Jagatpati Raiguru - Academia.edu (original) (raw)

Papers by Jagatpati Raiguru

Journal of Electronic Materials

We prepared a composite using activated carbon and functionalised multiwalled carbon nanotubes by... more We prepared a composite using activated carbon and functionalised multiwalled carbon nanotubes by a simple and cost-effective process and investigated its use for supercapacitor application. The electrochemical performance of the prepared composite has been investigated by galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) measurements in a three-electrode setup. The composite resulted in maximum specific capacitance of 395 F/g at 5 mV/s as measured by CV, and of 372 F/g at 60 A/g by GCD measurement in 3M KOH aqueous electrolyte. High power and energy density of 75.27 kW/kg and 25.31 WAEh/kg at 60 A/g have been respectively obtained for composite using GCD measurement. The long-term charge-discharge stability has been performed for the composite electrodes, and it is observed that 89% of capacitance is retained even after 5000 cycles. The achieved results suggest that the prepared activated carbon/multiwalled carbon nanotube composite can be a potential electrode material in high-performance supercapacitors for energy storage applications.

Supercapacitor (SC) also called ultracapacitor is an electrochemical energy storage device applie... more Supercapacitor (SC) also called ultracapacitor is an electrochemical energy storage device applied to store electrical charges and pulse power supply. It is expected that both energy and power density could be improved by making the SC composite structure using highly conducting materials multiwalled carbon nanotubes (MWCNTs) in activated carbon (AC). Also the performance of SC depends on some major factors of its electrode materials like high electrical conductivity, good mesoporocity, high specific surface area etc., so the structural and electrical study of MWCNTs incorporated in host activated carbon (AC) that forms nanocomposite prepared by a simple, low cost and environment friendly method has been reported. The structural properties of AC, MWCNTs and AC/MWCNTs have been examined by XRD, SEM and Raman spectroscopy. The enhancement of current in AC by adding MWCNTs has been analysed by current(I)-voltage(v) measurements. The observed results suggest that the prepared composite ...

Materials Today: Proceedings, 2021

Abstract A composite has been prepared by incorporating few layers of graphene sheets (FLGS) synt... more Abstract A composite has been prepared by incorporating few layers of graphene sheets (FLGS) synthesized by an electrochemical method in poly (3-hexylthiophene-2, 5-diyl) (P3HT): [6] , [6] -phenyl-C61-butyric acid methyl ester (PCBM). The composite has been used as active layer in the photovoltaic device (ITO/FLGS:P3HT:PCBM/Al) and the device characteristics were investigated. The as prepared FLGS has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV–Vis), and Raman spectroscopy. The performance of the composite based device has been studied under illumination and the results have been compared with the reference device (ITO/P3HT:PCBM/Al). Short circuit current density (Jsc) of 6.24 mA.cm−2, open circuit voltage (Voc) of 0.54 V, Fill factor (FF) of 44.22% and solar power conversion efficiency (PCE) of 1.49% have been obtained for reference photovoltaic device. After introducing FLGS in the active layer with P3HT:PCBM blend, improvement of Jsc of 8.2 mA.cm−2, Voc of 0.57 V, FF of 42.15% and solar power conversion efficiency of 1.97% have been observed. The performance improvement in FLGS incorporated device compared to the reference device is attributed to the advantage of electron accepting feature and high electron transport capability of FLGS.

