Dr. Annasaheb Moholkar | Shivaji University, Kolhapur, India (original) (raw)

Papers by Dr. Annasaheb Moholkar

Journal of Energy Storage

Applied Surface Science, 2007

The CdSe and Fe doped CdSe (Fe:CdSe) thin films have been electrodeposited potentiostatically ont... more The CdSe and Fe doped CdSe (Fe:CdSe) thin films have been electrodeposited potentiostatically onto the stainless steel and fluorine doped tin oxide (FTO) glass substrates, from ethylene glycol bath containing (CH3COO)2·Cd·2H2O, SeO2, and FeCl3 at room temperature. The doping concentration of Fe is optimized by using (photo) electrochemical (PEC) characterization technique. The deposition mechanism and Fe incorporation are studied by

Current Applied Physics, 2014

Vanadium pentoxide (V 2 O 5) mixed tungsten trioxide (WO 3) thin films have been synthesized by a... more Vanadium pentoxide (V 2 O 5) mixed tungsten trioxide (WO 3) thin films have been synthesized by a novel pulsed spray pyrolysis technique (PSPT) on glass and fluorine doped tin oxide (FTO) coated glass substrates at 400 C. Aqueous solutions of equimolar vanadium chloride and ammonium tungstate were mixed in volume proportions (5%, 10% and 15%) for the deposition of V 2 O 5 eWO 3 thin films. The structural, morphological, optical and electrochemical properties of V 2 O 5 eWO 3 thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V 2 O 5 were altered by mixing WO 3. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO 4 þ propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm 2 C À1 was observed for the V 2 O 5 film mixed with 15% WO 3. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.

Journal of Energy Storage

Chemical Physics Letters, 2021

Abstract Polyaniline (PANI) manganese dioxide (MnO2) nanocomposites were prepared by polymer coat... more Abstract Polyaniline (PANI) manganese dioxide (MnO2) nanocomposites were prepared by polymer coating and grafting approaches. The nanocomposites were fully characterized by XRD, TEM, ATR-IR and TG analyses. The PANI-grafted MnO2 nanocomposite exhibited a specific capacitance of 417 F/g at scan rate 5 mV/s-1. It showed the specific energy of 11.4 Wh/kg at specific power of 875 W/kg. Instead, the PANI-coated MnO2 nanocomposite exhibited a specific capacitance of 271 F/g at scan rate 5 mV/s-1. It showed the specific energy of 7.2 Wh/kg at specific power of 280 W/kg. The comparative analysis clearly demonstrated the superior performance of the polymer grafted nanocomposite.

Materials Science in Semiconductor Processing, 2021

Abstract In the present work, a simple, scalable and cost - effective synthesis approach has been... more Abstract In the present work, a simple, scalable and cost - effective synthesis approach has been used for preparation of V2O5 powder by thermal decomposition method. Firstly, the physicochemical properties such as XRD, FESEM, contact angle, BET etc., of V2O5 powder annealed at 400 0C, 500 0C, and 600 0C (denoted as V1, V2, and V3 respectively) were studied. Subsequently followed by a detailed investigation of the electrochemical properties. The electrochemical properties of active V2O5–Ni foam (VNF) electrode showed pseudocapacitive nature. The V1–NF electrode exhibits highest specific capacitance of 1227.2 F g-1 as compared with V2–NF (723.8 F g-1) and V3–NF (511.2 F g-1) at the scan rate of 1 mV s-1 in 1 M KOH aqueous electrolyte with three-electrode system. The optimum electrode showed specific capacitance retention of approximately 96.1 %, even after 2000 consecutive GCD cycles. Therefore, VNF is the promising electrode material for supercapacitor application.

Handbook of Research on Green Synthesis and Applications of Nanomaterials, 2022

Nanotechnology has been a dynamic research area over the past few decades because it assures the ... more Nanotechnology has been a dynamic research area over the past few decades because it assures the resolution to the problems that hamper progress. Currently, a new era of ‘green synthesis' is an emerging multidisciplinary field in nanotechnology which employs reliable, sustainable, low-cost, non-hazardous, and eco-friendly techniques. Green synthesis is considered a vital tool to reduce the negative impacts accompanying the traditional methods of synthesis for NPs commonly employed in industry and laboratory. This chapter unveils a comprehensive overview of the recent research on available green techniques for the synthesis of various nanocomposites in order to solve future generation challenges. This chapter also focuses on the green synthesis of various nanocomposites, synthesis parameters, potential applications, merits/demerits, and future prospects.

