Soma Gorai - Academia.edu (original) (raw)

Papers by Soma Gorai

... purity and composition of the prepared samples were also studied by energy dispersive X-ray a... more ... purity and composition of the prepared samples were also studied by energy dispersive X-ray analysis (EDAX). ... with different morphologies like flakes, sheets, rods and granules has been successfully synthesized over Sn metal foils ... [18] S. Gorai, D. Ganguly and S. Chaudhuri. ...

Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India<br&gt... more Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India E-mail: gorai_soma@rediffmail.com Manuscript received online 04 December 2020, accepted 24 December 2020 Solvothermal synthesis of copper sulphide (Cu39S28) microparticles by employing acetylacetone (Hacac) as the solvent is presented. Solvent acetylacetone is used for controlling the shape of the product. Morphological pattern and structure of the product were investigated by SEM and XRD, respectively. SEM images showed tube-like network structure of the product. The formation of Cu39S28 was confirmed by XRD analysis.

Journal of scientific research, 2020

The present study revealed the effect of different copper salts on the morphological patterns of ... more The present study revealed the effect of different copper salts on the morphological patterns of copper sulphide crystals. Different copper precursors such as copper chloride, copper nitrate, copper sulphate and copper acetate have been used for this purpose. Various morphologies of copper sulphide microparticles like different types of dendritic flowers, hexagonal, triangular, and spherical particles have been synthesized successfully. The product molecules were identified by using XRD and the morphological patterns of the crystals were observed by SEM.

Acta Crystallographica Section E Structure Reports Online, 2006

The title compound, [Ni(C 2 H 8 N 2) 3 ] 2 [Sn 2 Se 6 ], was synthesized under solvothermal condi... more The title compound, [Ni(C 2 H 8 N 2) 3 ] 2 [Sn 2 Se 6 ], was synthesized under solvothermal conditions in an ethylenediamine/water solution at 453 K. The compound contains discrete centrosymmetric [Sn 2 Se 6 ] 4À anions, which are dimers of two tetrahedral SnSe 4 groups sharing a common edge. The transition metal cation is six-coordinated by three ethylenediamine molecules in an octahedral geometry. We thank the Natural Science Foundation of China for supporting this work (20071006). metal-organic papers m2710 Duan et al. [Ni(C 2 H 8 N 2) 3 ] 2 [Sn 2 Se 6 ]

Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India<br&gt... more Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India E-mail: gorai_soma@rediffmail.com Manuscript received online 01 December 2020, accepted 29 December 2020 Applications of green chemistry perspective for nanoparticles (NPs) synthesis have gained much attention in recent years mainly to reduce the use of hazardous chemicals and also to eliminate the production of toxic materials. Green bio-based synthesis is an organic molecule mediated technique where nanoparticles are prepared by using naturally occurring reagents such as plant extracts, vitamins, biodegradable polymers, sugars, and microorganisms, etc. The nature of these biological entities influences the structure, size and morphology of synthesized NPs. During the past few decades, researchers have been paying more attention to the synthesis (both physically and chemically) of nontoxic semiconducting zinc sulfide nanopart...

Materials Research Bulletin, 2008

Thin films of indium sulfide (In2S3) micro- and nanorods were successfully prepared by sulfurizat... more Thin films of indium sulfide (In2S3) micro- and nanorods were successfully prepared by sulfurization of electrodeposited metal indium layers. The films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and UV–vis spectroscopy. From XRD and TEM observations it was concluded that the In2S3 nanorods and microrods have ∼50nm and ∼0.5μm diameter, respectively. A plausible

Materials Science and Engineering: B, 2005

A series of stoichiometric and non-stoichiometric copper sulphides have been successfully synthes... more A series of stoichiometric and non-stoichiometric copper sulphides have been successfully synthesized via the solvothermal route using ethylenediamine-water as the solvent system at 130 • C. The products were identified from X-ray powder diffraction patterns. Scanning electron microscope images showed different morphological patterns, such as six-petal dendritic flowers with or without center button, rods and microspheres. The solvent (ethylenediamine/ethylenediamine-water/water) played an important role to determine the morphology and stoichiometry of copper sulphide.

Materials Research Bulletin, 2007

ABSTRACT

Materials Letters, 2005

Flower-like dendritic Cu2S crystals are successfully synthesized from Cu(NO3)2 and thiourea via s... more Flower-like dendritic Cu2S crystals are successfully synthesized from Cu(NO3)2 and thiourea via solvothermal route, using an organic reagent ethylenediamine (en). Growth of dendritic flower and stoichiometry of copper sulphide depended upon reaction time at a constant temperature.

