Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer

Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their commercialization.The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs.In this work,we propose a strategy to stabilize high-performance PSCs with PCE over 23%by introducing a cesium-doped graphene oxide(GO-Cs)as an interlayer between the perovskite and hole-transporting material.The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80(the time where the device PCE reduces to 80%of its initial value)of 2143 h of operation at the maximum powering point under one sun illumination.

Synthesis and characterization of LiFePO_4 coating with aluminum doped zinc oxide

Aluminum doped zinc oxide （AZO）, as an electrically conductive material, was applied to coating on the surface of olivine-type LiFePO4 synthesized by solid-state method. The charge-discharge test results show that the rate performance and low-temperature performance of LiFePO4 are greatly improved by the surface treatment. Even at 20C rate, the discharge specific capacity of 100.9 mA.h/g was obtained by the AZO-coated LiFePO4 at room temperature. At -20 ℃, the discharge specific capacity at 0.2C for un-coated LiFePO4 and the coated one are 50.3 mA.h/g and 119.4 mA.h/g, respectively. It should be attributed to the electrically conductive AZO-coating which increases the electronic conductivity of LiFePO4. Furthermore, the surface-coating increases the tap-density of LiFePO4. The results indicate that the AZO-coated LiFePO4 is a good candidate of cathode material for applying in lithium power batteries.

Synthesis and Characterization of Zinc Oxide and Zinc Oxide Doped with Chlorine Nanoparticles as Novel <i>α</i>-Amylase Inhibitors

In this study we used a chemical solution method from oxalic acid (OX. acid) and zinc acetate (ZnAc) to prepare Zinc Oxide nanoparticles (ZnONPs) and Zinc Oxide nanoparticles doped with Chlorine (Cl:ZnONPs). The characterizations (FTIR, X-ray, SEM, TEM) of ZnONPs and Cl:ZnONPs were determined. Amylase inhibitors of ZnONPs and Cl:ZnONPs also were determined. SEM indicated that the ZnONPs and Cl:ZnONPs have an average particle size of 46.65 - 74.64 nm. TEM images of the ZnONPs and Cl:ZnONPs showed the round shaped. Compounds b, d and e exhibited significant inhibitory activity against amylase enzyme (from 69.21 ± 1.44 to 76.32 ± 0.78), respectively, and were comparable with that of acarbose (86.32 ± 0.63) at 1000 μg, thereby, projecting ZnONPs and Cl:ZnONPs as α-amylase inhibitors.

Preparation and Characterization of Transparent Conductive Zinc Doped Tin Oxide Thin Films Prepared by Radio-frequency Magnetron Sputtering

High transparent and conductive thin films of zinc doped tin oxide （ZTO） were deposited on quartz substrates by the radio-frequency （RF） magnetron sputtering using a 12 wt% ZnO doped with 88 wt% SnO2 ceramic target.The effect of substrate temperature on the structural,electrical and optical performances of ZTO films has been studied.X-ray diffraction （XRD） results show that ZTO films possess tetragonal rutile structure with the preferred orientation of （101）.The surface morphology and roughness of the films was investigated by the atomic force microscope （AFM）.The electrical characteristic （including carrier concentration,Hall mobility and resistivity） and optical transmittance were studied by the Hall tester and UV- VIS,respectively.The highest carrier concentration of -1.144×1020 cm-3 and the Hall mobility of 7.018 cm2（V ·sec）-1 for the film with an average transmittance of about 80.0% in the visible region and the lowest resistivity of 1.116×10-2 Ω·cm were obtained when the ZTO films deposited at 250 oC.

Preparation,Characterization and Electronic Properties of Fluorine-doped Tin Oxide Films

Tin oxide（SnO2） and fluorine doped tin oxide（FTO） films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by controlling precursor sol composition.Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration.Uniform and highly transparent FTO films,with more than 85%of optical transmittance,were obtained by annealing at 600℃.Florine doping of films was verified by analyzing the valence band region obtained by XPS.It was found that the fluorine doping affects the shape of valence band of SnO2 films.In addition,it was observed that the band gap of SnO2 is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.

Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

Indium doped zinc oxide （ZnO：In） thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO：In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10^-3 Ω. cm and particle grains. The doublelayers structure is designed to fabricate the ZnO：In thin film with low resistivity （2.58 × 10^-3 Ω. cm） and good surface morphology. It is found that the surface morphology of the double-layer ZnO：In film strongly depends on the substratelayer, and the second-layer plays a large part in the resistivity of the doublewlayer ZnO：In thin film. Both total and direct transmittances of the double-layer ZnO：In film are above 80% in the visible light region. Single junction a-Si：H solar cell based on the double-layer ZnO：In as front electrode is also investigated.

