Arrested Precipitation Technique Research Articles

Effect of indium (III) content on photoelectrochemical performance of MoBi(2−x)InxS5 thin films

Highly ordered quaternary semiconducting MoBi(2−x)InxS5 nanocrystalline thin films have been successfully synthesized via a relatively simple and convenient Arrested Precipitation Technique (APT). This solution based technique is being scaled up and may serve as the basis for the next generation of low cost solar cells. Depending on the chemical composition and synthesis conditions, the morphology of the nanocrystalline thin films can be controlled by [In]/[Bi] molar ratio. The structural, morphological, compositional and optical absorption properties of as-synthesized MoBi(2−x)InxS5 thin films are characterized using X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and UV–Vis–NIR spectrophotometry techniques. The photoelectrochemical (PEC) characterization of the films were carried out in 0.05 M I−/I3− redox electrolyte under dark and illuminated conditions. The maximum photocurrent density (411 μA/cm2) is obtained for molar ratio [In]/[Bi] = 1 using 500 W tungsten filament lamp with light intensity 30 mW/cm2.

Influence of vacuum annealing on the structural and photoelectrochemical properties of nanocrystalline MoBi2S5 thin films

In the present paper we report structural, optical, morphological and electrical properties of thin films of MoBi2S5 prepared by facile self organized arrested precipitation technique (APT) from aqueous alkaline bath. X-ray diffraction study on thin films suggests orthorhombic and rhombohedral mixed phase structure. The samples are further annealed under vacuum at 373 and 473 K. The EDS pattern shows minor loss of sulphur upto 473 K. The optical absorption in visible region shows direct allowed transition with band gap variation over 1.2–1.1 eV. Post-heat treated samples exhibit n-type electrical conductivity. SEM images show uniform distribution of spherical grains with diameter ∼200 nm for as-synthesized MoBi2S5 thin film. The grain size increases with annealing temperature and morphology becomes more compact due to crystallization of thin film. The surface roughness deduced from AFM, was in the range of 1.29–1.92 nm. The MoBi2S5 thin films are employed for the fabrication of photoelectrochemical solar cells as all the samples exhibit strong absorption in visible to near IR region. Due to vacuum annealing it gives a significant enhancement of power conversion efficiency (η) upto 0.14% as compared to as-synthesized MoBi2S5 thin film.

Development of nanocoral-like Cd(SSe) thin films using an arrested precipitation technique and their application

First-time synthesis of nanoflakes to nanocoral-like Cd(SSe) thin films using a novel arrested precipitation technique with triethanolamine as complexing agent (η = 0.57%).

Nanocrystalline MoBi2Se5 Ternary Mixed Metal Chalcogenide Thin-films for Solar Cell Applications

Optical, structural, morphological and photoelectrochemical properties were investigated of ternary MoBi2Se5 thin film prepared by simple arrested precipitation technique (APT). The precursors used were molybdenum, bismuth, triethanolamine complexes (TEA) along with organic additives. Ammonium molybdate, Bismuth nitrate and sodium selenosulphite were used as sources of Mo4+, Bi3+ and Se2− ions. The optical band gap of thin film was estimated to be 1.78eV. X-ray diffraction data reveals that the grown MoBi2Se5 thin film was highly nanocrystalline with orthorhombic structure. Scanning electron microscopy studies reveal that porous layer having elongated fibrous morphology with high surface area. The film was obtained with a well-defined composition, very close to the expected one. PEC application of prepared thin film were checked in Sulphide / Poly sulphide electrolyte which revealed that MoBi2Se5 thin film deposited on FTO coated glass exhibited maximum values of fill factor (FF) and conversion efficiency (η) with n type semiconductor nature.

