Efficiency

Raqi Shubietah's picture

Enhancement of n-Gaas Characteristics by Combined Heating, Cooling Rate And Metalloporphyrin Modification Techniques

Journal Title, Volume, Page: 
Solid State Sciences Volume 6, Issue 1, Pages 139-146
Year of Publication: 
2004
Authors: 
Raqi Shubeita
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Current Affiliation: 
Department of Pharmacy, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Iyad Saadeddin
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Hikmat S.Hilal
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Wajdy M. Ateereh
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Taleb Al-Tel
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Guy Campet
ICMCB-CNRS, 87, av. du Dr. A. Schweitzer, 33608, Pessac cedex, France
Preferred Abstract (Original): 

Different modification techniques, namely, preheating, controlling the cooling rate and modification with tetra(-4-pyridyl)porphyrinatomanganese(III) have been used to enhance photoelectrochemical characteristics of n-GaAs electrodes in light-to-electricity conversions. Combination of such three techniques together yielded electrodes with better darkcurrent density vs potential plots and photocurrent density vs potential plots. Higher efficiency and stability were also observed for electrodes modified by such combined techniques.


Enhancement of n-GaAs characteristics by combined heating, cooling rate and metalloporphyrin modification techniques

iyad's picture

Enhancement of n-Gaas Characteristics by Combined Heating, Cooling Rate And Metalloporphyrin Modification Techniques

Journal Title, Volume, Page: 
Solid State Sciences Volume 6, Issue 1, January 2004, Pages 139-146
Year of Publication: 
2004
Authors: 
Iyad Saadeddin
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Current Affiliation: 
Department of Physics, Faculty of Science, An-Najah National University, Palestine
Hikmat S.Hilal
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Wajdy M. Ateereh
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Taleb Al-Tel
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Raqi Shubeita
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, Palestine
Guy Campet
ICMCB-CNRS, 87, av. du Dr. A. Schweitzer, 33608, Pessac cedex, France
Preferred Abstract (Original): 

Different modification techniques, namely, preheating, controlling the cooling rate and modification with tetra(-4-pyridyl)porphyrinatomanganese(III) have been used to enhance photoelectrochemical characteristics of n-GaAs electrodes in light-to-electricity conversions. Combination of such three techniques together yielded electrodes with better darkcurrent density vs potential plots and photocurrent density vs potential plots. Higher efficiency and stability were also observed for electrodes modified by such combined techniques.


Enhancement of n-GaAs characteristics by combined heating, cooling rate and metalloporphyrin modification techniques

2052's picture

Efficiency of Removal of Cadmium from Aqueous Solutions by Plant Leaves and the Effects of Interaction of Combinations of Leaves on Their Removal Efficiency

Journal Title, Volume, Page: 
Journal of Environmental Management Volume 87, Issue 3, May 2008, Pages 521–532
Year of Publication: 
2008
Authors: 
R. Salim
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
M. Al-Subu
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Current Affiliation: 
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
E. Dawod
Department of Chemistry, Faculty of Science, An-Najah National University, Nablus, Palestine
Preferred Abstract (Original): 

Removal of cadmium from aqueous solutions using 20 species of plant leaves and combinations of these leaves have been studied. Several factors affecting the removal efficiency have been studied. The most efficient types of plant leaves for the removal of cadmium are those of styrax, plum, pomegranate and walnut. The interaction effect of the combined leaf samples on the efficiency of removal of cadmium has been found to be additive in combinations involving styrax plant leaves but seems to be antagonistic in all other combinations. The optimum experimental conditions for removal of cadmium have been found to be at pH 4.1, using high concentrations of naturally dried plant leaves, using ground leaves and to remove cadmium from agitated aqueous solutions. The percentage of metal removed at an initial cadmium concentration of 10 mg/l by the most efficient types of leaves have been found to be 85% for styrax leaves, 85% for plum leaves, 80% for pomegranate leaves, 78% for walnut leaves and 77% for meddler leaves. The presence of foreign ions or complexing agents has been found to reduce the efficiency of removal of cadmium by plant leaves. About 80–85% of the cadmium in charged plant leaves has been released under the influence of changing the pH of the solution, addition of competing ions and the addition of EDTA. The results of removal of cadmium by plant leaves have been found to follow the Freundlich adsorption isotherm, first-order reaction with respect to cadmium and to have intra-pore diffusion as the rate-limiting step.