Preparation and Characterization of Indium Doped Tin Oxide （ITO） via a Solvothermal Method

Tin-doped Indium Oxide （ITO） has been successfully prepared via solvothermal method with a mixture of Indium（Ill） acetylacetonate and Tin（IV） bis（acetylacetonate）dichioride in oleyamine solvent under the condition of the different reaction time from 12 h to 48 h for the first time. The morphology, phase composition and particle size of the ITO powder were characterized by TEM and XRD. Two significant properties required for ITO samples to become noncarbon support for Pt in PEMFCs including specific surface area and electrical conductivity were studied.

Polysulfides adsorption and catalysis dual-sites on metal-doped molybdenum oxide nanoclusters for Li-S batteries with wide operating temperature

The development of electrocatalysts with high catalytic activity is conducive to enhancing polysulfides adsorption and reducing activation energy of polysulfides conversion, which can effectively reduce polysulfide shuttling in Li-S batteries. Herein, a novel catalyst NiCo-MoO x /rGO (rGO = reduced graphene oxides) with ultra-nanometer scale and high dispersity is derived from the Anderson-type polyoxometalate precursors, which are electrostatically assembled on the multilayer rGO. The catalyst material possesses dual active sites, in which Ni-doped MoO x exhibits strong polysulfide anchoring ability, while Co-doped MoO x facilitates the polysulfides conversion reaction kinetics, thus breaking the Sabatier effect in the conventional electrocatalytic process. In addition, the prepared NiCo-MoO x /rGO modified PP separator (NiCo-MoO x /rGO@PP) can serve as a physical barrier to further inhibit the polysulfide shuttling effect and realize the rapid Li+ migration. The results demonstrate that Li-S coin cell with NiCo-MoO x /rGO@PP separator shows excellent cycling performance with the discharge capacity of 680 mAh·g^(−1) after 600 cycles at 1 C and the capacity fading of 0.064% per cycle. The rate performance is also impressive with the remained capacity of 640 mAh·g^(−1) after 200 cycles even at 4 C. When the sulfur loading is 4.0 mg·cm^(−2) and electrolyte volume/sulfur mass ratio (E/S) ratio is 6.0 μL·mg^(−1), a specific capacity of 830 mAh·g^(−1) is achieved after 200 cycles with a capacity decay of 0.049% per cycle. More importantly, the cell with NiCo-MoO x /rGO@PP separator exhibits cycling performance under wide operating temperature with the reversible capacities of 518, 715, and 915 mAh·g^(−1) after 100 cycles at −20, 0, and 60 °C, respectively. This study provides a new design approach of highly efficient catalysts for sulfur conversion reaction in Li-S batteries.

Single atom doping induced charge-specific distribution of Cu1-TiO_(2) for selective aniline oxidation via a new mechanism

Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.

Mixed iridium-nickel oxides supported on antimony-doped tin oxide as highly efficient and stable acidic oxygen evolution catalysts

Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.

Synthesis and Characterization of Rare Earth Ion Doped Nano ZnO

Zinc oxide(ZnO) doped with erbium at different concentrations was synthesized by solid-state reaction method and characterized by X-ray diffraction(XRD), scanning electron microscopic(SEM), UVabsorption spectroscopy, photoluminescence(PL) study and vibrating sample magnetometer. The XRD studies exhibit the presence of wurtzite crystal structure similar to the parent compound ZnO in 1% Er^(3+)doped Zn O,suggesting that doped Er^(3+)ions sit at the regular Zn^(2+)sites. However, same studies spread over the samples with Er^(3+)content>1% reveals the occurrence of secondary phase. SEM images of 1% Er^(3+)doped ZnO show the polycrystalline nature of the synthesized sample. UV-visible absorption spectrum of Er^(3+)doped ZnO nanocrystals shows a strong absorption peak at 388 nm due to ZnO band to band transition. The PL study exhibits emission in the visible region, due to excitonic as well as defect related transitions. The magnetizationfield curve of Er^(3+)doped ZnO nanocrystals showed ferromagnetic property at room-temperature.

Effects of Dysprosium Oxide Doping on Microstructure and Properties of Barium Titanate Ceramic

Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. Furthermore, the influences of dysprosium oxide doping fraction on grain size and dielectric properties of barium titanate ceramic, including dielectric constant and breakdown electric field strength , were investigated via scanning electron microscope, X-ray diffraction and electric property tester. The results show that dysprosium oxide can restrain abnormal grain growth during sintering and that fine-grained and high density of barium titanate ceramic can result in excellent dielectric properties. As mass fraction of dysprosium oxide is 0.6%, the lattice parameters of grain increase to the maximum because of the lowest vacancy concentration. The electric property parameters are cited as following： dielectric constant （25 ℃ ） reaches 4100, the change in relative dielectric constant with temperature is - 10% to 10% within the range of - 15 - 100 ℃, breakdown electric field strength （alternating current） achieves 3.2 kV·mm^-1, which can be used in manufacturing high voltage ceramic capacitors

Dielectric Properties at High Frequency of BSTO System Doped Dy_2O_3

Samples doped with different amount of dysprosium oxide into barium strontium titanate (BSTO) were prepared. Dielectric properties of the samples at high frequency were discussed. X-ray diffraction (XRD) method was employed for analyzing and comparing with the changes in the crystal lattice of the samples,and information of crystal growth was obtained through method of environmental scanning electron micrograph (ESEM). Influence of dysprosium oxide doping on dielectric properties of BSTO based ceramic system at high frequency was studied. Phenomenological coefficients of the samples were calculated on the base of tunability.