Effect of copper content on optostructural, morphological and photoelectrochemical properties of MoBi2−x Cu x Se4 thin films

In the present investigation we have reported a facile chemical route for the deposition of MoBi2−x Cu x Se4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) thin films at room temperature by using a simple and self-organised arrested precipitation technique. The deposited samples were characterised for their structural, morphological, optical and photoelectrochemical properties. X-ray diffraction patterns revealed that, undoped MoBi2Se5 shows a rhombohedral crystal structure, while mixed rhombohedral and orthorhombic crystal structures were observed with shifting of diffraction peaks after copper doping. The scanning electron microscopy and transmission electron microscopy images revealed that the surface morphology was improved with copper content. Compositional analysis of all samples was carried out by using energy dispersive X-ray spectroscopy. The direct band gap energy of all the samples estimated from absorbance spectra varies from 1.26 to 1.60 eV. The photoelectrochemical properties of all samples were studied in I−/I3 − redox electrolyte which demonstrated that the electrical conductivity was transformed from n-type to p-type after copper doping and photoelectrochemical response of p-type MoBi2−x Cu x Se4 thin film electrode was improved with increasing copper content. The mechanism of change in the type of electrical conductivity and augmentation in photoelectrochemical response after copper doping are discussed.

Synthesis and Thermoelectric Study of Sb (III) Doped Bi2(Te1-Xsex)3 Thin Films by Apt

Thermoelectric study of Sb (III) doped bismuth tellurium selenide ,Bi2-x Sbx(Te1-xSex)3 thin films were done.They are deposited by Arrested Precipitation Technique (APT). These thin films were prepared using a complexing agent triethanolamine (TEA) and a reducing agent sodium sulphite to avoid hydroxide formation of bismuth precursor Bi (NO3)3 and antimony precursor (SbCl3) in aqueous medium to favor the reaction with Te2- and Se2-chalcogen ions. The preparative conditions such as pH, concentration of precursors, temperature, rate of agitation and time were finalized at initial stages of deposition. As deposited films were annealed at constant temperature (373K) in muffle furnace and then characterized for optostructural, morphological, thermoelectric and figure of merit (ZT). The results demonstrate that the Bi2-x Sbx(Te1-xSex)3 thin films prepared by APT shows band gap in the range 1.46eV to 1.89eV. X-Ray Diffraction (XRD) pattern, Scanning Electron Microscopy (SEM) images reveals that Bi2-x Sbx(Te1-xSex)3 mixed metal chalcogenide films are of nanocrystalline nature and have rhombohedral structure and better morphology. EDAX study shows good stoichiometry. Electrical and TEP study shows Sb(III) doping in Bi2(Te1-xSex)3 mixed metal chalcogenide thin films are semiconducting having p-type conduction mechanism. The highest figure of merit obtained was 0.312 and 0.569 for D1 to D5 samples.

Synthesis and characterization of nanocrystalline MoBi2Te5 thin films for photoelectrode applications

Molybdenum bismuth telluride thin films have been prepared on clean glass substrate using arrested precipitation technique which is based on self-organized growth process. As deposited MoBi2Te5 thin films were dried in constant temperature oven at 110°C and further characterized for their optical, structural, morphological, compositional, and electrical analysis. Optical absorption spectra recorded in the wavelength range 300–800 nm showed band gap (E g) 1.44 eV. X-ray diffraction pattern and scanning electron microscopic images showed that MoBi2Te5 thin films are granular, nanocrystalline having rhombohedral structure. The compositional analysis showed close agreements in theoretical and experimental atomic percentages of Mo4+, Bi3+, and Te2− suggest that chemical formula MoBi2Te5 assigned to as deposited molybdenum bismuth telluride new material is confirmed. The electrical conductivity and thermoelectric power measurement showed that the films are semiconducting with n-type conduction. The fill factor and conversion efficiency was characterized by photoelectrochemical (PEC) technique. In this article, we report the optostructural, morphological, compositional, and electrical characteristics of nanocrystalline MoBi2Te5 thin films to check its suitability as photoelectrode in PEC cell.

Synthesis of fibrous reticulate nanocrystalline n-type MoBi2(Se1−xTex)5 thin films: Thermocooling applications

In the present investigation n-type MoBi2(Se1−xTex)5 nanocrystalline thin films with various compositions of Se and Te were successfully deposited on ultrasonically cleaned glass substrates using recently developed Arrested Precipitation Technique (APT). The effect of composition on optical, morphological, structural, electrical and thermocooling properties of MoBi2(Se1−xTex)5 were investigated using UV–vis–NIR Spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometer, thermoelectric power and thermocooling measurements. Thermoelectric properties including electrical conductivity (σ), Seeback coefficient (S) and figure of merit (ZT) were measured at 300K. Our aim is to investigate thermocooling behavior in respect of variation in composition of Se and Te in MoBi2(Se1−xTex)5 thin films along with optostructural and optoelectric properties.

