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The bio-inspired nanocomposites developed from reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) might be of great significance due to their exceptional physico-chemical properties. In the present work, the AuNPs/RGO nanocomposites were prepared by a green-synthesis approach using grape seed proanthocyanidin (GSP), which acts as a natural reducing and stabilizing agent. The simultaneous biosynthesis of RGO nanosheets from graphene oxide (GO) and AuNPs from chloroauric acid ions by GSP leads to the development of AuNPs/RGO nanocomposites, which were further confirmed by various analytical techniques. The analyses of the observed outcomes confirm the removal of oxygen containing moieties during the transformation process of GO to RGO. Further, AuNPs were decorated orderly on both sides of the RGO nanosheet surface with an average particle size of ~ 35 nm. The MTT-based cytotoxicity assay revealed the enhanced anticancer activity of the prepared AuNPs/RGO nanocomposites (IC50 = 15.6 μg/mL) against triple-negative breast cancer cells when compared to either AuNPs or RGO treatment alone. Moreover, enhanced ROS levels and subsequent alteration in mitochondrial membrane potential (Δψm) with nuclear fragmentation and apoptotic features were observed in AuNPs/RGO nanocomposites treated cells. This could be due to the synergistic effect of AuNPs/RGO in the triple-negative breast cancer cells.

In the present study, MnO2 nanoparticles were synthesized by simple facile hydrothermal method. The structural, morphological, and electrochemical behaviour of the synthesized nanoparticles were analyzed by XRD, SEM/EDX and CV. XRD confessed that the tetragonal structure of bare MnO2. The crystallite size of MnO2 nanoparticles obtained at MnCl2: KMnO4 (0.5: 0.4 M) was found to be 9.2 nm. The nanorod structures of the synthesised MnO2 nanoparticles were revealed by morphological studies. The electrochemical behaviour of nanorod like MnO2 nanoparticles showed a specific capacitance of 91 Fg−1 at lower scan rate of 10 mV s−1.

Sm3+ ions doped strontium lithium lead borate glasses (SLLB:Sm) were prepared using a conventional melt-quenching technique. The glasses were analyzed using X-ray diffractometry and Fourier transform infrared spectroscopy, optical absorption, fluorescence spectral analysis, and fluorescence lifetime decay. The Judd-Ofelt (J-O) parameters and radiative parameters of the SLLB:Sm10 glass (1.0 mol% Sm3+ ion-doped glass) were calculated using J-O theory. From the emission spectra, among all the synthesized glass, SLLB:Sm10 glass had the highest emission intensity for 4 G5/2 →6 H11/2 transition (610 nm). Emission parameters, such as stimulated emission cross-section and optical gain bandwidth, were calculated. For all concentrations of Sm3+ ions, the decay profile showed an exponential nature and decreased when the Sm3+ ion concentration was increased due to a concentration quenching effect. This result suggests that the synthesized SLLB:Sm10 glass could be used for application in high-density optical memory devices.

This work shows the changes in properties of industrial clay bricks collected from the traditional kiln situated at bank of Cauvery, Tamilnadu, India. Samples of local raw clay material already in use for the production of bricks and industrially produced fired brick materials were characterized by combined multi-analytical techniques to determine the relationships among chemical, mineralogical, textural and mechanical properties. FTIR absorption spectra of re-fired industrial clay bricks to different temperatures in air in the laboratory supply information about type of clay mineral presence, its original firing temperature and firing atmosphere. The minerals like quartz, plagioclase (albite or anorthite) and orthoclase were identified using XRD. In order to study the quality of the bricks they were submitted to mechanical analysis such as compressive strength, flexural rupture strength, water absorption, porosity and bulk density. The mechanical analysis reveals that when laboratory re-firing temperature exceeds the original firing temperature of industrial bricks, the compressive strength, flexural rupture strength and bulk density increases, whereas water absorption and porosity values decreases. The results showed that there is a drastic variation in the quality of the bricks collected from different parts of the same kiln.

SnO2 nanoparticles (NPs) were synthesized by facile hydrothermal method in the presence of polyethylene glycol (PEG), cetyl trimethylammonium bromide (CTAB) and sodium hexametaphosphate (SHMP) as surfactant. The synthesized samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high resolution scanning electron microscopy (HRSEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), UV–visible diffuse reflectance spectroscopy (UV–visible DRS) and photoluminescence (PL). The XRD studies revealed that the position of diffraction peaks agreed well with the reflection of a tetragonal structure of SnO2 phase. The structure of the SnO2 did not change by introducing surfactants but the crystallite size was decreased. The optical studies revealed a clear blue shift in the band gap energy (Eg) with a decrease in particle size. The PL intensity of SHMP assisted NPs is lower than that of bare SnO2 and other surfactant assisted SnO2 NPs, which indicated the suppression of the recombination of the photogenerated carriers. These results reveal that SHMP assisted SnO2 NPs is suitable for further electrochemical and photocatalytic activity. The surfactant (SHMP) assisted SnO2 photocatalyst exhibited the increased photocatalytic activities compared with the bare SnO2 photocatalyst. Furthermore, the SHMP assisted SnO2 electrode exhibited the increased supercapacitor performances.

