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Perovskite solar cells (PSCs) have broad application prospects in the field of renewable energy. The photovoltaic performance and long‐term stability of PSCs are important factors for the industrialization of PSCs. Passivation of perovskite films by antioxidants is an effective approach to not only reduce the density of defect states but also improve the environmental stability of the device. Herein, edaravone (EDA) is added to the perovskite precursor solution to passivate the defects and also scavenge ultraviolet(UV)‐induced free radicals during photoaging. The EDA‐optimized device achieves a champion power conversion efficiency (PCE) of 20.81%, and after 1000 h of exposure to the environment, the efficiency can maintain 72% of the original value. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have the great potential for the next‐generation energy application, while the serious issue about longevity has still been a long‐standing concern. The rapid crystallization process would inevitably introduce defects, and the perovskite film decomposed rapidly when exposed to water/oxygen. Herein, the reduced l‐glutathione (GSH) is introduced into the perovskite precursor to tailor the crystallization process and passivate defects, thus relief the detrimental ion migration. Furthermore, GSH can effectively inhibit the formation of superoxide. As a result, the optimized PSCs demonstrate the champion power conversion efficiency of 22.89% and maintained 91% of its initial efficiency under ambient environment for 1000 h. [ABSTRACT FROM AUTHOR]

Defects passivation strategy for the atop perovskite films is widely investigated, while the buried interface between the tin oxide electron transport layer and the perovskite active layer should gain more attention since the interfacial strains and surface hydroxyl are inevitable during the fabrication process which would affect the efficiency and stability of the fabricated perovskite devices. Herein, the CsF interlayer between SnO2 and perovskite film is adopted to release the interfacial strain and decrease the surface hydroxyl through the atomic interaction and chemical doping. Furthermore, the CsF can tailor the energy level of SnO2 for a more favorable alignment to reduce the energy loss and improve charge extraction. Correspondingly, the perovskite photovoltaic devices with the efficiency of 23.13% are achieved. Moreover, CsF‐doped devices demonstrate enhanced stability, which could maintain 87% of its initial efficiency after 1000 h under environmental storage. The developed CsF interfacial engineering provides a promising strategy for the interfacial modulation. [ABSTRACT FROM AUTHOR]

Perovskite-structured ABX3 halides are one of the most promising families of materials with many potential applications. However, the controllable growth methods of their crystal facets and the corresponding synthetic chemistry have not yet been resolved. In this paper, we report a ligand substitution strategy for the facet-tunable growth of perovskite structure KMF3 (M = Mg, Mn, Co, Ni and Zn) fluorides under mild hydrothermal conditions. The competition of the strong ligand of NH3 and weak ligand of F− in the octahedral crystal fields of M2+ results in different facet evolution routes for KMF3 samples with the M-site of empty-, partially- or fully-filled 3d orbitals. Although X-ray diffraction results indicated that all five KMF3 compounds are crystalized into the same space group (Pm3m, no. 221), the crystal shape of KMF3 with M = Mg, Mn, Co and Ni evolved from cubic shape to edge-truncated chamfer box shape, while KZnF3 evolved from cubic shape to corner-truncated cubic shape under the same set of synthetic conditions. The cubic shape habitat morphology of KMF3 crystals is enclosed by {100} facets, chamfer box {100} and {110} facets, and corner-truncated cube {100} and {111} facets. The crystal shape formation mechanism was analysed based on ligand field theory and the Bravais–Friedel–Donnay–Harker (BFDH) theory. We expect that the shape controllable synthetic method can benefit the growth of other halide material crystals, and the shape tunable crystals can find more important applications. [ABSTRACT FROM AUTHOR]

Mineralizer is a key factor in the hydrothermal crystallization of most metal oxide materials. However, the effect of mineralizer on crystal facet growth is not well understood. Herein, YbFeO3 is taken as a model compound to determine the effect of mineralizer on its shape evolution during a mild hydrothermal crystallization process. By adjusting the concentration and ratio of NaOH and KOH, the shapes of YbFeO3 crystals showed two different facet formation routes: NaOH stabilizes {110} and {002} facets, while KOH stabilizes {101} facets. The percentage of each family of crystal facets could be tailored by changing the concentrations of mineralizer and NH4+. The shape formation mechanism of YbFeO3 was analyzed based on Bravais–Friedel–Donnay–Harker theory, in addition to their facet structures and interactions between crystal facets and Na+, K+ and NH4+. This study will not only improve understanding of the role of mineralizers in oxide crystallization, but also provide a crystal facet controllable method for the hydrothermal synthesis of oxide materials with potential anisotropy applications. [ABSTRACT FROM AUTHOR]

