MoTe_(2)/Ta_(2)NiSe_(5)/MoTe_(2)范德华双异质结实现超快、宽带和偏振敏感光电探测器

高效光电探测器在监控、热成像、光通信和环境监测等领域具有广泛、迫切的应用需求.优化光电探测器参数如微型化、高量子效率、超快响应速度等,仍然是一项艰巨的任务.我们提出了一种由顶部/底部MoTe_(2)和中间Ta_(2)NiSe_(5)层组成的双范德华异质结.利用双异质结界面增强光收集效率和产生两个对立的内置电场,使得器件具有400到1550 nm的宽光谱响应,并表现出优异的性能,包括82.9%的外量子效率和3.5/4.2μs的快速响应速度.此外,利用二维Ta_(2)NiSe_(5)纳米片的面内各向异性,我们实现了在635和1550 nm波长下的极化灵敏度,分别为16.3和8.1.这项研究为开发高性能和多功能光电探测器提供了平台,为先进光电器件的设计和应用提供了新的方向.

Synthesis and characterization of (Ni,Sb)-co-doped rutile ceramic pigment via mechanical activation-assisted solid-state reaction

(Ni,Sb)-co-doped rutile yellow ceramic pigments were synthesized via a mechanical activation-assisted solid-state reaction in a stirred bead mill.The effects of mechanical grinding of the raw materials on the synthesis of (Ni,Sb)-co-doped rutile pigment were investigated.The results show that mechanical activation effectively decreased the crystallinity of the mixed precursors,thus enhancing their reactivity and the migration rate of ions.These effects lowered the temperature required for formation of the rutile phase.Compared with results from a mixture of separately ground precursors,the mixture of raw materials ground together was more effective for accelerating nickel/antimony ions doping into the TiO2structure and improved the color performance of the pigment.The pigment from the mixed raw materials ground for 2.0h and heat-treated at 1100℃ could be used as an environmentally-friendly ceramic yellow pigment owing to its low-toxicity,bright yellow hue,good chemical/thermal durability, and high cost-effectiveness.

Tribological and tribochemical properties of magnetite nanoflakes as additives in oil lubricants

This detailed the tribological and tribochemical properties of magnetite（Fe3O4） nanoflakes used as additives in #40 base oil in a four-ball tribo-tester.The average friction coefficient of the friction pair for lubricant containing the Fe3O4 nanoflakes of 1.5 wt%as a lubricant additive in the base oil is decreased by18.06%compared to that of solely base oil.The chemical composition of base oil with the Fe3O4 nanoflake additives did not change during the 48-h friction assessment.The decreased saturation magnetization and increased coercivity of magnetite nanoflakes occurred due to the distortion of the basal planes and the presence of hematite（α-Fe3O4） generated by the tribochemical reactions during the friction process.The multi-layer low-shear-stress tribochemical lubrication films on the surface of the friction pair could form because the nanoflake particles arrange and adhere onto the surface of the friction pair in an orderly manner,and the tribochemical reactions of the friction pair in the presence of the nanoflakes occur as Fe→FeO→Fe3O4→γ-FeOOH →γ-Fe2O3→α-Fe2O3.The formation of the films can improve the tribological properties.

Effect of alkalis on deacetylation of konjac glucomannan in mechano-chemical treatment

This paper presents experimental results on the effect of alkalis such as NaOH, KOH and Ca（OH）2 on deacetylation of a konjac glucomannan （KGM） powder under mechano-chemical （MC） treatment, The results show that the alkalinity of modifiers is a dominant factor for deacetylation of KGM, In addition, characteristics, such as swelling property, viscous stability and thermal behavior of the deacetylated KGM are analyzed

Preparation of Eu^(2+),Dy^(3+),Zr^(4+)ions co-doped strontium aluminate/molybdate multi-optical functional hybrid pigments for anti-counterfeiting

Eu^(2+),Dy^(3+)and Zr_(4+)ions co-doped strontium aluminate(i.e.,SrAl_(2)O_(4):Eu^(2+),Dy^(3+),Zr_(4+))/molybdate(i.e.,Ho2MoO6or Nd2MoO6)with photo-/mechano-luminescence and allochroic effect as multi-optical functional hybrid pigments were prepared via solid state reactions and subsequent mixing.The phosphor and hybrid pigments were characterized by X-ray diffraction,scanning electron microscopy with energy dispersive X-ray spectroscopy,ultraviolet-visible spectroscopy,L*a*b*color scale analysis,spectrophotometry and mechanoluminescent measurement.The results show that the optimum luminescent emission intensity of SrAl_(2)O_(4):Eu^(2+),Dy^(3+),Zr_(4+)phosphor can be obtained when 5 mol%Zr_(4+)ions is doped into the lattice.Under the excitation of 365 nm wavelength,the hybrid pigments prepared with the phosphor and molybdate at a mass ratio of 1:1 present a green broad band emission located at 460-650 nm due to 4f65d1→4f7transitions of Eu^(2+)ions.The hybrid pigments have the superior mechanoluminescent property and emit light after being exerted by mechanical stresses.Besides,the hybrid pigments also exhibit an allochroic effect under different illuminants.In addition,the anti-counterfeiting of the hybrid pigments as a promising application was also presented.

Inversion of particle size distribution from light-scattering data using a modified regularization algorithm

A modified regularization algorithm with a more proper operator was proposed for the inversion of particle size distribution （PSD） from light-scattering data in a laser particle sizer based on the Mie scattering principle. The Generalized Cross-Validation （GCV） method and the L-curve method were used for deter- mining the regularization parameter. The Successive Over-Relaxation （SOR） iterative method was used to increase the exactness and stability of the converged result. The simulated results based on the modified algorithm are in a good agreement with the experimental data measured for nine standard particulate samples, their mixtures as well as three natural particulate materials with irregular shapes, indicating that this modified regularization method is not only feasible but also effective for the simulation of PSD from corresponding light-scattering data.

Low temperature hydrothermal synthesis of SrTiO3 nanoparticles without alkali and their effective photocatalytic activity

SrTiO3 nanoparticle (NP) photocatalyst was synthesized with a facile and environmentalfriendly hydrothermal method using tetrabutyltitanate,strontium oxide,and ethanolamine as precursors at low temperature without alkali as mineralizer for the first time.The SrTiO3 nanoparticles were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),field emission scanning electron microscopy (FESEM),and N2 Brunauer-Emmett-Teller (BET) method.The SrTiO3 catalyst synthesized at 120 ℃ (STO-120) exhibited the highest photocurrent intensity among the samples synthesized at different hydrothermal temperatures.The high photocatalytic performance of STO-120 was mainly attributed to the more homogeneous and minimum nanoparticle size,the highest surface area,and the maximum light absorption property among the four different samples.This work presented an applicable and facile method to fabricate a highly active and stable SrTiO3 photocatalyst for organic pollutant degradation.