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Electrosynthesis of copper phosphide thin films for efficient water oxidation
Pawar, Sambhaji M.,Pawar, Bharati S.,Babar, Pravin T.,Aqueel Ahmed, Abu Talha,Chavan, Harish S.,Jo, Yongcheol,Cho, Sangeun,Kim, Jongmin,Inamdar, Akbar I.,Kim, Jin Hyeok,Kim, Hyungsang,Im, Hyunsik Elsevier 2019 Materials letters Vol.241 No.-
<P><B>Abstract</B></P> <P>A copper phosphide (Cu<SUB>3</SUB>P) thin film is synthesized on a Ni foam using a one-step electrodeposition method at room temperature and annealed at 300 °C in Ar atmosphere. The Cu<SUB>3</SUB>P film is amorphous and has a flat morphology with surface voids. It works as an electrocatalyst for water oxidation in an alkaline 1 M KOH electrolyte. It exhibits excellent catalytic oxygen evolution reaction with an overpotential of 310 mV, Tafel slope of 88 mV/dec, and good stability over 20 h of operation at 10 mA/cm<SUP>2</SUP>. The excellent OER performance is due to its large electrochemically active surface area and low charge transfer resistance at the catalyst-electrolyte interface after the annealing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Amorphous copper phosphide OER catalyst is synthesized by one-step electrodeposition. </LI> <LI> A smooth morphology with surface void is obtained after annealing. </LI> <LI> An overpotential of 310 mV at 10 mA/cm<SUP>2</SUP> with a Tafel slope of 88 mV/dec is demonstrated. </LI> <LI> Excellent long-term electrochemical durability is observed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Recent status of chemical bath deposited metal chalcogenide and metal oxide thin films
Pawar, S.M.,Pawar, B.S.,Kim, J.H.,Joo, O.S.,Lokhande, C.D. Elsevier 2011 Current Applied Physics Vol.11 No.2
Presently nanocrystalline materials have opened a new chapter in the field of electronic applications, since material properties could be changed by changing the crystallite size and/or thickness of the film. The synthesis of nanocrystalline metal chalcogenide and metal oxide thin films by chemical bath deposition (CBD) method is currently attracting considerable attention as it is relatively inexpensive, simple and convenient for large area deposition. Using CBD and modified CBD (which is also known as successive ionic layer adsorption and reaction, SILAR) methods, a large number of thin films have been deposited. This review is on the status of synthesizing thin films of metal chalcogenide and metal oxides by CBD and SILAR. Properties and applications of the thin films are also summarized.
Dye sensitized solar cells based on hydrothermally grown TiO<sub>2</sub> nanostars over nanorods
Pawar, Udayraj T.,Pawar, Sachin A.,Kim, Jin-Hyeok,Patil, Pramod S. Elsevier 2016 CERAMICS INTERNATIONAL Vol.42 No.7
<P><B>Abstract</B></P> <P>A rutile titanium dioxide nanostar over nanorods is synthesized by a simple and cost-effective hydrothermal deposition method onto conducting glass substrates. In order to study the effect of precursor concentrations on the growth of TiO<SUB>2</SUB>, the amount of Ti precursor is varied from 0.1mL to 0.5mL at the interval of 0.1mL. These TiO<SUB>2</SUB> thin films are characterized for their morphological, structural, optical and <I>J</I>–<I>V</I> properties using various characterization techniques. SEM images showed the formation of densely packed nanostars over nanorods for 0.3mL titanium tetraisopropoxide (TTIP). XRD patterns show the formation of polycrystalline TiO<SUB>2</SUB> with tetragonal crystal structure possessing rutile phase. Further, the TiO<SUB>2</SUB> thin films are used for dye sensitized solar cells using N3-dye.</P> <P>The films were photoelectrochemically active and can be viewed as a promising application in DSSC with maximum current density of 1.459mA/cm<SUP>2</SUP> with enhanced photovoltage of 696mV for the sample prepared at 0.3mL TTIP.</P>
Pawar, S.M.,Inamdar, A.I.,Pawar, B.S.,Gurav, K.V.,Shin, S.W.,Yanjun, Xiao,Kolekar, S.S.,Lee, Jung-Ho,Kim, Jin Hyeok,Im, Hyunsik Elsevier 2014 Materials Letters Vol.118 No.-