Israel Journal of Chemistry, 2015

Materials Science and Engineering: B, 2021

Abstract NiMn2O4 (NMO) powders have been prepared by facile sol–gel route, and the effect of anne... more Abstract NiMn2O4 (NMO) powders have been prepared by facile sol–gel route, and the effect of annealing temperature and the concentration of KOH electrolyte on its electrochemical performance has been investigated. The electrochemical performance of the NMO electrodes is tested via a three electrode arrangement in KOH electrolyte. The NMO electrode (NMO1) prepared from the powder synthesized at a temperature of 500 °C with an approximate crystallite size of 10 nm exhibits maximum specific capacitance of 571 Fg−1 at a scan rate of 5 mVs−1 in 1 M KOH electrolyte. The specific capacitance of the NMO1 electrode is found to be improved from 571 Fg−1 in 1 M KOH to 762 Fg−1 in 6 M KOH electrolyte. The improvement in the specific capacitance of the NMO1 working electrode in 6 M KOH electrolyte can be attributed to good electrochemical utilization and an effective charge storage mechanism.

Journal of Energy Storage, 2021

Journal of Electroanalytical Chemistry, 2021

Abstract NiMn2O4 (NMO) nanoparticles (NPs) with a cubic spinel structure have been synthesized vi... more Abstract NiMn2O4 (NMO) nanoparticles (NPs) with a cubic spinel structure have been synthesized via the sol–gel method. The surface morphology study explored the porous nature of the NMO NPs. The compositional analysis displayed the constituent elements Ni, Mn, and O in NMO NPs. Electrochemical properties of the electrodes prepared from NMO NPs are investigated in 1 M KOH, 1 M NaOH, and 1 M Na2SO4 electrolytes. At a scan rate of 5 mVs−1, a specific capacitance of 658 Fg−1is obtained for the NMO-Ni foam electrodes in 1 M NaOH electrolyte. At a current density of 0.5 mAcm−2, the determined values of specific energy and specific power for the NMO-Ni foam electrodes are 13.4 Whkg−1 and 523.8 Wkg−1, respectively, in 1 M NaOH electrolyte. The NMO-Ni foam electrodes showed 96.4 % capacitance retention in 1 M NaOH for 1000 cycles.

Measurement, 2019

Effect of substrate temperature on physicochemical and gas sensing properties of sprayed orthorho... more Effect of substrate temperature on physicochemical and gas sensing properties of sprayed orthorhombic V 2 O 5 thin films,

Optical Materials, 2018

Surfactant-free, ultrasound assisted modified successive ionic layer adsorption and reaction (M-S... more Surfactant-free, ultrasound assisted modified successive ionic layer adsorption and reaction (M-SILAR) method and home-made microcontroller based low-cost potentiostat system are employed to prepare zinc oxide (ZnO) nanostructure based thin films. The comparison between physicochemical as well as photoelectrochemical (PEC) properties of the nanostructures prepared via two different template free, simplistic and cost-effective green routes have been discussed in detail. X-ray diffraction and Raman analysis confirm the formation of phase pure ZnO with the hexagonal crystal structure. Surface morphology significantly affects the physicochemical as well as PEC properties of ZnO thin films. Nanorods (NRs) and nanosheets (NSs) based ZnO thin films sensitized with N3 dye have been directly used as photoelectrodes in the dye-sensitized solar cell (DSSC). The power conversion efficiency (PCE) of 0.59% is achieved with J sc of 4.04 mA/cm 2 and V oc of 0.44 V for the DSSC in which the M-SILAR deposited 1-D ZnO NRs based thin film is used as the photoanode. While relatively less PCE of 0.29% with J sc of 2.53 mA/cm 2 and V oc of 0.36 V is obtained for DSSC prepared using electrodeposited 2-D ZnO NSs. In the NSs like 2-D surface morphology, the presence of multiple grain boundaries are acted as traps for the diffusing electrons, which reduces the electron mobility through it.

