Effect of thickness of antimony selenide film on its photoelectric properties and microstructure

Antimony selenide(Sb2Se3) films are widely used in phase change memory and solar cells due to their stable switching effect and excellent photovoltaic properties. These properties of the films are affected by the film thickness. A method combining the advantages of Levenberg–Marquardt method and spectral fitting method(LM–SFM) is presented to study the dependence of refractive index(RI), absorption coefficient, optical band gap, Wemple–Di Domenico parameters, dielectric constant and optical electronegativity of the Sb2Se3films on their thickness. The results show that the RI and absorption coefficient of the Sb2Se3films increase with the increase of film thickness, while the optical band gap decreases with the increase of film thickness. Finally, the reasons why the optical and electrical properties of the film change with its thickness are explained by x-ray diffractometer(XRD), energy dispersive x-ray spectrometer(EDS), Mott–Davis state density model and Raman microstructure analysis.

Photoelectric Properties of Soluble ZnPc-Epoxy Derivative Doped with C_(60)

A kind of soluble phthalocyanine derivative （ZnPc-epoxy derivative） was synthesized, and the influence of C60 on the photoelectric properties of the derivative was studied. The results of ultraviolet-visible （UV-Vis） spectra show that the absorption of the complex is larger than that of the ZnPc-epoxy derivative at B belt. But compared with the derivative, the absorption of the complex decreased at Q belt. The fluorescence spectra show that C60 takes role as annihilation in ZnPc-epoxy derivative. Photo-current tests show that the ZnPc-epoxy derivative-C60 film exhibits increasing photoconductive property.

Photoelectric properties of thin Eu^(3+)-doped TiO_2 films sensitized by cis-RuL_2(SCN)_2·2H_2O

Thin nanocrystalline TiO2 films doped by europium ions (Eu3+) were obtained by the sol-gel method. The photoelectric properties of Eu3+-doped TiO2 film electrode sensitized by cis-RuL2(SCN)2·2H2O (L=cis-2,2′-bipyridine-4,4′-dicarboxlic acid) ruthenium complex were studied. The thin films were characterized by X-ray diffraction, atomic force microscopy and X-ray photoelectron spectroscopy. Effect of doping Eu3+ on microscopic structure and photoelectrical properties were discussed. The result shows that doping europium ions makes specific surface area of these films larger, which contributes to improving the photoelectric properties. It is found that an optimal composition doped with 0.2 mol.% Eu3+ exhibits the highest photoelectric properties. Isc is 0.37 mA·cm-2, which is 0.17 mA·cm-2 bigger than that of un-doped films; Voc is 405 mV, which is 50 mV bigger than that of un-doped films.

Inner Am monium Salt Carbocyanine Filmson SiSurface and Their Photoelectric Properties

Two inner salt carbocyanines were filmed chemically on the Si surface through Si-O-C bond. The structures were characterized by SERS and XPS. And the spectral response and surface photovoltage spectrum were measured. These results show that the Si wafer can be sensitized by dyes, and the filmed Si wafers have photovoltage effect.

Synthesis of rod-like bis-ester liquid crystals and their influence on photoelectric properties of liquid crystalline materials

Six novel rod-like magnetic liquid crystals have been prepared, in which trans-bicyclohexyl or trans-cyclohexylphenyl and biphenylcarboxylic acid phenyl ester mesogenic cores with n-propyl and n-pentyl substituents were terminated by 4-hydroxyl- TEMPO （TEMPO = 2,2,6,6-tetramethylpiperidine-l-oxy）. Their structures were confirmed by elemental analysis, IR and MS. Determined by SQUID, EPR, DSC and HS-POM （heat stage polarizing optical microscope）, the six compounds all have both magnetic and liquid crystalline properties; their temperature ranges of mesophase were from 16.0 to 24.8 ℃, and the magnetic liquid crystal molecules could obviously improve the response sensitivity of liquid crystal materials.