<P><B>Abstract</B></P> <P>Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> (CZTS) absorbers have been grown on Mo-coated glass substrates by the rapid thermal processing (RTP) sulfurization of stacked metallic precursor (CZT) films at different annealing temperatures ranging from 500 to 580°C for 5min in sulfur atmosphere. The effects of sulfurization temperature on the structural, morphological, chemical, and optical properties of the CZTS absorbers have been investigated. XRD and Raman studies reveal that the as-deposited stacked metallic precursor films consist of metal elements such as Zn, Sn and binary alloys such as Cu<SUB>6</SUB>Sn<SUB>5</SUB>, Cu<SUB>3</SUB>Sn and CuZn. The sulfurized CZTS absorber films have single phase polycrystalline kesterite crystal structure with dense morphology. At 580°C, the CZT metallic precursor film is fully sulfurized with Zn-rich and Sn-poor composition, and its bandgap energy is found to be 1.50eV. The solar cell fabricated with the CZTS absorber grown at an optimized sulfurization temperature of 580°C shows a conversion efficiency of ~5% for a 0.44cm<SUP>2</SUP> area with <I>V</I> <SUB> <I>oc</I> </SUB>=561mV, <I>J</I> <SUB> <I>sc</I> </SUB>=18.4mA/cm<SUP>2</SUP>, and <I>FF</I>=48.2.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Single phase Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> is synthesized by rapid thermal processing sulfurization. </LI> <LI> Higher annealing temperature improves the crystallinity of Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> absorber. </LI> <LI> Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> absorber is fully sulfurized at 580°C. </LI> <LI> A solar cell with a ~5% conversion efficiency is demonstrated. </LI> </UL> </P>
Pawar, Sambhaji M.,Pawar, Bharati S.,Hou, Bo,Kim, Jongmin,Aqueel Ahmed, Abu Talha,Chavan, Harish. S.,Jo, Yongcheol,Cho, Sangeun,Inamdar, Akbar I.,Gunjakar, Jayavant L.,Kim, Hyungsang,Cha, SeungNam,Im, The Royal Society of Chemistry 2017 Journal of materials chemistry. A, Materials for e Vol.5 No.25
<P>A high activity of a two-dimensional (2D) copper oxide (CuO) electrocatalyst for the oxygen evolution reaction (OER) is presented. The CuO electrode self-assembles on a stainless steel substrate<I>via</I>chemical bath deposition at 80 °C in a mixed solution of CuSO4and NH4OH, followed by air annealing treatment, and shows a 2D nanosheet bundle-type morphology. The OER performance is studied in a 1 M KOH solution. The OER starts to occur at about 1.48 V<I>versus</I>the RHE (<I>η</I>= 250 mV) with a Tafel slope of 59 mV dec<SUP>−1</SUP>in a 1 M KOH solution. The overpotential (<I>η</I>) of 350 mV at 10 mA cm<SUP>−2</SUP>is among the lowest compared with other copper-based materials. The catalyst can deliver a stable current density of >10 mA cm<SUP>−2</SUP>for more than 10 hours. This superior OER activity is due to its adequately exposed OER-favorable 2D morphology and the optimized electronic properties resulting from the thermal treatment.</P>
Pawar, Sambhaji M.,Pawar, Bharati S.,Babar, Pravin T.,Ahmed, Abu Talha Aqueel,Chavan, Harish S.,Jo, Yongcheol,Cho, Sangeun,Kim, Jongmin,Hou, Bo,Inamdar, Akbar I.,Cha, SeungNam,Kim, Jin Hyeok,Kim, Tae Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.470 No.-
<P><B>Abstract</B></P> <P>Efficient and low‐cost multifunctional electrodes play a key role in improving the performance of energy conversion and storage devices. In this study, ultrathin nanoporous CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets are synthesized on a nickel foam substrate using electrodeposition followed by air annealing. The CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet electrode exhibits a high specific capacitance of 1473 F g<SUP>─1</SUP> at 1 A g<SUP>─1</SUP> with a capacity retention of ∼93% after 5000 cycles in 3 M KOH solution. It also works well as an efficient oxygen evolution reaction electrocatalyst, demonstrating an overpotential of 260 mV at 20 mA cm<SUP>─2</SUP> with a Tafel slope of ∼64 mV dec<SUP>─1</SUP>. in 1 M KOH solution, which is the lowest reported among other copper-cobalt based transition metal oxide catalysts. The catalyst is very stable at >20 mA cm<SUP>─2</SUP> for more than 25 h. The superior electrochemical performance of the CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet electrode is due