CO Catalytic Oxide over Cu Atom Supported on Graphene Oxides from the First Principles

Via the first principles calculations, we predict that Cu doped graphene oxide （GO） is a much better nanocatalyst in terms of activity and feasibility. The high activity of Cu doped graphene oxides may be attributed to the charge transfer between the GO and Cu atom, resulting in an activated Cu atom. In the ER mechanism, the CO molecules directly react with the activated O2, then forming a metastable carbonate-like intermediate state （OOCO）. The reaction may proceed via two reaction paths of OOCO → CO2 ＋ O and CO ＋ OOCO → 2CO2, respectively. The calculated results show that the latter path is relatively more thermodynamically favorable with a modest energy barrier, so it should be more preferred. We expect our theoretical predictions to open a new avenue to fabricate carbon-based catalysts for CO oxidation with lower cost and higher activity.

Shape Controlled Preparation,Characterization and Gas Sensitivities of Shuttle-like Cr-doped α-Fe_2O_3 Nanoparticles

α-Fe2O3 nanoparticles doped with various molar fractions of Cr^3＋ were synthesized by a forced hydrolysis route and were characterized by X-ray diffraction（XRD）,scanning electronic microscopy（SEM）,X-ray photoelectron spectroscopy（XPS） and inductive coupled plasma（ICP） techniques.The particles reserve shuttle-like shape in the presence of Cr^3＋.The crystallite sizes of Fe2O3 become smaller with the increased Cr^3＋ concentration in solution.The responses of Cr doped α-Fe2O3 sensors were studied towards reducing gases such as ethanol,methanol,acetone,gasoline and n-hexane.Gas sensors based on these materials have higher sensitivities and rapid response/recovery time to alcohol than to hydrocarbon.

Characterization and Doping Effect of Cu-Doped ZnO Films

Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2,3,and 5 wt%).Cu-doped ZnO thin films were prepared on p-Si(100)substrate by screen printing method.Cu-doped ZnO/Si films were annealed at different temperatures from 300 to 700°C.In this study,Cu-doped ZnO structures were prepared by a simple precipitation technique,and characterized by various techniques such as XRD(X-ray diffraction)and SEM(scanning electron microscope).The electrical properties of Cu-doped ZnO/Si were measured.It has found that Cu-doped ZnO/Si films can be used as optoelectronic devices.

Synthesis and optical properties of turquoise-and green-colored brownmilleritetype Ba_2In_(2-x-y)Mn_xAl_yO_(5+x) codoped with manganese and aluminum

Brownmillerite-type oxides Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x）（0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5） were prepared at 1300°C through solid-state reaction. X-ray diffraction（XRD） analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl_2O_4 and Ba_2InAlO_5 impurities were observed in the XRD patterns. When substituted with a small amount of Mn（x ≤ 0.3）, the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） was confirmed to be ＋5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba_2In_（2-x-y）Mn_xAl_yO_（5＋x） samples is rooted in the existence of Mn^（5＋）; thus, the introduction of Al does not affect the optical properties of the compounds.

OXIDATIVE COUPLING OF METHANE OVER Na_2CO_3 DOPED ZIRCONIUM DIORIDE

Na_2CO_3/ZrO_2 catalyst shows a high activity of oxidative coupling of methane. It possesses stronger electron donor ability than that of ZrO_2 catalyst. The activation of methane is supposed to relate to the O_2^- or O_2^(2-) and O^- species.

Influence of TiO_2 on the Alkali Resistance and Structure of Invert Glass

Through measuring the alkali resistance of the invert glass and the quantity of SiO 2 and TiO 2 migrating fron the glass into the solution,the influence of TiO 2 on the alkali resistance of the glass is discussed and its structure is also analyzed by infrared spectroscopy.It is concluded that TiO 2 has double functions for the alkali resistance of the invert glass.On the one hand ,both TiO 2 polarizing the secondary ions in glass and TiO 2 isomorphism replacement of SiO 2 make the alkali resistance of the glass decrease.On the ther hand,TiO 2 patching network and anti erosion covering help to increase the alkali resistance.