This work provides an in-depth study of how the thermal conductivity of stoichiometric [110] BiTe nanowires becomes affected when reducing its diameter from an experimental and theoretical point of view. The thermal conductivity was observed to decrease more than 70% (from 1.78 ± 0.46 W K m to 0.52 ± 0.35 W K m) when the diameter of the nanowire was reduced one order of magnitude (from 300 nm to 25 nm). The Kinetic-Collective model was used to understand such a reduction, which can be explained by the impact that surface scattering has in acoustic phonons. The smaller the diameter of the nanowires is, the larger the alteration in the mean free path of the low-frequency phonons is. The model agrees well with the experimental data, and the reduction in the thermal conductivity of the nanowires can be explained in terms of an increment of phonon scattering.

This study reports the intercalation of pyridine molecules between neighboring layers of two-dimensional (2D) ferrous nitroprusside. In the material under study, the stacking of neighboring layers results in the formation of a long range ordered solid, where the 3D structure is supported by dipoledipole attractive interactions between neighboring pyridine molecules in the interlayer region. No chemical interactions were observed between layers, which preserve their identity as a 2D material. In this hybrid inorganic-organic solid, a thermal induced spin transitions from high to low spin on cooling and [a] 4967 [a] The values of δ are reported relative to sodium nitroprusside at 300 K; The fitting error for δ and Δ is no higher than 0.001 mm/s, and it remains below 0.01 mm/s for the value of Γ; Py =pyridine; LS = low spin; HS = high spin.

No abstract

When 1-methyl-2-pyrrolidone molecule (1m2p) interacts with the T[Ni(CN)4] layer, its carbonyl π bond homolytically disrupts and forms a coordination bond at the axial positions for the metal T, and hybrid inorganic-organic solids of formula unit T(L)2[Ni(CN)4], with T = Mn, Co, Ni, are obtained. The formed solids crystallize with a monoclinic unit cell in the C2/m space group where the metal T is found with octahedral coordination to four N ends of CN groups from a given layer and to two oxygen atoms from the organic ligands, while the inner metal (Ni) preserves its square planar coordination. In the interlayer region, the organic molecules achieve unusual planarity and are stacked through dipole-dipole interactions in a head-to-tail configuration to form a chain of molecular pillars. From such interactions, 3D pillared hybrid solids result. Upon the charge donation to the metal by oxygen atom from 1m2p, the latter becomes an organic radical whose SOMO frontier orbital has a strong π character, associated with an essentially planar structure. The unpaired electron is delocalized between neighboring C and N atoms at the ligand ring plane, and it is featured by an outstanding broad absorption band in the near-IR region. For Ni, the metal of highest polarizing power within the considered series, the existence of π overlapping interaction between organic ligand molecules leads to ferromagnetic ordering at low temperature, with TC = 10.07 K. For Mn and Co, related to the lower metal electron-withdrawing ability, the materials maintain the weak antiferromagnetic character resulting from the interaction between T metals in the layer -T-N≡C-Ni-C≡N-T- chains.

This study evaluates the effect of equimolar substitution of manganese by cobalt or nickel in hexacyanoferrate open frameworks as electrode for Na-ion batteries.