Chemical synthesis and photoelectrochemical study of CdS/rGO nanocomposite films

Nikam Ranjit P.,Lokhande Abhishekh C.,Khot Sambhaji D.,Mane Vikas J.,Lokhande Chandrakant D. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2

The cadmium sulfide/reduced graphene oxide (CdS/rGO) composite thin films were synthesized on stainless steel (SS) substrates using the successive ionic layer adsorption and reaction (SILAR) method. The physico-chemical properties of CdS/rGO films were studied. The X-ray diffraction (XRD) revealed the growth of nanocrystalline CdS/rGO films with a cubic crystal structure. The field-emission scanning electron microscopy (FE-SEM) images of CdS/rGO-80 composite thin films showed compact spherical nanoparticles and an optical band gap found to be 2.27 eV. The CdS/rGO-80 composite thin film displayed hydrophilic nature with a water contact angle of 33°. The photoelectrochemical (PEC) studies of CdS/rGO thin film in dark and under light exhibited n-type of electrical conductivity with an improved photoactivity over bare CdS in 1 M polysulfide (NaOH + Na2S + S) electrolyte. It is observed that rGO composited CdS thin film enhances the conversion efficiency (η) from 0.09 to 0.31% than bare CdS films. The electrical transport properties were investigated by electrochemical impedance spectroscopy (EIS) study in dark and under illumination conditions and corresponding equivalent circuit of the impedance model is developed.

Photoelectrochemical performance of surfactant (polyvinyl alcohol) assisted PbS thin films grown by chemical route

Nikam, S. S.,Suryawanshi, M. P.,Gaikwad, M. A.,Kim, J. H.,Moholkar, A. V. Springer Science + Business Media 2017 Journal of materials science. Materials in electro Vol.28 No.7

<P>Polyvinyl alcohol is used as a surfactant in the chemical bath deposition of PbS thin films, which causes compact, pinhole free and uniform PbS thin films. Influence of deposition time on the structural, optical, morphological, compositional, electro-chemical and photo-electrochemical (PEC) properties of the PbS thin films are studied. The charge transfer resistance is analysed using electrochemical impedance spectroscopy. The best PEC device fabricated using optimized deposition time (3 h) showed short circuit current density (J(sc)) of 1.68 mA. After annealing the optimised P-63 sample at 75 A degrees C for 1.5 h the composition changed from Pb rich to near stoichiometric. For typical PA sample J(sc) improves to 2.13 mA and photo conversion efficiency advances from 0.045 to 0.072%.</P>

CdS surface encapsulated ZnO nanorods: Synthesis to solar cell application

Nikam, Pratibha R.,Baviskar, Prashant K.,Sali, Jaydeep V.,Gurav, Kishor V.,Kim, Jin H.,Sankapal, Babasaheb R. Elsevier 2016 Journal of Alloys and Compounds Vol.689 No.-

<P><B>Abstract</B></P> <P>Surface coating of CdS nanoparticles over the ZnO nanorods have been performed by using simple successive ionic layer adsorption and reaction at room temperature. Initially, the seed/compact ZnO layer have been deposited via SILAR (successive ionic layer adsorption and reaction) on to fluorine doped tin oxide coated glass (FTO) substrate followed by synthesis of ZnO nanorods by chemical bath deposition method. The synthesized nano heterostructure was characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX) and high resolution-transmission electron microscopy (HR-TEM) techniques. The photovoltaic performance of the cell was recorded with a conversion efficiency of 0.123% under 100 mW/cm<SUP>2</SUP> simulated sunlight at AM 1.5G conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of ZnO nanorods using simple solution chemistry. </LI> <LI> Surface encapsulation of ZnO nanorods with CdS nanoparticles using SILAR method. </LI> <LI> CdS sensitized ZnO nano heterojunction solar cell show 0.123% efficiency. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The development of a heterostructure using one dimensional (1-D) confined nanomaterials of inorganic metal oxides and chalcogenides semiconductor. The heterostructure was constructed by using ZnO nanorods encapsulated with CdS nanoparticles without use of capping agent with precise control over the morphology and microstructure towards nano heterostructure solar cell application. The energy conversion efficiency (η) of 0.123% was obtained under standard illumination of simulated sun light.</P> <P>[DISPLAY OMISSION]</P>

