Virender Kundu

Structural and physical properties of vanadium doped copper bismuth borate glasses

The structural and physical properties of xCuO(30−x)Bi2O3−70B2O3; x = 0, 5, 10, 15, 20 & 25 mol % with 2 mol % V2O5 glasses prepared by normal melt quench technique have been investigated by means of FT-IR & physical measurement techniques. With the addition of copper oxide (x ≤ 10 mol%), the frequency bands in the higher region shift towards lower wave number, suggest the conversion of BO3 to BO4 structural units, which in turn give rise to the formation of Non Bridging Oxygen’s (NBOs). For further increase in CuO (i.e. for x ≥ 10 mol %), the frequency bands shift towards higher wave number, indicate the formation of Bridging Oxygen’s (BOs). The FTIR analysis reveals that the present glass system is based on the BiO3 pyramidal, BiO6 octahedral units and also on BO3 and BO4 structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.The structural and physical properties of xCuO(30−x)Bi2O3−70B2O3; x = 0, 5, 10, 15, 20 & 25 mol % with 2 mol % V2O5 glasses prepared by normal melt quench technique have been investigated by means of FT-IR & physical measurement techniques. With the addition of copper oxide (x ≤ 10 mol%), the frequency bands in the higher region shift towards lower wave number, suggest the conversion of BO3 to BO4 structural units, which in turn give rise to the formation of Non Bridging Oxygen’s (NBOs). For further increase in CuO (i.e. for x ≥ 10 mol %), the frequency bands shift towards higher wave number, indicate the formation of Bridging Oxygen’s (BOs). The FTIR analysis reveals that the present glass system is based on the BiO3 pyramidal, BiO6 octahedral units and also on BO3 and BO4 structural units. The systematic variation in density and molar volume in these glasses indicates the effect of CuO substitution.

Optical Properties of Alkaline Earth Ions Doped Bismuth Borate Glasses

The optical properties of glasses with composition xLi2O (30‐x) Bi2O3‐70B2O3; x = 0, 5, 10, 15 & 20 mol %, prepared by normal melt quench technique were investigated by means of UV‐VIS measurement. It was observed that the optical band gap of the present glass system decreases with increasing Li2O content up to 15 mol%, and with further increase in lithium oxide content i.e. x>15 mol% the optical band gap increases. It was also observed that the present glass system behaves as an indirect band gap semiconductor.

Investigation of copper telluride nanowires synthesized by electrochemical method

In the present study the copper telluride (Cu2Te) nanostructures of 100 nm diameter have been fabricated using electro deposition method from an aqueous solution on copper (Cu) and indium tin oxide (ITO) substrates. The synthesized nanostructures are characterized by scanning electron microscope and X‐ray diffraction. The XRD analysis confirmed the formation of nanowires of copper telluride. The photoluminescence emission spectrum was obtained at 457.56 nm for 100 nm copper telluride nanowires.

Structural and Morphological Study of Nickel Doped Tin Oxide Nanoparticles Synthesized Via Sol-Gel Technique

Zn-doped SnO2 nanoparticles were synthesized successfully by Sol-Gel technique with different doping concentration of zinc. The calcined nanoparticles at 400°C, were characterized by means of X-ray diffraction (XRD). XRD analysis reveals that the nanoparticles of various doping concentration are polycrystalline in nature and existed as tetragonal rutile structure. The particle size of the nanoparticles was calculated by Scherrer formula and was found in the range of 7-24 nm. The morphology and nature of nanoparticles was analyzed by using scanning electron microscope (SEM), study of images confirms the existence of very small, spherical and unvaryingly distributed crystalline nanoparticles. Energy dispersive X-ray (EDX) analysis confirms the presence of zinc. The formation of Sn–O phase and hydrous nature of pure and Zn-doped SnO2 nanoparticles were confirmed by FTIR study.Zn-doped SnO2 nanoparticles were synthesized successfully by Sol-Gel technique with different doping concentration of zinc. The calcined nanoparticles at 400°C, were characterized by means of X-ray diffraction (XRD). XRD analysis reveals that the nanoparticles of various doping concentration are polycrystalline in nature and existed as tetragonal rutile structure. The particle size of the nanoparticles was calculated by Scherrer formula and was found in the range of 7-24 nm. The morphology and nature of nanoparticles was analyzed by using scanning electron microscope (SEM), study of images confirms the existence of very small, spherical and unvaryingly distributed crystalline nanoparticles. Energy dispersive X-ray (EDX) analysis confirms the presence of zinc. The formation of Sn–O phase and hydrous nature of pure and Zn-doped SnO2 nanoparticles were confirmed by FTIR study.

