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In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and... more
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2).In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2). Electronic supplementary information (ESI) available: XRD pattern, SEM images of the ZnIn2S4 precipitant product at the bottom of the autoclave. XRD pattern, SEM images, UV-vis spectra of ZnIn2S4 film on FTO substrates after heat treatment at 400 °C for 30 min in an Ar atmosphere. See DOI: 10.1039/b000000x
Research Interests: Technology, Solar Cell, Scanning Electron Microscopy, Transmission Electron Microscopy, Heat Treatment, and 10 moreCrystal structure, High Resolution Transmission Electron Microscopy, Physical sciences, Reaction Time, Band Gap, Optical Properties, CHEMICAL SCIENCES, Spectrum, X ray diffraction, and Conversion Efficiency
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and... more
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2).In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2). Electronic supplementary information (ESI) available: XRD pattern, SEM images of the ZnIn2S4 precipitant product at the bottom of the autoclave. XRD pattern, SEM images, UV-vis spectra of ZnIn2S4 film on FTO substrates after heat treatment at 400 °C for 30 min in an Ar atmosphere. See DOI: 10.1039/b000000x
Research Interests: Technology, Solar Cell, Scanning Electron Microscopy, Transmission Electron Microscopy, Heat Treatment, and 10 moreCrystal structure, High Resolution Transmission Electron Microscopy, Physical sciences, Reaction Time, Band Gap, Optical Properties, CHEMICAL SCIENCES, Spectrum, X ray diffraction, and Conversion Efficiency
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its... more
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its greater potential, the number of papers published and research groups working in the application of melt electrospinning for novel applications is significantly lower than that of solvent electrospinning. However, it is worth mentioning that attempts were made to improve the design and development of melt electrospinning and fabricate fibrous materials using the set up during the last few decades. A lack of interest in melt electrospinning is probably associated with the difficulty of melting the polymers at a precise temperature range. This report provides an overview on the various design setups employed to achieve melt electrospinning and a wide variety of polymers used.
Research Interests:
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its... more
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its greater potential, the number of papers published and research groups working in the application of melt electrospinning for novel applications is significantly lower than that of solvent electrospinning. However, it is worth mentioning that attempts were made to improve the design and development of melt electrospinning and fabricate fibrous materials using the set up during the last few decades. A lack of interest in melt electrospinning is probably associated with the difficulty of melting the polymers at a precise temperature range. This report provides an overview on the various design setups employed to achieve melt electrospinning and a wide variety of polymers used.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and... more
Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and lamellar) can be controlled via the concentration of copolymer, resulting in two different types of micellar packing. The calcination temperature is also controlled to ensure a well-crystalline and stable porous framework. Finally, the synthesized mesoporous TiO(2) film is modified by adding P25 nanoparticles, which act as scattering centers and function as active binders to prevent formation of microcracks. Adding P25 nanoparticles into mesoporous structure helps to provide strong light-harvesting capability and large surface area for high -efficiency dye-sensitized solar cells (DSSC). The short-circuit photocurrent density (J(sc)) of the cell made from mixture of mesoporous TiO(2) and P25 nanoparticles displays a higher efficiency of approximately 6.5% compared to the other homogeneous films. A combination of factors such as increased surface area, introduction of light-scattering particles, and high crystallinity of the mesoporous films leads to enhanced cell performance.
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Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and... more
Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and lamellar) can be controlled via the concentration of copolymer, resulting in two different types of micellar packing. The calcination temperature is also controlled to ensure a well-crystalline and stable porous framework. Finally, the synthesized mesoporous TiO(2) film is modified by adding P25 nanoparticles, which act as scattering centers and function as active binders to prevent formation of microcracks. Adding P25 nanoparticles into mesoporous structure helps to provide strong light-harvesting capability and large surface area for high -efficiency dye-sensitized solar cells (DSSC). The short-circuit photocurrent density (J(sc)) of the cell made from mixture of mesoporous TiO(2) and P25 nanoparticles displays a higher efficiency of approximately 6.5% compared to the other homogeneous films. A combination of factors such as increased surface area, introduction of light-scattering particles, and high crystallinity of the mesoporous films leads to enhanced cell performance.