Photoelectrochemical Cell Performance Of Chemically Deposited MoBi2Te5 Thin Films

Molybdenum bismuth telluride thin films have been prepared on clean glass substrate using Arrested Precipitation Technique (APT) which is based on self organized growth process. As deposited MoBi2Te5 thin films were dried in constant temperature oven at 110 o C and further characterized for their optical, structural, morphological, compositional and electrical analysis. Optical absorption spectra recorded in the wavelength range 300-800 nm showed band gap (Eg) 1.44 eV. X-ray diffraction pattern and scanning electron microscopic images showed that MoBi2Te5 thin films were nanocrystalline having rhombohedral structure. The energy dispersive spectroscopic analysis of as deposited thin films showed close agreements in theoretical and experimental atomic percentages of Mo 4+ , Bi 3+ and Te 2- and suggest that the chemical formula MoBi2Te5 assigned to molybdenum bismuth telluride thin film material is confirm. The resistivity and thermoelectric power measurement studies showed that the films were semiconducting with n-type conduction. The fill factor and conversion efficiency (η) are determined by fabricating PEC cell using MoBi2Te5 thin film electrode. In this article we report the optostructural, morphological, compositional and thermoelectric characteristics of nanocrystalline MoBi2Te5 thin films to check its suitability as photoelectrode in PEC Cell.

ChemInform Abstract: Synthesis and X‐Ray Photoelectron Spectroscopy (XPS) and Thermoelectric Studies of Ternary Bi2(Te0.5Se0.5)3 Mixed‐Metal Chalcogenide Thin Films by the Arrested Precipitation Technique.

AbstractBi2(Te0.5Se0.5)3 thin films are deposited on glass substrates by the arrested precipitation technique using Bi(NO3)3, Na2SeSO3, Na2TeSO3, and Et3N as starting materials (pH 10.5, 55 °C, 1.5 h).

Effect of surfactant on optical and structural properties of chemically deposited MoBi2S5 thin films

In the present report, we have synthesized MoBi2S5 thin films by the Arrested Precipitation Technique (APT). The deposited thin films were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDS), UV-visible spectroscopy etc. Characterization tools were employed for structure, morphology, chemical composition and optical properties. Further, the effect of tri-n-octyl phosphine oxide (TOPO) on the formation and properties of the MoBi2S5 thin films were investigated. XRD patterns confirmed that the crystallite size of the MoBi2S5 thin film is decreased by using TOPO surfactant. EDS analysis results are in good agreement with the proposed chemical composition. SEM images reveal that grain size decreases from 200 to 160 nm in the presence of TOPO surfactant. The UV-visible absorption spectra of MoBi2S5 thin films show strong absorption in the wavelength range 400–1100 nm. The optical band gap was calculated from absorption spectra and lies in the range 1.20–1.35 eV. Finally, these prepared electrodes were tested for their photoelectrochemical (PEC) performance in polyiodide electrolyte and results are promising.

Synthesis and X-ray photoelectron spectroscopy (XPS) and thermoelectric studies of ternary Bi2(Te0.5Se0.5)3 mixed-metal chalcogenide thin films by the arrested precipitation technique

Arrested precipitation technique (APT) has been successfully employed for the deposition of Bi2(Te0.5Se0.5)3 thin films. Analytical grade bismuth nitrate complexes with triethanolamine (TEA), sodium tellurosulfite, and sodium selenosulfite were used as precursor materials. The film was obtained at 55 ± 0.5 °C in an aqueous alkaline medium (pH = 10.5 ± 0.2). As-deposited film was characterized by chemical compositional, optical, and electrical analyses. The optical absorption spectrum for the sample was recorded in the wavelength region 400–900 nm. It shows a high coefficient of absorption (α = 105 cm–1) with an allowed direct type of transition. X-ray diffraction (XRD) study of the film shows a nanocrystalline and rhombohedral structure. From scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray analysis (EDAX) studies, the deposited film shows uniform morphology and good stoichiometry. X-ray photoelectron spectroscopy (XPS) was used to study the binding energy and surface oxidation of the material. Electrical conduction study shows that material is an n-type semiconductor and shows good thermoelectric figure of merit.