The calcium-based lead borate glasses doped with 1 mol% Sm3+ ions were prepared using melt quenching technique. The prepared glass samples were analyzed through an X-ray diffractometer, FT-IR, Optical absorption, Emission, and fluorescence decay analysis. Physical properties have been calculated for the prepared glasses. The absorption spectrum has been recorded for 1.0 mol% Sm3+ ions doped calcium-based lead borate glasses. From the absorption spectrum, oscillatory strengths and JO intensity parameters have been calculated. The visible and near-infrared emission spectra were recorded with 402 nm excitation for 1.0 mol% Sm3+ ions. The prepared glass shows that the highest emission intensity for 4G5/2 → 6H11/2 transition centered at 610 nm. Emission properties for the prepared glass were calculated. Decay profile has been analyzed and lifetime value for 4G5/2 exited level of Sm3+ ion calculated for 1.0 mol% Sm3+ ions doped Ca-based lead borate glass: decay profile was well fitted for exponential decay 2, and the lifetime of 4G5/2 excited level is 1.041 ms. The obtained results suggested that the present 1.0 mol% Sm3+ ions doped calcium-based lead borate glass could be useful for the visible lasers and or photonic display devices applications.

In this work, pure and Zn-doped In2O3 nanostructures had been synthesized by facile template-free hydrothermal method. Structural, morphological and optical properties were characterized by using XRD, FT-IR, HR-SEM and HR-TEM, EDS, XPS, UV-DRS and PL measurement techniques. X-Ray Diffraction analysis showed that the prepared nanostructures were of pure cubic phase and the crystallite size was decreased with increased Zn dopant. HR-SEM and HR-TEM analysis showed morphological transformation with good crystallanity and decrease of particle size with doping. XPS spectra were recorded to reveal the composition and elemental state of Zn-doped In2O3. The optical properties of synthesized nanostructures were analyzed with UV–Vis DRS spectroscopy and band gap was found to decrease from 3.5 to 3.38 eV with Zn dopant concentration. The photoluminescence spectra displayed orange emission peaks at 600 nm for all prepared nanostructures. Photodegradation of Methylene Blue (MB) dye under ultra violet light radiation was studied with synthesized nanostructures.

Pure and silver doped ZnO thin films were successfully grown on glass substrates by spray pyrolysis technique. The effect of Ag doping different concentration (2, 4, 6 and 8 at.%) on the structural, surface morphological, electrical and optical properties of Ag:ZnO thin films were investigated by X-Ray diffraction (XRD), Scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), photoluminescence (PL) and Hall effect measurement respectively. The X-ray pattern results confirmed that the Ag:ZnO thin films were polycrystalline nature with the preferential orientation along (002) plane in wurtzite structure. The SEM image revealed that the surface morphology of the films nano flower shaped grains with Ag doping. The compositional analysis by EDS confirms the presence of Zn, O and Ag. The surface roughness of the films decreases with increase of silver doping concentration was investigated by Atomic force microscopy (AFM). Optical transmittance 85% and a minimum resistivity of 1.23 × 10−3 Ω cm, are achieved for films when Ag doped ZnO with 6 at.% and confirm that these films are suitable for transparent conductive oxide (TCO) applications.

Zinc Oxide thin films had been deposited on microscopic glass substrate using spray pyrolysis technique at different substrate temperatures. The X-ray diffraction pattern of the prepared films had shown the polycrystalline nature with the preferential orientation along (0 0 2) plane. SEM micrograph of the prepared films revealed the uniform distributions of the flowers shaped grains. The presence of zinc and oxygen is confirmed from the peaks at 1 keV, 8 keV and 0.44 keV using EDS analysis. The columnar arrangement of the grains with the average grain size ranging from 80 to 140 nm is observed from the AFM analysis. From the optical studies, the high transparency in the visible region with an average transmittance reaching values up to 80% is observed. The calculated values of Energy band gap Eg are found to vary from 3.06 eV to 3.26 eV with increase of substrate temperature from 325 °C to 425 °C. The rise and fall in the extinction coefficient is directly related to the absorption of light. A drastic increase of refractive index indicates the compactness of the prepared films. The photoluminescence spectra exhibited the emission peaks at 418 nm, 441 nm, 525 nm and 671 nm which were corresponding to violet, blue, green and red emission.

