Electromechanical and photoelectric properties of a novel semiconducting Janus InGaSSe monolayer

In recent years,Janus two-dimensional(2D)materials have received extensive research interests because of their outstanding electronic,mechanical,electromechanical,and optoelectronic properties.In this work,we explore the structural,electromechanical,and optoelectronic properties of a novel hypothesized Janus InGaSSe monolayer by means of first-principles calculations.It is confirmed that the Janus InGaSSe monolayer indeed show extraordinary charge transport properties with intrinsic electron mobility of 48139 cm^(2)/(V·s)and hole mobility of 16311 cm^(2)/(V·s).Both uniaxial and biaxial strains can effectively tune its electronic property.Moreover,the Janus InGaSSe monolayer possesses excellent piezoelectric property along both inplane and out-of-plane directions.The results of this work imply that the Janus InGaSSe monolayer is in fact an efficient photocatalyst candidate,and may provide useful guidelines for the discovery of other new 2D photocatalytic and piezoelectric materials.

SEMICONDUCTING AND METALLIC POLYMERS:THE FOURTH GENERATION OF POLYMERIC MATERIALS

INTRODUCTIONIn 1976, Alan MacDiarmid, Hideki Shirakawa and I, together with a talented group of graduate students andpost-doctoral researchers discovered conducting polymers and the ability to dope these polymers over the fullrange from insulator to metal. This was particularly exciting because it created a new field of research on theboundary between chemistry and condensed matter physics, and because it created a number of opportunities:

Semiconducting single-walled carbon nanotubes synthesized by S-doping

An approach was presented for synthesis of semiconducting single-walled carbon nanotubes(SWNTs) by sulfur(S) doping with the method of graphite arc discharge. Raman spectroscopy, UV-vis-NIR absorption spectroscopy and electronic properties measurements indicated the semconducting properties of the SWNTs samples. Simulant calculation indicated that S doping could induce convertion of metallic SWNTs into semiconducting ones. This strategy may pave a way for the direct synthesis of pure semiconducting SWNTs.

Semiconducting Mineral Photocatalytic Regeneration of Fe^(2+) Promotes Carbon Dioxide Acquisition by Acidithiobacillus ferrooxidans

Chemoautotrophic organisms have once been excluded from the development of universally applicable CO2 fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillusferrooxidans （A.f.） as a model chemoautotrophic microorganism to test the hypothesis that exogenetic photoelectrons from semiconducting mineral photocatalysis can enable the regeneration of Fe^2＋ that could be then used by A.f. and support its growth. In a simulated electrochemical system, where exogenetic electrons were provided by an electrochemical approach, an accelerated growth rate of A.f. was observed as compared with that in traditional batch cultivation. In a coupled system, where light-irradiated natural rutile provided the primary electron source to feed A.f., the bacterial growth rate as well as the subsequent CO2 fixation rate was demonstrated to be in a light-dependent manner. The sustaining flow of photogenerated electrons from semiconducting mineral to bacteria provided an inexhaustible electron source for chemoautotrophic bacteria growth and CO2 fixation. This finding might contribute to the development of novel effective CO2 fixation technology.

RBC Membrane Camouflaged Semiconducting Polymer Nanoparticles for Near-Infrared Photoacoustic Imaging and Photothermal Therapy

Semiconducting conjugated polymer nanoparticles(SPNs)represent an emerging class of phototheranostic materi-als with great promise for cancer treatment.In this report,low-bandgap electron donoracceptor(DA)-conjugated SPNs with sur-face cloaked by red blood cell membrane(RBCM)are developed for highly e ective photoacoustic imaging and photothermal therapy.The resulting RBCM-coated SPN(SPN@RBCM)displays remarkable near-infrared light absorption and good photosta-bility,as well as high photothermal conver-sion e ciency for photoacoustic imaging and photothermal therapy.Particularly,due to the small size(<5 nm),SPN@RBCM has the advantages of deep tumor penetration and rapid clearance from the body with no appreciable toxicity.The RBCM endows the SPNs with prolonged systematic circulation time,less reticuloendothelial system uptake and reduced immune-recognition,hence improving tumor accumulation after intravenous injection,which provides strong photoacoustic signals and exerts excellent photothermal therapeutic e ects.Thus,this work provides a valuable paradigm for safe and highly e cient tumor pho-toacoustic imaging and photothermal therapy for further clinical translation.

Majorana fermions induced fast-and slow-light in a hybrid semiconducting nanowire/superconductor device

We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices.

