Fast response of sprayed vanadium pentoxide (V₂O₅) nanorods towards nitrogen dioxide (NO₂) gas detection

Mane, A.A.,Suryawanshi, M.P.,Kim, J.H.,Moholkar, A.V. Elsevier BV * North-Holland 2017 Applied Surface Science Vol.403 No.-

<P><B>Abstract</B></P> <P>The V<SUB>2</SUB>O<SUB>5</SUB> nanorods have been successfully spray deposited at optimized substrate temperature of 400°C onto the glass substrates using vanadium trichloride (VCl<SUB>3</SUB>) solution of different concentrations. The effect of solution concentration on the physicochemical and NO<SUB>2</SUB> gas sensing properties of sprayed V<SUB>2</SUB>O<SUB>5</SUB> nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V<SUB>2</SUB>O<SUB>5</SUB> having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V<SUB>2</SUB>O<SUB>5</SUB>. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45eV to 2.42eV. The nanorods deposited with 30mM solution concentration shows the maximum response of 24.2% for 100ppm NO<SUB>2</SUB> gas concentration at an operating temperature of 200°C with response and recovery times of 13s and 140s, respectively. Finally, the chemisorption mechanism of NO<SUB>2</SUB> gas on the V<SUB>2</SUB>O<SUB>5</SUB> nanorods is discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of solution concentration on physicochemical properties of sprayed V<SUB>2</SUB>O<SUB>5</SUB> nanorods is studied. </LI> <LI> Good re­sponse and short re­sponse- re­covery times of V<SUB>2</SUB>O<SUB>5</SUB> nanorods towards NO<SUB>2</SUB> gas show it is potential material for fab­ri­ca­tion of NO<SUB>2</SUB> sensor. </LI> <LI> The chemisorption mechanism of NO<SUB>2</SUB> gas on the V<SUB>2</SUB>O<SUB>5</SUB> nanorods is discussed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

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

Mane, A.A.,Suryawanshi, M.P.,Kim, J.H.,Moholkar, A.V. Academic Press 2017 Journal of Colloid and Interface Science Vol. No.

<P><B>Abstract</B></P> <P>Vanadium pentoxide (V<SUB>2</SUB>O<SUB>5</SUB>) nanorods have been deposited onto the glass substrates by spraying 75ml of 30mM vanadium trichloride (VCl<SUB>3</SUB>) solution at optimized substrate temperature of 400°C. The XRD study confirms the formation of orthorhombic crystal structure of V<SUB>2</SUB>O<SUB>5</SUB> nanorods. The FE-SEM micrograph shows the nanorods-like morphology of V<SUB>2</SUB>O<SUB>5</SUB>. The presence of palladium (Pd) in the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> nanorods is confirmed using EDAX study. The gas sensing measurements show that the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> sensing material is an outstanding candidate for nitrogen dioxide (NO<SUB>2</SUB>) gas detection. Obtained results demonstrate that the Pd-sensitized V<SUB>2</SUB>O<SUB>5</SUB> nanorods show the superior selectivity for NO<SUB>2</SUB> gas in comparison with other gases such as NH<SUB>3</SUB>, H<SUB>2</SUB>S, CO, CO<SUB>2</SUB> and SO<SUB>2</SUB> at an operating temperature of 200°C. It shows the 75% response for 100ppm NO<SUB>2</SUB> gas concentration with response and recovery times of 22s and 126s, respectively. Finally, the gas sensing mechanism based on chemisorption process is proposed to illustrate how Pd nanoparticles affect the gas sensing characteristics (response and response-recovery times).</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Electrochromic performance of the mixed V2O5eWO3 thin films synthesized by pulsed spray pyrolysis technique

C.E. Patil,N.L. Tarwal,P.R. Jadhav,P.S. Shinde,H.P. Deshmukh,J.D. Song,A.V. Moholkar,M.G. Gang,김진혁,P.S. Patil 한국물리학회 2014 Current Applied Physics Vol.14 No.3

Vanadium pentoxide (V2O5) mixed tungsten trioxide (WO3) 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 V2O5eWO3 thin films. The structural, morphological, optical and electrochemical properties of V2O5eWO3 thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V2O5 were altered by mixing WO3. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO4 þ propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm2 C1 was observed for the V2O5 film mixed with 15% WO3. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.

Electrochromic performance of the mixed V₂O₅-WO₃ thin films synthesized by pulsed spray pyrolysis technique

Patil, C.E.,Tarwal, N.L.,Jadhav, P.R.,Shinde, P.S.,Deshmukh, H.P.,Karanjkar, M.M.,Moholkar, A.V.,Gang, M.G.,Kim, J.H.,Patil, P.S. Elsevier 2014 Current Applied Physics Vol.14 No.3

Vanadium pentoxide (V<SUB>2</SUB>O<SUB>5</SUB>) mixed tungsten trioxide (WO<SUB>3</SUB>) 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 <SUP>o</SUP>C. Aqueous solutions of equimolar vanadium chloride and ammonium tungstate were mixed in volume proportions (5%, 10% and 15%) for the deposition of V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB> thin films. The structural, morphological, optical and electrochemical properties of V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB> thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V<SUB>2</SUB>O<SUB>5</SUB> were altered by mixing WO<SUB>3</SUB>. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO<SUB>4</SUB> + propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm<SUP>2</SUP> C<SUP>-1</SUP> was observed for the V<SUB>2</SUB>O<SUB>5</SUB> film mixed with 15% WO<SUB>3</SUB>. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.

