The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
R.m.g. Rajapakse - One of the best experts on this subject based on the ideXlab platform.
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Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye
Journal of Semiconductors, 2018Co-Authors: G.r.r.a. Kumara, Chandana Sampath Kumara Ranasinghe, E.n. Jayaweera, U. Deshapriya, R.m.g. RajapakseAbstract:Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle Layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a Dense Layer of ZnO on FTO followed by a mesoporous Layer of interconnected ZnO nanoparticle Layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous Layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a Dense Layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a Dense Layer and that without a Dense Layer are 5.00 × 10−7 and 3.34 × 10−7 mol/cm2, respectively. The cell with the Dense Layer has an electron lifetime of 54.81 ms whereas that without the Dense Layer is 11.08 ms. As such, the presence of the Dense Layer improves DSC characteristics of ZnO-based DSCs.
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Development of Dye-Sensitized Solid-State ZnO/D149/CuSCN Solar Cell
International Journal of Nanoscience, 2014Co-Authors: Chandana Sampath Kumara Ranasinghe, G.r.r.a. Kumara, E.n. Jayaweera, H. M. N. Bandara, R.m.g. RajapakseAbstract:Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO -based interconnected nanoparticulate (20 nm) mesoporous Layer with ZnO -based Dense Layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN . The surface morphologies of the ZnO Dense Layer, ZnO porous Layer and CuSCN Layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ ZnO Dense Layer/ ZnO porous Layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the Dense Layer resistance (which is proportional to the thickness of the Dense Layer) and the porous Layer thicknesses. The optimum Dense Layer is found to have 1500 Ω/□ sheet resistance. The cell with porous Layer thickness of 9 μm at this Dense Layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55 V, a fill factor of 0.51 and a short-circuit current density of 8.2 mA cm-2.
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Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell
Electrochimica Acta, 2013Co-Authors: G.r.r.a. Kumara, J.k. Tiskumara, Chandana Sampath Kumara Ranasinghe, I.s. Rathnayake, W.m.n.m.b. Wanninayake, E.n. Jayaweera, L.r.a.k. Bandara, R.m.g. RajapakseAbstract:This paper describes the preparation and characterization of FTO/TiO2 Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO Dense Layer are described. As the thickness (and hence the sheet resistance) of the TiO2 Dense Layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0 Omega/square and beyond which it decreases. At this optimum thickness of the TiO2 Dense Layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous Layer is 15 mu m. Use of ZnO Dense Layer instead of TiO2 Dense Layer also shows the similar trend of variation of solar cell parameters as the thickness of the Dense Layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO Dense Layer is 2500 Omega/square and the thickness of the ZnO porous Layer is 15 mu m. (C) 2013 Elsevier Ltd. All rights reserved.
G.r.r.a. Kumara - One of the best experts on this subject based on the ideXlab platform.
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Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye
Journal of Semiconductors, 2018Co-Authors: G.r.r.a. Kumara, Chandana Sampath Kumara Ranasinghe, E.n. Jayaweera, U. Deshapriya, R.m.g. RajapakseAbstract:Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle Layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a Dense Layer of ZnO on FTO followed by a mesoporous Layer of interconnected ZnO nanoparticle Layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous Layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a Dense Layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a Dense Layer and that without a Dense Layer are 5.00 × 10−7 and 3.34 × 10−7 mol/cm2, respectively. The cell with the Dense Layer has an electron lifetime of 54.81 ms whereas that without the Dense Layer is 11.08 ms. As such, the presence of the Dense Layer improves DSC characteristics of ZnO-based DSCs.
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Development of Dye-Sensitized Solid-State ZnO/D149/CuSCN Solar Cell
International Journal of Nanoscience, 2014Co-Authors: Chandana Sampath Kumara Ranasinghe, G.r.r.a. Kumara, E.n. Jayaweera, H. M. N. Bandara, R.m.g. RajapakseAbstract:Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO -based interconnected nanoparticulate (20 nm) mesoporous Layer with ZnO -based Dense Layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN . The surface morphologies of the ZnO Dense Layer, ZnO porous Layer and CuSCN Layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ ZnO Dense Layer/ ZnO porous Layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the Dense Layer resistance (which is proportional to the thickness of the Dense Layer) and the porous Layer thicknesses. The optimum Dense Layer is found to have 1500 Ω/□ sheet resistance. The cell with porous Layer thickness of 9 μm at this Dense Layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55 V, a fill factor of 0.51 and a short-circuit current density of 8.2 mA cm-2.
