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Cu 2 O/ZnO has been envisaged as a potential material system for the next-generation thin film solar cells. Thus far, the experimental efforts to obtain conversion efficiencies close to the theoretically predicted value have failed. Combining aberration-corrected (scanning) transmission electron microscopy and density functional theory modeling, we studied the interfaces between single-crystal caxis-oriented ZnO and high-quality magnetron-sputtered Cu 2 O films. Strikingly, our study shows that the first ∼5 nm of the Cu−oxide films has the structure of the monoclinic CuO phase. The CuO layer is textured with the (111), (111̅ ), (1̅ 11), (11̅ 1̅ ) (1̅ 1̅ 1), (11̅ 1), (1̅ 11̅ ,) and (100) planes parallel to the (0001) and (0001̅ ) ZnO interfaces. The ionic arrangement on these planes resembles the hexagonal arrangement of the ZnO interface, and epitaxy exists across the interface. A continued epitaxial growth of [111]-oriented Cu 2 O follows resulting in epitaxial 180°rotation twins in the Cu 2 O layer. For the case with the (100) CuO interfacial plane we have (111)[11̅ 0] Cu2O ∥(100)[011] CuO ∥(0001)[112̅ 0] ZnO . Because of a closer lattice matching of CuO with ZnO and Cu 2 O, the total strain and energy is reduced compared to a pure (111) Cu2O ∥(0001) ZnO interface. The existence of CuO is anticipated to be a contributing factor for the low conversion efficiencies obtained experimentally.

The capability of battery materials to deliver not only high lithium storage capacity, but also the ability to operate at high charge/discharge rates is an essential property for development of new batteries. In the present work, the influence on the charge/discharge rate behaviour of substoichiometric concentrations of phosphorus (P) in silicon (Si) nanoparticles was studied. The results revealed an increase in rate capability as a function of the P concentration between 0 and 5.2 at %, particularly during delithiation. The stoichiometry of the nano-particles was found to strongly affect the formation of the Li 3.5 Si phase during lithiation. Cyclic stability experiments demonstrated an initial increase in capacity for the SiP x materials. Galvanostatic intermittent titration technique and electrochemical impedance spectroscopy demonstrated the increased lithium diffusivity with inclusion of P. Density functional theory and ab initio molecular dynamics were deployed to provide a rationale for the electrochemical behaviour of SiP x .