salshakshir@najah.edu's picture

Metalloporphyrin/Polysiloxane Modified N-Gaas Surfaces: Effect on Photoelectrochemical Efficiency and Surface Stability

Journal Title, Volume, Page: 
Journal of Electroanalytical Chemistry (2002) Volume: 527, Issue: 1-2, Pages: 47-55
Year of Publication: 
2002
Authors: 
Samar Shakhshir
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, Palestine
Current Affiliation: 
Department of Chemistry, An-Najah National University, Nablus, Palestine
Hikmat S. Hilal
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, Palestine
Moayyad Masoud
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, Palestine
Najeh Jisrawi
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, Palestine
Preferred Abstract (Original): 

Tetra(-4-pyridyl)porphyrinatomanganese(III)sulfate (as an MnIII+MnII ion mixture) was embedded into a polysiloxane polymer matrix and attached to the surfaces of the n-GaAs electrode. The n-GaAs/polymer/MnP system was annealed under nitrogen and used for a photoelectrochemical study in a water/LiClO4/Fe(CN)6 3 −/Fe(CN)6 4− system. The values of short-circuit currents, measured after minutes of illumination, were significantly enhanced by modification. The modified electrode surfaces were more stable to degradation, in the dark and under illumination, than the unmodified ones. Furthermore, the modified electrodes showed higher light-to-electricity conversion efficiency than the unmodified ones. The methodology described here is advantageous in the sense that the semiconductor electrode properties can be enhanced in more than one aspect at the same time.

2197's picture

Multiperturbation Approach to Potential Energy Surfaces for Polyatomic Molecules

Journal Title, Volume, Page: 
J. Chem. Phys. 102, 4919 (1995)
Year of Publication: 
1995
Authors: 
Donald H. Galvan
Instituto de Fisica de UNAM, Laboratorio de Ensenada, Apto. Postal 2681, Ensenada, Baja California 22800, Mexico
Moh’d Abu‐Jafar
Department of Physics and Molecular Science Program, Southern Illinois University at Carbondale, Carbondale, Illinois 62901‐4401
Current Affiliation: 
Department of Physics, Faculty of Sciences, An-Najah National University, Palestine
Frank C. Sanders
Department of Physics and Molecular Science Program, Southern Illinois University at Carbondale, Carbondale, Illinois 62901‐4401
Preferred Abstract (Original): 
In Z-dependent perturbation theory, the lowest-order wave functions for a polyatomic molecule are not only independent of the nuclear charges, but also of the total number of nuclear centers and electrons in the molecule. The complexity of the problem is then determined by the highest order retained in the calculation. Choosing the simplest possible unperturbed Hamiltonian, we describe an n-electron, m-center polyatomic molecule as n ‘‘hydrogenic’’ electrons on a single center perturbed by electron–electron and electron–nucleus Coulomb interactions. With this H0 , the first-order wave function for any polyatomic molecule will be a sum of products of hydrogenic orbitals with either two-electron, one-center or one-electron, two-center first-order wave functions. These first-order wave functions are obtained from calculations on He-like and H2 1-like systems. Similarly, the nth-order wave function decouples so that the most complex terms are just the nth-order wave functions of all the p-electron, q-center subsystems (p1q5n12) contained in the molecule. We illustrate applications of this method with some results, complete through third order in the energy, for H31-like molecules. These are compared with accurate variational results available in the literature. We conclude that, through this order, this perturbation approach is capable of yielding results comparable in accuracy to variational calculations of moderate complexity. The ease and efficiency with which such results can be obtained suggests that this method would be useful for generating detailed potential energy surfaces for polyatomic molecules. © 1995 American Institute of Physics.
Hikmat S. Hilal's picture

Enhancement of n-Gaas Characteristics by Combined Heating, Cooling Rate And Metalloporphyrin Modification Techniques

