Photoelectrochemistry
n-GaAs Band-Edge Repositioning by Modification with Metalloporphyrin/Polysiloxane Matrices
Wed, 2013-04-24 13:01 — Samar Al ShakhshirTetra(-4-pyridyl)porphyrinatomanganese(III)sulfate, MnP, (in the forms of MnIII and MnII mixture), was embedded into a polysiloxane polymer matrix and attached to the surfaces of n-GaAs wafers. The n-GaAs=polymer=MnP system was annealed under nitrogen and used for photoelectrochemical study in water=LiClO4=Fe(CN)3 6 = Fe(CN)4 6 system. The results indicated a positive shift in the value of the flat-band potential of the semiconductor due to MnP. This was manifested by shifting the values of the dark-current onset potential and the photo-current open-circuit potential towards more positive values. These findings are potentially valuable in future applications of solar energy in hydrogen and oxygen production from water.
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TwitterMetalloporphyrin/Polysiloxane Modified N-Gaas Surfaces: Effect on Photoelectrochemical Efficiency and Surface Stability
Wed, 2013-04-24 12:25 — Samar Al ShakhshirTetra(-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.
Metalloporphyrin/Polysiloxane Modified N-Gaas Surfaces: Effect on Photoelectrochemical Efficiency and Surface Stability
Wed, 2011-03-09 10:04 — Hikmat S. Hilal, D.Sc.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.
n-GaAs Band-Edge Repositioning by Modification with Metalloporphyrin/Polysiloxane Matrices
Wed, 2010-04-21 14:32 — Hikmat S. Hilal, D.Sc.Tetra(-4-pyridyl)porphyrinatomanganese(III)sulfate, MnP, (in the forms of MnIII and MnII mixture), was embedded into a polysiloxane polymer matrix and attached to the surfaces of n-GaAs wafers. The n-GaAs=polymer=MnP system was annealed under nitrogen and used for photoelectrochemical study in water=LiClO4=Fe(CN)3 6 = Fe(CN)4 6 system. The results indicated a positive shift in the value of the flat-band potential of the semiconductor due to MnP. This was manifested by shifting the values of the dark-current onset potential and the photo-current open-circuit potential towards more positive values. These findings are potentially valuable in future applications of solar energy in hydrogen and oxygen production from water.
