• M Raghavender

      Articles written in Journal of Chemical Sciences

    • Functionalized zinc porphyrin as light harvester in dye sensitized solar cells

      L Giribabu Ch Vijay Kumar M Raghavender K Somaiah P Yella Reddy P Venkateswara Rao

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      A new photosensitizer having two rhodanine acetic acid groups at meso-positions of a zinc porphyrin [meso-Rhod-Zn-Rhod] has been synthesized and characterized by UV-Visible, 1H NMR, MALDI-MS, fluorescence spectroscopies and cyclic voltammetry. The new photosensitizer was tested in dye-sensitized solar cells with three different liquid redox electrolytes and compared its efficiency (𝜂) with dyad. Both dyad and triad were also tested in DSSC using a polymer gel redox electrolyte and observed low efficiency because of small short circuiting current i.e. ISc though the IPCE is significantly high. The probable reason for the low efficiency small ISc has been attributed to the internal resistance of the cell.

    • High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells

      M Chandrasekharam Ch Srinivasarao T Suresh M Anil Reddy M Raghavender G Rajkumar M Srinivasu P Yella Reddy

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      Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyridyl) (4,4'-dicarboxy-2,2'-bipyridyl) (NCS2) (H112) was synthesized and characterized by 1H-NMR, MASS, Spectrofluorometer and UV-Vis spectroscopes. The photo-voltaic performance of the sensitizer was evaluated in Dye Sensitized Solar Cell (DSSC) under irradiation of AM 1.5 G solar light and the photovoltaic characteristics were compared with those of reference cells of HRS1 and N719 fabricated under comparable conditions. Compared to N719, H112 sensitizer showed enhanced molar extinction coefficient and relatively better monochromatic incident photon-to-current conversion efficiency (IPCE) across the spectral range of 400 to 800 nm with solar energy-to-electrical conversion efficiency (𝜂) of 2.43% [open circuit photovoltage (VOC) = 0.631V, short-circuit photocurrent density (JSC) = 8.96 mA/cm2, fill factor (ff) = 0.430], while 𝜂 values of 2.51% (VOC = 0.651V, JSC = 9.41 mA/cm2, ff = 0.410) and 2.74% (VOC = 0.705 V, JSC = 8.62 mA/cm2, ff = 0.455) were obtained for HRS1 and N719 sensitized solar cells respectively. The introduction of 4,$4'$-bis(4-tert-butylstyryl) moieties on one of the bipyridine moieties of N719 complex shows higher light absorption abilities, IPCE and JSC.

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