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Vanalakar S.A.,Chonnam National University | Vanalakar S.A.,Commerce and Education College | Agawane G.L.,Chonnam National University | Kamble A.S.,Chonnam National University | And 3 more authors.
Solar Energy Materials and Solar Cells | Year: 2015

Ternary chalcogenide semiconductor Cu2SnS3 (CTS) is an emerging material, attracting increasing interest for the applications in thin film solar cells. Here we report a pulsed laser deposition route to synthesize compact and single phase CTS thin films for the first time. The effects of the annealing temperature on the formation of CTS films were investigated. XRD and Raman studies revealed that the annealed CTS thin films have a polycrystalline nature with a cubic crystal structure, and the crystalline size of the CTS thin films increases as the annealing temperature increases. The direct optical band gap energy of the CTS thin film annealed at 400°C is found to be 1.01 eV. Hall effect measurements indicate that the film has a p-type conductivity with a hole mobility of 0.51 cm2/V s. Finally, a thin film solar cell was fabricated with a SLG/Mo/CTS/CdS/i-ZnO/AZO/Al structure. A photo-electric conversion efficiency of 0.82% was achieved with a short circuit current density of 11.90 mA/cm2. We are successful in achieving the better values of VOC for the CTS solar cells. The route developed here may provide an alternative approach to produce CTS thin film solar cells. © 2015 Elsevier B.V. All rights reserved.

Bhat T.S.,Shivaji University | Vanalakar S.A.,Commerce and Education College | Devan R.S.,University of Pune | Mali S.S.,Chonnam National University | And 5 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

Thin films of Lead Selenide (PbSe) having compact nanoarchitectures were synthesized by a facile and cost-efficient successive ionic layer adsorption and reaction (SILAR) technique. The structural, morphological, optical and compositional properties were studied using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), UV–vis spectrophotometer, and X-ray photoelectron spectroscopy (XPS) techniques. Moreover, the effect of SILAR cycles on the morphology of PbSe thin films was investigated. XRD patterns revealed the formation of crystalline PbSe with the cubic crystal structure. FESEM images show shape evolution from nanoparticulate to merged pyramidal—like structure with variation in size from ~200 to 430 nm. The optical direct band gap energy of PbSe were varies from 1.32 to 1.20 eV with the increase in deposition cycles. The HRTEM and SAED results show the crystalline nature of the sample which is in good agreement with the XRD. The electrical characterizations were performed in order to obtain the ohmic behavior in the metal–semiconductor interface. The deposited thin films show a good ohmic behavior. © 2016, Springer Science+Business Media New York.

Wandre T.M.,Shivaji University | Gaikwad P.N.,Shivaji University | Tapase A.S.,Shivaji University | Garadkar K.M.,Shivaji University | And 4 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

The nanocomposites of TiO2–CeO2 are synthesized by a simple and cost-effective sol–gel method with cetyl trimethyl ammonium bromide (cationic surfactant) as capping agent at 500 °C. The X-ray diffraction analysis revealed phase purity of synthesized product. The X-ray photoelectron spectroscopy showed Ti4+ oxidation state of Ti element while Ce element was exist as a mixture of Ce3+ and Ce4+ oxidation state. The UV–Vis diffuse reflectance spectra clearly indicate the positive alteration in the optical response of TiO2 nanoparticles by the introduction of CeO2 nanoparticles. Scanning electron microscopic study revealed the formation of nanoclusters of spherical particles with uniform size distribution. Energy dispersive X-ray analysis confirmed the elemental composition. Fourier transform infrared spectroscopy analysis confirmed the presence of Ti–O–Ti stretching modes in the range of 900–400 cm−1. Photoluminescence spectroscopy was used to study the rate of recombination and transfer behaviors of photoexcited electron–hole pairs in the nanocomposites. Further, the photocatalytic activity of pure TiO2 nanoparticles and nanocomposite of TiO2 was studied using methyl orange. The TiO2:CeO2 nanocomposites exhibit high dye degradation compare with pure TiO2 nanoparticles. The composite TiO2:CeO2 (7:3) shows highest photocatalytic degradation of methyl orange dye in UV (60 min) and sunlight (90 min). © 2015, Springer Science+Business Media New York.

Vanalakar S.A.,Chonnam National University | Vanalakar S.A.,Commerce and Education College | Kamble A.S.,Chonnam National University | Shin S.W.,Chonnam National University | And 6 more authors.
Solar Energy | Year: 2015

Solution-synthesized nanostructured Cu2ZnSnS4 (CZTS) has attracted significant attention as a promising candidate for use as an efficient and inexpensive photovoltaic energy convertor material. In general, the solution synthesized route involves the use of toxic and explosive chemicals. The current report emphasizes a non-toxic surfactant mediated hydrothermal route for the synthesis of CZTS NPs (CZTS NPs) without the use of toxic chemicals. The physical and chemical properties of the CZTS NPs were studied using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) techniques. The XRD and Raman spectroscopy results confirmed the formation of single-phase kesterite CZTS NPs. TEM analysis revealed the formation of well-dispersed CZTS NPs that were ~5-10nm in size. The sodium dodecyl sulfate surfactant played a key role in the formation of the CZTS NPs. The optical absorption studies revealed that the CZTS NPs had an optical band gap of 1.85eV, which is favorable for photovoltaic applications. The synthesized CZTS NPs could be used in the form of ink, which could be used to directly coat large area thin film solar cells. Moreover, the probable reaction mechanism for the formation of surfactant assisted CZTS NPs is proposed in present report. © 2015 Elsevier Ltd.

Vanalakar S.A.,Commerce and Education College | Vanalakar S.A.,Chonnam National University | Patil V.L.,Commerce and Education College | Harale N.S.,Shivaji University | And 5 more authors.
Sensors and Actuators, B: Chemical | Year: 2015

Metal oxide gas sensors are promising devices that are widely used to detect various gases at moderate temperatures. In this study, nitrogen di-oxide (NO2) sensors were fabricated using zinc oxide (ZnO) nanorod arrays. ZnO nanorod arrays (ZNAs) with various rod lengths were deposited using a wet chemical route with zinc acetate as a precursor. The structural and surface morphological properties of the ZNAs were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The XRD patterns showed ZNAs with wurtzite crystal structures that were preferentially oriented in the (0 0 2) direction. The intensity of the (0 0 2) plane was found to vary with the length of the nanorods. FESEM micrographs show that the ZNAs had a vertical alignment perpendicular to the substrate, and the diameter and length of the nanorods increased as the nanorod deposition time was increased. The gas sensing performance was studied as a function of the nanorod length, operating temperature, time and gas concentration. The length and inter-rod space was observed to play a crucial role in determining the gas sensing performance of the devices. ZNA gas sensors deposited for 9 h and operating at a temperature of 175 °C were able to detect NO2 at a concentration of 100 ppm with a high sensitivity of 3100%. © 2015 Elsevier B.V. All rights reserved.

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