a two-dimensional perovskite enables the controlled growth of three-dimensional α-formamidinium lead iodide films. The highly orientated perovskite films yield a solar cell with good operational stability and device efficiency.

Electrochemical acetaldehyde production from CO₂ could provide a sustainable alternative to petrochemical-based methods but catalyst development is typically slow. Now, a high-throughput method accelerates the catalyst selection and production process from years to a few months, resulting in the identification of a copper cluster catalyst with 92% selectivity for acetaldehyde from CO₂.

Simultaneous application of mechanical and chemical effects during materials synthesis can increase control of crystallization, but use of this strategy in preparing halide perovskite films is underexplored. Now, a method that integrates rapid chemical crystallization with mechanical shearing enables the fabrication of perovskite films with long-range crystalline order and enhanced optoelectronic properties.

Site-selective C–H bond functionalization of silanes is challenging because of the presence of multiple C–H bonds. Now, a photocatalytic method for the radical β-C(sp³)–H functionalization of silanes using the β-silicon effect is developed, enabling the aminoalkylation, alkylation and arylation of simple silanes to prepare more complex organosilicon compounds.

Simultaneously achieving high energy and carbon efficiency in ethanol electrosynthesis is challenging. Now, an interfacial cation matrix (ICM) is developed that modifies the catalyst microenvironment to increase these performance metrics towards multicarbon products in the acidic CO₂ reduction reaction. Furthermore, combining a tailored Cu–Ag catalyst with the ICM facilitates selective ethanol electrosynthesis.

Singly bonded, low-valent group 13 compounds are rare, and their reactions are typically limited to oxidative additions. Now, a compound with a singly bonded gallium(i) centre has been prepared using a sterically hindered ligand. This compound exhibits varied reactivity, undergoing both oxidative addition and redox-invariant carbometallation reactions.

Sulfur(vi) fluoride exchange and modular diazotransfer reactions have advanced click chemistry, but their mechanisms and reactivity profiles are not well understood. Now, a computational study of these reactions provides mechanistic insights and predictive reactivity models for modular diazotransfer, facilitating the development of an easy-to-prepare and -handle diazotransfer reagent with excellent reactivity.