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Abstract An unusual self‐assembly pattern is observed for highly ordered 1500‐nm‐thick films of monodisperse 13‐nm‐sized colloidal PbSe quantum dots, originating from their faceted truncated cube‐like shape. Specifically, self‐assembled PbSe dots exhibited attachment to the substrate by <001> planes followed by an interconnection through the {001} facets in plan‐view and {110}/{111} facets in cross‐sectional‐view, thus forming a cubic superlattice. The thermoelectric properties of the PbSe superlattice thin films are investigated by means of frequency domain thermoreflectance, scanning thermal probe microscopy, and four‐probe measurements, and augmented by computational efforts. Thermal conductivity of the superlattice films is measured as low as 0.7 W m⁻¹ K⁻¹at room temperature due to the developed nanostructure. The low values of electrical conductivity are attributed to the presence of insulating oleate capping ligands at the dots’ surface and the small contact area between the PbSe dots within the superlattice. Experimental efforts aiming at the removal of the oleate ligands are conducted by annealing or molten‐salt treatment, and in the latter case, yielded a promising improvement by two orders of magnitude in thermoelectric performance. The result indicates that the straightforward molten‐salt treatment is an interesting approach to derive thermoelectric dot superlattice thin films over a centimeter‐sized area. 

Abstract A computational search for stable structures among both α and β phases of ternary ATB₄borides (A= Mg, Ca, Sr, Ba, Al, Ga, and Zn,Tis3dor4dtransition elements) has been performed. We found that α-ATB₄compounds withA= Mg, Ca, Al, andT = V, Cr, Mn, Fe, Ni, and Co form a family of structurally stable or almost stable materials. These systems are metallic in non-magnetic states and characterized by the formation of the localized molecular-like state of3dtransition metal atom dimers, which leads to the appearance of numerous Van Hove singularities in the electronic spectrum. The closeness of such singularities to the Fermi level can be easily tuned by electron doping. For the atoms in the middle of the3drow (Cr, Mn, and Fe), these singularities led to magnetic instabilities and magnetic ground states with a weakly metallic or semiconducting nature. Such states appear as non-trivial coexistence of the different spin ladders formed by magnetic dimers of3delements. These magnetic states can be characterized as an analog of the spin glass state. Experimental attempts to produce MgFeB₄and associated challenges are discussed, and promising directions for further synthetic studies are formulated. 

Noncentrosymmetric (NCS) silicon phosphides have recently shown promise as nonlinear optical materials due to the balance of strong second harmonic generation (SHG) activity and large laser damage threshold (LDT) values. While arsenides of electropositive metals, such as Ba, Mg, Zn, and Cd were explored, no NLO properties for transition metal tetrel arsenides have yet been reported. IrSi 3 As 3 is a novel compound, isostructural to IrSi 3 P 3 , which allows a direct investigation on the impact of the heavier pnictogen on structural and optical properties. The direct bandgap is reduced from 1.8 eV for IrSi 3 P 3 to 1.55 eV for IrSi 3 As 3 . Unlike many NLO chalcogenides, IrSi 3 As 3 has a small bandgap without compromising the balance between SHG signal and high LDT values. IrSi 3 As 3 was found to outperform both its phosphide analogue IrSi 3 P 3 , as well as the state-of-the-art infrared SHG standard AgGaS 2 (AGS) in SHG activity and the LDT. 

The solvothermal synthetic exploration of the Bi–S–halogen phase space resulted in the synthesis of two bismuth sulfohalides with common structural motifs. Bi 13 S 18 I 2 was confirmed to have the previously reported composition and crystal structure. In contrast, the bromide analogue was shown to have a formula of neither Bi 19 S 27 Br 3 nor Bi 13 S 18 Br 2 , in contrast to the previous reports. The composition, refined from single crystal X-ray diffraction and confirmed by elemental analysis, high-resolution powder X-ray diffraction, and total scattering, is close to Bi 13 S 17 Br 3 due to the partial S/Br substitution in the framework. Bi 13 S 18 I 2 and Bi 13 S 17 Br 3 are n -type semiconductors with similar optical bandgaps of ∼0.9 eV but different charge and heat transport properties. Due to the framework S/Br disorder, Bi 13 S 17 Br 3 exhibits lower thermal and electrical conductivities than the iodine-containing analogue. The high Seebeck coefficients and ultralow thermal conductivities indicate that the reported bismuth sulfohalides are promising platforms to develop novel thermoelectric materials.