Synthesis and characterization of new quaternary MoBiInSe5 mixed metal chalcogenide thin films

Abstract Uniform mixed quaternary metal chalcogenide thin films of MoBiInSe 5 have been successfully deposited on microglass slides substrate support using simple arrested precipitation technique (APT). The precursors used were molybdenum, bismuth, indium, triethanolamine in complex form and sodium selenosulphite as a source of Mo 4+ , Bi 3+ , In 3+ and Se 2− along with organic additives, respectively. The compositional analysis and morphology of the as deposited thin films were studied using energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD) and scanning electron microscope (SEM). The effect of preparative parameters such as concentration of precursors, complexing agent, P H , temperature, rate of agitation on morphology of the as deposited thin films was studied. The chemical composition was found to be stoichiometric. Morphological studies show that, refinement of grain size was strongly influenced by preparative parameters. In the present investigation we have described growth kinetics of MoBiInSe 5 chalcogenide thin films using arrested precipitation technique (APT). The compositional and morphological results of as deposited MoBiInSe 5 thin films showed the possibility of this material as best candidate for broadband photo convertor. DC electrical conductivity and TEP study shows that the material is n-type semiconductor.

Effect of Sb doping on thermoelectric properties of chemically deposited bismuth selenide films

Bi 2− x Sb x Se 3 thin films with x = 0, 0.02, 0.04, 0.06, 0.08 and 0.10 were elaborated under optimum conditions using the arrested precipitation technique and their thermoelectric properties were studied as a function of Sb content ( x). The thermoelectric power and electrical conductivity measurement have been carried out on the films in the temperature range 300–500 K. Temperature-dependent electrical conductivity measurements verified semiconducting behaviour. From the thermoelectric power measurements it follows that the dominant carriers in all these films are holes. It was observed that thermal conductivity of Bi 2− x Sb x Se 3 film series decreases when the Sb content ( x) increases. The thermoelectric power factors of films have been found to be maximum for Bi 1.98Sb 0.02Se 3 composition at room temperature. Thermoelectric performance (ZT) in Bi 2− x Sb x Se 3 materials increases substantially at higher temperatures suggesting that these materials are promising for high temperature applications.

Growth mechanism and characterisation of chemically grown Sb doped Bi 2Se 3 thin films

The synthesis of combinatorial Bi 2− x Sb x Se 3 thin films by arrested precipitation technique (APT) using triethanolamine-bismuth, triethanolamine-antimony and sodium selenosulphite as sources of Bi 3+, Sb 3+ and Se 2−, respectively is investigated on commercial glass substrates. The growth mechanism of film formation, composition and surface morphology of the as deposited films were studied as a function of preparative parameters and bath composition. The films were monophasic, polycrystalline and covered the surface of the substrate completely. Energy dispersive X-ray analysis gave coherent elemental composition indicating single phase BiSbSe 3 was made. The good results obtained for Bi 2− x Sb x Se 3 thin films revealed that arrested precipitation technique is best suited for the deposition of large area thin films on conducting/nonconducting substrates to produce materials for device applications.

Preparation and characterisation of chemically deposited mixed (Bi1−x,Sbx)2S3 thin films

Bismuth antimony sulphide (Bi1−x,Sbx)2S3 thin films have been deposited on glass substrates using arrested precipitation technique. Ingredients used for the deposition include triethanolamine complex of bismuth, aqueous thioacetamide and antimony trichloride. Stoichiometric mixtures of these ingredients are used for deposition of thin uniform and adhesive films on microslides. The preparative parameters such as temperature, pH, time, concentration of the reactants and substrate rotations are optimised to obtain good quality films. The morphology of as deposited films was examined by SEM and X-ray diffraction pattern. The optoelectronic properties of bismuth antimony chalcogenide thin films are strongly influenced by chemical composition of the films. Optical study shows that the films have an optical band gap of 2·3 eV for Sb2S3 and 1·8 eV for Bi2S3. Therefore, it is proposed to determine chemical composition of as deposited thin films by energy dispersive X-ray microanalysis and atomic absorption spectroscopy methods. The results obtained by these techniques show correct stoichiometry for all composition of the films grown by arrested precipitation technique. The purpose of the present paper is to study the preparative parameters, optical, electrical properties and morphology of bismuth antimony sulphide thin films. These films have ‘n’ type conduction with high electric resistance. X-ray diffraction study shows that (Bi1−x,Sbx)2S3 is a ternary mixed chalcogenide, microcrystalline in nature. The growth mechanism, optical and structural properties of as deposited mixed metal chalcogenide thin films of (Bi1−x, Sbx)2S3 are discussed in the present paper.

