Cs2AgBiBr6 having a double perovskite structure is expected to achieve non-lead and stable optoelectronic devices, and has received wide attention recently. A strategy for improving of perovskite films via Rubidium cation (Rb+) is for the first time reported. When Rb+ was incorporated into Cs2AgBiBr6 to form (Cs1-xRbx)(2)AgBiBr6, the absorption at long wavelength was enhanced and the density of defect state was reduced without changing the crystal lattice. Furthermore, the mechanism of Rb+ doping to improve double perovskites and the optimal doping ratio was studied in this report. The average power conversion efficiency of doped devices is nearly 15% higher than that of standard devices from 20 devices of each group. Moreover, in the champion device, the power conversion efficiency achieved 1.52% with a high fill factory of 0.788.
The Ambisonic technique has been widely used for soundfield recording and reproduction recently. However, the basicAmbisonic decoding method will break down when the play-back loudspeakers distribute unevenly. Various methods havebeen proposed to solve this problem. This paper introducesseveral improvements to a recently proposed Ambisonic de-coding method, the matching projection method, for unevenloudspeaker layouts. The first improvement is energy preserv-ing; the second is introducing the “in-phase” weight, and thethird is introducing partial projection coefficients. To eval-uate the improved method, we compared it with the origi-nal one and the all-round Ambisonic decoding method witha 2-dimension unevenly arranged loudspeaker array. The re-sult shows our method greatly improves the original methodwhere the loudspeaker arranges very sparsely or densely.
This paper analyzes the determinants of stock market participation decisions using officially compiled aggregate stock account opening data in China. Different from the literature that often focuses on one particular dimension, our paper systematically evaluates the relative importance of disposable income, demographic variables, macroeconomic factors, stock market conditions, and social communication on both the level and the change of the participation rate. We find that the level of the participation rate is predominately determined by the income factor, followed by various measures of social communication. Social communication plays the most important role in the change of the participation rate, acting as a multiplier to stimulate stock market participation. The effects are more pronounced in high income, high education, high population density groups, and during the bull market period.
Soil archaea plays a vital role in the functioning of dryland ecosystems, which are expected to expand and get drier in the future as a result of climate change. However, compared with bacteria and fungi, the impacts of increasing aridity on archaea in these ecosystems remain largely unknown. Here, soil samples were collected along a typical aridity gradient in semi-arid regions in Inner Mongolia, China, to investigate whether and how the increasing aridity affects archaeal communities. The results showed that archaeal richness linearly decreased with increasing aridity. After partialling out the effects of soil properties based on partial least squares regression, the significant aridity-richness relationship vanished. The composition of archaeal communities was distributed according to the aridity gradient. These variations were largely driven by the changes in the relative abundance of Thaumarchaeota, Euryarchaeota and unclassified phyla. Niche-based processes were predominant in structuring the observed archaeal aridity-related pattern. The structural equation models further showed that aridity indirectly reduced archaeal richness through improving soil electrical conductivity (EC) and structured community composition by changing soil total nitrogen (TN). These results suggested that soil salinization and N-losses might be important mechanisms underlying the increasing aridity-induced alterations in archaeal communities, and highlighted the importance of soil niches in mediating the indirect impacts of increasing aridity on archaea.
The electron-transporting materials (ETMs) with excellent electron injection (EI) and electron transporting properties are prerequisites for highly efficient organic light-emitting diodes (OLEDs). In this work, we report a novel ETM, 2,7-di([3,2 `:6 `,3 `'-terpyridin]-4 `-yl)-9,9 `-spirobifluorene (27-mTPSF), which is synthesized by combining electron-withdrawing terpyridine (TPY) moieties with rigid twisted spirobifluorene. This rigid twisted structure helps to maintain the morphological stability of the amorphous film and contributes to the enhancement of the device lifetime. The nitrogen atom at the meta-position on the peripheral pyridine in 27-mTPSF can enhance the horizontal molecular orientation and the electron-transporting property. A green phosphorescent OLED (PhOLED) based on tris[2-(p-tolyl)pyridine]iridium(iii) (Ir(mppy)(3)) as the emitter and 27-mTPSF as ETM displayed a maximum external quantum efficiency (EQE) of 23.1%, and a half-life (T-50) of 77, 4330 and 243 495 h at an initial luminance of 10 000, 1000 and 100 cd m(-2), respectively, which are significantly superior to those of the device based on the conventional ETM 1,3,5-tris(N-phenylbenzimid azol-2-yl-benzene (TPBi). These results indicate a potential application for the ``(A)(n)-D-(A)(n)'' structured terpyridine ETMs.
