Groups-dependent phosphines as the organic redox for point defects elimination in hybrid perovskite solar cells

Lead(Pb)^(0) and iodine(I)^(0) point defects generated during perovskite solar cell(PSC)fabrication and photoconversion form deep band energy levels as the carriers’recombination centers.These defects not only deteriorate device efficiency,but also facilitate chemical degradation with ion migration,resulting in restricted device lifetime.Herein,we present a novel type of phosphines as the point defects stabilizer for hybrid perovskite solar cells with enhanced performances.Three phosphines with varied side groups of tributyl,trioctyl and triphenyl are exampled as the dopants in perovskite films.The group dependent redox properties were observed in the perovskite film,dependent on their molecular weights and steric hinderances of phosphines.The partially oxidized tributyl phosphine(TBUP)with additional tributyl phosphine oxides(TBPO)is efficient in reduction of lead(Pb)^(0) and iodine(I)^(0) concentrations during the device fabrication and operation.The device with TBUP-TBPO pair showed enhanced power conversion efficiency(PCE)to 20.48% and maintain 91.7% of their initial PCEs after 500 h at 65℃ thermal annealing.Thus,this work presents an efficient route of utilize the phosphine species to reduce point defects in the perovskite film,which promoting further development of novel phosphorous additives with defects stabilization,interface passivation and encapsulation for low-cost solution processed PSCs.

2D polyaniline with exchangeable interlayer fluid for fast and stable volumetric dual ion storage

Two-dimensional(2D) layered materials are widely applied in energy devices including lithium-ion battery and supercapacitor due to their unique properties,such as tunable interlayer structure,numerous active sites,large aspect ratio versatile interlayer chemistry.In this work,2D layered tungstate acidlinked polyaniline(TALP) presented a fluid-in-solid structure,which allowed facile exchange of the interlayer fluid from moisture to conventional Li^(+) containing electrolyte.With fast and stable dual ion storage(Li^(+) and PF_(6)^(-)),TALP demonstrates high-rate volumetric capacity(39 mAh cm_(-3) at 2000 mA g^(-1)) and good stability(2000 cycles at 200 mA g^(-1)) within the working potential window of 1.5-4.5 V versus Li^(+)/Li.

Graphene oxide:An emerging electromaterial for energy storage and conversion

This paper gives a comprehensive review of the recent progress on electrochemical energy storage devices using graphene oxide(GO).GO,a single sheet of graphite oxide,is a functionalised graphene,carrying many oxygen-containing groups.This endows GO with various unique features for versatile applications in batteries,capacitors and fuel cells.Specific applications are considered principally including use in electrodes as the active materials to enhance the performance or as substrates to diversify the structures,in solid-state electrolytes and membranes to improve the ionic conductivity and mechanical properties,and in interlayers to protect the electrodes,membranes or current collectors.Furthermore,the challenges and future prospects are discussed in the paper for encouraging further research and development of GO applications.

Boosting the cycling stability of rechargeable magnesium batteries by regulating the compatibility between nanostructural metal sulfide cathodes and non-nucleophilic electrolytes

Rechargeable magnesium batteries are attractive candidates for energy storage due to their high theoretical specific capacities,free of dendrite formation and natural abundance of magnesium.However,the development of magnesium secondary batteries is severely limited by the lack of high-performance cathode materials and the incompatibility of electrode materials with electrolytes.Herein,we report the application of CuS nanoflower cathode material based on the conversion reaction mechanism for highly reversible magnesium batteries with boosted electrochemical performances by adjusting the compatibility between the cathode and electrolyte.By applying non-nucleophilic electrolytes based on magnesium bis(hexamethyldisilazide)and magnesium chloride dissolved in the mixed solvent of tetrahydrofuran and N-butyl-N-methyl-piperidinium bis((trifluoromethyl)sulfonyl)imide(Mg(HMDS)_(2)-MgCl_(2)/THF-PP14TFSI)or magnesium bis(trifluoromethanesulfonyl)imide,magnesium chloride and aluminium chloride dissolved in dimethoxyethane(Mg(TFSI)2-MgCl_(2)-AlCl_(3)/DME),the magnesium batteries with CuS nanoflower cathode exhibit a high discharge capacity of~207 mAh·g^(–1)at 100 mA·g^(–1)and a long life span of 1,000 cycles at 500 mA·g^(–1).This work suggests that the rational regulation of compatibility between electrode and electrolyte plays a very important role in improving the performance of multi-valent ion secondary batteries.

DETERMINATION OF HISTIDINE BY DIFFERENTIAL PULSE ADSORPTIVE STRIPPING VOLTAMMETRY OF ITS NICKEL(Ⅱ)COMPLEX

Abstract: Histidine was determined at the 5. 0 ×10-1.0×10-5mol/L level by differential pulse adsorptive cathodic etripping voltammetry at a hanging mercury drop electrode using the reduction peak of its nickel(Ⅱ) complex at -1. 16v(vs. Ag(AgCl) obtained in pH-10. 2 borate buffer solution. Other amino acid. do not interfere . This methed has been used for the direct determination of histidiue in serum.

The Simultaneous Determination of Cu Ph Cd and Sb by Derivative Adsorption Chronopotentiometry

The behaviour of the complexes of copper,lead,cadmium and antimony with salicylfluorone (SAF) adsorbed on HMDE has been investigated by derivative chronopotentiometry in NH_3/NH_4C1. The dependence of the peak height on the dt/dE vs E curve on preconcentration time, the pH of solution and the constant reducing current are discussed. This method achieved the simultaneous determination of copper, lead, cadmium and antimony in human hair.