Room temperature synthesis of compact TiO 2 thin films for 3-D solar cells by chemical arrested route

Essential requirement of compact TiO 2 thin films for 3-D solar cells prefers high temperature techniques (≥400 °C) such as spray pyrolysis or sputtering. Under optimized preparative conditions, compact, uniform, adherent and pinhole free, TiO 2 thin films were synthesized at room temperature by using arrested precipitation technique on ITO substrates. As-deposited and heat-treated TiO 2 films were amorphous with small enlargement in grain size as evidenced from XRD and SEM studies. Small blue shift was detected due to annealing and attributed to change in grain size. As deposited and heat-treated TiO 2 films were used in this study showed water contact angles 66.14° and 66.44°, respectively. Efforts were also taken to use these films in dye-sensitized solar cells after introducing cis-dithiocyanato (4,4′-dicarboxylic acid-2,2′-bipyridide) ruthenium (II) (N 3) dye but no significant improvement due to low contact angle in photo-electrochemical cell performance was observed due to high compactness.

Biological Routes to Metal Alloy Ferromagnetic Nanostructures

Magnetic nanoparticles have potential applications in high-density memory devices, but their complicated synthesis often requires high temperatures, expensive reagents, and postsynthesis annealing to achieve the desired magnetic properties. Current synthetic methods for magnetic nanoparticles often require post-synthetic modifications, suggesting that the practical application of magnetic nanoparticles will depend on the development of alternative synthetic strategies. We report a biological template to directly grow magnetic nanoparticles of desired material composition and phase under ambient conditions. A phage display methodology was adapted to identify peptide sequences that both specifically bind to the ferromagnetic L10 phase of FePt and control the crystallization of FePt nanoparticles using a modified arrested precipitation technique. TEM, electron diffraction, STEM, and X-ray diffraction all indicate these nanoparticles are composed of an FePt alloy with some degree of chemical ordering, and SQU...

Chemical synthesis and compositional analysis of mixed [Mo(S1 - xSex)2] semiconductor thin films

The synthesis of binary MoS2, MoSe2 and mixed [Mo(S1 − xSex)2] thin films onto a glass substrates using arrested precipitation technique (APT) is presented in this investigation. Growth kinetics and mechanism of film formation were studied for these films and are explained in brief. The stoichiometry of the film is confirmed by analyzing films using Extractive spectrophotometric (ESP), atomic absorption spectroscopic (AAS) and electron difftraction X-ray microanalysis (EDAX) techniques. The semiconductor solution containing Mo(VI) and Se(IV) is extracted with N-n-octylaniline in xylene and determined by ESP, AAS and EDAX techniques. Further these films are characterized for its semiconducting behavior to test the suitability of molybdenum chalcogenides as a photoelectrode to convert radiant energy into electricity. It is found that stoichiometry of the film formed by our recently developed arrested precipitation technique (APT) has strong influence on photoconduction in molybdenum chalcogenide photoelectrodes.

Electrical and optical properties of bismuth sulphotelluride [Bi 2(S 1− xTe x) 3] thin films prepared by arrested precipitation technique (APT)

Semiconducting bismuth sulphotelluride [Bi 2(S 1− x Te x ) 3] thin films were grown by using initial ingredients bismuth triethanolamine complex, thioacetamide and sodium tellurosulphite in an aqueous alkaline medium. Thin, uniform, tightly adherent and densely packed deposits are obtained by employing arrested precipitation technique (APT). The optical absorption studies revealed that the films have high absorption coefficient with a band to band (direct) type transitions and the energy gap decreased typically from 1.62 eV for pure Bi 2S 3 down to 0.65 eV for pure Bi 2Te 3. The transition of the material is found to be band to band direct type. The electrical conductivity measurements showed increase in the conductivity with increased tellurium content ( x) in the film. From TEP measurements the films showed n-type of conduction mechanism for all the samples. The thermo power is of the order of μV/K.