Memristive Behavior Based on Ba-Doped SrTiO3 Films

The Sr0.95Ba0.05 TiO3 （SBT） nanometer film is prepared on the commercially available Pt/TiO2/SiO2/Si substrate by radio-frequency magnetron sputtering. The x-ray diffraction pattern and the scanning electron microscope image of the cross-sectional profile of the SBT nanometer film are depicted. The memristive mechanism is inferred. The mathematical model M（q） = 12.3656 - 267.4038｜q（t）｜is calculated, where M（q） denotes the memristance depending on the quantity of electric charge, and q（t） denotes the quantity of electric charge depending on the time. The theoretical I-V characteristics of the SBT nanometer film are obtained by the mathematical model. The results show that the theoretical I-V characteristics are consistent with the measured I-V characteristics. Moreover, the mathematical model could guide the research on applications of the memristor.

Synthesis of Ba-doped porous LaFeO_(3) microspheres with perovskite structure for rapid detection of ethanol gas

In this work,porous La_(1-x)Ba_(x)FeO_(3)(x=0.01,0.02,0.03,0.04 and 0.05) microspheres of the orthorhombic perovskite phase were prepared by an environment-friendly one-step hydrothermal method with a series of characterization of the six sensing nanomaterials.Characterization results show that their grain size is between 21.2 and 23.2 nm,and the grain growth is inhibited with the increase in Ba-doping concentration.The samples are all spherical with a diameter of about 10 μm,and the surface is very rough.By the gas sensing study of the samples,the results show that the La_(1-x)Ba_(x)FeO_(3) sensor exhibits a fairly high response to the ethanol gas.In particular,the La_(1-x)Ba_(x)FeO_(3) microspheres with a Ba-doping concentration of 2 mol% showed not only a significant improvement in sensitivity but also a rather rapid response recovery time compared to the undoped samples,demonstrating the superiority as an ethanol sensing nanomaterial.More importantly,the optimum operating temperature of La0.98Ba0.02FeO_(3) is only 200℃,while that of the pure LaFeO_(3) is 260℃.The Ba-doped porous microspheres prepared are a high-performance sensing material capable of rapid and accurate detection of ethanol.

Enhanced electrochemical performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3−δ)cathode via Ba-doping for intermediate-temperature solid oxide fuel cells

La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)is recognized as one of the most promising cathode materials for the highly-desired intermediatetemperature solid oxide fuel cell(IT-SOFC)technology.However,it is still challenged by polarization losses due to reduced operation temperatures.In this work,a series of Ba^(2+)-doped La0.6-xBaxSr0.4Co0.2Fe0.8O3-δ(LBSCFx,x=0.05,0.10,0.15,and 0.20)materials are successfully synthesized and their electrochemical performances are evaluated as a cathode for IT-SOFC technology.The study shows that,compared to the un-doped LSCF,the Ba^(2+)-doped LBSCF possess higher electrical conductivities at 500-800℃ and display lower polarization resistances to oxygen adsorption/dissociation.As a result,the Ni-SDC|SDC|LBSCF0.20 cell(SDC=samarium-doped cerium,Sm_(0.2)Ce_(0.8)O_(1.9))delivers a high maximum power density of 0.704 W/cm^(2)at 750℃,which is>30%higher than the Ni-SDC|SDC|LSCF cell.This work reveals that Ba^(2+)-doping is effective in enhancing oxygen catalytic activity of LSCF-based cathode materials,demonstrating a new and commercial-feasible strategy in developing high performance cathode materials for the IT-SOFC technology.

Barium charge transferred doped carbon dots with ultra-high quantum yield photoluminescence of 99.6% and applications

Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical properties.In this study,a facile and rapid approach was developed for the preparation of barium-doped carbon dots(Ba-CDs) with yellow fluo rescence emission and high quantum yields.Surface chemistry and the chemical architecture of the Ba-CDs was revealed under various spectroscopic methods.This work provides more insights into the effects of charge transfer caused by Ba heteroatoms,which is considered as the most challenging step in the investigation on luminescence mechanism.Remarkably,the prepared Ba-CDs were successfully applied as fluorescent probes in the detection of trace water in organic solvents(ethanol,isopropanol,acetone,tetrahydrofuran).Comparing with traditional fluorescent probes for water detection in organic solvents,Ba-CDs detection provides a more sensitive,much faster and more economical approach.