Inorganic Chemistry Communications, 2021

Abstract A new hybrid composite of activated carbon (AC)/multiwalled carbon nanotubes (MWCNTs)-Zn... more Abstract A new hybrid composite of activated carbon (AC)/multiwalled carbon nanotubes (MWCNTs)-ZnFe2O4 has been prepared by the modest and low-cost method for its application as supercapacitor electrode material. The carbon-based composite electrode gives excellent cycle stability with moderate capacitance. So the capacitance of carbon-based composite electrode could be further improved by incorporating metal oxides as they involve reversible redox reaction. In this regard, zinc ferrite (ZnFe2O4) among various metal oxides is being considered as important additive material towards supercapacitor (SC) applications owing to its excellent physical and chemical properties. Hence, ZnFe2O4 is integrated with the carbon composite of MWCNTs and AC for better SC performance and cycle stability. The composite has resulted in maximum specific capacitance of 613 F/g at 5 mV/s when measured from cyclic voltammetry (CV) in 3M KOH electrolyte. The measurement from galvanostatic charge-discharge (GCD) on synthesised composite has shown capacitance of 609 F/g at 1 A/g and that implying the significant storage performance of the prepared hybrid material. The stability, which is vital for the application of the composite, has been subjected for stability test and found that it retained 91% of the capacitance even after 10000 cycles. Further, the synthesised materials have been characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH). The variation of current as a function of the applied voltage was analysed by current-voltage (I-V) measurements. These results suggest that the prepared composite can proficiently serve as a reliable choice for the electrode material for high-performance supercapacitor applications.

Journal of Physics: Materials, 2020

Carbon nanotubes (CNTs) along with reduced graphene oxide (RGO) are synthesized using modest meth... more Carbon nanotubes (CNTs) along with reduced graphene oxide (RGO) are synthesized using modest methods and their composites with the polymers PEDOT:PSS and P3HT are prepared using an easy solution method. An attractive improvement in the composites’ physical properties with wt% increase of the filler material is observed, encouraging their applications in the fabrication of organic solar cells (OSCs). Using the composites in appropriate layers of the device architecture, OSCs have been fabricated by spin coating, and the incorporation of filler CNTs and RGO has been observed to result in considerable improvement in the power conversion efficiency (PCE) of all OSCs. To study the stability of the devices, the electrical properties of the OSCs have been periodically investigated in two different environments to understand the impact of both intrinsic and extrinsic degradation. The incorporation of filler carbon nanomaterials has been noticed to be successful in significantly prolonging t...

DAE SOLID STATE PHYSICS SYMPOSIUM 2019, 2020

Materials Today: Proceedings, 2020

Abstract Carbon nanotubes (CNTs) have been synthesized by a simple and efficient pyrolysis techni... more Abstract Carbon nanotubes (CNTs) have been synthesized by a simple and efficient pyrolysis technique, and composites of CNTs with PEDOT:PSS, and with P3HT:PCBM blend have been prepared by a modest solution treatment. Bulk heterojunction organic photovoltaic cell (OPVC) has been fabricated by spin coating technique with configuration ITO/PEDOT:PSS/P3HT:PCBM/Al to serve as reference OPVC. Three more OPVCs have been fabricated by the same procedure, the first one with CNTs/PEDOT:PSS composite replacing PEDOT:PSS, second one with CNTs/P3HT:PCBM composite replacing P3HT:PCBM blend, and the third one with both replacements. The performances of all the OPVCs at room temperature have been compared and CNTs have been observed to cause extraordinary increment in the power conversion efficiency (PCE) as well as other electrical parameters of all the devices depending on the layer in which they have been incorporated. To extend the study for understanding further advantages of CNTs incorporation in fighting against degradation, all the fabricated OPVCs have been exposed to open atmosphere and their electrical properties have been measured at room temperature in regular intervals. Encouragingly positive outcomes have been attained, demonstrating not only a well maintained enhancement in the PCE, but also a considerably improved device stability. The best performing OPVC has achieved 24% more PCE and 67% more lifetime in open atmosphere than the reference device, which clearly does indicate the significance of applications of filler CNTs to improve not only the performance but also the stability of OPVCs.

DAE SOLID STATE PHYSICS SYMPOSIUM 2019, 2020

Journal of Materials Science: Materials in Electronics, 2020

Пропонується використовувати нейронні мережі на основі базисно радіальних функцій як метод для ро... more Пропонується використовувати нейронні мережі на основі базисно радіальних функцій як метод для розпізнавання графічних образів. Продемонстрована працездатність мережі на прикладі розпізнавання цифр. Предлагается использовать нейронные сети на основе базисно радиальных функций в качестве метода для распознавания графических образов. Продемонстрирована работоспособность сети на примере распознавания цифр. It is proposed to use neural network based on radial basic functions as a method for recognition of graphic images. The capacity of network is rotined on the example of recognition of numbers.

