Pressure-induced dramatic changes in organic-inorganic halide perovskites.

Organic-inorganic halide perovskites have emerged as a promising family of functional materials for advanced photovoltaic and optoelectronic applications with high performances and low costs. Various chemical methods and processing approaches have been employed to modify the compositions, structures, morphologies, and electronic properties of hybrid perovskites. However, challenges still remain in terms of their stability, the use of environmentally unfriendly chemicals, and the lack of an insightful understanding into structure-property relationships. Alternatively, pressure, a fundamental thermodynamic parameter that can significantly alter the atomic and electronic structures of functional materials, has been widely utilized to further our understanding of structure-property relationships, and also to enable emergent or enhanced properties of given materials. In this perspective, we describe the recent progress of high-pressure research on hybrid perovskites, particularly regarding pressure-induced novel phenomena and pressure-enhanced properties. We discuss the effect of pressure on structures and properties, their relationships and the underlying mechanisms. Finally, we give an outlook on future research avenues in which high pressure and related alternative methods such as chemical tailoring and interfacial engineering may lead to novel hybrid perovskites uniquely suited for high-performance energy applications

Physicochemical Properties and Lipophilicity of Polydatin-Lecithin Complex

Purpose: To investigate the physicochemical properties and lipophilicity of polydatin-lecithin complex.Methods: The complex of polydatin-lecithin was prepared by solvent method. The physicochemical properties of the complex were investigated by ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), differential scanning calorimetry (DSC), x ray diffractometry (XRD) and scanning electron microscopy (SEM). Its solubility in n-octanol at 25 °C was examined by high performance liquid chromatography (HPLC).Results: The UV and IR spectra of the complex showed an additive effect of polydatin-lecithin, in which the characteristic absorption of their respective peaks were retained. DSC and XRD results suggest that the complex mainly showed the presence of lecithin with the characteristic peaks for polydatin absent, while SEM demonstrated that polydatin was dispersed in lecithin. HPLC analysis found that the solubility of polydatin in n-octanol at 25 °C was enhanced from 0.41 mg/mL to 21.98 mg/mL by complexing with lecithin, indicating that the lipophilicity of polydatin was significantly improved.Conclusion: Polydatin and lecithin in the complex are combined by non-covalent bonds, and did not form a new compound. The lipophilicity of polydatin increased to 21.98 mg/mL from 0.41 mg/mL as a result of complexation.Keywords: Polydatin, Lecithin, Complex, Physicochemical property, Lipophilicit

Strongly enhanced oxygen ion transport through samarium-doped CeO2 nanopillars in nanocomposite films

Enhancement of oxygen ion conductivity in oxides is important for low-temperature (<500 °C) operation of solid oxide fuel cells, sensors and other ionotronic devices. While huge ion conductivity has been demonstrated in planar heterostructure films, there has been considerable debate over the origin of the conductivity enhancement, in part because of the difficulties of probing buried ion transport channels. Here we create a practical geometry for device miniaturization, consisting of highly crystalline micrometre-thick vertical nanocolumns of Sm-doped CeO2 embedded in supporting matrices of SrTiO3. The ionic conductivity is higher by one order of magnitude than plain Sm-doped CeO2 films. By using scanning probe microscopy, we show that the fast ion-conducting channels are not exclusively restricted to the interface but also are localized at the Sm-doped CeO2 nanopillars. This work offers a pathway to realize spatially localized fast ion transport in oxides of micrometre thickness. © 2015 Macmillan Publishers Limited. All rights reserved133431sciescopu

Strongly enhanced oxygen ion transport through samarium-doped CeO2 nanopillars in nanocomposite films

Enhancement of oxygen ion conductivity in oxides is important for low-temperature (<500 °C) operation of solid oxide fuel cells, sensors and other ionotronic devices. While huge ion conductivity has been demonstrated in planar heterostructure films, there has been considerable debate over the origin of the conductivity enhancement, in part because of the difficulties of probing buried ion transport channels. Here we create a practical geometry for device miniaturization, consisting of highly crystalline micrometre-thick vertical nanocolumns of Sm-doped CeO(2) embedded in supporting matrices of SrTiO(3). The ionic conductivity is higher by one order of magnitude than plain Sm-doped CeO(2) films. By using scanning probe microscopy, we show that the fast ion-conducting channels are not exclusively restricted to the interface but also are localized at the Sm-doped CeO(2) nanopillars. This work offers a pathway to realize spatially localized fast ion transport in oxides of micrometre thickness

Allelopathic Potential of Invasive Plantago virginica on Four Lawn Species

Plantago virginica L. has invaded many lawn ecosystems in the Eastern part of China. The invasion has incurred an economic cost to remove them. In order to prevent the invasion, it is critical to understand the invasive mechanisms of this species. However, few studies have been conducted on the allelopathic mechanisms of its invasion. In this study, we examined allelopathic effects of P. virginica on germination of seeds and growth of seedlings of four widely used lawn species. We found extensive allelopathic potential of P. virginica on other lawn species, which varied with species and developmental stage. While most effects of the extracts of P. virginica were inhibitory, some variables in some species were promoted by the addition of the extracts. The extracts of P. virginica significantly inhibited seed germination of Agrostis matsumurae. While the overall differences in seed germination rate of Poa annua were significant among treatments, difference between control and any of the treatments was not significant. The height of seedlings of A. matsumurae and Cynodon dactylon was significantly lower under the treatments of adding extracts of P. virginica. In contrast, growth of seedlings of Festuca elata and P. annua did not show significant differences among treatments. The root length of A. matsumurae, C. dactylon and P. annua was suppressed by the extracts of P. virginica whereas root length of F. elata was not affected. Aboveground biomass of A. matsumurae and F. elata was significantly higher than control, except for F. elata at the concentration of 50mg/mL, whereas aboveground biomass of C. dactylon and P. annua was reduced at higher concentrations of the extracts. Except for A. matsumurae, root biomass of the other three lawn species declined under the treatments with the extracts of P. virginica. Our results revealed that P. virginica had allelopathic potential on four lawn species and supported the theory of “novel weapons hypothesis”. Invasion by P. virginica in lawn can be moderated by selecting those species that are not affected or promotionally affected by it.Yeshttp://www.plosone.org/static/editorial#pee

Newly recorded species of Aulonoraphidinales(Bacillariophyta) from Great Xing′an Mountains,China

Samples were collected from Great Xing′an Mountains during 2004 to 2007.Six taxa of Aulonoraphidinales were identified as the newly recorded species in China.They are:Hantzschia calcifuga Reichardt & Lange-Bertalot, Nitzschia homburgiensis Lange-Bertalot, Nitzschia nana Grunow, Nitzschia terrestris (Petersen) Hustedt, Stenopterobia anceps (Lewis) Brébisson, Stenopterobia delicatissima (Lewis) Brébisson ex Van Heurck.The morphological features and habitat distribute pattern of these taxa were reported in this paper