Materials Letters, 2003

Wet chemical synthesis of single phase CuInS 2 powder using copper chloride dihydrate (99%), indi... more Wet chemical synthesis of single phase CuInS 2 powder using copper chloride dihydrate (99%), indium chloride, thiourea and ammonia (25%) is presented. Attempts were made to achieve synthesis of a ternary precursor in the liquid state leading to its total and direct conversion to the ternary compound on heat treatment. Compositions of the synthesized powder for different pH (3.2-11.8) were analysed by EDAX to test sensitivity towards pH value. XRD analysis showed predominant peaks of (112), (020), (024), (132) and (136) confirming phase purity of the material. Optical study of the powder prepared with pH value within 8-11 indicated a band gap f 1.5 eV.

Materials Chemistry and Physics, 2005

A simple polyol-mediated solvothermal method has been proposed to synthesize copper indium sulphi... more A simple polyol-mediated solvothermal method has been proposed to synthesize copper indium sulphide. XRD studies reveal that the products are well crystallized. SEM indicates rod-like (with different aspect ratio) and star-shaped flake-like morphology of the products. The products are also characterized by optical studies and compositional analysis (XRF). XRF results show the formation of stoichiometric and non-stoichiometric copper indium sulphides depending on the reaction conditions.

Materials Chemistry and Physics, 2007

... The room temperature photoluminescence emission spectra of the samples under 260 nm excitatio... more ... The room temperature photoluminescence emission spectra of the samples under 260 nm excitation showed UV emission at around 380 nm corresponding to ... The materials arephotoluminescent and emit UV radiation which can be attributed to interband electronic transitions. ...

Materials Chemistry and Physics, 2004

Using a simple surfactant-assisted pathway, various shapes of crystalline copper sulphide (Cu 2 S... more Using a simple surfactant-assisted pathway, various shapes of crystalline copper sulphide (Cu 2 S) such as micro and submicron particles, nanorods and nanowires have been synthesized. This type of shape tailoring was possible by varying the molar ratio of cationic and anionic surfactants. Under appropriate condition, uniform nanowires were obtained. This was revealed from scanning and transmission electron microscopy. XRD analysis confirms the formation of monoclinic Cu 2 S. The optical band gap determined from reflectance spectra was found to have values within the range of 1.22-1.24 eV. The aspect ratio of the nanorods was found to increase with the increase of the concentration of anionic surfactant.

Crystal Growth & Design, 2006

Large-scale well-crystalline InS nanowires have been successfully prepared for the first time fro... more Large-scale well-crystalline InS nanowires have been successfully prepared for the first time from a metallic indium precursor by a simple solvothermal route without using any template or catalyst. From X-ray diffraction and energy-dispersive X-ray analysis studies, stability of InS is suggested to be within the temperature range of 180-265°C. Both the diameter and the yield of nanowires show a proportional increment with temperature.

Crystal Growth & Design, 2006

Crystalline SnS wires of micro-and nanometer scale have been synthesized over tin metal foils at ... more Crystalline SnS wires of micro-and nanometer scale have been synthesized over tin metal foils at room temperature using a simple surfactant-assisted approach. Scanning electron microscopy, transmission electron microscopy, UV-Vis-near infrared (NIR) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the SnS nanowires. X-ray diffraction (XRD) analysis confirmed the formation of the pure orthorhombic phase of SnS. The optical band gap of the samples was found to be ∼1.4 eV. From the investigation, the formation of nanowires could be explained in two steps: initial cracking/splitting of the nanoflakes was followed by a top-growth mechanism to form ultralong nanowires. Effects of various experimental parameters on the growth mechanism were investigated. Present studies have shown that this facile process also can be extended for the synthesis of other low dimensional structures.

Materials Science and Engineering: B, 2006

In 2 S 3-SiO 2 nanocomposite films (with molar ratios of In 2 S 3 :SiO 2 = 15:85, 10:90 and 5:95)... more In 2 S 3-SiO 2 nanocomposite films (with molar ratios of In 2 S 3 :SiO 2 = 15:85, 10:90 and 5:95) were prepared on quartz substrates by sol-gel method. Highly confined nanoparticles of In 2 S 3 (radius ∼ 1.8-7 nm) were obtained in SiO 2 matrix, indicating SiO 2 to be a good capping agent for the nanoparticles. The films were annealed in air at different temperatures (473-623 K) and characterized by optical, microstructural and photoluminescence measurements. XRD studies showed that annealing in air upto 623 K leads to the formation of oxide free In 2 S 3 nanoparticles. The broad Photoluminescence peak observed at ∼353 nm showed a marked blue shift associated with a decrease in intensity with increasing concentration of In 2 S 3 in the matrix.

