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This work quantifies the effect of misfit and threading dislocations on the surface energies of PbTe-PbSe interfaces, with the defect structures of the interfaces being obtained from atomistic and multiscale simulations of their manufacturing processes. Simulation results show that direct bonding produces semi-coherent interfaces with two-dimensional misfit dislocation networks, while heteroepitaxial processes produce complex three dimensional dislocation structures with both misfit and threading dislocations. Surface energies at these interfaces were determined by computing the interaction energies across these interfaces. Compared with coherent interfaces, directly bonded interfaces exhibit up to ~23% lower surface energy, while the surface energies of epitaxially grown interfaces can be nearly 50 % lower. The results demonstrate significant effects of dislocations on interfacial energy. 

Understanding how solvents influence the mechanism of intercalation is essential to advancing layered materials for energy storage devices, catalysis, and molecular electronics. In this study, we explore intercalation into the layered vanadium phosphate host using ferrocene as the reducing agent and guest, revealing three distinct solvent-dependent mechanistic pathways that depend on the solvent-host interaction, ferrocene concentration, and product lattice energy. Different aliphatic organonitrile solvents, while they do not react directly with VOPO4•2H2O, can nevertheless affect the ratio between stage 1 and stage 2 products and a kinetics analysis suggests the two products follow different mechanistic pathways. In contrast to the aliphatic nitriles, primary alcohol molecules can directly insert into VOPO4•2H2O layers. With in-situ measurements, pre-intercalation of the alcohol, followed by co-intercalation of alcohol and the guest, are observed experimentally for the first time. A stage 1 phase is formed in 1-propanol, and a stage 2 phase is formed in ethanol, indicating the propanol-host interaction is moderate, allowing ferrocene to fully occupy the host layers, whereas the ethanol-host interaction is too strong to be completely expelled by the guest. These differences underscore the influence of solvent-host interactions during intercalation, enhancing understanding of solvent-assisted intercalation and its applications in hybrid materials. 

A sustainable and robust supply chain of rare earth elements (REEs) is necessary to meet our consumer, national security and clean energy goals. However, current intra-REE separation technologies (e.g.solvent extraction) are costly and carry a heavy environmental burden. Therefore, the development of new aqueous based ligands that are selective for individual REEs will be integral in future REE production systems. To develop these ligands, an understanding of how ligand coordination structure relates to selectivity is imperative. We used X-ray absorption spectroscopy (XAS) to observe the local structure around four lanthanide (Ln) ions (La, Ce, Pr and Nd) complexed by water and several relevant chelating ligands [lanmodulin EF-hand 1 peptides (LanM1), ethylenediaminetetraacetic acid (EDTA), aminotris(methylenephosphonic acid) (ATMP) and citric acid]. To collect these liquid-phase XAS spectra, we developed a new flow cell that prevents bubble interference and beam damage to the samples. In the X-ray absorption near-edge structure (XANES), we observed energy shifts in the white line, white line broadening and differences in the white line intensity of different Ln–ligand complexes between ligands. In the extended X-ray absorption fine structure (EXAFS), we distinguished differences in peak intensity and distance between coordinating ligands. Differences in the local coordination structure between Ln–LanM1 peptide complexes were more subtle compared with the other ligands (La–water, La–EDTA, La–ATMP and La–citric acid complexes). Further XANES and EXAFS studies, in combination with modelling and other techniques, could greatly improve our structural knowledge of how these aqueous ligands bind Ln ions and how they can be used to design more selective ligands for more efficient and sustainable REE separations.