AIP Conference Proceedings, 2020

Integrated Ferroelectrics, 2020

Herein, we reported the effect of cobalt (Co) doping on the optical band gap of LaFeO 3 (LFO). Th... more Herein, we reported the effect of cobalt (Co) doping on the optical band gap of LaFeO 3 (LFO). The Co doped nanoparticles were prepared by a simple sol-gel technique with composition LaFe 1-x Co x O 3 by varying content ratio of x ¼ 0, 0.4, 0.5 and 0.6. Structure of the LFO and Co doped LFO nanoparticles have been investigated by X-ray diffraction (XRD) pattern. Whereas, surface morphology of LFO and Co doped LFO has been ascertained by scanning electron microscopy (SEM). The observed optical properties investigated by UV-Vis spectroscopy suggest decrease in band gap with Co doping in LFO, which can be useful for optoelectronic applications.

Superlattices and Microstructures, 2018

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Easy and large area synthesis of CuO/CdSe NWs: A new Type-II heterostructure material. FESEM and TEM confirms the formation of CuO/CdSe NWs. XRD patterns, Raman Spectra confirms the existence of two phase i.e. CuO and CdSe. The ultraviolet photodetector based on CuO/CdSe NWs has been fabricated and it shows strong and enhanced response. The strong and enhanced response of the photodetector is explained by band alignment, charge separation and charge transfer.

IOP Conference Series: Materials Science and Engineering, 2018

Cu2ZnSnS4 (CZTS) has emerged as a potential absorber towards inorganic photovoltaic device applic... more Cu2ZnSnS4 (CZTS) has emerged as a potential absorber towards inorganic photovoltaic device application for its outstanding properties like non toxicity, earth abundancy nature, optimal band gap matched with solar spectrum (1.45-1.65eV), high absorption coefficient (10 4 cm-1). Here, a low cost, environment friendly facile hydrothermal route to synthesize phase pure CZTS nanoparticles using Cu (II), Zn (II), Sn (II) inorganic metal salts and thiourea as Sulphur source in distilled water solution as precursor is reported. The as synthesized samples characterized by X-Ray diffraction (XRD) and RAMAN confirmed structure and phase of CZTS nanocrystals. The morphology of the prepared CZTS have been characterized by scanning electron microscopy (SEM). The particle size is found in the range 4-5 nm with crystalline nature have been characterized by transmission electron microscope (TEM). The optical band gap of the as prepared samples is calculated to be 1.65eV from UV-Visible analysis which proves it can be used towards photovoltaic applications.

Materials Today: Proceedings, 2019

The deficit in obtaining targeted photo conversion efficiency for (Cu 2 ZnSnS 4) CZTS based photo... more The deficit in obtaining targeted photo conversion efficiency for (Cu 2 ZnSnS 4) CZTS based photovoltaic cell results either from insufficient photo charge carrier generation or e-/h + pair transportation towards the end of electrodes, which lowers the device V oc and J sc. On this regard, semiconducting absorber material merged with highly mobile reduced graphene oxide (rGO) as filler form a bridging network within active layer facilitates both improvement in charge carrier separation as well as transportation to electrodes before recombination occurs. A simple solution casting approach for CZTS nanoparticle anchored rGO composite for photovoltaic device application is reported here. The presence and distribution of CZTS nanoparticles over the surface of rGO sheet is confirmed from XRD, Raman, SEM and UV-Visible analysis.