A"donor–acceptor"structured semiconductor polymer for near infrared fluorescence imaging guided photodynamic therapy

Near infrared(NIR)fluorescence imaging guided photodynamic therapy(PDT)is a technique which has been developed in many clinical trials due to its advantage of real-time optical monitoring,specific spatiotemporal selectivity,and minimal invasiveness.For this,photosensitizers with NIR fluorescence emission and high^(1)O_(2)generation quantum yield are highly desirable.Herein,we designed and synthesized a"donor-acceptor"(D-A)structured semiconductor polymer(SP),which was then wrapped with an amphiphilic compound(Pluronic■F127)to prepare water-soluble nanoparticles(F-SP NPs).The obtained F-SP NPs exhibit good water solubility,excellent particle size stability,strong absorbance at deep red region,and strong NIR fluorescent emission characteristics.The maximal mass extinction coe±cient and fluorescence quantum yield of these F-SPs were calculated to be 21.7 L/(g·cm)and 6.5%,respectively.Moreover,the^(1)O_(2)quantum yield of 89%for F-SP NPs has been achieved under 635 nm laser irradiation,which is higher than Methylene Blue,Ce6,and PpIX.The outstanding properties of these F-SP NPs originate from their unique D-A molecular characteristic.This work should help guide the design of novel semiconductor polymer for NIR fluorescent imaging guided PDT applications.

Obtaining the thin Semiconductive Covering Re-Se From Sulphate Electrolyte

There have been investigated the kinetics and mechanism of the cathode electrodeposition of thin coverings Re-Se?from the sulphate electrolyte, containing NH4ReO4, SeO2 and H2SO4. On the base of X-ray phase analysis and by the method of cyclic avometry there have been determined the content of obtained coverings, electrosettled at the various concentrations of components in electrolyte. The co-deposition process was shown to be attended by depolarization, which is due to the energy release upon the formation of the alloy.

Photoactive materials based on semiconducting nanocarbons——A challenge opening new possibilities for photocatalysis

This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (semiconducting) materials to prepare hybrid materials. The semiconducting properties of the nanocarbons, and the possibility to have the band gap within the visible-light region through defect band engineering, introduction of light heteroatoms and control/manipulation of the curvature or surface functionalization are discussed. These materials are conceptually different from the 'classical' semiconducting photocatalysts, because semiconductor domains with tuneable characteristics are embedded in a conductive carbon matrix, with the presence of various functional groups (as C=0 groups) enhancing charge separation by trapping electrons. These nanocarbons open a range of new possibilities for photocatalysis both for energetic and environmental applications. The use of nanocarbons as quantum dots and photo luminescent materials was also analysed. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Applications of Secondary Electron Composition Contrast Imaging Method in Microstructure Studies on Heterojunction Semiconductor Devices and Multilayer Materials

The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+Si1-xGex/pSi heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.

Modulating Bandgap and HOCO/LUCO Energy of Semiconducting Polymer by Copolymerization or Incorporation of Electron Withdrawing/Releasing Groups

The modulation of bandgap and HOCO/LUCO energies of conjugated polymers by copolymerization or by incorporation of electron withdrawing/releasing groups is studied.The study was conducted by band structure calculation applying density functional theory with generalized gradient approximation.The polymers and copolymers were modeled as 1D infinite system with periodical boundary condition along the molecular direction.It is concluded that the bandgap and HOCO/LUCO energies of conjugated polymers depend on both electron withdrawing/releasing effects and non-bonding interaction between a side group and the conjugated systems.

STUDY ON COMPLEX IMPEDANCE SPECTROSCOPY OF CU-IMPLANTED SEMICONDUCTING(Ba_(o·72)Pb_(o·28))TiO_3 CERAMICS

The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.

Structure and Semiconducting Character of a Polymeric Iodoplumbate Coordination Complex

A new polymeric iodoplumbate complex [Zn（DMF）6][Pb2I6] 1 has been prepared and characterized by elemental analysis and single-crystal X-ray analysis. Its structure contains infinite iodoplumbate chains constructed by the [PbI5] subunit. EHT crystal orbital calculation and the experimental results show that this material is an unconventional semiconductor and the electrical character is associated with its structural feature.

X—RAY STRUCTURE OF A SEMICONDUCTING ORGANOMETALLIC SALT,[FeCp(Tol)]_2[Ni(mnt)_2]

The title compound was prepared and characterized.Its crystal Structure was determined by X—ray diffraction analysis,and consists of segregated cation and an- ion stacks in the perpendicular directions.Crystal data:monoclinic,P2_1/c,Mr=765.21, a=7.882(2)b=15.526(4),c=13.736(2)β=99.87(2)~0,V=1656.0(6)~3,Ac =1.53g/cm^3,Z=2,F(000)=780,R=0.040 and R_w=0.056.