Materials Chemistry and Physics, 2005

Herein, ␤-indium sulphide (In 2 S 3) sub-micron particles with cage-like network structures were ... more Herein, ␤-indium sulphide (In 2 S 3) sub-micron particles with cage-like network structures were synthesized via the sonochemical route. The time for ultrasonic treatment of the alcoholic solution of indium chloride and thioacetamide was found to be the prime factor for the formation of a cage-like network structure. The product was characterized by several techniques.

Nanoscale oxide semiconductors have been studied enormously for their distinctive optical, electr... more Nanoscale oxide semiconductors have been studied enormously for their distinctive optical, electronic, magnetic, catalytic and medicinal properties as compared with the traditional and commercial bulk materials [1-3]. These unique properties generated researchers' interest in the synthesis of nanoscale materials with different sizes, shapes, and compositions. For this purpose, during the last two decades,! a vast number of physical and chemical synthetic routes have been established. In recent years, for reducing or removing the use of toxic chemicals, the comparatively new and largely unexplored bio-mediated green synthesis technique has been developed. This biogenic synthesis of nanoparticles depends on the source materials [4-10] such as plants and plant parts, bacteria, fungus and other bio-based molecules (protein, vitamin, molecules etc.) used in the procedure. The plant phytochemicals which have antioxidant property is mainly responsible for the preparation of metal and metal oxide nanoparticle. Besides, many biological components have abilities to act as templates in the synthesis and help to produce a self assembled nanoscale material [11, 12]. So a novel and economically beneficial bio-based green synthesis method may be a better alternative choice for the synthesis of metal oxide nanoparticles compared to commonly used chemical and physical methods. Among the semiconducting nanoparticles, Tin oxide (SnO 2) has been studied intensely because of its potential applicability to lithium-ion batteries [13], transparent conducting electrodes in ionic devices [14], anti-reflective coatings [15], solid-state gas sensors [16], solar cells [17], catalytic support materials [18], energy storage [19], medicine [20] etc. A large number of physical and chemical methods have already been reported in the literature to fabricate different types of SnO 2 nanostructures such as hydrothermal method [21], solvothermal [22], microwave synthesis [23], co-precipitation method [24], sol-gel [25], spray pyrolysis [26], chemical vapor deposition [27], thermal evaporation of oxide powders [28], rapid oxidation of elemental tin [29], micro emulsion [30] etc. However, due to many disadvantages of these routes like toxicity of the chemicals, expensive equipment, energy waste and environmental pollution developing facile and green methods for synthesizing tin oxide nanoparticles has drawn much importance in the recent years and still, research is going on upon it. This review briefly summarizes the recently reported biogenic synthesis of SnO 2 nanoparticles (Nps) using plant extracts and

Synthesis and characterization of CuInS 2 powder sample prepared by a simple and convenient solvo... more Synthesis and characterization of CuInS 2 powder sample prepared by a simple and convenient solvothermal method is reported. The influence of the variation of Cu/In molar ratio from 0.69 to 1.25 on the particle morphology, crystal structure and optical properties of CuInS 2 samples was studied. The X-ray diffraction studies indicated that the samples were polycrystalline in nature. SEM images of the samples revealed that the copper-rich products were uniform microspheres with smooth surfaces, whereas microspheres formed by network of interconnected flakes were obtained for indium-rich products. The optical band gaps (E g) of the products decreased from 1.60 to 1.43 eV with variation of Cu/In molar ratio. The variation of the Urbach tail width with Cu/In molar ratio indicated that the density of the defects is much higher for the indium-rich CuInS 2 , which was clearly revealed from Raman measurements.

Journal of scientific research, 2020

Acta Crystallographica Section E Structure Reports Online, 2006

Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India<br&gt... more Department of Chemistry, Asansol Girls' College, Asansol-713 304, West Bengal, India E-mail: gorai_soma@rediffmail.com Manuscript received online 01 December 2020, accepted 29 December 2020 Applications of green chemistry perspective for nanoparticles (NPs) synthesis have gained much attention in recent years mainly to reduce the use of hazardous chemicals and also to eliminate the production of toxic materials. Green bio-based synthesis is an organic molecule mediated technique where nanoparticles are prepared by using naturally occurring reagents such as plant extracts, vitamins, biodegradable polymers, sugars, and microorganisms, etc. The nature of these biological entities influences the structure, size and morphology of synthesized NPs. During the past few decades, researchers have been paying more attention to the synthesis (both physically and chemically) of nontoxic semiconducting zinc sulfide nanopart...

Materials Research Bulletin, 2008

Materials Science and Engineering: B, 2005

Materials Research Bulletin, 2007

ABSTRACT

Materials Letters, 2005

Materials Letters, 2003

Materials Chemistry and Physics, 2005

Materials Chemistry and Physics, 2007

Materials Chemistry and Physics, 2004

Crystal Growth & Design, 2006

Materials Science and Engineering: B, 2006

Materials Chemistry and Physics, 2005