Naughty Paul

Is one electron sufficient to bring about significant σ bonding between two atoms? The chemist’s view on the chemical bond is usually tied to the concept of shared electron pairs, and not too much experimental evidence exists to challenge this firm belief. Whilst species with the unusual one-electron σ-bonding motif between homonuclear atoms have so far been identified mainly by spectroscopic evidence, we present herein the first crystallographic characterization, augmented by a detailed quantum-chemical validation, for a radical anion featuring a B⋅B one-electron-two-center σ bond.

One is enough: The first structurally characterized radical anion containing a B⋅B one-electron σ bond shows a significantly shorter B⋅⋅⋅B distance than the uncharged starting material, while the boron centers largely maintain their local planarity.

Nanoscale CdTe-CdS bulk heterojunctions are constructed in situ by annealing mercaptoethylamine-stabilized CdTe nanocrystals (NCs), which exhibit efficient separation, transport, and injection of photogenerated carriers. Inorganic NC solar cells based on the CdTe-CdS bulk heterojunction exhibit a power conversion efficiency of up to 4% and an internal quantum efficiency approaching 100%.

Rare earth (RE) nanoparticles have attracted considerable attention due to their unique optical and magnetic properties associated with f-electrons. The recent accomplishments in RE nanoparticle synthesis have aroused great interest of scientists to further explore their biomedical applications. This Research News summarizes recent achievements in controlled synthesis of magnetic and luminescent RE nanoparticles, surface modification, and toxicity studies of RE nanomaterials, and highlights state-of-the-art in in vivo applications of RE nanoparticles.

Owing to the unique magnetic and optical properties associated with f-electrons, rare earth (RE) nanoparticles show great potential for versatile in vivo applications, especially sensitive tumor imaging according to animal experiments. Recent achievements in the synthesis, surface modification, in vivo application, and toxicity of RE nanoparticles are summarized, and their perspectives for clinical applications are discussed.

Enhanced photocatalytic activities by Au core Novel Au/Cu₂ZnSnS₄ core/shell nanoparticles (NPs) are synthesized for the first time via wet chemistry approach. The insertion of Au core into CZTS NPs dramatically enhances light absorption due to surface plasmon resonance effect, especially in the Vis-NIR region. Au/CZTS core/shell NPs show much higher photocatalytic activities for hydrogen evolution compared with other CZTS nanostructures.

A stretchable, wearable dye-sensitized solar-cell textile is developed from elastic, electrically conducting fiber as a counter electrode and spring-like titanium wire as the working electrode. Dyesensitized solar cells are demonstrated with energy-conversion efficiencies up to 7.13%. The high energy-conversion efficiencies can be well maintained under stretch by 30% and after stretch for 20 cycles.

An elemental-sulfur-based synthesis is reported, which, combined with processing to improve the size dispersion and passivation, results in a low-cost high-quality platform for small-bandgap PbS-CQD-based devices. Size-selective precipitation and cadmium chloride passivation are used to improve the power conversion efficiency of 1 eV bandgap CQD photovoltaic devices dramatically, which leads to record power conversion efficiency for a 1 eV PbS CQD solar cell of 5.4%.

The first inorganic lead(IV) compound without oxygen, nitrogen or halogen ligands attached to the lead atom was obtained as the potassium salt of the tetraselenidoplumbate(IV) anion [Pb^IVSe₄]⁴⁻. It is stable under inert conditions which may enable the transfer of the chemistry of chalcogenidogermanate(IV) or chalcogenidostannate(IV) materials, to the lead homologues.

Against all odds: The first inorganic lead(IV) compound without oxygen, nitrogen, or halogen ligands attached to the lead atom was obtained upon solvothermal reaction of a phase with the nominal composition “K₂PbSe₂” in ethane-1,2-diamine (en). It contains the ortho-selenidoplumbate(IV) anion [Pb^IVSe₄]⁴⁻, which, for reasons of relativistic effects on lead, is not intuitive; until now, tetrahedral [TE₄]⁴⁻ units (E=S, Se, Te) were only known for the lighter homologues T=Si, Ge, Sn.