Synthesis and characterization of iron and copper doped β-MnO2 nanoparticles

Manganese dioxide (β-MnO2; Pyrolusite) nanoparticles doped with 1 and 2 mol % of iron and copper oxide contents have been synthesized by sol–gel technique and characterized by XRD, SEM, Raman, FTIR, UV-Vis spectroscopy and Magnetization measurements. The particle size is found to vary from 23 to 15 nm with increase of dopant concentration. The surface morphology of all samples was studied by Scanning Electron Microscopy and shows the small agglomeration. The agglomeration increases with increase in doping concentration may be attributed to the strength of vander Waals forces, changes with particle size leads to increase in surface area of MnO2 nanoparticles. The two main Raman peaks correspond to the stretching mode of MnO6 octahedral, and the peaks at lower wave number are attributed to the deformation modes of the metal-oxygen chain of Mn-O-Mn in MnO2 octahedral lattice. The FTIR spectra of pure and doped Manganese dioxide nanoparticles were recorded in the spectral range 400-4000 cm−1. The weak absorption peak at 2300 cm−1 and 2360 cm−1 may be attributed to alkynes groups. The fundamental absorption peaks at 1620 cm−1 & 3400 cm−1 are assigned to the bending and stretching vibrations of O-H group. The optical band gap was determined from UV-Vis absorption spectra and found to increase with decrease in particle size and is attributed to quantum confinement effect. The increase in coercivity (189 kOe to 385.1 kOe) with decrease in particle size also indicates the quantum phenomenon at nanoscale.Manganese dioxide (β-MnO2; Pyrolusite) nanoparticles doped with 1 and 2 mol % of iron and copper oxide contents have been synthesized by sol–gel technique and characterized by XRD, SEM, Raman, FTIR, UV-Vis spectroscopy and Magnetization measurements. The particle size is found to vary from 23 to 15 nm with increase of dopant concentration. The surface morphology of all samples was studied by Scanning Electron Microscopy and shows the small agglomeration. The agglomeration increases with increase in doping concentration may be attributed to the strength of vander Waals forces, changes with particle size leads to increase in surface area of MnO2 nanoparticles. The two main Raman peaks correspond to the stretching mode of MnO6 octahedral, and the peaks at lower wave number are attributed to the deformation modes of the metal-oxygen chain of Mn-O-Mn in MnO2 octahedral lattice. The FTIR spectra of pure and doped Manganese dioxide nanoparticles were recorded in the spectral range 400-4000 cm−1. The weak absorpt...

Structural, morphological, optical and photocatalytic investigation of Ag-doped TiO2

The pure and Ag-doped TiO2 nanoparticles were prepared by using Titanium isoproxide (TTIP), silver nitrate sodium hydroxide and sodium hydroxide. The calcined nanoparticles at 400°C were characterized by means of X-ray diffraction (XRD). XRD analyses reveal that the nanoparticles of various doping concentration were having anatase phase. The particle size was calculated by Scherrer formula and was found 11.08 nm for pure TiO2 and 8.86 nm for 6 mol % Ag doped TiO2. The morphology and nature of nanoparticles was analyzed by using scanning electron microscope (SEM), the optical absorption spectra of pure TiO2 and Ag-doped TiO2 nanoparticles showed that absorption edge increases towards longer wavelength from 390 nm (pure) to 450 nm (doped), also band gap energy calculated from Tauc’s plot decrease from 3.20eV to 2.92eV with increase in doing. The measurement of photocatalytic properties of pure TiO2 and Ag-doped TiO2 nanoparticles showed that Ag-doped TiO2 degrades MB dye more efficiently than pure TiO2.

Investigation of tin oxide nanofibers synthesized via bio-template technique

In the present paper tin oxide nanofibers have been by synthesized using cotton as bio-template via sol-gel route. This is comparatively a new synthesis technique. The structure and morphology of the obtained SnO2 nanofibers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX). The optical properties of the same have been studied by using UV-Vis spectroscopy. The observed XRD pattern showed that peaks are very narrow and sharp which indicates crystalline nature of samples. SEM images gave an idea about the sample morphology and confirm that the obtained sample were nanofibers. The optical absorbance spectrum of the sample under study was recorded in UV-visible region (200nm- 800nm). The band gap of the sample was found to be 3.95 eV which is higher than their bulk counterpart.

Methanol assisted synthesis and characterization of tin oxide nanoparticles

Tin oxide nanoparticles (NPs) of size 12 nm, were synthesized at room temperature by the reaction of Sncl4.5H2O dissolved in Methanol via sol-gel method. The structural, optical and Photoluminescence (PL) properties of tin oxide nanoparticles have been studied by XRD, SEM, UV-Vis and Photoluminescence spectroscopic techniques. The X-ray diffraction measurement shows the tetragonal structure of the tin oxide nanoparticles. The average particle size of the sample was determined from the line broadening of (110) peak of XRD. The optical band gap of the sample was determined from UV-Visible spectrum and found 3.73 eV. The sample under study exhibits a strong emission at 384 nm in PL spectrum, which may be ascribed to the contribution of oxygen’s vacancies and defects in SnO2 nanoparticles.

Physical and electrical properties of copper oxide doped bismuth borate glasses

The role of CuO on the physical and electrical properties in x CuO.(25-x)Bi2O3.75B2O3;(5≤x≤20) glass system has been investigated. The glasses were prepared by normal melt quench technique. The density and molar volume of the glasses decreases with increase in CuO (mol %). The dc conductivity was measured in the temperature range 413-513 K. The conduction mechanism in these glasses was discussed in terms of small polaron hopping (SPH) theory proposed by Mott. The activation energy is found to decrease with increasing copper oxide content. The dc conductivity increases with increase in CuO content and ranging from 6.02×10−12 (Ωm)−1 to 1.096×10−10 (Ωm)−1 at 450K.

DSC and DC conductivity of ZnO.LiF.B2O3 glasses

Melt-quench technique has been used to prepare fluoroborate glasses with ZnO content and having compositions x ZnO. (40-x) LiF. 60 B2O3 (x = 0, 5, 10, 15 and 20). DSC characterization is carried out to observe glass transition temperature. Two glass transition temperatures are observed for each of the reported samples. Both transition temperatures are found to increase with increase in ZnO content. DC conductivity is examined with respect to temperature variations. Results show that the conductivity is ionic in nature and varies with the variations in ZnO concentration.