Research Interests:
This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates... more
This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates by a drop casting method, and their application as counter electrodes in dye-sensitized solar cells (DSSCs). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements of this solution processed Ppy/f-MWCNT nanocomposite film
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This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates... more
This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates by a drop casting method, and their application as counter electrodes in dye-sensitized solar cells (DSSCs). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements of this solution processed Ppy/f-MWCNT nanocomposite film
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Research Interests:
Research Interests:
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Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in... more
Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in large-area electronics as well as green energy systems. This paper reviews the electronic and optoelectronic properties of these networks and highlights their potential applications in field-effect transistors, optoelectronic devices, and solar cells. Techniques to grow nanowires and their subsequent integration into networks using contact printing and electrospinning are described. Electrical properties of field-effect transistors fabricated from contact printed nanowire networks are discussed, and means of integration of the nanowire networks of heterogenous materials that enable ambipolar device operation are outlined. Photocurrent properties of these nanowires are described, including the dye sensitization of large-bandgap SnO2 nanowires. The final section deals with the advantages of employing nanowire networks in dye-sensitized solar cells and the dependence of solar cell performance on morphology and surface area.
Research Interests:
Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in... more
Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in large-area electronics as well as green energy systems. This paper reviews the electronic and optoelectronic properties of these networks and highlights their potential applications in field-effect transistors, optoelectronic devices, and solar cells. Techniques to grow nanowires and their subsequent integration into networks using contact printing and electrospinning are described. Electrical properties of field-effect transistors fabricated from contact printed nanowire networks are discussed, and means of integration of the nanowire networks of heterogenous materials that enable ambipolar device operation are outlined. Photocurrent properties of these nanowires are described, including the dye sensitization of large-bandgap SnO2 nanowires. The final section deals with the advantages of employing nanowire networks in dye-sensitized solar cells and the dependence of solar cell performance on morphology and surface area.
Research Interests:
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective... more
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective mineralization for successful regeneration of damaged tissues. The simultaneous electrospraying of nanohydroxyapatite (HA) on electrospun polymeric nanofibrous scaffolds might be more promising for bone tissue regeneration. In the current study, nanofibrous scaffolds of gelatin (Gel), Gel/HA (4:1 blend), Gel/HA (2:1 blend) and Gel/HA (electrospin-electrospray) were fabricated for this purpose. The morphology, chemical and mechanical stability of nanofibres were evaluated by means of field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and with a universal tensile machine, respectively. The in vitro biocompatibility of different nanofibrous scaffolds was determined by culturing human foetal osteoblasts and investigating the proliferation, alkaline phosphatase (ALP) activity and mineralization of cells. The results of cell proliferation, ALP activity and FESEM studies revealed that the combination of electrospinning of gelatin and electrospraying of HA yielded biocomposite nanofibrous scaffolds with enhanced performances in terms of better cell proliferation, increased ALP activity and enhanced mineralization, making them potential substrates for bone tissue regeneration.
Research Interests: Nanofibers, Hydroxyapatite, Cell Adhesion, Multidisciplinary, Extracellular Matrix, and 14 moreBone Regeneration, Bone graft, Humans, Animals, Gelatin, Alkaline phosphatase, Fourier transform infrared spectroscopy, Fetus, Cell Proliferation, Osteoblasts, Materials Testing, Field Emission Scanning Electron Microscopy, Durapatite, and Bone and Bones
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective... more
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective mineralization for successful regeneration of damaged tissues. The simultaneous electrospraying of nanohydroxyapatite (HA) on electrospun polymeric nanofibrous scaffolds might be more promising for bone tissue regeneration. In the current study, nanofibrous scaffolds of gelatin (Gel), Gel/HA (4:1 blend), Gel/HA (2:1 blend) and Gel/HA (electrospin-electrospray) were fabricated for this purpose. The morphology, chemical and mechanical stability of nanofibres were evaluated by means of field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and with a universal tensile machine, respectively. The in vitro biocompatibility of different nanofibrous scaffolds was determined by culturing human foetal osteoblasts and investigating the proliferation, alkaline phosphatase (ALP) activity and mineralization of cells. The results of cell proliferation, ALP activity and FESEM studies revealed that the combination of electrospinning of gelatin and electrospraying of HA yielded biocomposite nanofibrous scaffolds with enhanced performances in terms of better cell proliferation, increased ALP activity and enhanced mineralization, making them potential substrates for bone tissue regeneration.