A surfactant assisted precipitation method is employed for the preparation of nanostructured magnesium oxide with flake-like nanoparticles. The influence of surfactant on the crystallite size and morphology of MgO was studied using various parameters. The synthesized MgO nanomaterials were characterized by using FTIR, XRD, FE-SEM and EDAX analytical techniques in order to evaluate the formation, crystalline phase morphologies, microstructures and chemical compositions. The powder X-ray power diffraction (XRD) analysis revealed the average crystalline size of 15.34 nm with cubic structure. The crystallite size increased with increasing amount of PEGs. Field Emission Scanning Electron Microscopy (FFSEM) and Transmission Electron Microscopy (TEM) showed that the surfactant strongly affect the size and morphology of nanostructure. Fourier-transform infrared spectroscopy studies indicated the formation of MgO with the characteristic vibration mode of Mg-O. Further, the antibacterial effect of MgO nanoparticles evaluated against pathogenic bacteria by agar diffusion method showed that the nanoparticles have reasonable antibacterial activity against both gram positive (S.aureus) and gram negative (E.coli) pathogenic bacterial strains and retains potential application in pharmaceutical and biomedical industries.

Highly oriented Zn doped TiO 2 thin films (0, 2, 4, 6 and 8 at%) were deposited by spray pyrolysis technique. X-ray diffraction analysis showed a strong orientation along (101) direction for 6 at% Zn with polycrystalline tetragonal anatase phase. Scanning electron microscopy observations revealed uniform distribution of spherical-shaped grains, whereas columnar arrangement of tetragonal-shaped grains with porous nature was revealed from atomic force microscopy. Transmittance spectra indicated a decrease in the energy band gap with increasing doping concentration; i.e. 3.55 up to 3.21 eV, attributed to grain refinement to the nanoscale regime. The optical constants such as refractive index and extinction coefficient as a function of wavelength, were determined; the low extinction coefficient values confirmed the good quality of the thin films. Photoluminescence spectra showed strong emissions at 423 and 437 nm with a weak emission at 505 nm, which confirmed the lesser defect density in 6 at% Zn film. The electrical properties studied by Hall Effect measurements revealed that the 6 at% Zn led to an increase in the carrier concentration, as well as an increase in the mobility with a least resistivity. The efficiency of dye sensitized solar cells, assembled by using natural dye extracted from Hibiscus Surattensis as sensitizer and Zn-doped TiO 2 nanocrystalline thin films as a photoelectrode, was found to be around 1.22%.

Copper doped tin sulphide (SnS: Cu) thin films have been prepared by the spray pyrolysis technique at the substrate temperature of 350 °C. The optical and electrical properties of the films were studied as a function of copper dopant concentration (up to 10 at.%). The optical measurements showed the energy band gap, refractive index and extinction co-efficient values varied with increase in Cu concentration and the PL spectra showed the strong emission peak around at 765 nm. The film has the lowest resistivity while higher carrier concentration and mobility were obtained at 8 at.% of Cu.

In this work, highly oriented pure and Tin-doped Titanium dioxide (Sn-doped TiO2) with porous nature photoelectrodes were deposited on ITO glass plates using spray pyrolysis technique. The XRD pattern revealed the formation of anatase TiO2 with the maximum intensity of (101) plane while doping 6 at% of Sn. The morphological studies depicted the porous nature with the uniform arrangement of small-sized grains. The presence of tin confirmed with the EDX spectra. The size of particles of 13 nm was observed from High Resolution Transmission Electron Microscopy (HR-TEM) analysis. The average transmittance was about 85% for the doped photoelectrode and was observed for the photoelectrode deposited with 6 at% of tin, with decreased energy band gap. The PL study showed the emission peak at 391 nm. The maximum carrier concentration and Hall mobility was observed for the photoelectrode deposited with 6 at% of tin. With these studies, the DSSCs were prepared separately with the dye extracted from Hibiscus Rosasinesis and Hibiscus Surttasinesis and their efficiency was maximum for the DSSC prepared with 6 at% of tin.