to the synergetic effect of the direct growth of 2D nanosheet structure and a large electrochemically active surface area associated with nanopores on the CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ultrathin nanoporous CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets electrode synthesized by electrodeposition. </LI> <LI> High specific capacitance and good cycling stability were obtained. </LI> <LI> Highly efficient OER electrocatalyst with an overpotential of 260 mV at 20 mA/cm<SUP>2</SUP>. </LI> <LI> Excellent long-term electrochemical durability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Pawar, S.M.,Pawar, B.S.,Hou, Bo,Ahmed, A.T.A.,Chavan, H.S.,Jo, Yongcheol,Cho, Sangeun,Kim, Jongmin,Seo, Jiwoo,Cha, SeungNam,Inamdar, A.I.,Kim, Hyungsang,Im, Hyunsik Elsevier 2019 Journal of industrial and engineering chemistry Vol.69 No.-
<P><B>Abstract</B></P> <P>High-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets are grown on Ni foam using electrodeposition followed by air annealing for a Li-ion battery anode. The anode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g (82% coulombic efficiency) and excellent high-rate performance with 95% capacity retention (1100mAh/g after 200 cycles at 1A/g). The outstanding battery performance of the CuCo<SUB>2</SUB>O<SUB>4</SUB> anode is attributed to its binder-free direct contact to the current collector and high-density nanosheet morphology. The present experimental findings demonstrate that the electrodeposited binder-free CuCo<SUB>2</SUB>O<SUB>4</SUB> material may serve as a safe, low-cost, long-cycle life anode for Li-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of high-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets via electrodeposition method. </LI> <LI> CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet electrode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g. </LI> <LI> Excellent rate capability and stability with 95% capacity retention after 200 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
S.M. Pawar,B.S. Pawar,Bo Hou,A.T.A. Ahmed,H.S. Chavan,조용철,조상근,김종민,서지우,차승남,A. I. Inamdar,김형상,임현식 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-
High-density CuCo2O4 nanosheets are grown on Ni foam using electrodeposition followed by airannealing for a Li-ion battery anode. The anode exhibits a high discharge capacity of 1244 mAh/g at 0.1 A/g (82% coulombic efficiency) and excellent high-rate performance with 95% capacity retention(1100 mAh/g after 200 cycles at 1 A/g). The outstanding battery performance of the CuCo2O4 anode isattributed to its binder-free direct contact to the current collector and high-density nanosheetmorphology. The present experimentalfindings demonstrate that the electrodeposited binder-freeCuCo2O4 material may serve as a safe, low-cost, long-cycle life anode for Li-ion batteries.
Effect of bath temperature on the properties of nanocrystalline ZnO thin films.
Pawar, S M,Gurav, K V,Shin, S W,Choi, D S,Kim, I K,Lokhande, C D,Rhee, J I,Kim, J H American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.5
<P>The nanocrystalline zinc oxide (ZnO) thin films have been prepared by chemical bath deposition (CBD) method from aqueous zinc nitrate solution at room temperature (25 degrees C) and at higher temperature (75 degrees C). The changes in structural, morphological and optical properties were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical absorption. The structural studies revealed that the film deposited at room temperature showed mixed phases of ZnO and Zn(OH)2 with wurtzite and orthorhombic crystal structure whereas at higher temperature, the deposited film is ZnO with wurtzite crystal structure. After air annealing at 400 degrees C, all the films converted into pure ZnO with wurtzite crystal structure. The films deposited at room temperature showed fibrous surface morphology with interconnected flakes while films deposited at higher temperature shows well-developed nano-rod morphology. Optical study shows that band gap energy (E(g)) of as-deposited thin films deposited at room temperature and at higher temperature are 3.81 and 3.4 eV, decreases up to 3.20 eV, after annealing treatment.</P>