Materials Science in Semiconductor Processing, 2018

In this study, the pulsed laser deposition technique was applied for the preparation and characte... more In this study, the pulsed laser deposition technique was applied for the preparation and characterization of Cu 2 (Zn x Mg 1-x)SnS 4 (CZMTS) thin films for solar cell applications. The effects of various zinc/magnesium compositional ratios on the properties of the CZMTS thin films were investigated. The field emission scanning electron microscopy studies revealed that the CZMTS thin films exhibited dense, uniform and smooth surfaces. The X-ray diffraction studies on the as-deposited and annealed CZMTS thin films showed the prominent peak from the (112) plane for kesterite phase Cu 2 ZnSnS 4. The Raman studies on the CZMTS thin films further confirmed formation of kesterite phase and beneficial MoS 2 layer. Further, the Hall measurement studies on CZMTS thin films confirmed p-type electrical conductivity behavior. The conductivity increased from 2.31 S/cm to 7.98 S/cm with increased Mg concentration. The X-ray energy dispersive spectroscopy studies revealed formation of stoichiometric thin films. The direct optical band gap for the CZMTS thin films were found to be in the range of 1.3-1.5 eV, suggesting their potential application as a low cost and earth abundant thin film solar cell absorber material.

Journal of Colloid and Interface Science, 2017

Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pento... more Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pentoxide nanorods for detection of nitrogen dioxide gas,

Journal of Materials Science: Materials in Electronics, 2015

Nanocrystalline cubic Cu2O thin films are developed by simple and cost-effective modified success... more Nanocrystalline cubic Cu2O thin films are developed by simple and cost-effective modified successive ionic layer adsorption and reaction method. This method increases the growth rate and reduces the overall deposition time. The synthesized Cu2O thin films were characterized for their different physico-chemical properties. The film deposited for 25 cycles exhibits optical band gap energy of 2.16 eV, phase pure cubic Cu2O structure, foggy like surface morphology and hydrophobic in nature. The photoelectrochemical device fabricated using Cu2O thin film showed an efficiency of 0.35 %.

Journal of Colloid and Interface Science, 2016

The molybdenum trioxide (MoO3) thin films have been successfully deposited onto the glass substra... more The molybdenum trioxide (MoO3) thin films have been successfully deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition technique at various substrate temperatures ranging from 300°C to 450°C with an interval of 50°C. The effect of substrate temperature on the structural, morphological, optical and gas sensing properties of MoO3 thin films has been thoroughly investigated. X-ray diffraction analysis reveals that all the films have an orthorhombic crystal structure and are polycrystalline in nature. FE-SEM micrographs depict the formation of nanobelts-like morphology. AFM study reveals that the RMS surface roughness of MoO3 thin films increases from 8.6nm to 12nm with increase in substrate temperature from 300°C to 400°C and then decreases to 11.5nm for substrate temperature of 450°C. Optical results show that the band gap of MoO3 thin films decreases from 3.92eV to 3.44eV. The selectivity studies show that the gas response of various gases varies as NH3<SO2<CO2<CO<H2S<NO2. Moreover, typical MoO3 film deposited at substrate temperature of 400°C is highly selective and sensitive for detection of NO2 gas in comparison with other gases. The maximum response of 30.5 % is obtained towards 100ppm NO2 gas concentration at an operating temperature of 200°C with response and recovery times of 20s and 160s, respectively. Finally, NO2 gas sensing mechanism model based on the chemisorption process is discussed.

Journal of Materials Science: Materials in Electronics, 2017

Ceramics International, 2015

Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were deposited by spray pyrolysis techniqu... more Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were deposited by spray pyrolysis technique at constant substrate temperature. The effects of the copper concentration on the structural, morphological and optical properties of the films were investigated. The copper concentration was varied from 0.15 to 0.25 M in the steps of 0.05 M. The structural studies revealed that the Cu poor film shows low intense peaks, but as Cu concentration increases a relatively more intense and sharper diffraction peaks (112), (200), (220), and (312) of the kesterite crystal structure were observed. Raman spectroscopy analysis confirmed the formation of phase-pure CZTS films. From the morphological studies, it is found that the grain size increased as the Cu concentration increases from 0.15 to 0.25 M. The optical band-gap values were estimated to be 1.61, 1.52 and 1.45 eV for copper concentration 0.15, 0.20 and 0.25 M, respectively. Photoelectrochemical cells using films of different copper concentrations were fabricated and the best cell exhibited an efficiency of 1.09% for 0.25 M of copper concentration.