Perovskite structured rare-earth chromites are one of the most promising families of functional materials in solid oxide fuel cells, multiferroic materials, and sensors. Here, we report a mild hydrothermal method to synthesize DyCrO3 and HoCrO3 monodispersed single crystals. The synthesis conditions, crystal structure, Raman spectra and temperature- and field-dependent magnetic properties were studied. The two samples are indexed to the Pbnm space group. The shapes of the crystals are plates with a narrow particle size distribution in the range of 4–5 μm. Raman spectra of the samples show typical vibration modes of CrO6 clusters and stretching modes of RE3+. Temperature dependent magnetization shows a weak antiferromagnetism to paramagnetism transition at ca. 100 K for the two samples. [ABSTRACT FROM AUTHOR]

Recently, the development of recyclable, stable, highly efficient water-splitting catalysts is urgent. Herein, we report magnetic La0.7Sr0.3MnO3 hollow microspheres, which show high activity, stability and long lifetime for photocatalytic water oxidation at room temperature. Our design route for this green catalyst may be applied to other environmental- and energy-related technological aspects. [ABSTRACT FROM AUTHOR]

A low temperature, one-pot route to iron-doped rare-earth chromite perovskite was proposed. Fe half-doped rare-earth chromites, REFe0.5Cr0.5O3 (RE = La, Tb, Ho, Er, Yb, Lu and Y) were prepared via a mild hydrothermal method and their magnetic properties were studied. All of these materials are well-crystallized and the profile refinement of powder X-ray diffraction (XRD) data showed that each of them adopts an orthorhombic distorted (Pbnm) perovskite structure. The temperature dependence of the magnetization curves indicate an improved order of arrangement of Fe3+ and Cr3+ at the B-site in some samples. Hysteresis measurements of YFe0.5Cr0.5O3 indicate that saturated and remnant magnetization were improved greatly compared to that prepared via the solid state method. [ABSTRACT FROM AUTHOR]

Review: 138 refs. [ABSTRACT FROM AUTHOR]

The double peroskite Lu 2 NiMnO 6 was synthesized by a facile hydrothermal method. X-ray power diffraction (XRD) analysis shows it adopts monoclinic structure with space group P2 1 /n , indicating an ordered arrangement at B sites. Valence states analysis done by XPS shows Ni 2+ /Mn 4+ configuration. Raman spectrum reveals an ordered structure in the sample, in agreement with the XRD results. The degree of ordering was greatly enhanced after the sample was annealed at 873 K. Magnetism of the as-grown and annealed samples was analyzed using DC and AC magnetization, as well as Magnetization-Hysteresis. Dielectric anomaly independent on frequency was observed close to the magnetic ordering temperature, indicating the possibility of ferroelectricity and further magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Perovskite structured rare-earth chromites are one of the most promising families of functional materials in solid oxide fuel cells, multiferroic materials, and sensors. Here, we report a mild hydrothermal method to synthesize DyCrO3 and HoCrO3 monodispersed single crystals. The synthesis conditions, crystal structure, Raman spectra and temperature- and field-dependent magnetic properties were studied. The two samples are indexed to the Pbnm space group. The shapes of the crystals are plates with a narrow particle size distribution in the range of 4–5 μm. Raman spectra of the samples show typical vibration modes of CrO6 clusters and stretching modes of RE3+. Temperature dependent magnetization shows a weak antiferromagnetism to paramagnetism transition at ca. 100 K for the two samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] La0.75Sr0.25MnO3 nanofibers prepared by electrospinning method exhibit high thermal stability and surface area. [•] The nanofibers show higher catalytic activity for CO and CH4 than nanoparticles prepared via hydrothermal method. [•] The nanofibers could provide more Mn4+ sites and adsorbed surface oxygen. [ABSTRACT FROM AUTHOR]