Semiconducting CdIn2Se4 thin films have been deposited on to the conducting glass substrates using pulsed electrodeposition technique. X-ray diffraction (XRD) shows the films are polycrystalline in nature having cubic crystal structure. Energy dispersive analysis (EDAX) spectrum of the surface composition confirms the nearly stoichiometric CdIn2S4 nature of the film. Atomic force microscope (AFM) shows that the deposited films are well adherent and grains are uniformly distributed over the surface of substrate. The surface roughness and grain size increased from 0.2 nm and 12 nm to 0.7 nm and 20 nm respectively with increase of duty cycle. The films are highly transparent in the visible region with an average transmittance reaching up to 80%, which indicates the better crystalline nature with less defects. The CdIn2Se4 thin films show band gap energies of the films decreased from 3.12 eV to 3.77 eV. Keywords: Structural studies, XPS, AFM, Optical properties and photosensitivity

Nickel diselenide (NiSe2) had been conflated from the reaction of nickel acetate tetra hydrate (C4H14NiO8) with selenium (Se) powder by simple hydrothermal method at 200 °C for 5 hrs. The structural analysis revealed that the synthesized samples are consists of cubic structure. The electrochemical performance was obtained from the cyclic voltammetery (CV) and galvanostatic charge discharge (GCD) profiles. The prepared NiSe2 exhibited the specific capacitance value of 384 Fg−1 at scan rate of 2 mVs−1. The obtained results ensure that the NiSe2 nanoparticles could act as an enhanced working electrode for the upcoming generation of supercapacitors.

Bare and Zn doped SnO2 nanoparticles (NPs) were synthesized by hydrothermal method using Sodium hexametaphosphate (SHMP) as a capping agent. The structural, morphological and optical properties of the synthesized NPs were examined using XRD, FTIR, HRSEM, TEM, UV–visible DRS and PL. The XRD results indicated a good crystallinity of the sample and confirmed the tetragonal structure, and well agreed with the results of TEM. The chemical bondings of Sn–O–Sn functional group were confirmed by FTIR absorption peaks appearing at 650 cm−1. The spherical like morphology was observed in HRSEM analysis. EDS spectra confirmed the presence of elements Sn, Zn and O. Further, the optical band gaps of doped NPs were decreased due to the effect of band gap shrinkage. The photocatalytic performance of the doped NPs was tested by the degradation of Methyl violet (MV) under sunlight. Compared to the bare and SHMP assisted SnO2 photocatalysts, the doped NPs showed enhanced photocatalytic activities. In addition, the electrochemical performance of the doped NPs was investigated by CV, GCD and EIS studies. The results of capacitance behavior revealed the improved capacitance performance for SnO2 on Zn doping. The obtained results confirmed that this material is promising candidate for photocatalytic and supercapacitor application.

Bare and Zr doped SnO2 nanoparticles (NPs) were synthesized by hydrothermal technique using Sodium hexametaphosphate (SHMP) as a surfactant. The structural, functional, morphological, chemical composition and optical properties of the synthesized nanoparticles were characterized. The photocatalytic performance of the synthesized nanoparticles is carried out under sunlight irradiation using methyl violet (MV) dye. Additionally, the electrochemical behavior of the synthesized nanoparticles is investigated as supercapacitor electrode materials through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) studies. The experimental results revealed that incorporation of Zr into the SnO2 matrix had increased the photocatalytic activity and electrochemical performance compare with the bare and SHMP assisted SnO2 nanoparticles.

Pure and In-doped ZnO thin films were deposited onto glass substrates by spray pyrolysis technique. XRD results showed that all films were polycrystalline in nature with the wurzite structure. A change in preferential orientation from (0 0 2) to (1 0 1) plane was observed with increase in content of Indium. A reduce in crystallite size was observed with increase of In content. The small sized grains with the porous nature of the film was observed from SEM analysis. AFM study depicted polycrystalline nature and uniformly distributed grains with small pores in the doped film. A decrease in band gap was noticed with increase in In content. The absence of green emission in PL spectra indicated the decreased oxygen defects. The decrease in the resistivity with increase of Hall mobility was noted for the doped film. A better antibacterial activity was observed against Staphylococcus aureus by doped ZnO thin film.

Titanium dioxide (TiO2) thin films had been deposited with various substrate temperatures by spray pyrolysis technique onto ITO substrates. All films exhibited polycrystalline nature with the preferred orientation along (101) plane. At the substrate temperature 450 °C, the film favored the formation of anatase phase. The higher substrate temperature (475 °C) favored the appearance of rutile structure. The SEM image of the film at substrate temperature (Ts=450 °C) showed high structural quality with the porous nature. The typical AFM image of TiO2 film deposited at the substrate temperature, 450 °C depicted the regular arrangement of fine closely packed tetragonal structured grains. The transmittance of the spectra exhibited above 85% with energy band gap of 3.6 eV. From the study of photoluminescence, the emission at 417 nm, 437 nm and with weak emission at 551 nm was observed, which confirmed the lesser defects in the samples. The electrical resistivity was found to be 6.856×10(1) Ω cm for the substrate temperature 450 °C. The efficiency of anatase TiO2 photoelectrode deposited at the substrate temperature 450 °C based cell was much higher than the efficiency of TiO2 photoelectrode deposited at the substrate temperature 475 °C based cell.