Realization of semiconducting Cu_(2)Se by direct selenization of Cu(111)

Bulk group IB transition-metal chalcogenides have been widely explored due to their applications in thermoelectrics.However,a layered two-dimensional form of these materials has been rarely reported.Here,we realize semiconducting Cu_(2)Se by direct selenization of Cu(111).Scanning tunneling microcopy measurements combined with first-principles calculations allow us to determine the structural and electronic properties of the obtained structure.X-ray photoelectron spectroscopy data reveal chemical composition of the sample,which is Cu_(2)Se.The observed moire pattern indicates a lattice mismatch between Cu_(2)Se and the underlying Cu(111)-√3×√3 surface.Differential conductivity obtained by scanning tunneling spectroscopy demonstrates that the synthesized Cu_(2)Se exhibits a band gap of 0.78 eV.Furthermore,the calculated density of states and band structure demonstrate that the isolated Cu_(2)Se is a semiconductor with an indirect band gap of-0.8 eV,which agrees quite well with the experimental results.Our study provides a simple pathway varying toward the synthesis of novel layered 2D transition chalcogenides materials.

Fabrication and Characterization of Fe-Doped In2O3 Dilute Magnetic Semiconducting Nanowires

Fe-doped In2O3 dilute magnetic semiconducting nanowires are fabricated on A u-deposited Si substrates by the chemical vapor deposition technique. It is confirmed by energy dispersive x-ray spectroscopy （EDS）, x-ray photoelectron spectroscopy （XPS） and Raman spectroscopy that Fe has been successfully doped into lattices of In2O3 nanowires. The EDS measurements reveal a large amount of oxygen vacancies existing in the Fe-doped In2O3 nanowires. The Fe dopant exists as a mixture of Fe2＋ and Fe3＋, as revealed by the XPS. The origin of room-temperature ferromagnetism in Fe-doped In2O3 nanowires is explained by the bound magnetic polaron model.

SEMICONDUCTING PROPERTIES OF In_2O_3 ANODIC FILM

The good potentiality of the In_2O_3 anodic film as a photoanodic material has been demonstrated.The anodic oxidation of In substrate in alkaline solution for obtaining In_2O_3 film has been developed and their semiconducting properties have been investigated through capacitance, photoelectrochemistry and electroreflection measurements.

Theory of Conductivity in Semiconducting Single-Wall Carbon Nanotubes

The conduction of a single-wall carbon nanotube depends on the pitch. If there are an integral number of carbon hexagons per pitch, then the system is periodic along the tube axis and allows “holes” (not “electrons”) to move inside the tube. This case accounts for a semiconducting behavior with the activation energy of the order of around 3 meV. There is a distribution of the activation energy since the pitch and the circumference can vary. Otherwise nanotubes show metallic behaviors (significantly higher conductivity). “Electrons” and “holes” can move in the graphene wall (two dimensions). The conduction in the wall is the same as in graphene if the finiteness of the circumference is disregarded. Cooper pairs formed by the phonon exchange attraction moving in the wall is shown to generate a temperature-independent conduction at low temperature (3 - 20 K).

Combined Effect of Uniaxial Strain and Magnetic Field on the Exciton States in Semiconducting Single-Walled Carbon Nanotubes

The exciton states of semiconducting carbon nanotubes are calculated by a tight-binding model supplemented by Coulomb interactions under the combined effect of uniaxial strain and magnetic field. It is found that the excitation energies and absorption spectra of zigzag tubes（11,0） and（10,0） show opposite trends with the strain under the action of the magnetic field. For the（11,0） tube, the excitation energy decreases with the increasing uniaxial strain, with a splitting appearing in the absorption spectra. For the（10,0） tube, the variation trend firstly increases and then decreases, with a reversal point appearing in the absorption spectra. More interesting,at the reversal point the intensity of optical absorption is the largest because of the degeneracy of the two bands nearest to the Fermi Level, which is expected to be observed in the future experiment. The similar variation trend is also exhibited in the binding energy for the two kinds of semiconducting tubes.

Preparation and Photoelectric Conversion Mechanism of Semiconducting ITO/Cu_2O Electrodes

Semiconducting cuprous oxide films were electrodeposited onto conducting glasses coated with Indium Tin Oxide （ITO） using potentiostatic method. The electrodes were examined by means of X-Ray Diffraction （XRD） and X-ray Photoelectron Spectrum （XPS）. The results indicate that the prepared films are cubic Cu2O crystals, and annealing enhances the size and preferred orientation of the films. The photoelectric conversion mechanism of semiconducting ITO/Cu2O electrodes in 0.1 mol/L potassium sulfate （K2SO4） solution is further discussed by using Linear Sweep Voltammetry （LSV） method. The differences of photoelectric conversion of electrodes are reasonably deduced and proved through surfactant modifying, annealing or not, respectively.