Porphyrins occur in a number of important biomolecules and are also synthetically made for use as probe component of chemical and biological sensors. The performance of dye sensitized solar cells with two different po...Porphyrins occur in a number of important biomolecules and are also synthetically made for use as probe component of chemical and biological sensors. The performance of dye sensitized solar cells with two different porphyrin dyes was investigated in this work. The two porphyrin complexes comprised of a metal-free 5, 10, 15, 20-meso-tetrakis-(9H-2-fluorene-yl) porphyrin (H2TFP) and its Zinc complex (ZnTFP). UV-Vis, Fluorescence, and Fourier transformed infrared measurements of the two dyes were carried out to evaluate their absorption, emission and binding characteristics. Both dyes absorbed light in the UV-visible region all the way to the near-infrared. The surface morphology and elemental analysis of the porphyrin dye sensitized photoanodes were determined using Field Emission Scanning Electron Microscopy Imaging and Transmission Electron Microscopy Imaging. Cyclic voltammetry studies, current-voltage characteristics and the electrochemical impedance spectroscopic studies were also carried out. Solar-to-electric energy efficiency of H2TFP dye sensitized solar cell was higher (0.11%) than that of the zinc complex (0.08%). Thus the metal free porphyrin generated more power than the zinc complex under similar conditions. The impedance measurement also displayed less overall resistance for the free porphyrin (50 Ω) compared with the zinc complex (130 Ω). The LUMO levels of H2TFP and ZnTFP sensitizers were -0.87 eV and -0.77 eV respectively. Both of these LUMO values are higher than the lower bound level of the conduction band of TiO2 (-4.0 eV), ensuring the efficient injection of an electron from the excited porphyrin dye to the conduction band of the titanium dioxide.展开更多
Dye sensitized solar cell represents a promising method for the conversion of solar energy to electric energy. In the present work free N,N'-bis(salicyli-dene)ethylenediamine and its copper (II) complex were synth...Dye sensitized solar cell represents a promising method for the conversion of solar energy to electric energy. In the present work free N,N'-bis(salicyli-dene)ethylenediamine and its copper (II) complex were synthesized, characterized, and investigated for use as dye sensitizers in the fabrication of dye sensitized solar cells. The dyes were characterized using UV-Vis, Steady State Florescence, and Fluorescence Lifetime, Thermogravimetric Analysis, Differential Scanning Calorimetry, and Cyclic Voltammetry. The thermogravimetric analyses of the ligand and the ligand Copper complex demonstrate the stabilizing effect of the copper ion on the ligand complex. Additionally, the copper ion is shown to stabilize the structure, as evidenced by the 150oC increase in the extrapolated onset temperature of the decomposition event. The ligand copper complex is further stabilized by the presence of the copper, which is determined by the 6.34% residue that remained at the end of the thermogravimetric analysis, compared with 0% residue when applying the same condition for the ligand without copper. The current-voltage characteristics of the cells and the electrochemical impedance were determined. The photovoltaic performance of the solar cell devices fabricated using N,N'-bis(salicylidene) ethylenediamine dye was found to be slightly better than those produced from the copper complex. The solar to electric power efficiency of the ligand-based dye sensitized solar cell was 0.14% and that of the copper complex was found to 0.12%. Although the difference in the cell efficiency is quite small, it is obvious that the insertion of Copper into the ligand did not enhance the performance of the solar cells. The photocurrent-photovoltage results are consistent with the absorption spectra that showed a more prominent band for the ligand. The free hydroxyl groups, present in the ligand but absent from the copper complex owing to their coordination with the copper metal, could be responsible for the difference in the performance of the devices. The hydroxyl groups get attached to the TiO2 and facilitate the transfer of electrons.展开更多
文摘Porphyrins occur in a number of important biomolecules and are also synthetically made for use as probe component of chemical and biological sensors. The performance of dye sensitized solar cells with two different porphyrin dyes was investigated in this work. The two porphyrin complexes comprised of a metal-free 5, 10, 15, 20-meso-tetrakis-(9H-2-fluorene-yl) porphyrin (H2TFP) and its Zinc complex (ZnTFP). UV-Vis, Fluorescence, and Fourier transformed infrared measurements of the two dyes were carried out to evaluate their absorption, emission and binding characteristics. Both dyes absorbed light in the UV-visible region all the way to the near-infrared. The surface morphology and elemental analysis of the porphyrin dye sensitized photoanodes were determined using Field Emission Scanning Electron Microscopy Imaging and Transmission Electron Microscopy Imaging. Cyclic voltammetry studies, current-voltage characteristics and the electrochemical impedance spectroscopic studies were also carried out. Solar-to-electric energy efficiency of H2TFP dye sensitized solar cell was higher (0.11%) than that of the zinc complex (0.08%). Thus the metal free porphyrin generated more power than the zinc complex under similar conditions. The impedance measurement also displayed less overall resistance for the free porphyrin (50 Ω) compared with the zinc complex (130 Ω). The LUMO levels of H2TFP and ZnTFP sensitizers were -0.87 eV and -0.77 eV respectively. Both of these LUMO values are higher than the lower bound level of the conduction band of TiO2 (-4.0 eV), ensuring the efficient injection of an electron from the excited porphyrin dye to the conduction band of the titanium dioxide.
文摘Dye sensitized solar cell represents a promising method for the conversion of solar energy to electric energy. In the present work free N,N'-bis(salicyli-dene)ethylenediamine and its copper (II) complex were synthesized, characterized, and investigated for use as dye sensitizers in the fabrication of dye sensitized solar cells. The dyes were characterized using UV-Vis, Steady State Florescence, and Fluorescence Lifetime, Thermogravimetric Analysis, Differential Scanning Calorimetry, and Cyclic Voltammetry. The thermogravimetric analyses of the ligand and the ligand Copper complex demonstrate the stabilizing effect of the copper ion on the ligand complex. Additionally, the copper ion is shown to stabilize the structure, as evidenced by the 150oC increase in the extrapolated onset temperature of the decomposition event. The ligand copper complex is further stabilized by the presence of the copper, which is determined by the 6.34% residue that remained at the end of the thermogravimetric analysis, compared with 0% residue when applying the same condition for the ligand without copper. The current-voltage characteristics of the cells and the electrochemical impedance were determined. The photovoltaic performance of the solar cell devices fabricated using N,N'-bis(salicylidene) ethylenediamine dye was found to be slightly better than those produced from the copper complex. The solar to electric power efficiency of the ligand-based dye sensitized solar cell was 0.14% and that of the copper complex was found to 0.12%. Although the difference in the cell efficiency is quite small, it is obvious that the insertion of Copper into the ligand did not enhance the performance of the solar cells. The photocurrent-photovoltage results are consistent with the absorption spectra that showed a more prominent band for the ligand. The free hydroxyl groups, present in the ligand but absent from the copper complex owing to their coordination with the copper metal, could be responsible for the difference in the performance of the devices. The hydroxyl groups get attached to the TiO2 and facilitate the transfer of electrons.