Pure and zinc-doped titanium dioxide (Zn-doped TiO2) thin films were deposited on indium tin oxide coated glass plates using spray pyrolysis technique. The XRD pattern revealed the formation of anatase TiO2 with the maximum intensity of (101) plane with doping of zinc. The morphological studies depicted the porous nature, with the uniform arrangement of small-sized grains (SEM). The presence of zinc confirmed the EDX spectra. High resolution transmission electron microscope revealed the agglomerated spherical-like morphology and the particle size in the range of 10–20 nm. It was observed that the average transmittance was about 85 % for the zinc doped TiO2 film, which decreased the energy band gap. The PL study showed the emission peak at 418 nm for the doped films. The low resistivity maximum carrier concentration and Hall mobility was observed in Zn doped TiO2 films. The prepared Zn doped TiO2 thin film was proposed as the promising photocatalyst for the degradation and decolorization of methylene blue dye. The efficiency of anatase TiO2 photoelectrode deposited at the substrate temperature 450 °C based cell was much higher than the efficiency of Zn doped TiO2 photoelectrode cell.

Aluminum-doped zinc oxide (ZnO:Al) thin films were deposited onto glass substrates using spray pyrolysis technique with the substrate temperature of 400 °C. X-ray diffraction analysis indicated that the films were polycrystalline with hexagonal wurtzite structure preferentially oriented along (002) direction. Surface morphology of the films obtained by scanning electron microscopy showed that the grains were of nanoscale size with porous nature for 6 at.% of Al. Atomic force microscopy observations revealed that the particles size and surface roughness of the films decreased with Al-doping. Optical measurements indicated that ZnO:Al (6 at.%) exhibited a band gap of 3.11 eV, which is lower than that of pure ZnO film, i.e. 3.42 eV. Photoluminescence analysis showed weak NBE emission at 396 nm for Al-doped films. The low resistivity, high hall mobility and carrier concentration values were obtained at a doping ratio of 6 at.% of Al. The effective incorporation of 6 at.% of Al into ZnO lattice by occupying Zn sites yielded a well-pronounced antibacterial activity against Staphylococcus aureus.

Titanium dioxide (TiO2) thin films had been deposited onto glass substrates at various substrate temperatures by spray pyrolysis technique. X-ray diffraction analysis of deposited TiO2 films exhibited nanocrystalline nature and preferentially oriented along (101) direction. Scanning electron microscopy depicted that the films were uniform and adherent to the glass substrate. The field emission scanning electron microscopy (FE-SEM) films, exhibiting almost spherical shape of nanosized particles, was observed. The size of particles of 9.2 nm was observed from high-resolution transmission electron microscopy analysis. The decreased surface roughness observed in atomic force microscopy was due to the decrease in grain size with increased substrate temperatures. All films exhibited a transmittance of about 80 % in the visible region. The direct band gap values were from 2.1 to 3.6 eV by increasing substrate temperature. The photoluminescence spectra measurements indicated that the intensity of emission peaks significantly varies with substrate temperature. Further, these TiO2 films showed effective antibacterial activity against tested pathogens. Photocatalytic activity of the TiO2 thin film was studied using an organic dye, methylene blue, under solar irradiation.

Undoped and zirconium doped indium oxide (ZrIO) thin films were deposited on glass substrate at a substrate temperature of 450 °C by spray pyrolysis method. The effect of zirconium (Zr) dopant concentration (0–11 at.%) on the structural, morphological, optical and electrical properties of n-type ZrIO films were studied. X-ray diffraction (XRD) results confirmed the polycrystalline nature of the ZrIO thin film with cubic structure. The grain size was decreased from 25 to 15.75 nm with Zr doping. The scanning electron microscopy (SEM) showed that the surface morphology of the films were changed with Zr doping. The surface roughness of the films was investigated by atomic force microscopy (AFM) and was found to be increased with the increasing of Zr doping percentage. A blue shift of the optical band gap was observed. The optical band was gap decreased from 3.50 to 3.0 eV with increase in Zr concentrations. Room temperature photoluminescence (PL) measurement of the deposited films indicated the incorporation of Zr in In2O3 lattice. The film had low resistivity of 6.4 × 10−4 Ω cm and higher carrier concentration of 2.5 × 1020 was obtained at a doping ratio of 7 at.%.