Journal Title, Volume, Page: 
Solid State Sciences Volume 6, Issue 1, January 2004, Pages 139-146
Year of Publication: 
2004
Authors: 
Hikmat S.Hilal
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Current Affiliation: 
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Wajdy M. Ateereh
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Taleb Al-Tel
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Raqi Shubeita
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Iyad Saadeddin
Faculty of Science, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Guy Campet
ICMCB-CNRS, 87, av. du Dr. A. Schweitzer, 33608, Pessac cedex, France
Preferred Abstract (Original): 

Different modification techniques, namely, preheating, controlling the cooling rate and modification with tetra(-4-pyridyl)porphyrinatomanganese(III) have been used to enhance photoelectrochemical characteristics of n-GaAs electrodes in light-to-electricity conversions. Combination of such three techniques together yielded electrodes with better darkcurrent density vs potential plots and photocurrent density vs potential plots. Higher efficiency and stability were also observed for electrodes modified by such combined techniques.


Enhancement of n-GaAs characteristics by combined heating, cooling rate and metalloporphyrin modification techniques

Hikmat S. Hilal's picture

Metalloporphyrin/Polysiloxane Modified N-Gaas Surfaces: Effect on Photoelectrochemical Efficiency and Surface Stability

Journal Title, Volume, Page: 
Journal of Electroanalytical Chemistry (2002) Volume: 527, Issue: 1-2, Pages: 47-55
Year of Publication: 
2002
Authors: 
Hikmat S. Hilal
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine
Current Affiliation: 
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine
Moayyad Masoud
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine
Samar Shakhshir
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine
Najeh Jisrawi
Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine
Preferred Abstract (Original): 

Tetra(-4-pyridyl)porphyrinatomanganese(III)sulfate (as an MnIII+MnII ion mixture) was embedded into a polysiloxane polymer matrix and attached to the surfaces of the n-GaAs electrode. The n-GaAs/polymer/MnP system was annealed under nitrogen and used for a photoelectrochemical study in a water/LiClO4/Fe(CN)6 3 −/Fe(CN)6 4− system. The values of short-circuit currents, measured after minutes of illumination, were significantly enhanced by modification. The modified electrode surfaces were more stable to degradation, in the dark and under illumination, than the unmodified ones. Furthermore, the modified electrodes showed higher light-to-electricity conversion efficiency than the unmodified ones. The methodology described here is advantageous in the sense that the semiconductor electrode properties can be enhanced in more than one aspect at the same time.

iyad's picture

Effect of Cooling Rate of Pre-Annealed Cds Thin Film Electrodes Prepared by Chemical Bath Deposition: Enhancement of Photoelectrochemical Characteristics

Journal Title, Volume, Page: 
Electrochimica Acta 54 (2009) 3433–3440
Year of Publication: 
2009
Authors: 
Iyad Saadeddin
Department of Physics, An-Najah N. University, PO Box 7, Nablus, Palestine
Current Affiliation: 
Department of Physics, An-Najah N. University, PO Box 7, Nablus, Palestine
Hikmat S. Hilal
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, Palestine
Rania M.A. Ismail
Clean Energy and Conservation Energy Study Program, An-Najah N. University, PO Box 7, Nablus, Palestine
Amer El-Hamouz
Department of Chemical Engineering, An-Najah N. University, PO Box 7, Nablus, Palestine
Ahed Zyoud
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, Palestine
Preferred Abstract (Original): 

Thin films of CdS, deposited by chemical bath deposition (CBD) onto films of fluorine-doped tin oxide/glass (glass/FTO) substrates were prepared and investigated for photoelectrochemical conversion (PEC) of light into electricity. Knowing the hazardous nature of CdS, the focal theme of this work was to modify the electrodes by simple economic ways to maximize their conversion efficiency and minimize their degradation under PEC conditions. This was to avoid leaching out of hazardous Cd2+ ions. Different parameters have been investigated for this purpose. Multi-deposition preparation, redox couple, and electrode etching affected electrode PEC characteristics. Consistent with earlier literature, annealing the electrode enhanced its conversion efficiency and stability. On the other hand, effect of cooling rate of pre-annealed CdS electrodes, prepared by CBD, on their PEC characteristics has been investigated here for the first time. Controlling the cooling rate was one major factor that affected CdS surface morphology, conversion efficiency and stability under PEC conditions. The major recommendation coming out here is that PEC characteristics of CdS thin film electrodes can be significantly enhanced by pre-annealing the electrode at ∼250 °C followed by its slow cooling.