Journal of Energy Storage

Applied Surface Science, 2007

The CdSe and Fe doped CdSe (Fe:CdSe) thin films have been electrodeposited potentiostatically ont... more The CdSe and Fe doped CdSe (Fe:CdSe) thin films have been electrodeposited potentiostatically onto the stainless steel and fluorine doped tin oxide (FTO) glass substrates, from ethylene glycol bath containing (CH3COO)2·Cd·2H2O, SeO2, and FeCl3 at room temperature. The doping concentration of Fe is optimized by using (photo) electrochemical (PEC) characterization technique. The deposition mechanism and Fe incorporation are studied by

Current Applied Physics, 2014

Vanadium pentoxide (V 2 O 5) mixed tungsten trioxide (WO 3) thin films have been synthesized by a... more Vanadium pentoxide (V 2 O 5) mixed tungsten trioxide (WO 3) thin films have been synthesized by a novel pulsed spray pyrolysis technique (PSPT) on glass and fluorine doped tin oxide (FTO) coated glass substrates at 400 C. Aqueous solutions of equimolar vanadium chloride and ammonium tungstate were mixed in volume proportions (5%, 10% and 15%) for the deposition of V 2 O 5 eWO 3 thin films. The structural, morphological, optical and electrochemical properties of V 2 O 5 eWO 3 thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V 2 O 5 were altered by mixing WO 3. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO 4 þ propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm 2 C À1 was observed for the V 2 O 5 film mixed with 15% WO 3. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.

Journal of Energy Storage

Chemical Physics Letters, 2021

Abstract Polyaniline (PANI) manganese dioxide (MnO2) nanocomposites were prepared by polymer coat... more Abstract Polyaniline (PANI) manganese dioxide (MnO2) nanocomposites were prepared by polymer coating and grafting approaches. The nanocomposites were fully characterized by XRD, TEM, ATR-IR and TG analyses. The PANI-grafted MnO2 nanocomposite exhibited a specific capacitance of 417 F/g at scan rate 5 mV/s-1. It showed the specific energy of 11.4 Wh/kg at specific power of 875 W/kg. Instead, the PANI-coated MnO2 nanocomposite exhibited a specific capacitance of 271 F/g at scan rate 5 mV/s-1. It showed the specific energy of 7.2 Wh/kg at specific power of 280 W/kg. The comparative analysis clearly demonstrated the superior performance of the polymer grafted nanocomposite.

Materials Science in Semiconductor Processing, 2021

Abstract In the present work, a simple, scalable and cost - effective synthesis approach has been... more Abstract In the present work, a simple, scalable and cost - effective synthesis approach has been used for preparation of V2O5 powder by thermal decomposition method. Firstly, the physicochemical properties such as XRD, FESEM, contact angle, BET etc., of V2O5 powder annealed at 400 0C, 500 0C, and 600 0C (denoted as V1, V2, and V3 respectively) were studied. Subsequently followed by a detailed investigation of the electrochemical properties. The electrochemical properties of active V2O5–Ni foam (VNF) electrode showed pseudocapacitive nature. The V1–NF electrode exhibits highest specific capacitance of 1227.2 F g-1 as compared with V2–NF (723.8 F g-1) and V3–NF (511.2 F g-1) at the scan rate of 1 mV s-1 in 1 M KOH aqueous electrolyte with three-electrode system. The optimum electrode showed specific capacitance retention of approximately 96.1 %, even after 2000 consecutive GCD cycles. Therefore, VNF is the promising electrode material for supercapacitor application.

Handbook of Research on Green Synthesis and Applications of Nanomaterials, 2022

Nanotechnology has been a dynamic research area over the past few decades because it assures the ... more Nanotechnology has been a dynamic research area over the past few decades because it assures the resolution to the problems that hamper progress. Currently, a new era of ‘green synthesis' is an emerging multidisciplinary field in nanotechnology which employs reliable, sustainable, low-cost, non-hazardous, and eco-friendly techniques. Green synthesis is considered a vital tool to reduce the negative impacts accompanying the traditional methods of synthesis for NPs commonly employed in industry and laboratory. This chapter unveils a comprehensive overview of the recent research on available green techniques for the synthesis of various nanocomposites in order to solve future generation challenges. This chapter also focuses on the green synthesis of various nanocomposites, synthesis parameters, potential applications, merits/demerits, and future prospects.