Pristine TiO2 and Sn-doped TiO2 thin films with different Sn doping levels (2, 4, 6 and 8 at.%) were deposited by employing a simplified spray pyrolysis technique. The XRD pattern of the films confirmed tetragonal structure with the polycrystalline nature. The films exhibited a pure anatase titanium dioxide (TiO2) with a strong orientation along (101) plane. The scanning electron microscopy image of 6 at.% Sn-doped TiO2 thin film depicted nanosized grains with porous nature. The atomic force microscopy study had shown the columnar arrangement of grains with the increase in particle size and surface roughness for 6 at.% Sn-doped TiO2 thin films. The optical transmittance was increased with the decrease in the optical energy band gap. The optical constants such as extinction coefficient and refractive index were determined. The intensity of the photoluminescence emission was observed at 398 nm for doped films. The resistivity decreased with the increasing carrier concentration and Hall mobility. The incorporation of Sn into TiO2 matrix yielded a well-pronounced antibacterial activity for Bacillus subtilis.

Transparent and conducting thin films of pure and Sn-doped ZnO (ZnO:Sn) were deposited onto ITO coated glass substrates by spray pyrolysis technique at 350 °C. Structural, morphological, optical, and electrical properties of the as-prepared thin films were characterized by X-ray diffraction, atomic force microcopy (AFM), Transmission electron microscopy, UV–Vis spectroscopy and photoluminescence, as well as Hall Effect, respectively. The results indicated that all the films were polycrystalline with a hexagonal wurtzite structure exhibiting preferential orientation along (002) direction up to 1 at.% of Sn and random orientation for higher doping. AFM study revealed that the grain size and roughness of the films decreased with increasing Sn doping concentration. The optical gap increased slightly from 3.37 to 3.48 eV due to Burstein–Moss effect. PL spectra showed a strong UV emission peak and a relatively weak green emission peak reflecting the crystalline nature and less oxygen defects, respectively. The electrical conductivity increased with increasing Sn doping concentration, but for higher doping concentration (>1 at.%), the conductivity decreased. The power conversion efficiency of DSSCs based on Sn doped-ZnO thin film exhibited higher efficiency (0.74 %) compared to pure ZnO film because of its large surface area for adsorption of dye molecules. This result indicates that Sn-doped ZnO film has promising application in the field of DSSCs, and the optimization of porous film fabrication condition is efficient for the improvement of ZnO based DSSCs performance.

In this study, the ancient potteries from Tamilnadu (Nedungur: Lat.10° 57′N; Long.77°51′E) were collected and investigated for their chemical and mineralogical characteristics to estimate their firing temperature and firing atmosphere. The physical and chemical state of iron (Fe2+/Fe3+) and iron oxide phases obtained using Mossbauer spectra were used to establish the temperature and atmosphere of firing. The clay mineral type and its structural deformation due to firing were established using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Fourier Transform Infrared (FTIR) Spectroscopy. The data collected from these techniques show that quartz was the predominant mineral, followed by traces of albite, orthoclase and Fe-bearing minerals (hematite and magnetite) and suggested that the firing temperature of potteries lies in the range of 600–800 °C in oxidizing atmosphere. The mineral types and domain states of the constituent magnetic fine particles were elucidated using the variation of susceptibility at various frequencies and temperature under low field. An attempt has also been made to correlate the magnetic parameters from the percentage of Fe2+/Fe3+ and iron oxides. The information obtained paves a way for a better understanding of the technological development that took place in the ancient past and also the suitability of the samples for the determination of reliable ancient geomagnetic field intensity values.

ZnO thin films had been successfully prepared by spray pyrolysis (SP) technique on ITO/Glass substrates at different substrate temperature in the range 250–400 °C using Zinc acetylacetonate as precursor. The X-ray diffraction studies confirmed the hexagonal wurtzite structure with preferred orientation along (0 0 2) plane at substrate temperature 350 °C and the crystallite size was found to vary from 18 to 47 nm. The morphology of the films revealed the porous nature with the roughness value of 8–13 nm. The transmittance value was found to vary from 60% to 85% in the visible region depending upon the substrate temperature and the band gap value for the film deposited at 350 °C was 3.2 eV. The obtained results revealed that the structures and properties of the films were greatly affected by substrate temperature. The near band edge emission observed at 398 nm in PL spectra showed better crystallinity. The measured electrical resistivity for ZnO film was ∼3.5 × 10−4 Ω cm at the optimized temperature 350 °C and was of n-type semiconductor. The obtained porous nature with increased surface roughness of the film and good light absorbing nature of the dye paved way for implementation of quality ZnO in DSSCs fabrication. DSSC were assembled using the prepared ZnO film on ITO coated glass substrate as photoanode and its photocurrent – voltage performance was investigated.