physica status solidi (a), 2019

The influence of graphene oxide (GO) using modified Hummer's method on the dielectric properties ... more The influence of graphene oxide (GO) using modified Hummer's method on the dielectric properties of Pb (Zr 1 À x Ti x) O 3 (PZT) using sol-gel route is investigated. The as-prepared PZT, GO, and PZT/GO composites are characterized by X-ray diffraction, field emission scanning electron microscope, and Raman spectroscopy. The dielectric measurements of PZT/GO composites are conducted in frequency ranges from 100 Hz to 1 MHz and from room temperature to 80 C. The dielectric constants of PZT/GO composites are larger than PZT at a frequency 100 Hz, and the dielectric losses are higher than PZT attributed to the presence of space-charge polarization near the grain boundary interfaces. The observed experimental profile shows about the existence of grains and grain boundaries as confirmed by the impedance analysis. With the increasing content of GO% in the PZT/GO composite, the remnant polarization is approximately constant and coercive electric fields decreases due to space-charge effects as obtained from the P-E loop measured at room temperature. The remnant polarization drastically reduces with higher wt% of GO (2 wt%) due to the conducting behavior of the PZT/GO composites. Therefore, the obtained higher dielectric constant of the prepared PZT/GO composites signifies that it may be suitable for various related applications.

DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019

Composites have been prepared using five different concentrations (1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%... more Composites have been prepared using five different concentrations (1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%) of reduced graphene oxide (RGO) in Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The structural, morphological, optical and electrical properties of the composites have been studied using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-Visible spectroscopy and I-V measurement techniques respectively and were compared to those of pristine PEDOT:PSS. The conductivity for the materials has been observed to enhance with increase in wt.% of RGO in PEDOT:PSS, whereas the absorption in visible region was found to be hardly affected. Photovoltaic cells (PVCs) have been fabricated using pristine PEDOT:PSS and the composites as transparent electrodes and the device parameters were obtained by characterizing through I-V measurement. A maximum photo conversion efficiency (PCE) of 2.581 % has been obtained with corresponding short-circuit current density (Jsc) of 8.946 mA/cm 2 and open-circuit voltage (Voc) of 0.6129 V for PVC fabricated using composite which contained 5wt.% of rGO in PEDOT:PSS.

DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019

In order for the realization of application of graphene in various research fields its wetability... more In order for the realization of application of graphene in various research fields its wetability is a real concern.In this report, the hydrophillic properties of the graphene has been investigated.The objective material graphene has been prepared by electrochemical method and characterized by FESEM,TEM, XRD,UV-Vis,FTIR and Raman spectroscopy.Our investigation reveals that the hydrophilic properties of graphene which aren't directly depend on the substrates but it is related to its Fermi level, which are responsible for the cooperation of graphene and water molecules using contact angle measurement i.e. if the Fermi level is shifting towards or further than its Dirac points, via applying DC voltage, enhanced the hydrophilicity of graphene is changed. The nature of hydrophilicity has been correlated by measuring I-V characteristics.

IOP Conference Series: Materials Science and Engineering, 2018

Graphene with two dimensional structures is a very exceptional material, since it has advantage o... more Graphene with two dimensional structures is a very exceptional material, since it has advantage of being excellent conducting material. Few layer of graphene sheets (FLGS) have been successfully prepared by an electrochemical method directly from graphite using oxalic acid as electrolyte. The prepared few layer FLGS have been characterized by X-ray diffraction(XRD), UV-Vis spectroscopy, field emission scanning electron microscope(FESEM), transmission electron microscope(TEM). The characterization reveals that the prepared FLGS is very good in quality. The measured current (I) vs voltage (v) shows that FLGS are highly conducting in nature. The hydrophobicity/Hydrophilicity of the prepared FLGS have been investigated for various applications.

AIP Conference Proceedings, 2018

In this energy crisis era, the urgent calls for clean energy converter realizes the importance of... more In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron–hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ∼1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ∼104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The incorporation of CNTs shows effectiveness in charge carrier transfer pathways which ultimately could enhance the photo conversion efficiency (PCE) of photovoltaic device cell (PVC). Here, a facile hydrothermal one-pot synthesis of CZTS nanoparticles and MWCNTs composite towards photovoltaics application is reported. The phase and structural analysis of CZTS nanoparticles as well as CZTS/MWCNTs composite is done by XRD. From FERSEM and TEM (LRTEM & HRTEM) analysis the CZTS nanoparticles decorated over the surface of MWCNTs is confirmed. The optical band gap of CZTS/MWCNTs composite is estimated to be 1.62 eV from UV-Visible spectra.In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron–hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ∼1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ∼104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The i...