Research Interests: Nanofibers, Hydroxyapatite, Cell Adhesion, Multidisciplinary, Extracellular Matrix, and 14 moreBone Regeneration, Bone graft, Humans, Animals, Gelatin, Alkaline phosphatase, Fourier transform infrared spectroscopy, Fetus, Cell Proliferation, Osteoblasts, Materials Testing, Field Emission Scanning Electron Microscopy, Durapatite, and Bone and Bones
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials,... more
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials, are used in photovoltaics either as photoelectrode in dye solar cells (DSCs) or to build metal oxide p–n junctions. Progress made in utilization of metal oxides for photoelectrode in DSC is reviewed in this article. Basic operational principle and factors that control the photoconversion efficiency of DSC are briefly outlined. The d-block binary metal oxides viz. TiO2, ZnO, and Nb2O5 are the best candidates as photoelectrode due to the dissimilarity in orbitals constituting their conduction band and valence band. This dissimilarity decreases the probability of charge recombination and enhances the carrier lifetime in these materials. Ternary metal oxide such as Zn2SnO4 could also be a promising material for photovoltaic application. Various morphologies such as nanoparticles, nanowires, nanotubes, and nanofibers have been explored to enhance the energy conversion efficiency of DSCs. The TiO2 served as a model system to study the properties and factors that control the photoconversion efficiency of DSCs; therefore, such discussion is limited to TiO2 in this article. The electron transport occurs through nanocrystalline TiO2 through trapping and detrapping events; however, exact nature of these trap states are not thoroughly quantified. Research efforts are required not only to quantify the trap states in mesoporous metal oxides but new mesoporous architectures also to increase the conversion efficiency of metal oxide-based photovoltaics.
Research Interests:
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials,... more
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials, are used in photovoltaics either as photoelectrode in dye solar cells (DSCs) or to build metal oxide p–n junctions. Progress made in utilization of metal oxides for photoelectrode in DSC is reviewed in this article. Basic operational principle and factors that control the photoconversion efficiency of DSC are briefly outlined. The d-block binary metal oxides viz. TiO2, ZnO, and Nb2O5 are the best candidates as photoelectrode due to the dissimilarity in orbitals constituting their conduction band and valence band. This dissimilarity decreases the probability of charge recombination and enhances the carrier lifetime in these materials. Ternary metal oxide such as Zn2SnO4 could also be a promising material for photovoltaic application. Various morphologies such as nanoparticles, nanowires, nanotubes, and nanofibers have been explored to enhance the energy conversion efficiency of DSCs. The TiO2 served as a model system to study the properties and factors that control the photoconversion efficiency of DSCs; therefore, such discussion is limited to TiO2 in this article. The electron transport occurs through nanocrystalline TiO2 through trapping and detrapping events; however, exact nature of these trap states are not thoroughly quantified. Research efforts are required not only to quantify the trap states in mesoporous metal oxides but new mesoporous architectures also to increase the conversion efficiency of metal oxide-based photovoltaics.
Research Interests:
Research Interests:
Research Interests:
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Research Interests:
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In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and... more
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2).In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2). Electronic supplementary information (ESI) available: XRD pattern, SEM images of the ZnIn2S4 precipitant product at the bottom of the autoclave. XRD pattern, SEM images, UV-vis spectra of ZnIn2S4 film on FTO substrates after heat treatment at 400 °C for 30 min in an Ar atmosphere. See DOI: 10.1039/b000000x
Research Interests: Technology, Solar Cell, Scanning Electron Microscopy, Transmission Electron Microscopy, Heat Treatment, and 10 moreCrystal structure, High Resolution Transmission Electron Microscopy, Physical sciences, Reaction Time, Band Gap, Optical Properties, CHEMICAL SCIENCES, Spectrum, X ray diffraction, and Conversion Efficiency
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its... more
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its greater potential, the number of papers published and research groups working in the application of melt electrospinning for novel applications is significantly lower than that of solvent electrospinning. However, it is worth mentioning that attempts were made to improve the design and development of melt electrospinning and fabricate fibrous materials using the set up during the last few decades. A lack of interest in melt electrospinning is probably associated with the difficulty of melting the polymers at a precise temperature range. This report provides an overview on the various design setups employed to achieve melt electrospinning and a wide variety of polymers used.