Israel Journal of Chemistry, 2015

Materials Science and Engineering: B, 2021

Abstract NiMn2O4 (NMO) powders have been prepared by facile sol–gel route, and the effect of anne... more Abstract NiMn2O4 (NMO) powders have been prepared by facile sol–gel route, and the effect of annealing temperature and the concentration of KOH electrolyte on its electrochemical performance has been investigated. The electrochemical performance of the NMO electrodes is tested via a three electrode arrangement in KOH electrolyte. The NMO electrode (NMO1) prepared from the powder synthesized at a temperature of 500 °C with an approximate crystallite size of 10 nm exhibits maximum specific capacitance of 571 Fg−1 at a scan rate of 5 mVs−1 in 1 M KOH electrolyte. The specific capacitance of the NMO1 electrode is found to be improved from 571 Fg−1 in 1 M KOH to 762 Fg−1 in 6 M KOH electrolyte. The improvement in the specific capacitance of the NMO1 working electrode in 6 M KOH electrolyte can be attributed to good electrochemical utilization and an effective charge storage mechanism.

Journal of Energy Storage, 2021

Journal of Electroanalytical Chemistry, 2021

Abstract NiMn2O4 (NMO) nanoparticles (NPs) with a cubic spinel structure have been synthesized vi... more Abstract NiMn2O4 (NMO) nanoparticles (NPs) with a cubic spinel structure have been synthesized via the sol–gel method. The surface morphology study explored the porous nature of the NMO NPs. The compositional analysis displayed the constituent elements Ni, Mn, and O in NMO NPs. Electrochemical properties of the electrodes prepared from NMO NPs are investigated in 1 M KOH, 1 M NaOH, and 1 M Na2SO4 electrolytes. At a scan rate of 5 mVs−1, a specific capacitance of 658 Fg−1is obtained for the NMO-Ni foam electrodes in 1 M NaOH electrolyte. At a current density of 0.5 mAcm−2, the determined values of specific energy and specific power for the NMO-Ni foam electrodes are 13.4 Whkg−1 and 523.8 Wkg−1, respectively, in 1 M NaOH electrolyte. The NMO-Ni foam electrodes showed 96.4 % capacitance retention in 1 M NaOH for 1000 cycles.

Measurement, 2019

Effect of substrate temperature on physicochemical and gas sensing properties of sprayed orthorho... more Effect of substrate temperature on physicochemical and gas sensing properties of sprayed orthorhombic V 2 O 5 thin films,

Optical Materials, 2018

Surfactant-free, ultrasound assisted modified successive ionic layer adsorption and reaction (M-S... more Surfactant-free, ultrasound assisted modified successive ionic layer adsorption and reaction (M-SILAR) method and home-made microcontroller based low-cost potentiostat system are employed to prepare zinc oxide (ZnO) nanostructure based thin films. The comparison between physicochemical as well as photoelectrochemical (PEC) properties of the nanostructures prepared via two different template free, simplistic and cost-effective green routes have been discussed in detail. X-ray diffraction and Raman analysis confirm the formation of phase pure ZnO with the hexagonal crystal structure. Surface morphology significantly affects the physicochemical as well as PEC properties of ZnO thin films. Nanorods (NRs) and nanosheets (NSs) based ZnO thin films sensitized with N3 dye have been directly used as photoelectrodes in the dye-sensitized solar cell (DSSC). The power conversion efficiency (PCE) of 0.59% is achieved with J sc of 4.04 mA/cm 2 and V oc of 0.44 V for the DSSC in which the M-SILAR deposited 1-D ZnO NRs based thin film is used as the photoanode. While relatively less PCE of 0.29% with J sc of 2.53 mA/cm 2 and V oc of 0.36 V is obtained for DSSC prepared using electrodeposited 2-D ZnO NSs. In the NSs like 2-D surface morphology, the presence of multiple grain boundaries are acted as traps for the diffusing electrons, which reduces the electron mobility through it.