Journal of Electronic Materials

We prepared a composite using activated carbon and functionalised multiwalled carbon nanotubes by... more We prepared a composite using activated carbon and functionalised multiwalled carbon nanotubes by a simple and cost-effective process and investigated its use for supercapacitor application. The electrochemical performance of the prepared composite has been investigated by galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) measurements in a three-electrode setup. The composite resulted in maximum specific capacitance of 395 F/g at 5 mV/s as measured by CV, and of 372 F/g at 60 A/g by GCD measurement in 3M KOH aqueous electrolyte. High power and energy density of 75.27 kW/kg and 25.31 WAEh/kg at 60 A/g have been respectively obtained for composite using GCD measurement. The long-term charge-discharge stability has been performed for the composite electrodes, and it is observed that 89% of capacitance is retained even after 5000 cycles. The achieved results suggest that the prepared activated carbon/multiwalled carbon nanotube composite can be a potential electrode material in high-performance supercapacitors for energy storage applications.

Supercapacitor (SC) also called ultracapacitor is an electrochemical energy storage device applie... more Supercapacitor (SC) also called ultracapacitor is an electrochemical energy storage device applied to store electrical charges and pulse power supply. It is expected that both energy and power density could be improved by making the SC composite structure using highly conducting materials multiwalled carbon nanotubes (MWCNTs) in activated carbon (AC). Also the performance of SC depends on some major factors of its electrode materials like high electrical conductivity, good mesoporocity, high specific surface area etc., so the structural and electrical study of MWCNTs incorporated in host activated carbon (AC) that forms nanocomposite prepared by a simple, low cost and environment friendly method has been reported. The structural properties of AC, MWCNTs and AC/MWCNTs have been examined by XRD, SEM and Raman spectroscopy. The enhancement of current in AC by adding MWCNTs has been analysed by current(I)-voltage(v) measurements. The observed results suggest that the prepared composite ...

Materials Today: Proceedings, 2021

Abstract A composite has been prepared by incorporating few layers of graphene sheets (FLGS) synt... more Abstract A composite has been prepared by incorporating few layers of graphene sheets (FLGS) synthesized by an electrochemical method in poly (3-hexylthiophene-2, 5-diyl) (P3HT): [6] , [6] -phenyl-C61-butyric acid methyl ester (PCBM). The composite has been used as active layer in the photovoltaic device (ITO/FLGS:P3HT:PCBM/Al) and the device characteristics were investigated. The as prepared FLGS has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV–Vis), and Raman spectroscopy. The performance of the composite based device has been studied under illumination and the results have been compared with the reference device (ITO/P3HT:PCBM/Al). Short circuit current density (Jsc) of 6.24 mA.cm−2, open circuit voltage (Voc) of 0.54 V, Fill factor (FF) of 44.22% and solar power conversion efficiency (PCE) of 1.49% have been obtained for reference photovoltaic device. After introducing FLGS in the active layer with P3HT:PCBM blend, improvement of Jsc of 8.2 mA.cm−2, Voc of 0.57 V, FF of 42.15% and solar power conversion efficiency of 1.97% have been observed. The performance improvement in FLGS incorporated device compared to the reference device is attributed to the advantage of electron accepting feature and high electron transport capability of FLGS.

Inorganic Chemistry Communications, 2021

Abstract A new hybrid composite of activated carbon (AC)/multiwalled carbon nanotubes (MWCNTs)-Zn... more Abstract A new hybrid composite of activated carbon (AC)/multiwalled carbon nanotubes (MWCNTs)-ZnFe2O4 has been prepared by the modest and low-cost method for its application as supercapacitor electrode material. The carbon-based composite electrode gives excellent cycle stability with moderate capacitance. So the capacitance of carbon-based composite electrode could be further improved by incorporating metal oxides as they involve reversible redox reaction. In this regard, zinc ferrite (ZnFe2O4) among various metal oxides is being considered as important additive material towards supercapacitor (SC) applications owing to its excellent physical and chemical properties. Hence, ZnFe2O4 is integrated with the carbon composite of MWCNTs and AC for better SC performance and cycle stability. The composite has resulted in maximum specific capacitance of 613 F/g at 5 mV/s when measured from cyclic voltammetry (CV) in 3M KOH electrolyte. The measurement from galvanostatic charge-discharge (GCD) on synthesised composite has shown capacitance of 609 F/g at 1 A/g and that implying the significant storage performance of the prepared hybrid material. The stability, which is vital for the application of the composite, has been subjected for stability test and found that it retained 91% of the capacitance even after 10000 cycles. Further, the synthesised materials have been characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH). The variation of current as a function of the applied voltage was analysed by current-voltage (I-V) measurements. These results suggest that the prepared composite can proficiently serve as a reliable choice for the electrode material for high-performance supercapacitor applications.