Nanoscale SnS2 and Zn doped SnS2 were synthesized by solid state reaction method and characterized by powder X-ray diffraction (XRD), FT-IR, FT-Raman, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), photoluminescence (PL) and UV–vis spectra. The photocatalytic activity of SnS2 and Zn doped SnS2 were tested with red reactive 120 (RR 120) dye. The hexagonal SnS2 phase was confirmed through XRD. The morphological study revealed that the products were nanoflakes with average thickness of 60 nm. The photocatalytic results indicated that the Zn doping enhanced the photocatalytic activity of SnS2 and could be effectively used as photocatalyst for degradation of environmental pollutant - RR 120 dye.

A spray pyrolysis technique was used to deposit the silver doped tin sulfide (SnS:Ag) thin films on glass substrates at the substrate temperature of 350 °C. The variation in structural, optical and electrical properties of SnS with silver incorporation was investigated. The XRD spectra showed the improvement in crystallinity while increasing the doping concentration of Ag. The lower electrical resistivity of 8.63×10−1 Ω cm and the optical band gap of 1.33 eV were obtained at 8 at% of Ag.

Tin sulphide (SnS) thin films were deposited on glass substrate at different substrate temperature (Ts = 325 °C, 350 °C and 375 °C) by pyrolytic decomposition using stannous chloride and thiourea as precursor solutions. Also, indium-doped SnS thin films were prepared by using InCl3 as dopant source. The dopant concentration [In/Sn] was varied from 2 at% to 6 at%. The XRD analysis revealed that the films were polycrystalline in nature having orthorhombic crystal structure with a preferred grain orientation along (1 1 1) plane. Due to In doping, the orientation of the grains in the (1 1 1) plane was found to be deteriorated. Atomic force microscopy (AFM) measurements revealed that the surface roughness of the films decreased due to indium doping. The optical properties were investigated by measuring the transmittance characteristics which were used to find the optical band gap energy, refractive index and extinction coefficient. The energy band gap value was decreased from 1.60 to 1.43 eV with increasing In concentration. The photoluminescence (PL) measurements of thin films showed strong emission band centered at 760 nm. Using Hall Effect measurements electrical resistivity, carrier concentration and Hall mobility have been determined.

Thin films of tin sulfide were deposited onto glass substrates by pyrolytic decomposition using stannous chloride and thiourea as precursors. The properties of thin films based on deposition parameters such as substrate temperature ( T s ), molarity of precursor solution ( M ) and spray rates ( R ) were studied. The deposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis spectroscopy and Hall Effect measurements. The XRD patterns of the films exhibited polycrystalline nature with orthorhombic crystal structure. The crystallite size varied from 30 to 107 nm with the change of deposition parameters. The band gap, electrical resistivity values and the type of conductivity with respect to deposition parameters were also observed.

Bismuth doped tin sulfide (SnS:Bi) thin films were deposited onto glass substrates by the spray pyrolysis technique at the substrate temperature of 350 °C. The effect of doping concentration [Bi/Sn] on their structural, optical and electrical properties was investigated as a function of bismuth doping between 0 and 8 at%. The XRD results showed that the films were polycrystalline SnS with orthorhombic structure and the crystallites in the films were oriented along (111) direction. Atomic force microscopy revealed that the particle size and surface roughness of the films increased due to Bi-doping. Optical analysis exhibited the band gap value of 1.40 eV for SnS:Bi (6 at%) which was lower than the band gap value for 0 at% of Bi (1.60 eV). The film has low resistivity of 4.788×10−1 Ω-cm and higher carrier concentration of 3.625×1018 cm−3 was obtained at a doping ratio of 6 at%.

Titanium dioxide (TiO2) thin films have been deposited on microscopic glass substrate by spray p yrolysis technique. The effect of deposition parameters such as substrate temperature, molarity (precursor concentration) and solution spray rate on the structural, surface morphological and optical properties of the films ha ve been studied. The prepared films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) with EDS and UV-Vis spectroscopy. The XRD patterns indicated that the films have amorphous and polycrystalline structure and the size of the crystallite s have been changed from 9 to 48 nm. The optical band gap of the TiO2 films is determined to be about 3.40 to 3.65 eV to the change of deposition co nditions.