Effects of dopant (Al, Ga, and In) on the characteristics of ZnO thin films prepared by RF magnetron sputtering system

Kyu Ung Sim,신승욱,A.V. Moholkar,문종하,Jae Ho Yun,김진혁 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The un-doped and Al, Ga, and In doped (3 wt.%) ZnO thin films have been prepared on glass substrates using RF magnetron sputtering at 350 ℃. The effects of these dopants on the structural, morphological,electrical, and optical properties of deposited films have been studied. XRD study showed that all doped ZnO thin films have the polycrystalline nature with hexagonal wurtzite phase having c-axis preferred out-of-plane orientation. The cross-sectional FE-SEM micrographs showed that all the films have columnar structure. AFM images showed that doped ZnO thin films have better surface smoothness than undoped ZnO thin films regardless of doping elements. The GZO thin film have the optimal electrical properties among all doped samples in terms of the carrier concentration (6.13 × 1023 cm-3), charge carrier mobility (28.2 ㎠ V-1 s-1), and a minimum resistivity (3.61 × 10-4 Ω cm). UV–Vis spectrometer results showed that all the films are highly transparent in the visible region and the band gap energy of the films varies from 3.25 eV to 3.75 eV for the different dopants. PL spectra showed the un-doped and doped ZnO thin film exhibited a violet emission in the 390–405 nm range, with different intensities, which is due to difference in concentration of zinc vacancies.

A chemical approach for synthesis of photoelectrochemically active Cu₂ZnSnS₄ (CZTS) thin films

Suryawanshi, M.P.,Shin, S.W.,Ghorpade, U.V.,Gurav, K.V.,Agawane, G.L.,Hong, C.W.,Yun, J.H.,Patil, P.S.,Kim, J.H.,Moholkar, A.V. Association for Applied Solar Energy ; Elsevier Sc 2014 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.110 No.-

A cost-effective chemical approach is developed for the synthesis of photoelectrochemically active Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> (CZTS) thin films. More specifically, CZTS precursor thin films are prepared by the sequential deposition of Cu<SUB>2</SUB>SnS<SUB>3</SUB> and ZnS layers using a successive ionic adsorption and reaction (SILAR) technique. The CZTS precursor thin films are sulfurized at different temperatures ranging from 500 to 575<SUP>o</SUP>C at intervals of 25<SUP>o</SUP>C. The influence of different sulfurization temperatures on the structural, compositional, morphological, and optical properties, as well as on the photoelectrochemical performance is studied. The films sulfurized at 575<SUP>o</SUP>C showed a prominent kesterite phase with a nearly stoichiometric composition, dense microstructure with the desired thickness, and an optical band gap energy of 1.47eV. The photoelectrochemical (PEC) cell fabricated using CZTS thin film sulfurized at 575<SUP>o</SUP>C showed the highest short circuit current density (J<SUB>sc</SUB>) of 8.27mA/cm<SUP>2</SUP> with a power conversion efficiency (η) of 1.06%.

A facile and low-cost synthesis of promising absorber materials on Cu₂ZnSn(S_<i>x</i>,Se_1−<i>x</i>)₄ nanocrystals consisting of earth abundant elements with tunable band gap characteristics

Shin, Seung Wook,Han, Jun Hee,Park, Yeon Chan,Agawane, G. L.,Jeong, Chae Hwan,Yun, Jae Ho,Moholkar, A. V.,Lee, Jeong Yong,Kim, Jin Hyeok The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.40

<P>In this paper, we report a facile, low cost synthesis and characterization of kesterite Cu<SUB>2</SUB>ZnSn(S<SUB><I>x</I></SUB>,Se<SUB>1−<I>x</I></SUB>)<SUB>4</SUB> (CZTSSe) nanocrystals (NCs) by a two-step process involving a solution-based precursor and a post-annealing route. The effects of different Se vaporization temperatures, ranging from 350 °C to 550 °C, on the structural, chemical, compositional, and optical properties of CZTSSe NCs were investigated. X-ray diffraction patterns, Raman spectroscopy, and transmission electron microscopy results indicated that the precursor powder showed several broad peaks that could not be assigned to Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> (CZTS), ZnS, Cu<SUB>2−<I>x</I></SUB>S, Sn<SUB>2</SUB>S<SUB>3</SUB> and Cu<SUB>2</SUB>SnS<SUB>3</SUB>. However, the post-annealed NCs with and without Se vaporization were a single kesterite CZTS phase without a secondary phase. UV-vis spectroscopy results showed that the absorption coefficients of all the post-annealed NCs were over 10<SUP>4</SUP> cm<SUP>−1</SUP> in the visible region, and the optical band gap energy decreased systematically from 1.46 eV to 1.14 eV with increasing Se vaporization temperatures.</P> <P>Graphic Abstract</P><P>In this paper, we report a facile, low cost synthesis and characterization of kesterite Cu<SUB>2</SUB>ZnSn(S<SUB><I>x</I></SUB>,Se<SUB>1−<I>x</I></SUB>)<SUB>4</SUB> (CZTSSe) nanocrystals (NCs) by a two-step process. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm33802e'> </P>