Photoelectric properties of p-β-FeSi_2/n-4H-SiC heteroj unction near-infrared photodiode

We give the first report on the experimental investigation of a p-β-FeSi2/n-4H-SiC heterojunction. A β-/%FeSiE/n-4H-SiC heterojunction near-infrared photodiode was fabricated on 4H-SiC substrate by magnetron sputtering and rapid thermal annealing （RTA）. Sharp film-substrate interfaces were confirmed by scanning elec-tron microscopy （SEM）. The current density-voltage and photoresponse characteristics were measured. The measurements showed that the device exhibited good rectifying properties. The photocurrent density was about 1.82 mA/cm^2 at a bias voltage of -1 V under illumination by a 5 mW, 1.31 μm laser, and the dark current density was approximately 0.537 mA/cm^2. The detectivity was estimated to be 8.8×10^9 cmHzl/2/W at 1.31 μm. All of the measurements were made at room temperature. The results suggest that the p-β-FeSiE/n-4H-SiC heterojunctions can be used as near-infrared photodiodes that are applicable to optically-activated SiC-based devices.

Substrate temperature effects on the structural and photoelectric properties of ZnS:In films

Indium doped ZnS （ZnS：In） films were prepared on glass substrate using thermal evaporation technol- ogy. It was found that the structural, optical and electrical properties of ZnS：ln films strongly depend on the substrate temperature （Ts）. By X-ray diffraction （XRD）, atomic force microscopy （AFM）, transmittance spectroscopy, and electric performance measurements, the effect of Ts on ZnS：In film is studied in detail. It reveals that Ts has impor- tant effect on ZnS grain size, crystallinity, lattice disorder, etc., which further leads to the obvious influence on its optical and electrical performance. Under the optimized Ts, the performance, especially the conductivity, achieved in this work is far higher than that reported for other n-type ZnS films.

Ethynylene-Linked Oligomers Based on Benzodithiophene:Synthesis and Photoelectric Properties

Two conjugated ethynyl-linked oligomers,oligo(benzodithiophene-ethynylene-benzothiadiazole)(O1)and oligo(benzodithiophene-ethynylene-carbazole)(O2),were synthesized by Sonogashira coupling reaction.Their de-grees of polymerization were 7 and 10,respectively.Their photophysical and electrochemical properties were in-vestigated.O1 exhibitd two strong absorption bands at 404 nm and 483 nm,and O2 at 401 nm and 429 nm.The re-sults of UV-Vis,cyclic voltammetry(CV)and theoretical calculations showed that O1 has a narrower band gap than O2.The conductivities of O1 and O2 were 1.05×10^(−15) and 6.98×10^(−16) S/cm,respectively,and would increase to 1.23×10^(−10) and 1.05×10^(−10) S/cm after doping with iodine.

Preparation and Photoelectric Properties of Patterned Ag Nanoparticles on FTO/Glass Substrate by Laser Etching and Driving Layer Strategy

An effective method based on laser etching and driving layer strategy was proposed to prepare patterned Ag nanoparticles(Ag NPs)on fluorine-doped tin oxide(FTO)/glass substrate and thus to enhance the photoelectric properties.This method successively included depositing an aluminum-doped zinc oxide(AZO)driving layer,laser etching,depositing an Ag layer,furnace annealing and laser removal.Different AZO and Ag layer thicknesses were adopted,and the surface morphology,crystal structure and photoelectric properties were investigated.An Ag NPs/FTO/glass sample without an AZO driving layer was prepared for comparison.It was found that furnace annealing of the Ag layer combined with the AZO driving layer,rather than that without the AZO driving layer,was more conducive to generating patterned Ag NPs.Using a 20-nmthick AZO layer and a 150-nm-thick Ag layer led to the formation of uniformly distributed Ag NPs being aligned along the laser-etched grooves to form a pattern.The as-obtained sample had the best comprehensive photoelectric property with an average transmittance of 79.95%,a sheet resistance of 7.11Ω/sq and the highest figure of merit of 1.50×10^(-2)Ω^(-1),confirming the feasibility of the proposed method and providing enlightenment for related researches of transparent conductive oxide-based films.

Analysis on the Characteristic Properties of PEDOT Nano-particle Based on Reversed Micelle Method

Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,we deeply investigated the optical,electrical and the thermal stability of PEDOT nanoparticles.The main results are as follows： the small-sized PEDOT nanoparticles were prepared and utilized by different methods,such as ultraviolet/visible （UV-Vis） spectroscopy,Fourier-transform infrared （FT- IR） spectrum,scanning electron microscopy（SEM） and so on.The results show that the amount of oxidizer,ultrasonic treatment,polymerizing temperature and doping degree can influent morphology,electrical ability and gas sensitivity of PEDOT nanoparticles.The Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the better orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles than conventional PEDOT.