Journal of Physics: Materials, 2020

Carbon nanotubes (CNTs) along with reduced graphene oxide (RGO) are synthesized using modest meth... more Carbon nanotubes (CNTs) along with reduced graphene oxide (RGO) are synthesized using modest methods and their composites with the polymers PEDOT:PSS and P3HT are prepared using an easy solution method. An attractive improvement in the composites’ physical properties with wt% increase of the filler material is observed, encouraging their applications in the fabrication of organic solar cells (OSCs). Using the composites in appropriate layers of the device architecture, OSCs have been fabricated by spin coating, and the incorporation of filler CNTs and RGO has been observed to result in considerable improvement in the power conversion efficiency (PCE) of all OSCs. To study the stability of the devices, the electrical properties of the OSCs have been periodically investigated in two different environments to understand the impact of both intrinsic and extrinsic degradation. The incorporation of filler carbon nanomaterials has been noticed to be successful in significantly prolonging t...

DAE SOLID STATE PHYSICS SYMPOSIUM 2019, 2020

Materials Today: Proceedings, 2020

Abstract Carbon nanotubes (CNTs) have been synthesized by a simple and efficient pyrolysis techni... more Abstract Carbon nanotubes (CNTs) have been synthesized by a simple and efficient pyrolysis technique, and composites of CNTs with PEDOT:PSS, and with P3HT:PCBM blend have been prepared by a modest solution treatment. Bulk heterojunction organic photovoltaic cell (OPVC) has been fabricated by spin coating technique with configuration ITO/PEDOT:PSS/P3HT:PCBM/Al to serve as reference OPVC. Three more OPVCs have been fabricated by the same procedure, the first one with CNTs/PEDOT:PSS composite replacing PEDOT:PSS, second one with CNTs/P3HT:PCBM composite replacing P3HT:PCBM blend, and the third one with both replacements. The performances of all the OPVCs at room temperature have been compared and CNTs have been observed to cause extraordinary increment in the power conversion efficiency (PCE) as well as other electrical parameters of all the devices depending on the layer in which they have been incorporated. To extend the study for understanding further advantages of CNTs incorporation in fighting against degradation, all the fabricated OPVCs have been exposed to open atmosphere and their electrical properties have been measured at room temperature in regular intervals. Encouragingly positive outcomes have been attained, demonstrating not only a well maintained enhancement in the PCE, but also a considerably improved device stability. The best performing OPVC has achieved 24% more PCE and 67% more lifetime in open atmosphere than the reference device, which clearly does indicate the significance of applications of filler CNTs to improve not only the performance but also the stability of OPVCs.

DAE SOLID STATE PHYSICS SYMPOSIUM 2019, 2020

Journal of Materials Science: Materials in Electronics, 2020

Пропонується використовувати нейронні мережі на основі базисно радіальних функцій як метод для ро... more Пропонується використовувати нейронні мережі на основі базисно радіальних функцій як метод для розпізнавання графічних образів. Продемонстрована працездатність мережі на прикладі розпізнавання цифр. Предлагается использовать нейронные сети на основе базисно радиальных функций в качестве метода для распознавания графических образов. Продемонстрирована работоспособность сети на примере распознавания цифр. It is proposed to use neural network based on radial basic functions as a method for recognition of graphic images. The capacity of network is rotined on the example of recognition of numbers.

