5 research outputs found
Czochralski growth and characterization of TbxGd1āxScO3 and TbxDy1āxScO3 solid-solution single crystals
TbxGd1āxScO3 and TbxDy1āxScO3 solid-solution single crystals were grown by the Czochralski method to validate the practicality of solid solutions between neighboring RE scandates (REScO3). Within this material family, it is demonstrated that fine-tuning the pseudo-cubic lattice parameters between nearly all endmembers is now possible by adjusting the chemical composition of the mixed crystals. Film-tailored substrate lattice spacings enable fine adjustments of epitaxial strain or the growth of nearly strain-free heteroepitaxial films. Investigations of the chemical composition of the grown crystals revealed low segregation, which qualifies the solid-solutions as suitable substrate materials. The melting behavior was studied by differential thermal analysis. To calculate the thermal conductivity, Ī»(T), the heat capacity and thermal diffusivity were measured by differential scanning calorimetry and the laser flash technique, respectively. It was found that the thermal conductivity shows a minimum near 900 K and increases untypically at higher temperatures.2868287
Approach for a Simplified Fabrication Process for IBC-SHJ Solar Cells with High Fill Factors
Structural Evolution from 0D Units to 3D Frameworks in Pb Oxyhalides: Unexpected Strongly Corrugated Layers in Pb 7 O 6 Br 2
International audienc
Structural Evolution from 0D Units to 3D Frameworks in Pb Oxyhalides: Unexpected Strongly Corrugated Layers in Pb<sub>7</sub>O<sub>6</sub>Br<sub>2</sub>
Novel Pb<sub>7</sub>O<sub>6</sub>Br<sub>2</sub> (<b>1</b>) lead oxybromide was prepared from
Pb oxybromide melt by the ārapid quenchingā route. Bonding
scheme, thermal expansion, and structural properties were studied.
The structural features of this unexpectedly complex phase are described
on the basis of lone electron pair stereochemical activity and PbāBr
versus PbāO bonding scheme. The structure of <b>1</b> contains a number of cavities, which can be assigned to the self-containments
of the lone electron pairs on Pb<sup>2+</sup> cations. āEmptyā
ā”Pb<sub>4</sub> chains are observed in between of the folding
sides of the adjacent strongly corrugated oxocentered [Pb<sub>7</sub>O<sub>6</sub>]<sup>2+</sup> layers. Highly isotropic thermal expansion
of <b>1</b> appeared to be unexpected. The possible explanations
of such a behavior in <b>1</b> are given. The structure of <b>1</b> is an interesting example of tetrahedral framework with
mixed chemical bonding and is the densest known among Pb oxyhalides
with the density of 18.4 tetrahedra/1000 Ć
<sup>3</sup>. Current
study shows that oxocentered layers derivatives from Ī±-PbO can
be very flexible and form rather dense three-dimensional structural
topologies. The properties and structure are compared to other phases
crystallizing in the anhydrous PbOāPb<i>X</i><sub>2</sub> (X = F, Cl, Br, I) systems, illustrate the complexity of
lead oxyhalides, and reveal new and general pathways for the targeted
synthesis of new phases with the PbāO units of desired dimensionality.
The indirect gap value of ā¼2.04 eV obtained from generalized
gradient approximation calculations demonstrates potentially good
photocatalytic properties of <b>1</b>