Thin films of antimony doped tin sulphide (SnS:Sb) with different antimony concentrations have been prepared by the spray pyrolysis technique at the substrate temperature of 350 °C. The physical properties of the films were studied as a function of increase in antimony dopant concentration (up to 10 at.%). The films were characterized by different techniques to study their structural, optical and electrical properties. The X-ray diffraction analysis revealed that the films were polycrystalline in nature and having orthorhombic crystal structure with a preferred orientation in (1 1 1) direction. Due to Sb doping, the crystalline quality and the preferential orientation of SnS films were improved up to 6 at.% of doping concentration. However, when doping concentration was increased above 6 at.%, the crystalline quality and the preferential orientation of SnS films was deteriorated. Atomic force microscopy images revealed that the surface roughness of the films increased due to Sb doping. Optical measurements showed that the band gap values decreased from 1.60 eV to 1.15 eV with increase in Sb concentration. The photoluminescence spectra displayed that all the samples have an emission peak centered at 760 nm. At 6 at.% of Sb doping, the film has the lowest resistivity of 2.598 × 10−2 Ω cm while the carrier concentration was high.

Indium oxide (In 2 O 3 ) thin films are successfully deposited on microscopic glass substrate at different temperatures by spray pyrolysis technique using Indium acetate as precursor solution. The physical properties of these films are characterized by XRD, SEM, AFM, UV–visible, PL and Photo acoustic measurements. XRD analysis revealed that the films are polycrystalline in nature having cubic crystal structure with a preferred grain orientation along (2 2 2) plane. The average transmittance in the visible region is found to vary from 60% to 93% depending upon the substrate temperature. The complete vibrational analysis has been carried out and the optimized parameters are calculated using HF and DFT (LSDA, B3LYP and B3PW91) methods with 3-21G(d,p) basis set for In 2 O 3 . The fundamental frequencies are calculated and assigned according to the experimental frequencies. Furthermore, 13 C NMR and 1 H NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) technique with HF/B3LYP/B3PW91 methods on same basis set. A study of the electronic properties; absorption wavelengths, excitation energy, dipole moment, Kubo gap (HOMO and LUMO) and frontier molecular orbital energies, are performed by HF and DFT methods. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) is executed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the compound are calculated in gas phase.

FTIR spectroscopy is a powerful tool for assessing both chemical and mineralogical composition of the clay and fired materials. In the present study an attempt has been made to investigate the thermal transformation of red clay. Fourier transform infrared (FTIR) spectroscopy has been used to find the mineralogical transformations of red clay due to firing in the range of 400–1100 °C. From this analysis, red clay has relatively well crystalline kaolinite, rich in quartz, goethite, and hematite. The increasing firing temperatures lead to the vanishing of kaolinite and the development of mullite. Mullite is developed from silica and clay mineral. Finally, in order to demonstrate the reliability of FTIR attributions, XRD and TG-DTA were performed. The results show that the FTIR technique has the potential to become applicable for the characterization of natural clay, fired clay materials and high temperature minerals.

Undoped and Indium doped tin disulphide (SnS2) thin films had been deposited onto glass substrates at Ts = 300 °C using spray pyrolysis technique under atmospheric pressure with stannous chloride, indium chloride and thiourea as precursors. The structural, optical and electrical properties of the deposited films were characterized. The XRD pattern revealed that the undoped and doped films had preferred orientation along (002) plane with hexagonal structure. FESEM micrographs had shown that morphologies of the films changed with indium doping. Optical constant such as refractive index (n), extinction coefficient (k), real and imaginary parts of dielectric constants were evaluated from transmittance and reflectance spectra in UV-Visible spectroscopy. The optical absorption data were used to determine the band gap energy and it was found to be 2.75 eV for undoped and 2.50 eV for indium doped films respectively. The room temperature dark resistivity was found to be 4.545 × 103 Ω-cm and 5.406 × 103 Ω-cm for undoped and In-doped films respectively.

In this work, the pulse electrodeposition technique has been employed for the first time to deposit SnSe films from a bath containing Analar grade 50 mM tin chloride (SnCl4) and 5 mM SeO2. The XRD profile of SnSe thin films deposited at different duty cycles indicate the peaks corresponding to SnSe. Atomic force microscopy studies indicated that the surface roughness increased from 0.5 to 1.5 nm with duty cycle. The transmission spectra exhibited interference fringes. The value of refractive index at 780 nm was 2.1, this value decreased to 1.95 with decrease of duty cycle. The room temperature resistivity increased from 0.1 to 10 Ωcm with decrease of duty cycle. Photo electrochemical cell studies were made using the films deposited at different duty cycles. For duty cycles greater than 15% photo output was observed. For a film deposited at 50% duty cycle, an open circuit voltage of 0.55 V and a short circuit current density of 5.0 mA cm−2 at 60 mW cm−2 illumination. Capacitance voltage measurements indicated Vfb = 0.67 V (SCE) and p type, carrier density = 6.98 × 1016 cm−3.