AIP Conference Proceedings, 2020

Integrated Ferroelectrics, 2020

Herein, we reported the effect of cobalt (Co) doping on the optical band gap of LaFeO 3 (LFO). Th... more Herein, we reported the effect of cobalt (Co) doping on the optical band gap of LaFeO 3 (LFO). The Co doped nanoparticles were prepared by a simple sol-gel technique with composition LaFe 1-x Co x O 3 by varying content ratio of x ¼ 0, 0.4, 0.5 and 0.6. Structure of the LFO and Co doped LFO nanoparticles have been investigated by X-ray diffraction (XRD) pattern. Whereas, surface morphology of LFO and Co doped LFO has been ascertained by scanning electron microscopy (SEM). The observed optical properties investigated by UV-Vis spectroscopy suggest decrease in band gap with Co doping in LFO, which can be useful for optoelectronic applications.

Superlattices and Microstructures, 2018

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Easy and large area synthesis of CuO/CdSe NWs: A new Type-II heterostructure material. FESEM and TEM confirms the formation of CuO/CdSe NWs. XRD patterns, Raman Spectra confirms the existence of two phase i.e. CuO and CdSe. The ultraviolet photodetector based on CuO/CdSe NWs has been fabricated and it shows strong and enhanced response. The strong and enhanced response of the photodetector is explained by band alignment, charge separation and charge transfer.

IOP Conference Series: Materials Science and Engineering, 2018

Cu2ZnSnS4 (CZTS) has emerged as a potential absorber towards inorganic photovoltaic device applic... more Cu2ZnSnS4 (CZTS) has emerged as a potential absorber towards inorganic photovoltaic device application for its outstanding properties like non toxicity, earth abundancy nature, optimal band gap matched with solar spectrum (1.45-1.65eV), high absorption coefficient (10 4 cm-1). Here, a low cost, environment friendly facile hydrothermal route to synthesize phase pure CZTS nanoparticles using Cu (II), Zn (II), Sn (II) inorganic metal salts and thiourea as Sulphur source in distilled water solution as precursor is reported. The as synthesized samples characterized by X-Ray diffraction (XRD) and RAMAN confirmed structure and phase of CZTS nanocrystals. The morphology of the prepared CZTS have been characterized by scanning electron microscopy (SEM). The particle size is found in the range 4-5 nm with crystalline nature have been characterized by transmission electron microscope (TEM). The optical band gap of the as prepared samples is calculated to be 1.65eV from UV-Visible analysis which proves it can be used towards photovoltaic applications.

Materials Today: Proceedings, 2019

The deficit in obtaining targeted photo conversion efficiency for (Cu 2 ZnSnS 4) CZTS based photo... more The deficit in obtaining targeted photo conversion efficiency for (Cu 2 ZnSnS 4) CZTS based photovoltaic cell results either from insufficient photo charge carrier generation or e-/h + pair transportation towards the end of electrodes, which lowers the device V oc and J sc. On this regard, semiconducting absorber material merged with highly mobile reduced graphene oxide (rGO) as filler form a bridging network within active layer facilitates both improvement in charge carrier separation as well as transportation to electrodes before recombination occurs. A simple solution casting approach for CZTS nanoparticle anchored rGO composite for photovoltaic device application is reported here. The presence and distribution of CZTS nanoparticles over the surface of rGO sheet is confirmed from XRD, Raman, SEM and UV-Visible analysis.