A Simple Aqueous Precursor Solution Processing of Earth-Abundant Cu₂SnS₃ Absorbers for Thin-Film Solar Cells

Suryawanshi, Mahesh P.,Ghorpade, Uma V.,Shin, Seung Wook,Pawar, Sachin A.,Kim, In Young,Hong, Chang Woo,Wu, Minhao,Patil, Pramod S.,Moholkar, Annasaheb V.,Kim, Jin Hyeok American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.18

<P>A simple and eco-friendly method of solution processing of Cu2SnS3 (CTS) absorbers using an aqueous precursor solution is presented. The precursor solution was prepared by mixing metal salts into a mixture of water and ethanol (5:1) with monoethanolamine as an additive at room temperature. Nearly carbon-free CTS films were formed by multispin coating the precursor solution and heat treating in air followed by rapid thermal annealing in S vapor atmosphere at various temperatures. Exploring the role of the annealing temperature in the phase, composition, and morphological evolution is essential for obtaining highly efficient CTS-based thin film solar cells (TFSCs). Investigations of CTS absorber layers annealed at various temperatures revealed that the annealing temperature plays an important role in further improving device properties and efficiency. A substantial improvement in device efficiency occurred only at the critical annealing temperature, which produces a compact and void-free microstructure with large grains and high crystallinity as a pure-phase absorber layer. Finally, at an annealing temperature of 600 degrees C, the CTS thin film exhibited structural, compositional, and microstructural isotropy by yielding a reproducible power conversion efficiency of 1.80%. Interestingly, CTS TFSCs exhibited good stability when stored in an air atmosphere without encapsulation at room temperature for 3 months, whereas the performance degraded slightly when subjected to accelerated aging at 80 degrees C for 100 h under normal laboratory conditions.</P>

Simplistic surface active agents mediated morphological tweaking of CdS thin films for photoelectrochemical solar cell performance

S.A. Vanalakar,M.P. Suryawanshi,S.S. Mali,A.V. Moholkar,J.Y.Kim,P.S. Patil,김진혁 한국물리학회 2014 Current Applied Physics Vol.14 No.12

This study reports on the formation of cadmium sulfide (CdS) nanostructures with controlled morphology synthesized via a simple chemical route in surface active agent environment. The effect of organic surface active agents (surfactants) as sodium dodecyl sulfate (SDS), polyethylene glycol (PEG) and cetyltrimethylammonium bromide (CTAB) on structural, morphological, optical and photoelectrochemical properties of CdS thin films have been studied. Our results reveal that the organic surfactants play key roles in tweaking the surface morphology. A compact spongy ball like morphology was observed for the CdS samples grown without organic surfactants. The cauliflower's with nanopetals from the CTAB, whereas crowded star fish like morphology is observed in PEG-mediated growth. Water hyacinth like morphology is tweaked using SDS. Considering the importance of these nanostructures, the growth mechanism has been discussed in details. Additionally, the samples are photoelectrochemically (PEC) active and having a compact surface with a nanoporous structure twig helps in improved photoelectrochemical performance compared to that of CdS deposits from surfactant free solution. This is a simplistic way to tune the morphology using surfactants, which can be applied to other energy conversion applications.

Simplistic surface active agents mediated morphological tweaking of CdS thin films for photoelectrochemical solar cell performance

Vanalakar, S.A.,Suryawanshi, M.P.,Mali, S.S.,Moholkar, A.V.,Kim, J.Y.,Patil, P.S.,Kim, J.H. Elsevier 2014 CURRENT APPLIED PHYSICS Vol.14 No.12

This study reports on the formation of cadmium sulfide (CdS) nanostructures with controlled morphology synthesized via a simple chemical route in surface active agent environment. The effect of organic surface active agents (surfactants) as sodium dodecyl sulfate (SDS), polyethylene glycol (PEG) and cetyltrimethylammonium bromide (CTAB) on structural, morphological, optical and photoelectrochemical properties of CdS thin films have been studied. Our results reveal that the organic surfactants play key roles in tweaking the surface morphology. A compact spongy ball like morphology was observed for the CdS samples grown without organic surfactants. The cauliflower's with nanopetals from the CTAB, whereas crowded star fish like morphology is observed in PEG-mediated growth. Water hyacinth like morphology is tweaked using SDS. Considering the importance of these nanostructures, the growth mechanism has been discussed in details. Additionally, the samples are photoelectrochemically (PEC) active and having a compact surface with a nanoporous structure twig helps in improved photoelectrochemical performance compared to that of CdS deposits from surfactant free solution. This is a simplistic way to tune the morphology using surfactants, which can be applied to other energy conversion applications.