Research Interests:
Research Interests:
Research Interests:
Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and... more
Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO(2)) films. The pore structure (quasi-hexagonal and lamellar) can be controlled via the concentration of copolymer, resulting in two different types of micellar packing. The calcination temperature is also controlled to ensure a well-crystalline and stable porous framework. Finally, the synthesized mesoporous TiO(2) film is modified by adding P25 nanoparticles, which act as scattering centers and function as active binders to prevent formation of microcracks. Adding P25 nanoparticles into mesoporous structure helps to provide strong light-harvesting capability and large surface area for high -efficiency dye-sensitized solar cells (DSSC). The short-circuit photocurrent density (J(sc)) of the cell made from mixture of mesoporous TiO(2) and P25 nanoparticles displays a higher efficiency of approximately 6.5% compared to the other homogeneous films. A combination of factors such as increased surface area, introduction of light-scattering particles, and high crystallinity of the mesoporous films leads to enhanced cell performance.
Research Interests:
This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates... more
This paper reports facile fabrication of polypyrrole (Ppy)/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposite films on rigid fluorine-doped tin oxide (FTO) and flexible ITO-coated polyethylene naphthalate (PEN) substrates by a drop casting method, and their application as counter electrodes in dye-sensitized solar cells (DSSCs). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements of this solution processed Ppy/f-MWCNT nanocomposite film
Research Interests:
Research Interests:
Research Interests:
Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in... more
Oxide nanowire networks or oxide nanonets leverage some of the exceptional functionalities of one-dimensional nanomaterials along with the fault tolerance and flexibility of interconnected nanowires to creating exciting opportunities in large-area electronics as well as green energy systems. This paper reviews the electronic and optoelectronic properties of these networks and highlights their potential applications in field-effect transistors, optoelectronic devices, and solar cells. Techniques to grow nanowires and their subsequent integration into networks using contact printing and electrospinning are described. Electrical properties of field-effect transistors fabricated from contact printed nanowire networks are discussed, and means of integration of the nanowire networks of heterogenous materials that enable ambipolar device operation are outlined. Photocurrent properties of these nanowires are described, including the dye sensitization of large-bandgap SnO2 nanowires. The final section deals with the advantages of employing nanowire networks in dye-sensitized solar cells and the dependence of solar cell performance on morphology and surface area.
Research Interests:
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective... more
Currently, the application of nanotechnology in bone tissue regeneration is a challenge for the fabrication of novel bioartificial bone grafts. These nanostructures are capable of mimicking natural extracellular matrix with effective mineralization for successful regeneration of damaged tissues. The simultaneous electrospraying of nanohydroxyapatite (HA) on electrospun polymeric nanofibrous scaffolds might be more promising for bone tissue regeneration. In the current study, nanofibrous scaffolds of gelatin (Gel), Gel/HA (4:1 blend), Gel/HA (2:1 blend) and Gel/HA (electrospin-electrospray) were fabricated for this purpose. The morphology, chemical and mechanical stability of nanofibres were evaluated by means of field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and with a universal tensile machine, respectively. The in vitro biocompatibility of different nanofibrous scaffolds was determined by culturing human foetal osteoblasts and investigating the proliferation, alkaline phosphatase (ALP) activity and mineralization of cells. The results of cell proliferation, ALP activity and FESEM studies revealed that the combination of electrospinning of gelatin and electrospraying of HA yielded biocomposite nanofibrous scaffolds with enhanced performances in terms of better cell proliferation, increased ALP activity and enhanced mineralization, making them potential substrates for bone tissue regeneration.