The electron-transporting materials (ETMs) with excellent electron injection (EI) and electron transporting properties are prerequisites for highly efficient organic light-emitting diodes (OLEDs). In this work, we report a novel ETM, 2,7-di([3,2 `:6 `,3 `'-terpyridin]-4 `-yl)-9,9 `-spirobifluorene (27-mTPSF), which is synthesized by combining electron-withdrawing terpyridine (TPY) moieties with rigid twisted spirobifluorene. This rigid twisted structure helps to maintain the morphological stability of the amorphous film and contributes to the enhancement of the device lifetime. The nitrogen atom at the meta-position on the peripheral pyridine in 27-mTPSF can enhance the horizontal molecular orientation and the electron-transporting property. A green phosphorescent OLED (PhOLED) based on tris[2-(p-tolyl)pyridine]iridium(iii) (Ir(mppy)(3)) as the emitter and 27-mTPSF as ETM displayed a maximum external quantum efficiency (EQE) of 23.1%, and a half-life (T-50) of 77, 4330 and 243 495 h at an initial luminance of 10 000, 1000 and 100 cd m(-2), respectively, which are significantly superior to those of the device based on the conventional ETM 1,3,5-tris(N-phenylbenzimid azol-2-yl-benzene (TPBi). These results indicate a potential application for the ``(A)(n)-D-(A)(n)'' structured terpyridine ETMs.
Creep behavior of rocks could impair fracture conductivity and wellbore stability during gas production from highly matured organic-rich shales in South China, of which the organic matter is mainly in the form as solid bitumen and is thought to be a major contributor for the creep deformation. To get a better insight into this phenomenon, this paper for the first time characterizes the mechanical properties and creep behavior of a millimeter-sized solid bitumen sample by using quasi-static state creep tests and Dynamic Mechanical Analysis in nanoindentation, and reports their dependences on indentation size and loading rate, respectively. Mechanical properties (including hardness and Young's modulus) are found to be negatively related with both indentation size and loading rate. The extremely small creep strain rate sensitivity (m) of solid bitumen indicates a localized shear flow inside. And m exhibits slightly positive dependences on indentation size and loading rate. The potential mechanisms controlling the deformation of solid bitumen under indentation are also discussed.
With different functional groups and hydrophobic/hydrophilic properties, natural organic matters (NOMs) displayed different combining capacities with metal ions. By using XAD-4 and DAX-8 resins, NOMs in natural lake were isolated into three fractions, i.e., HoB (hydrophobic base), HoA (hydrophobic acid) and HiM (hydrophilic matter). Afterwards, influences on Cu(II) adsorption onto titanate nanotubes (TNTs) were compared with varying NOMs and initial pH. As results, HoB can significantly control Cu(II) adsorption at pH 5, with the adsorption capacity increased 15% for 0.5 mg L−1 of HoB (ca. 120 mg g−1), which could be attributed to the formation of HoB-Cu complexation and electrostatic bridge effect of HoB with optimal concentration. Due to the easier ionization and complexation with Cu(II) at lower pH, HoA showed more obvious impaction on Cu(II) adsorption at pH 2. While HiM can influence Cu(II) adsorption at all pH ranges due to its hydrophilic groups and weak affinity to both TNTs and Cu(II). Furthermore, HoB dramatically changed the Langmuir model, with sharp increase of adsorption capacity as equilibrium Cu(II) increased, suggesting its significant involvement in Cu(II) adsorption. X-ray photoelectron spectroscopy (XPS) analysis revealed the absorbed Cu(II) existed in the form of TNTs‑OCu, TNTs‑COOCu and Cu(OH)2, proving Cu(II) adsorption mechanism including both direct adsorption by TNTs and bridging connection with NOMs. Moreover, the CO and OCO groups content ranked as HiM > HoB > HoA, while TNTs‑COOCu content ranked as HoA > HoB > HiM, suggesting HoB had the moderate connection with both TNTs and Cu(II), thus the impact on Cu(II) adsorption was remarkable.