The dyes extracted from pomegranate and berry fruits were successfully used in the fabrication of natural dye sensitized solar cells (NDSSC). The morphology, porosity, surface roughness, thickness, absorption and emission characteristics of the pomegranate dye sensitized photo-anode were studied using various analytical techniques including FESEM, EDS, TEM, AFM, FTIR, Raman, Fluorescence and Absorption Spectroscopy. Pomegranate dye extract has been shown to contain anthocyanin which is an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity. The solar cell’s photovoltic performance in terms of efficiency, voltage, and current was tested with a standard illumination of air-mass 1.5 global (AM 1.5 G) having an irradiance of 100 mW/cm2. After optimization of the photo-anode and counter electrode, a photoelectric conversion efficiency (η) of 2%, an open-circuit voltage (Voc) of 0.39 mV, and a short-circuit current density (Isc) of 12.2 mA/cm2 were obtained. Impedance determination showed a relatively low charge-transfer resistance (17.44 Ω) and a long lifetime, signifying a reduction in recombination losses. The relatively enhanced efficiency is attributable in part to the use of a highly concentrated pomegranate dye, graphite counter electrode and TiCl4 treatment of the photo-anode.

The branching ratios for the reaction N+CH3 →Products, have been determined in a discharge-flow system coupled with mass-spectrometric detection of both reactants and products. The major products are H2 CN+H, with about 10% of the reaction proceeding to give HCN+H2 . Experiments carried out on the reaction of N atoms with the deuterated methyl radical showed that the branching ratio for formation of D2 CN+D is about 0.9 and for DCN+D2 formation about 0.1 independent of T from 200 to 363 K. The results are consistent with the energetics and orbital symmetry properties of the reactant and product molecules. Implications for the atmosphere of Titan are discussed.

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the charge type of product ions, ZaZb.Beside the importance of back electron transfer to the excited-state reactants, the electrostatic effects within product ion pairs (wp) reflect on the dissociation process to free product ions, **34 (eq 18), as well. *34 and the equilibrium constant, Ku = *34/*43, RuCN+/-...Q-/+ RuCN+/-+ Q-/+ (18a) *43 Ru(bpy)3+/3+"'Q+/-^=2 Ru(bpy)3+/3+ + Q+/~(18b) *43for the quenching reactions in eq 11-14 are included in Table IV.38 Reductive quenching of *Ru(bpy)32+, producing electrostatically repulsive ions favors dissociation to free product ions (case I; AH* > 0). On the other hand, free product ions are likely to form ion pairs again in the case of the reactions in eq [11][12][13] (K34 = 0.094-0.0059 M-1), and consequently, the fate of product ions will be back electron transfer to the excited state (case II; AH* < 0) and/or to the ground state. However, if back electron transfer to the ground state (*b) is the major deactivation path, AH* should be positive (case I). Since *b is a spin-forbidden process as demonstrated by Ohno et al.,39 *b will contribute to *q to a lesser extent as compared with *32. Summary and Concluding RemarksIn a series of publications,1•2'9'33 we revealed the mechanisms of the redox quenching of several excited-state Ru(II) complexes by various organic electron donors and acceptors. Although the free energy relationships of *q are very similar to each other, the Conversion and Storage of Solar Energy (61040046).

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