Research Interests: Nanofibers, Hydroxyapatite, Cell Adhesion, Multidisciplinary, Extracellular Matrix, and 14 moreBone Regeneration, Bone graft, Humans, Animals, Gelatin, Alkaline phosphatase, Fourier transform infrared spectroscopy, Fetus, Cell Proliferation, Osteoblasts, Materials Testing, Field Emission Scanning Electron Microscopy, Durapatite, and Bone and Bones
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials,... more
The incessant demand for energy forces us to seek it from sustainable resources; and concerns on environment demands that resources should be clean as well. Metal oxide semiconductors, which are stable and environment friendly materials, are used in photovoltaics either as photoelectrode in dye solar cells (DSCs) or to build metal oxide p–n junctions. Progress made in utilization of metal oxides for photoelectrode in DSC is reviewed in this article. Basic operational principle and factors that control the photoconversion efficiency of DSC are briefly outlined. The d-block binary metal oxides viz. TiO2, ZnO, and Nb2O5 are the best candidates as photoelectrode due to the dissimilarity in orbitals constituting their conduction band and valence band. This dissimilarity decreases the probability of charge recombination and enhances the carrier lifetime in these materials. Ternary metal oxide such as Zn2SnO4 could also be a promising material for photovoltaic application. Various morphologies such as nanoparticles, nanowires, nanotubes, and nanofibers have been explored to enhance the energy conversion efficiency of DSCs. The TiO2 served as a model system to study the properties and factors that control the photoconversion efficiency of DSCs; therefore, such discussion is limited to TiO2 in this article. The electron transport occurs through nanocrystalline TiO2 through trapping and detrapping events; however, exact nature of these trap states are not thoroughly quantified. Research efforts are required not only to quantify the trap states in mesoporous metal oxides but new mesoporous architectures also to increase the conversion efficiency of metal oxide-based photovoltaics.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and... more
In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2).In this paper, ZnIn2S4 perpendicular nanosheet films have been directly deposited on FTO substrates by a facile hydrothermal method and investigated as the electrode materials for solar cells. The crystal structure, morphology, and optical properties of the obtained ZnIn2S4 films were characterized by measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrum (EDS), X-ray photoelectron spectrum (XPS) and UV-vis spectra. The results revealed a uniform perpendicular ZnIn2S4 film with thickness of 4 μm and with an average nanosheet thickness of about 30 nm on FTO substrate, along with the band gap of 2.35 eV. The reaction conditions influencing the formation of ZnIn2S4 films, such as the substrate treatment and reaction time were investigated. A possible mechanism for the formation of ZnIn2S4 films on FTO substrates under hydrothermal conditions has been proposed. Furthermore, after heat treatment, the ZnIn2S4 film electrode exhibited a photoelectrical conversion efficiency of 0.23% in FTO/ZnIn2S4/polysulfide/Au liquid-junction solar cell under AM 1.5 (100 mW cm-2). Electronic supplementary information (ESI) available: XRD pattern, SEM images of the ZnIn2S4 precipitant product at the bottom of the autoclave. XRD pattern, SEM images, UV-vis spectra of ZnIn2S4 film on FTO substrates after heat treatment at 400 °C for 30 min in an Ar atmosphere. See DOI: 10.1039/b000000x
Research Interests: Technology, Solar Cell, Scanning Electron Microscopy, Transmission Electron Microscopy, Heat Treatment, and 10 moreCrystal structure, High Resolution Transmission Electron Microscopy, Physical sciences, Reaction Time, Band Gap, Optical Properties, CHEMICAL SCIENCES, Spectrum, X ray diffraction, and Conversion Efficiency
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its... more
Melt electrospinning is a technique for the production of micro and nanofibers which can be an interesting alternative to conventional solvent electrospinning. In this process, the solvents are replaced by polymer melts. Despite its greater potential, the number of papers published and research groups working in the application of melt electrospinning for novel applications is significantly lower than that of solvent electrospinning. However, it is worth mentioning that attempts were made to improve the design and development of melt electrospinning and fabricate fibrous materials using the set up during the last few decades. A lack of interest in melt electrospinning is probably associated with the difficulty of melting the polymers at a precise temperature range. This report provides an overview on the various design setups employed to achieve melt electrospinning and a wide variety of polymers used.