Enhanced Photoelectric Property of Mo-C Codoped TiO2 Films Deposited by RF Magnetron Cosputtering

Mo-C codoped TiO2 films were prepared by RF magnetron cosputtering. Ultraviolet-visible spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray Analysis and X-Ray Diffraction were used to study the influences of codoping on energy gap, surface morphology, valence states of elements, ions content and crystal structure, respectively. The concentration of photogenerated carriers was measured by studying photocurrent density, while catalytic property was evaluated by observing degradation rate of methylene blue under visible light. A Mo-doped TiO2 film, whose content of Mo had been optimized in advance, was prepared and later used for subsequent comparisons with codoped samples. The result indicates that Mo-C codoping could curtail the energy gap and shift the absorption edge toward visible range. Under the illumination of visible light, codoped TiO2 films give rise to stronger photocurrent due to smaller band gaps. It is also found that Mo, C codoping results in a porous surface, whose area declines gradually with increasing carbon content. Carbon and Molybdenum doses were delicately optimized. Under the illumination of visible light, sample doped with 9.78at% carbon and 0.36at% Mo presents the strongest photocurrent which is about 8 times larger than undoped TiO2 films, and about 6 times larger than samples doped with Mo only.

Preparation and characterization of TiO_(2) photoelectrode codoped with aluminum and boron and its application in dye-sensitized solar cell

Nanocrystalline titania films codoped with aluminum and boron were prepared by cathodic vacuum arc deposition.In the process,titanium alloy target was used under an O_(2) /Ar atmosphere,and sensitization of films were carried out by natural dye-sensitized complex in anhydrous ethanol.The structure,surface morphology and UV-vis spectra of titania films codoped were measured by X-ray diffraction analysis,scanning electron microscopy and ultraviolet-visible spectrometer.The as-deposited films are found to be amorphous.The films annealed were examined to be of anatase structure with orientation along the(101)planes,the average crystal size is in the range between 41 and 45 nm.SEM results show that there are some pores in the codoped titania films,the optical properties of the dye-sensitized films were also measured which reveals that the spectral responses of films shift to the visible region.Under simulated sunlight illumination,the overall energy conversion efficiency of dye-sensitized nanocrystalline solar cell is 0.9%.

Enhancement of Overall Photovoltaic Efficiency by Changing the Position of the Attaching Group-RSO3^-on the Hemicyanine Dye Molecules

A new photoresponsive D--A dye, mPS, has been designed and synthesized. Compared to the parent dye PS, IPCE values in the region from 400 nm to 560 nm was greatly improved upon changing the attaching group from the p- position to the o- position of the p-conjugation bridge. A solar cell based on mPS generated a remarkably high overall yield of 5.4% under irradiation of 80.0 mW cm-2 white light from a Xe lamp. Compared with PS, the overall yield ?increased by 64%.

Compositional and structural engineering of inorganic nanowires toward advanced properties and applications

As natural one-dimensional confined electron transport channels and photonpropagation paths, nanowires (NWs) display unmatched properties and hugepotential for application in diverse fields. The ability to construct a nanoscalefunctional system would enable significant advances in the currently desiredminiaturized device integration. To date, the basic properties of all types ofnanowire crystals, including metallic NWs, as well as group IV-related, III-V/II-VI compounds, and metal oxide NWs, are well understood. Regarding futurework, compositional (ie, doping and alloying) and structural (defect andheterostructure) designs to flexibly realize custom-made functionality areemphasized. Along this line, recent progress is reviewed, including the basicproperties (nanowire mechanics, electronics, and photonics) and applicationssuch as photodetectors and chemical/biological sensors. A review of the correlationsbetween the compositional/structural configuration of nanowires and thecorresponding functionality is also presented. The future development directionof this field is concluded and highlighted at the end.

Recent progress on intramolecular charge-transfer compounds as photoelectric active materials

This article summarized the recent advance on the structural design and synthetic strategies of intramolec- ular charge-transfer compounds as well as their potential ap- plications in two-photon absorption chromophores, organic photovoltaics and organic light-emitting diodes.