physica status solidi (a), 2019

The influence of graphene oxide (GO) using modified Hummer's method on the dielectric properties ... more The influence of graphene oxide (GO) using modified Hummer's method on the dielectric properties of Pb (Zr 1 À x Ti x) O 3 (PZT) using sol-gel route is investigated. The as-prepared PZT, GO, and PZT/GO composites are characterized by X-ray diffraction, field emission scanning electron microscope, and Raman spectroscopy. The dielectric measurements of PZT/GO composites are conducted in frequency ranges from 100 Hz to 1 MHz and from room temperature to 80 C. The dielectric constants of PZT/GO composites are larger than PZT at a frequency 100 Hz, and the dielectric losses are higher than PZT attributed to the presence of space-charge polarization near the grain boundary interfaces. The observed experimental profile shows about the existence of grains and grain boundaries as confirmed by the impedance analysis. With the increasing content of GO% in the PZT/GO composite, the remnant polarization is approximately constant and coercive electric fields decreases due to space-charge effects as obtained from the P-E loop measured at room temperature. The remnant polarization drastically reduces with higher wt% of GO (2 wt%) due to the conducting behavior of the PZT/GO composites. Therefore, the obtained higher dielectric constant of the prepared PZT/GO composites signifies that it may be suitable for various related applications.

DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019

Composites have been prepared using five different concentrations (1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%... more Composites have been prepared using five different concentrations (1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%) of reduced graphene oxide (RGO) in Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The structural, morphological, optical and electrical properties of the composites have been studied using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-Visible spectroscopy and I-V measurement techniques respectively and were compared to those of pristine PEDOT:PSS. The conductivity for the materials has been observed to enhance with increase in wt.% of RGO in PEDOT:PSS, whereas the absorption in visible region was found to be hardly affected. Photovoltaic cells (PVCs) have been fabricated using pristine PEDOT:PSS and the composites as transparent electrodes and the device parameters were obtained by characterizing through I-V measurement. A maximum photo conversion efficiency (PCE) of 2.581 % has been obtained with corresponding short-circuit current density (Jsc) of 8.946 mA/cm 2 and open-circuit voltage (Voc) of 0.6129 V for PVC fabricated using composite which contained 5wt.% of rGO in PEDOT:PSS.

DAE SOLID STATE PHYSICS SYMPOSIUM 2018, 2019

In order for the realization of application of graphene in various research fields its wetability... more In order for the realization of application of graphene in various research fields its wetability is a real concern.In this report, the hydrophillic properties of the graphene has been investigated.The objective material graphene has been prepared by electrochemical method and characterized by FESEM,TEM, XRD,UV-Vis,FTIR and Raman spectroscopy.Our investigation reveals that the hydrophilic properties of graphene which aren't directly depend on the substrates but it is related to its Fermi level, which are responsible for the cooperation of graphene and water molecules using contact angle measurement i.e. if the Fermi level is shifting towards or further than its Dirac points, via applying DC voltage, enhanced the hydrophilicity of graphene is changed. The nature of hydrophilicity has been correlated by measuring I-V characteristics.

IOP Conference Series: Materials Science and Engineering, 2018

Graphene with two dimensional structures is a very exceptional material, since it has advantage o... more Graphene with two dimensional structures is a very exceptional material, since it has advantage of being excellent conducting material. Few layer of graphene sheets (FLGS) have been successfully prepared by an electrochemical method directly from graphite using oxalic acid as electrolyte. The prepared few layer FLGS have been characterized by X-ray diffraction(XRD), UV-Vis spectroscopy, field emission scanning electron microscope(FESEM), transmission electron microscope(TEM). The characterization reveals that the prepared FLGS is very good in quality. The measured current (I) vs voltage (v) shows that FLGS are highly conducting in nature. The hydrophobicity/Hydrophilicity of the prepared FLGS have been investigated for various applications.

AIP Conference Proceedings, 2018

In this energy crisis era, the urgent calls for clean energy converter realizes the importance of... more In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron–hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ∼1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ∼104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The incorporation of CNTs shows effectiveness in charge carrier transfer pathways which ultimately could enhance the photo conversion efficiency (PCE) of photovoltaic device cell (PVC). Here, a facile hydrothermal one-pot synthesis of CZTS nanoparticles and MWCNTs composite towards photovoltaics application is reported. The phase and structural analysis of CZTS nanoparticles as well as CZTS/MWCNTs composite is done by XRD. From FERSEM and TEM (LRTEM & HRTEM) analysis the CZTS nanoparticles decorated over the surface of MWCNTs is confirmed. The optical band gap of CZTS/MWCNTs composite is estimated to be 1.62 eV from UV-Visible spectra.In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron–hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ∼1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ∼104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The i...