NEW GERAGHTY TYPE CONDENSING OPERATORS AND SOLVABILITY OF NONLINEAR QUADRATIC VOLTERRA-STIELTJES INTEGRAL EQUATION

Vishal Nikam,Dhananjay Gopal,Habib ur Rehman,Thanatporn Bantaojai 경남대학교 기초과학연구소 2020 Nonlinear Functional Analysis and Applications Vol.25 No.4

The true motivation of this article is to provide sucient conditions with theaid of Geraghty type condensing operators that guarantee the existence of a solution of non-linear quadratic Volterra-Stieltjes integral equation. We also address several new fixed pointtheorems that ensure the existence of a xed point for Geraghty type condensing operatorsin real Banach spaces. An example and numerical approximations are presented to justifythe basis of our results.

Embryogenic callus culture of Tribulus terrestris L. a potential source of harmaline, harmine and diosgenin

T. D. Nikam,Mohammad Ali Ebrahimi,V. A. Patil 한국식물생명공학회 2009 Plant biotechnology reports Vol.3 No.3

In the present study, a simple one medium formulation protocol for callus culture, somatic embryogenesis and in vitro production of b-carboline alkaloids and diosgenin in Tribulus terrestris L. was developed. Extensive callus induction and proliferation was obtained in leaf explant on Murashige and Skoog (MS) medium supplemented with 5.0 lM 6 benzyl adenine (BA) and 2.5 lM a-naphthaleneacetic acid (NAA). The embryogenic callus was maintained on subculture to fresh parental medium at 4-week intervals over a period of 28 months. The frequency of embryo formation was at a maximum (18.1 ± 0.9 per g of callus) on MS medium containing 5.0 lM BA and 2.5 lM NAA together with 75 mg l-1 casein hydrolysate. Globular embryo developed into torpedo stage embryo under the influence of starvation. The accumulation of b-carboline alkaloids (harmaline and harmine) and steroidal saponin (diosgenin) in nonembryogenic and embryogenic callus culture derived from leaf explant was compared with root, leaf, stem, and fruit of the mother plant. The embryogenic callus accumulated equivalent amounts of harmaline (66.4 ± 0.5 lg/g dry weight), harmine (82.7 ± 0.6 lg/g dry weight), and diosgenin (170.7 ± 1.0 lg/g dry weight) to that of the fruit of T. terrestris. The embryogenic callus culture of this species might offer a potential source for production of important pharmaceuticals. In the present study, a simple one medium formulation protocol for callus culture, somatic embryogenesis and in vitro production of b-carboline alkaloids and diosgenin in Tribulus terrestris L. was developed. Extensive callus induction and proliferation was obtained in leaf explant on Murashige and Skoog (MS) medium supplemented with 5.0 lM 6 benzyl adenine (BA) and 2.5 lM a-naphthaleneacetic acid (NAA). The embryogenic callus was maintained on subculture to fresh parental medium at 4-week intervals over a period of 28 months. The frequency of embryo formation was at a maximum (18.1 ± 0.9 per g of callus) on MS medium containing 5.0 lM BA and 2.5 lM NAA together with 75 mg l-1 casein hydrolysate. Globular embryo developed into torpedo stage embryo under the influence of starvation. The accumulation of b-carboline alkaloids (harmaline and harmine) and steroidal saponin (diosgenin) in nonembryogenic and embryogenic callus culture derived from leaf explant was compared with root, leaf, stem, and fruit of the mother plant. The embryogenic callus accumulated equivalent amounts of harmaline (66.4 ± 0.5 lg/g dry weight), harmine (82.7 ± 0.6 lg/g dry weight), and diosgenin (170.7 ± 1.0 lg/g dry weight) to that of the fruit of T. terrestris. The embryogenic callus culture of this species might offer a potential source for production of important pharmaceuticals.

Differential Osmotic Adjustment to Iso-osmotic NaCl and PEG Stress in the in vitro Cultures of Sesuvium portulacastrum (L.) L.