Photoelectronic properties and devices of 2D Xenes

Two-dimensional materials,especially graphene-like emerging single-element materials two-dimensional(2D)Xenes,have attracted great research interest since the advent of the graphene.In this review paper,12 kinds of different Xenes were introduced according to the group and element quality,and their main synthesis methods are outlined.The advantages and limitations of the synthesis methods are analyzed in detail.By summarizing the current photoelectronic properties of 2D Xenes materials,it is found that Xenes in the same group have similar properties,such as the buckling properties of the fourth group and the anisotropy of the fifth group.In addition,the performance of photoelectronic applications based on 2D Xenes materials are summarized,and some possible methods are proposed to improve the perfor-mance of future 2D Xenes material photoelectronic devices.

Photovoltaic and photoelectric response of Sn_(2)P_(2)S_(6) ferroelectric films

In the present work,the comparative study of the electric response of Sn_(2)P_(2)S_(6) films to the visible light action was carried out without and under external electric field.The light flux modulated by a chopper induces the integral response comprising time-dependent photoelectric and photovoltaic components.It was shown that spontaneous polarization influences the electric response characteristics.

Multi-time scale photoelectric behavior in facile fabricated transparent and flexible silicon nanowires aerogel membrane

In recent years,transparent and flexible materials have been widely pursued in electronics and optoelectronics fields for usage as planar electrodes,energy conversion components and sensing units.As the most widely applied semiconductor material,the related progress in silicon is of great significance although with large difficulty.Herein,we report a one-step method to achieve flexible and transparent silicon nanowires aerogel membrane.A competitive carrier kinetics involving interfacial trapped carriers and the valence electrons transition is demonstrated,according to the photoelectric performance of a sandwiched graphene/silicon nanowires membrane/AI device,i.e.,rapidly positive photoresponse dominated by laser excited^ee-carriers generation(〜500 ms)and subsequent slow negative photocurrent evolution due to laser heating involved multi-levels process(>10 s).These results contribute to fabrication of silicon nanowire self-assembly structures and also the exploration of their optoelectrical properties in flexible and transparent devices.

A Comparative Study on the Microstructure and Properties of ITO Targets and Thin Films Prepared from Two Different Powders

With the rapid development of indium tin oxide(ITO)in the electronic display industry,choosing which raw powders to prepare high-quality ITO targets has always been a controversial topic.In the work,in order to clearly understand the effect of the raw powders on the microstructure and properties of ITO targets and thin films,tin-doped indium oxide(dITO)and In_(2)O_3-SnO_(2)mixed(mITO)powders were chosen to prepare ITO targets for depositing the films and a comparative study on their microstructure and properties was conducted.It is found that,(1)dITO targets possess a higher solid solubility of tin in indium oxide and more uniform elemental distribution,while there are a higher density,a finer grain size and a higher mass ratio of In_(2)O_3 to SnO_(2)for the mITO targets;(2)dITO films with more coarser columnar grains and a rougher surface prefer to grow along the[100]direction in an Ar atmosphere;(3)the conductive property of ITO films only depends on the doping amount of tin and is independent of the raw powders and the preparation process of the target source;(4)dITO films possess the superior optical property and narrower optical band gap;(5)the etching property of mITO films is superior to that of dITO films due to the lower solid solubility of tin in indium oxide.

Dual strategy of modulating growth temperature and inserting ultrathin barrier to enhance the wave function overlap in type-Ⅱ superlattices

Maximizing wave function overlap(WFO)within type-II superlattices(T2SL)is demonstrated to be important for improving their photoelectric properties,such as optical transition strength and quantum efficiency,which,however,remains a great challenge for now.Herein,the dual strategy of modulating growth temperature and inserting ultrathin AlAs barrier into the AlSb layers is presented to enhance the WFO in InAs/AlSb T2SL.The charge distributions and strain states indicate that moderate growth temperature of 470°C promotes the As-Sb exchange at AlSb-on-InAs(AOI)interfaces,which would introduce skew of energy band structure towards InAs-on-AlSb(IOA)interface.Such band structure could drive electrons and holes to the IOA interfaces simultaneously,thus resulting in the enhanced WFO.On this basis,insertion of relatively thick(0.3 nm)AlAs layers is found to squeeze more holes towards adjacent interfaces,boosting the WFO further.The InAs/AlSb superlattices with optimized WFO reveal better optical performance,where the peak intensity shows 50%improvement in the PL spectra than the original one.Moreover,a dual-miniband radiative transition mechanism appears in the InAs/AlSb superlattice with relatively thick AlAs intercalation,which helps broaden the wavelength range of the superlattice.