Full Text

elhamouz's picture

Effect of cooling rate of pre-annealed CdS thin film electrodes prepared by chemical bath deposition: Enhancement of photoelectrochemical characteristics

Journal Title, Volume, Page: 
Electrochimica Acta 54 (2009) 3433–3440
Year of Publication: 
2009
Authors: 
Hikmat S. Hilal
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Rania M.A. Ismail
Clean Energy and Conservation Energy Study Program, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Amer El-Hamouz
Department of Chemical Engineering, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Current Affiliation: 
Department of Chemical Engineering, An-Najah National University, Nablus, Palestine
Ahed Zyoud
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Iyad Saadeddin
Department of Physics, An-Najah N. University, PO Box 7, Nablus, West Bank, Palestine
Preferred Abstract (Original): 
Thin films of CdS, deposited by chemical bath deposition (CBD) onto films of fluorine-doped tin oxide/glass (glass/FTO) substrates were prepared and investigated for photoelectrochemical conversion (PEC) of light into electricity. Knowing the hazardous nature of CdS, the focal theme of this work was to modify the electrodes by simple economic ways to maximize their conversion efficiency and minimize their degradation under PEC conditions. This was to avoid leaching out of hazardous Cd2+ ions. Different parameters have been investigated for this purpose. Multi-deposition preparation, redox couple, and electrode etching affected electrode PEC characteristics. Consistent with earlier literature, annealing the electrode enhanced its conversion efficiency and stability. On the other hand, effect of cooling rate of pre-annealed CdS electrodes, prepared by CBD, on their PEC characteristics has been investigated here for the first time. Controlling the cooling rate was one major factor that affected CdS surface morphology, conversion efficiency and stability under PEC conditions. The major recommendation coming out here is that PEC characteristics of CdS thin film electrodes can be significantly enhanced by pre-annealing the electrode at ∼250 °C followed by its slow cooling.
ahedzyoud's picture

Effect Of Cooling Rate of Pre-Annealed Cds Thin Film Electrodes Prepared by Chemical Bath Deposition: Enhancement of Photoelectrochemical Characteristics

Journal Title, Volume, Page: 
Electrochimica Acta, vol. 54, no. 12, pp. 3433-3440
Year of Publication: 
2009
Authors: 
Ahed Zyoud
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, Palestine
Current Affiliation: 
Department of Chemistry, An-Najah N. University, PO Box 7, Nablus, Palestine
Hikmat S. Hilal
Department of Chemisry, An-Najah N. University, PO Box 7, Nablus, Palestine
Ismail Rania M. A.
Clean Energy And Conservation Energy Study Program, An-Najah N. University, PO Box 7, Nablus, Palestine
Amer EL-Hamouz
Department of Chemical Engineering, An-Najah N. University, PO Box 7, Nablus, Palestine
Iyad Saadeddin
Department of Physics, An-Najah N. University, PO Box 7, Nablus, Palestine
Preferred Abstract (Original): 

Thin films of CdS, deposited by chemical bath deposition (CBD) onto films of fluorine-doped tin oxide/glass (glass/FTO) substrates were prepared and investigated for photoelectrochemical conversion (PEC) of light into electricity. Knowing the hazardous nature of CdS, the focal theme of this work was to modify the electrodes by simple economic ways to maximize their conversion efficiency and minimize their degradation under PEC conditions. This was to avoid leaching out of hazardous Cd2+ ions. Different parameters have been investigated for this purpose. Multi-deposition preparation, redox couple, and electrode etching affected electrode PEC characteristics. Consistent with earlier literature, annealing the electrode enhanced its conversion efficiency and stability. On the other hand, effect of cooling rate of pre-annealed CdS electrodes, prepared by CBD, on their PEC characteristics has been investigated here for the first time. Controlling the cooling rate was one major factor that affected CdS surface morphology, conversion efficiency and stability under PEC conditions. The major recommendation coming out here is that PEC characteristics of CdS thin film electrodes can be significantly enhanced by pre-annealing the electrode at ∼250 °C followed by its slow cooling.

Full Text

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