Crystallochemical changes of (Pb5Ca5)(VO4)6F2 apatite under electron irradiation were examined by transmission electron microscopy. The apatite, a synthetic analog of vanadinite, was moderately stable towards a less intense 300-keV LaB6 source, while it changed rapidly in structure when exposed to the higher flux of a 200-keV field emission gun. The electron beam induced transformation of vanad...

Single crystals of dineodymium(III) dititanium(IV) hepta-oxide, Nd2Ti2O7, were synthesized by the flux method and found to belong to the family of compounds with perovskite-type structural motifs. The asymmetric unit contains four Nd, four Ti and 14 O-atom sites. The perovskite-type slabs are stacked parallel to (010) with a thickness corresponding to four corner-sharing TiO6 octa-hedra. The Nd...

In this work, we describe a room-temperature, solution-processable organic electron extraction layer (EEL) for high-performance planar heterojunction perovskite solar cells (PHJ PVSCs). This EEL is composed of a bilayered fulleropyrrolidinium iodide (FPI)-polyethyleneimine (PEIE) and PC61BM, which yields a promising power conversion efficiency (PCE) of 15.7% with insignificant hysteresis. We re...

Thermochemical water and carbon dioxide splitting with concentrated solar energy is a technology for converting renewable solar energy into liquid hydrocarbon fuels as an alternative to fossil fuels, which are dominating in today's energy mix. For the conversion reaction to be efficient, special redox materials are necessary to perform the necessary chemical reactions in a thermochemical cycle....

We use first-principles density functional theory calculations to investigate the ground-state structure of sulfide perovskite BaZrS3. The material has a lower band gap than its oxide analog BaZrO3. Neither are ferroelectric in the ground state at T=0 K. We also examine the IR-active phonon contributions to the dielectric constant of BaZrS3, which are then compared to those of BaZrO3. The roles...

Using the Kondo lattice model with classical spins in infinite dimension, magnetic phase transition in the perovskite-type 3d transition-metal oxide La1−xSrxMnO3 is theoretically studied. On the Bethe lattice, the self-consistency equations are solved exactly. Curie temperatures at the region of double-exchange ferromagnetism 0.1 <∼ x <∼ 0.25 as well as the Nèel temperature at x = 0 are well re...

For the recently synthesized post-perovskite (PPV) CaPtO3 we investigate the electronic band structure properties in connection with hypothetical perovskite PV–CaPtO3 within density functional theory using pseudopotential and all electron methods. Both systems are found insulating in agreement with a tetravalent Pt(IV) low spin d6 state. The equilibrium values of the volume and energy point to ...

We fabricated formamidinium lead iodide perovskite solar cell for analysis of the photovoltaic mechanism based on the interpretation of the capacitance variation under illumination. It was shown that the low-frequency capacitance increases proportional to incident light intensity, and in addition it increases proportional to absorber thickness. Furthermore, the voltage dependence of capacitance...

Cation segregation on perovskite oxide surfaces affects vastly the oxygen reduction activity and stability of solid oxide fuel cell (SOFC) cathodes. A unified theory that explains the physical origins of this phenomenon is therefore needed for designing cathode materials with optimal surface chemistry. We quantitatively assessed the elastic and electrostatic interactions of the dopant with the ...