Materials Science in Semiconductor Processing, 2018

In this study, the pulsed laser deposition technique was applied for the preparation and characte... more In this study, the pulsed laser deposition technique was applied for the preparation and characterization of Cu 2 (Zn x Mg 1-x)SnS 4 (CZMTS) thin films for solar cell applications. The effects of various zinc/magnesium compositional ratios on the properties of the CZMTS thin films were investigated. The field emission scanning electron microscopy studies revealed that the CZMTS thin films exhibited dense, uniform and smooth surfaces. The X-ray diffraction studies on the as-deposited and annealed CZMTS thin films showed the prominent peak from the (112) plane for kesterite phase Cu 2 ZnSnS 4. The Raman studies on the CZMTS thin films further confirmed formation of kesterite phase and beneficial MoS 2 layer. Further, the Hall measurement studies on CZMTS thin films confirmed p-type electrical conductivity behavior. The conductivity increased from 2.31 S/cm to 7.98 S/cm with increased Mg concentration. The X-ray energy dispersive spectroscopy studies revealed formation of stoichiometric thin films. The direct optical band gap for the CZMTS thin films were found to be in the range of 1.3-1.5 eV, suggesting their potential application as a low cost and earth abundant thin film solar cell absorber material.

Journal of Colloid and Interface Science, 2017

Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pento... more Superior selectivity and enhanced response characteristics of palladium sensitized vanadium pentoxide nanorods for detection of nitrogen dioxide gas,

Journal of Materials Science: Materials in Electronics, 2015

Nanocrystalline cubic Cu2O thin films are developed by simple and cost-effective modified success... more Nanocrystalline cubic Cu2O thin films are developed by simple and cost-effective modified successive ionic layer adsorption and reaction method. This method increases the growth rate and reduces the overall deposition time. The synthesized Cu2O thin films were characterized for their different physico-chemical properties. The film deposited for 25 cycles exhibits optical band gap energy of 2.16 eV, phase pure cubic Cu2O structure, foggy like surface morphology and hydrophobic in nature. The photoelectrochemical device fabricated using Cu2O thin film showed an efficiency of 0.35 %.

Journal of Colloid and Interface Science, 2016

The molybdenum trioxide (MoO3) thin films have been successfully deposited onto the glass substra... more The molybdenum trioxide (MoO3) thin films have been successfully deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition technique at various substrate temperatures ranging from 300°C to 450°C with an interval of 50°C. The effect of substrate temperature on the structural, morphological, optical and gas sensing properties of MoO3 thin films has been thoroughly investigated. X-ray diffraction analysis reveals that all the films have an orthorhombic crystal structure and are polycrystalline in nature. FE-SEM micrographs depict the formation of nanobelts-like morphology. AFM study reveals that the RMS surface roughness of MoO3 thin films increases from 8.6nm to 12nm with increase in substrate temperature from 300°C to 400°C and then decreases to 11.5nm for substrate temperature of 450°C. Optical results show that the band gap of MoO3 thin films decreases from 3.92eV to 3.44eV. The selectivity studies show that the gas response of various gases varies as NH3<SO2<CO2<CO<H2S<NO2. Moreover, typical MoO3 film deposited at substrate temperature of 400°C is highly selective and sensitive for detection of NO2 gas in comparison with other gases. The maximum response of 30.5 % is obtained towards 100ppm NO2 gas concentration at an operating temperature of 200°C with response and recovery times of 20s and 160s, respectively. Finally, NO2 gas sensing mechanism model based on the chemisorption process is discussed.

Journal of Materials Science: Materials in Electronics, 2017

Ceramics International, 2015

Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were deposited by spray pyrolysis techniqu... more Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were deposited by spray pyrolysis technique at constant substrate temperature. The effects of the copper concentration on the structural, morphological and optical properties of the films were investigated. The copper concentration was varied from 0.15 to 0.25 M in the steps of 0.05 M. The structural studies revealed that the Cu poor film shows low intense peaks, but as Cu concentration increases a relatively more intense and sharper diffraction peaks (112), (200), (220), and (312) of the kesterite crystal structure were observed. Raman spectroscopy analysis confirmed the formation of phase-pure CZTS films. From the morphological studies, it is found that the grain size increased as the Cu concentration increases from 0.15 to 0.25 M. The optical band-gap values were estimated to be 1.61, 1.52 and 1.45 eV for copper concentration 0.15, 0.20 and 0.25 M, respectively. Photoelectrochemical cells using films of different copper concentrations were fabricated and the best cell exhibited an efficiency of 1.09% for 0.25 M of copper concentration.