STUDIES ON THE SAPONIN CONSTITUENTS OF GYNOSTEMMA LONGIPES

Two new cornpounds,saponin I and saponin II,were isolated from Gynostemma longipes f.Y.Wu. The struetures have been characterized on the basis of cbenical and speetroseopie evidence. ^-~.

A Study on the Simultaneous Determination of Copper and Tin in the Presence of Lead

A very sensitive electrochemical procedure for trace determination of copper and tin in the presence of lead using cathodic adsorption voltammetry is presented.The complex of copper,tin with salicylfluorone (SAF) is adsorbed on the hanging mercury drop electrode (HMDE) and the reduction current of the accumulated complex is measured by voltammetry.This method achieves the simultaneous determination of copper and tin,and has been applied to determine canned food.Anodic stripping voltarnmetry (ASV)is an effeCtive electroanajytital technique for themeasurement Of trace metal ions.But there are serious interferences due to overlapping strippingpeak and forming of intermetamc complex in complicated syStem.The results are usUally notsatisfaCtory. The dffeulty of simultaneous determination Of copper and tin in the presence of leadis the strong tendency of tin (IV ) species to hydrolyZO and polwnerise as well as the overlap ofthe stripping Peaks of tin and lead by anodic stripping voltarnmetry at mercury electrodes. Inaddition, tin and copper easily created into intermetailic complex on HMDE and the tin peak isrestrained by copper;it is very dimcult to determine them,individually or simultaneously.Various approaches have been employed to improve the selectivity of tin measurement bystripping voltammetry.These include prior separation['J, flow or medium--exchange schemes[23 orthe addtion Of surfactants' L3) We have determined Zr[4), Ga[sj, V['J, Sb[7) etc,by Cathodicstripping VOltammetry (csv) using nuorone claSs ligand as complexing agent.In this paper, wereport a hashly sensitive and selective stripping approach for sdriultaneous determination of copperand tin in the presence of lead' The method has been used to sampled of canned food.

A STUDY ON THE ADSORPTION VOLTAMEMTRY OF THE INDIUMSEMIXYLENOL ORANGE

The electrochemical behaviour of the indium complex with semixylenol orange at a handing mercury electrode has been investigated in HAc-NaAc solution(PH=3. 66). Tile mpchanism of the electrode reaction was reaction was found to be reduction of in (Ⅲ ) L2 adsoyhed (In the electrode by irreversible chargestransrer to metal amalgam. In Hg. The detection limit and the linear range are 6. 5X10-11mol/L and 3. 0X10-10-1.5 mol/L respectively. This method has been applied to determine indium in samples of nickel and nickel sulfate.

Controllable growth and flexible optoelectronic devices of regularly-assembled Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks

Regularly assembled structures of nanowires, such as aligned arrays, junctions and interconnected networks, have great potential for the applications in logical circuits, address decoders, photoelectronic devices and transparent electrodes. However, for now it is still lack of effective approaches for constructing nanowire bifurcated junctions and crosslinked networks with ordered orientations and high quality. Herein, we report the controlled growth of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks with well-aligned directions and high crystalline degree by utilizing the proportional lattice match between nanowires and substrates. Taking advantages of the “tip-to-stem splice” assembly of individual nanowires, the precise orientation alignments of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks were successfully realized. The controlled growth mechanism and structural evolution process have been elucidated by detailed atomic structure characterizations and modeling. The highly crystal quality and direct energy bandgap of as-assembled photodetectors based on individual bismuth sulfide nanowires enabled high photoresponsivity and fast switch time under light illumination. The three-terminal devices based on nanowire bifurcated junctions present rapid carrier transport across the junction. The flexible photodetectors based on nanowire crosslinked networks show very minimal decay of photocurrent after long-term bending test. This work may provide new insights for the guided construction and regular assembly of low-dimensional ordered functional nanostructures towards advanced nanotechnologies.

Double transition metal atoms anchored on Graphdiyne as promising catalyst for electrochemical nitrogen reduction reaction

Ammonia synthesis by electrochemical nitrogen reduction technique is an attractive alternative to traditional Haber-Bosch process.Currently,development of an efficient and effective electrocatalyst is one of the remaining key challenges.In this work,density functional theory(DFT)computations were systematically employed on double transition metal atoms(Fe,Co,Ni,Cu and Mo)anchored Graphdiyne(GDY)for nitrogen reduction reaction(NRR).The Co-Ni heteronuclear complex and Mo-Mo homonuclear complex showed the highest NRR activity while demonstrating synergistic effect of double atomic catalytic sites towards the promising NRR activity.

Structural characterization of 1β,11α-dihydroxycanrenone biotrans-formed from canrenone by Aspergillus ochraceus SIT34205

Canrenone（1） was biotransformed into 11α-hydroxycanrenone（2） and a main byproduct（3） by Aspergillus ochraceus SIT34205.Compound 3 was separated and purified using silica gel column chromatography,and its structure was characterized via MS and NMR methods.These results indicated that 3 was 1β,11α-dihydroxycanrenone and the product of further hydroxylation of 2.Thus,investigating the structure and synthesis of 3 may be a promising method to improve the efficiency and purity of 2.