The effect of Mn-doped ZnSe passivation layer on the performance of CdS/CdSe quantum dot-sensitized solar cells

ZnSe as a surface passivation layer in quantum dot-sensitized solar cells plays an important role in preventing charge recombination and thus improves the power conversion efficiency(PCE).However, as a wide bandgap semiconductor, ZnSe cannot efficiently absorb and convert long-wavelength light.Doping transition metal ions into ZnSe semiconductors is an effective way to adjust the band gap, such as manganese ions.In this paper, it is found by the method of density functional theory calculation that the valence band of ZnSe moves upward with manganese ions doping, which leads to acceleration of charge separation, wider light absorption range, and enhancing light harvesting.Finally, by using ZnSe doped with manganese ions as the passivation layer, the TiO2/CdS/CdSe co-sensitized solar cell has a PCE of 6.12%, and the PCE of the solar cell increases by 9% compared with the undoped one(5.62%).

Importance of metal location in M-H zeolite for synergistically catalyzing dimethyl ether carbonylation

Mordenite(MOR)has shown great potential to catalyze dimethyl ether(DME)carbonylation to methyl acetate(MA)in industry.The synergy between metal species and Brønsted acid sites accelerates DME conversion.Here we designed and prepared two catalysts with different Ag locations by seed-directed growth method and two-step impregnation method(named as Ag@HMOR and Ag/HMOR-out,respectively),to explain the effect of Ag location on catalytic performance.The results of TEM,XPS,CO-IR and UV–Vis showed that Ag species mainly presented as Ag^(0) species over both Ag@HMOR and Ag/HMOR-out.Meanwhile,Ag^(0) species mainly located in the micropores of Ag@HMOR,while as for Ag/HMOR-out,Ag^(0) mainly existed on external surface.After comparing the performance of the catalysts with different Ag positions,we confirmed that the Ag^(0) species encapsulated in the channels of HMOR promoted the DME carbonylation,which revealed the importance of spatial adjacency on the acid-metal catalysts.

Removal of Androgens and Estrogens from Water by Reactive Materials

Nowadays, endocrine disruptor compounds in the water system have become a concern due to the risk of contamination to wild life and humans even at the nanogram level. Excess estrogens and androgens are a major contributor group of endocrine compounds. Statistical surveys have shown that dairy farms contribute to over 90% of the total estrogens in the UK and US. Reporter gene assays (RGAs) is being developed to assess the efficiency of reactive materials to remove target hormonal contaminants from dairy farm wastewater. This study demonstrates that 2 g of reactive materials (granular activated carbon (GAC), zero-valent iron (ZVI) and organoclay) efficiently removed over 50% of 17β-estradiol and 92% Testosterone over a 24 h period from 20 ml of HPLC grade water spiked at a concentration of 1000 ng l-1. Therefore, these materials may be useful adsorbents for the advanced treatment of residual natural hormones in dairy farm wastewater.

A Comprehensive Study of the High Temperature Performance and Microstructure of Different High Tc Piezoelectric Ceramics

The expanding demand for piezoelectric devices working at elevated temperatures,particularly those for aerospace and automotive industries,has stimulated a great deal of research effort on high Cu-rie Temperature(T C)piezoelectric ceramics.The fabrication of this type of piezoelectric ceramics is

Phase coexistence and evolution in sol-gel derived BY-PT-PZ ceramics with significantly enhanced piezoelectricity and high temperature stability

In this study,high Curie Temperature(T_(c))perovskite ceramics of optimized composition 0.55(0.1BiYbO_(3)-0.9PbTiO_(3))-0.45PbZrO_(3) with unique double orthorhombic main phases were prepared by a modified solgel method.Compared to the usual solid-state prepared sample,the sol-gel derived sample has a 1.6 times higher d_(33) of 325 pC/N,a 2.4 times higher remnant polarization,and a much better high temperature stability with similar depolarization temperature(T_(d))and T_(c).Comprehensive analysis of the xerogel prepared over a wide calcination temperature(T_(cal))range of 300-1000℃ revealed that perovskite structure appeared at only 400℃ and it became the main phase above 500℃.Comparison of XRD refinement results showed that calcination and sintering induced subtle and continuous phase transition,namely,the 400-900℃ calcined powders with coexisted tetragonal(P4mm)and orthorhombic(Pbam)phase changed to a rather stable double orthorhombic(Pmmm and Pbam)main phase in all the differently sintered ceramics,as similar to the 1000
C calcined powders.The stable phase coexistence well explains the enhanced performance.The results also demonstrate that optimized sol-gel processing can provide high T_(c) ceramics with desirable multi-phase structure and significantly enhanced performance at a lower temperature.