Lokhande, Vinayak Haribhau,Nikam, Tukaram Dayaram,Penna, Suprasanna 한국작물학회 2010 Journal of crop science and biotechnology Vol.13 No.4

The influence of iso-osmotic (-0.7 MPa) NaCl and PEG stress on growth, osmotic adjustment and antioxidant defense mechanisms was investigated in the in vitro cultures of Sesuvium portulacastrum (L.) L. The decreased relative growth rate (RGR) and water content of PEG-stressed calli in comparison to NaCl was found to be correlated with differences observed in the energy expenditure for the maintenance of osmotic balance. Osmotic adjustment in the NaCl-stressed calli favored higher accumulation of saline ions and soluble sugars, whereas PEG-stressed calli confirmed increased levels of organic osmolytes (proline, glycine betaine and soluble sugars). Permeability of $Na^+$ ions across the membrane revealed increased relative electrolytic leakage (REL) in NaCl-stressed calli, however non-penetrating and highly viscous solution of PEG amplified the peroxidation of membrane lipids. Increased activities of superoxide dismutase and catalase displayed efficient removal of toxic reactive oxygen species in comparison to ascorbate peroxidase in the calli exposed to iso-osmotic stress. These findings suggest that differential tolerance potential to iso-osmotic NaCl and PEG stress in terms of osmotic adjustment appears to be the prime defense mechanism of Sesuvium for its survival under iso-osmotic stress conditions at the expense of reduced growth and water content.

Mono-segment (segment 2) donor hepatectomy for pediatric liver transplantation

Rajan GARG,Vinayak NIKAM,Anurag SHRIMAL,Prashantha S RAO,Mitul SHAH,Ravi MOHANKA 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

Influence of plant growth regulators on somatic embryogenesis in Niger (Guizotia abyssinica Cass.): an edible oilseed crop

Chambhare Mahadev Ramkisan,Nikam Tukaram Dayaram 한국작물학회 2022 Journal of crop science and biotechnology Vol.25 No.2

An improved protocol of direct somatic embryogenesis (SE) and shoot regeneration was developed, for the frst-time, using leaf explants from in vitro raised shoots of Guizotia abyssinica. We have studied the efect of cytokinins and auxins viz. 6-benzylaminopurine (BAP), kinetin, indole-3-acetic acid (IAA), α-naphthaleneacetic acid (NAA) and 2,4-dichloro phenoxyacetic acid (2,4-D), individually and in combination for their efectiveness to induce direct SE and shoot regeneration. MS medium containing 1.0 mg L−1 BAP together with 0.5 mg L−1 IAA showed maximum frequency of explants responding for SE and number of somatic embryos per explant. Somatic embryos germinated within 2 weeks of transfer to MS medium supplemented with 0.25 mg L−1 BAP whereas plantlet development with rooting was observed on MS containing 0.25 mg L−1 NAA in the next 2 weeks. This regeneration system increased the efciency of explants responding to SE by 100%, reduced the time taken for SE by 4–6 weeks, minimized the infuence of environmental factors and HgCl2 on response of explant, and also chances of appearance of developmental aberrations due to exposure to 2,4-D and callus intervention. Over 90% of regenerated plantlets survived following hardening and transfer to a mixture of sand and soil. Morphological, cytological, and fow cytometric analysis suggested that the plantlets were phenotypically and genetically similar. The method provides an efcient tissue culture system for rapid propagation and for genetic manipulation studies

Pure laparoscopic living donor left lateral sectionectomy in pediatric transplantation: First case in Western India

Rajan GARG,Prashantha S RAO,Vinayak NIKAM,Anurag SHRIMAL,Mitul SHAH,Ravi MOHANKA 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

High photonic effect of organic dye degradation by CdSe–graphene–TiO2 particles

Trisha Ghosh,오원춘,조광윤,Kefayat Ullah,Vikram Nikam,박종연,Ze-Da Meng 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

Photocatalytic activity of CdSe (cadmium selenide) decorated graphene composites coupled with TiO2(titanium oxide) was investigated with organic dye solutions. The characterizations of composites were studied by X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscope (SEM),and with transmission electron microscope (TEM). The degradation of methyl orange (MO) and rhodamine B (RhB) was observed by measuring the decrease in the concentration by UV spectrophotometer. The synergistic effect of graphene on CdSe and TiO2 was demonstrated by comparative study. The composites were tested for recyclability, investigating the stability of CdSe–graphene/TiO2 composites.