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Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell
Electrochimica Acta, 2013Co-Authors: G.r.r.a. Kumara, J.k. Tiskumara, Chandana Sampath Kumara Ranasinghe, I.s. Rathnayake, W.m.n.m.b. Wanninayake, E.n. Jayaweera, L.r.a.k. Bandara, R.m.g. RajapakseAbstract:This paper describes the preparation and characterization of FTO/TiO2 Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO Dense Layer are described. As the thickness (and hence the sheet resistance) of the TiO2 Dense Layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0 Omega/square and beyond which it decreases. At this optimum thickness of the TiO2 Dense Layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous Layer is 15 mu m. Use of ZnO Dense Layer instead of TiO2 Dense Layer also shows the similar trend of variation of solar cell parameters as the thickness of the Dense Layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO Dense Layer is 2500 Omega/square and the thickness of the ZnO porous Layer is 15 mu m. (C) 2013 Elsevier Ltd. All rights reserved.
Chandana Sampath Kumara Ranasinghe - One of the best experts on this subject based on the ideXlab platform.
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Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye
Journal of Semiconductors, 2018Co-Authors: G.r.r.a. Kumara, Chandana Sampath Kumara Ranasinghe, E.n. Jayaweera, U. Deshapriya, R.m.g. RajapakseAbstract:Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle Layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a Dense Layer of ZnO on FTO followed by a mesoporous Layer of interconnected ZnO nanoparticle Layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous Layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a Dense Layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a Dense Layer and that without a Dense Layer are 5.00 × 10−7 and 3.34 × 10−7 mol/cm2, respectively. The cell with the Dense Layer has an electron lifetime of 54.81 ms whereas that without the Dense Layer is 11.08 ms. As such, the presence of the Dense Layer improves DSC characteristics of ZnO-based DSCs.
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Development of Dye-Sensitized Solid-State ZnO/D149/CuSCN Solar Cell
International Journal of Nanoscience, 2014Co-Authors: Chandana Sampath Kumara Ranasinghe, G.r.r.a. Kumara, E.n. Jayaweera, H. M. N. Bandara, R.m.g. RajapakseAbstract:Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO -based interconnected nanoparticulate (20 nm) mesoporous Layer with ZnO -based Dense Layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN . The surface morphologies of the ZnO Dense Layer, ZnO porous Layer and CuSCN Layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ ZnO Dense Layer/ ZnO porous Layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the Dense Layer resistance (which is proportional to the thickness of the Dense Layer) and the porous Layer thicknesses. The optimum Dense Layer is found to have 1500 Ω/□ sheet resistance. The cell with porous Layer thickness of 9 μm at this Dense Layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55 V, a fill factor of 0.51 and a short-circuit current density of 8.2 mA cm-2.
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Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell
Electrochimica Acta, 2013Co-Authors: G.r.r.a. Kumara, J.k. Tiskumara, Chandana Sampath Kumara Ranasinghe, I.s. Rathnayake, W.m.n.m.b. Wanninayake, E.n. Jayaweera, L.r.a.k. Bandara, R.m.g. RajapakseAbstract:This paper describes the preparation and characterization of FTO/TiO2 Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO Dense Layer are described. As the thickness (and hence the sheet resistance) of the TiO2 Dense Layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0 Omega/square and beyond which it decreases. At this optimum thickness of the TiO2 Dense Layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous Layer is 15 mu m. Use of ZnO Dense Layer instead of TiO2 Dense Layer also shows the similar trend of variation of solar cell parameters as the thickness of the Dense Layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO Dense Layer is 2500 Omega/square and the thickness of the ZnO porous Layer is 15 mu m. (C) 2013 Elsevier Ltd. All rights reserved.
E.n. Jayaweera - One of the best experts on this subject based on the ideXlab platform.
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Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye
Journal of Semiconductors, 2018Co-Authors: G.r.r.a. Kumara, Chandana Sampath Kumara Ranasinghe, E.n. Jayaweera, U. Deshapriya, R.m.g. RajapakseAbstract:Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle Layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a Dense Layer of ZnO on FTO followed by a mesoporous Layer of interconnected ZnO nanoparticle Layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous Layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a Dense Layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a Dense Layer and that without a Dense Layer are 5.00 × 10−7 and 3.34 × 10−7 mol/cm2, respectively. The cell with the Dense Layer has an electron lifetime of 54.81 ms whereas that without the Dense Layer is 11.08 ms. As such, the presence of the Dense Layer improves DSC characteristics of ZnO-based DSCs.