Enhancement of MoTe2 near-infrared absorption with gold hollow nanorods for photodetection

Infrared(IR)light photodetection based on two dimensional(2D)materials of proper bandgap has attracted increasing attention.However,the weak IR absorption in 2D materials,due to their ultrathin attribute and indirect bandgap in multilayer structures,degrades their performance when used as IR photodetectors.In this work,we utilize the fact that few-layer MoTe2 flake has a near-IR(NIR)bandgap and demonstrate a^60-fold enhancement of NIR response by introducing a gold hollow nanorods on the surface.Such gold hollow nanorods have distinct absorption peak located also at the NIR regime,therefore induces strong resonance,benefitting NIR absorption in MoTe2,resulting in strong near-field enhancement.With the evidence from steady and transient state optical spectra,we confirm that the enhancement of NIR response originates only photon absorption,rather than electron transport at interfaces as observed in other heterostructures,therefore,precluding the requirement of high-quality interfaces for commercial applications.

A density functional theory study on the mechanism of dimethyl ether carbonylation over heteropolyacids catalyst

Dimethyl ether(DME)carbonylation is considered as a key step for a promising route to produce ethanol from syngas.Heteropolyacids(HPAs)are proved to be efficient catalysts for DME carbonylation.In this work,the reaction mechanism of DME carbonylation was studied theoretically by using density functional theory calculations on two typical HPA models(HPW,HSiW).The whole process consists of three stages:DME dissociative adsorption,insertion of CO into methoxyl group and formation of product methyl acetate.The activation barriers of all possible elementary steps,especially two possible paths for CO insertion were calculated to obtain the most favorable reaction mechanism and rate-limiting step.Furthermore,the effect of the acid strength of Brønsted acid sites on reactivity was studied by comparing the activation barriers over HPW and HSiW with different acid strength,which was determined by calculating the deprotonation energy,Mulliken population analyses and adsorption energies of pyridine.

Warehouse automation by logistic robotic networks:a cyber-physical control approach

In this paper we provide a tutorial on the background of warehouse automation using robotic networks and survey relevant work in the literature.We present a new cyber-physical control method that achieves safe,deadlock-free,efficient,and adaptive behavior of multiple robots serving the goods-to-man logistic operations.A central piece of this method is the incremental supervisory control design algorithm,which is computationally scalable with respect to the number of robots.Finally,we provide a case study on 30 robots with changing conditions to demonstrate the effectiveness of the proposed method.

Structure tailorable triple-phase and pure double-polar-phase flexible IF-WS_(2)@poly(vinylidene fluoride)nanocomposites with enhanced electrical and mechanical properties

A new low-cost high-permittivity flexible nanocomposite consisting of a polyvinylidene fluoride(PVDF)matrix and fullerene-like tungsten disulfide nanoparticle(IF-WS2 NP)filler was fabricated via a simple solution route.A comprehensive investigation by X-ray diffraction,attenuated total reflection-infrared spectroscopy,and differential scanning calorimetry(DSC)showed that 0.5e1 vol% of IF-WS_(2) induced a nonpolar α-phase to coexisting triple-phase transition in PVDF,whereas a slightly higher loading of 2 vol% induced pure double-polar β- and γ-phases.These results indicate that the structure and properties of the fabricated nanocomposite are easily tailorable.DSC during heating and cooling cycles and morphology observations further indicated that a polar phase was induced by the nucleation effect of the IF-WS2 NPs and electrostatic interactions.As a consequence of the multiphase coexistence and structure homogeneity,nanocomposites with approximately 0.5-1 vol% of IF-WS_(2) NPs showed enhanced dielectric and energy-storage performance as well as enhanced tensile strength and elongation.The new phase-tailorable nanocomposites with balanced properties are promising for applications as energystorage capacitors,piezoelectric sensors,and other flexible multifunctional components.The results of this study will serve to deepen the understanding of the polymer polymorph and provide directions on new routes for fabrication of smart materials.

A C3HC4-type RING finger protein regulates rhizobial infection and nodule organogenesis in Lotus japonicus

During the establishment of rhizobia-legume symbiosis, the cytokinin receptor LHK1 （Lotus Histidine Kinase 1） is essential for nodule formation. However, the mechanism by which cytokinin signaling regulates symbiosis remains largely unknown. In this study, an LHK1-interacting protein, LjCZF% was identified and further characterized. LjCZF1 is a C3HC4-type RiNG finger protein that is highly conserved in plants. LjCZF1 specifically interacted with LHK1 in yeast two-hybrid, in vitro pull-down and co-immunoprecipitation assays conducted in tobacco. Phosphomimetic mutation of the potential threonine （T167D） phosphorylation site enhanced the interaction between LjCZF1 and LHK1, whereas phosphorylation mutation （T167A） eliminated this interaction. Transcript abundance of LjCZF1 was up-regulated significantly after inoculation with rhizobia. The LORE1 insertion mutant and clustered regularly interspaced short palindromic repeats （CRISPR）/CRISPR- associated protein 9-mediated knockout mutant Lotus japonicus plants demonstrated significantly reduced number of infection threads and nodules. In contrast, plants over-expressing LjCZF1 exhibited increased numbers of infection threads and nodules. Collectively, these data support the notion that LjCZF1 is a positive regulator of symbiotic nodulation, possibly through interaction with LH K1.