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Development of Dye-Sensitized Solid-State ZnO/D149/CuSCN Solar Cell
International Journal of Nanoscience, 2014Co-Authors: Chandana Sampath Kumara Ranasinghe, G.r.r.a. Kumara, E.n. Jayaweera, H. M. N. Bandara, R.m.g. RajapakseAbstract:Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO -based interconnected nanoparticulate (20 nm) mesoporous Layer with ZnO -based Dense Layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN . The surface morphologies of the ZnO Dense Layer, ZnO porous Layer and CuSCN Layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ ZnO Dense Layer/ ZnO porous Layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the Dense Layer resistance (which is proportional to the thickness of the Dense Layer) and the porous Layer thicknesses. The optimum Dense Layer is found to have 1500 Ω/□ sheet resistance. The cell with porous Layer thickness of 9 μm at this Dense Layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55 V, a fill factor of 0.51 and a short-circuit current density of 8.2 mA cm-2.
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Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell
Electrochimica Acta, 2013Co-Authors: G.r.r.a. Kumara, J.k. Tiskumara, Chandana Sampath Kumara Ranasinghe, I.s. Rathnayake, W.m.n.m.b. Wanninayake, E.n. Jayaweera, L.r.a.k. Bandara, R.m.g. RajapakseAbstract:This paper describes the preparation and characterization of FTO/TiO2 Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO Dense Layer/ZnO nanoporous Layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO Dense Layer are described. As the thickness (and hence the sheet resistance) of the TiO2 Dense Layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0 Omega/square and beyond which it decreases. At this optimum thickness of the TiO2 Dense Layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous Layer is 15 mu m. Use of ZnO Dense Layer instead of TiO2 Dense Layer also shows the similar trend of variation of solar cell parameters as the thickness of the Dense Layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO Dense Layer is 2500 Omega/square and the thickness of the ZnO porous Layer is 15 mu m. (C) 2013 Elsevier Ltd. All rights reserved.
G. Taller - One of the best experts on this subject based on the ideXlab platform.
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Effective buoyancy ratio: a new parameter for characterizing thermo-chemical mixing in the Earth's mantle
Solid Earth, 2015Co-Authors: Attila Galsa, Mátyás Herein, L. Lenkey, M. P. Farkas, G. TallerAbstract:Abstract. Numerical modeling has been carried out in a 2-D cylindrical shell domain to quantify the evolution of a primordial Dense Layer around the core–mantle boundary. Effective buoyancy ratio, Beff was introduced to characterize the evolution of the two-Layer thermo-chemical convection in the Earth's mantle. Beff decreases with time due to (1) warming of the compositionally Dense Layer, (2) cooling of the overlying mantle, (3) eroding of the Dense Layer through thermal convection in the overlying mantle and (4) diluting of the Dense Layer through inner convection. When Beff reaches the instability point, Beff = 1, effective thermo-chemical convection starts, and the mantle will be mixed (Beff = 0) over a short time period. A parabolic relationship was revealed between the initial density difference of the Layers and the mixing time. Morphology of large low-shear-velocity provinces and results from seismic tomography and normal mode data suggest a value of Beff ≥ 1 for the mantle.
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Effective buoyancy ratio: a new parameter to characterize thermo-chemical mixing in the Earth's mantle
2014Co-Authors: Attila Galsa, Mátyás Herein, L. Lenkey, M. P. Farkas, G. TallerAbstract:Abstract. Numerical modeling has been carried out in a 2-D cylindrical shell domain to quantify the evolution of a primordial Dense Layer around the core mantle boundary. Effective buoyancy ratio, Beff was introduced to characterize the evolution of the two-Layer thermo-chemical convection in the Earth's mantle. Beff decreases with time due to (1) warming the compositionally Dense Layer, (2) cooling the overlying mantle, (3) eroding the Dense Layer by thermal convection in the overlying mantle, and (4) diluting the Dense Layer by inner convection. When Beff reaches the instability point, Beff = 1, effective thermo-chemical convection starts, and the mantle will be mixed (Beff = 0) during a short time. A parabolic relation was revealed between the initial density difference of the Layers and the mixing time. Morphology of large low shear velocity provinces as well as results from seismic tomography and normal mode data suggest a value of Beff ≥ 1 for the mantle.