Suresh Thogiti | Yeungnam University (original) (raw)

Papers by Suresh Thogiti

Research paper thumbnail of Effect of Iodine Concentration in the Quasi-Solid State Electrolyte on the Photovoltaic Performance of Dye-Sensitized Solar Cells

Molecular Crystals and Liquid Crystals, 2015

Research paper thumbnail of Comparison of triphenylamine based single and double branched organic dyes in dye-sensitized solar cells

Electronic Materials Letters, 2015

Research paper thumbnail of Influence of Thermal and Solvent Annealing on the Morphology and Photovoltaic Performance of the Solution Processed, D-A-D type Small Molecules-Based Bulk Heterojunction Solar Cells

Research paper thumbnail of Julolidine—Based Organic Dyes with Neutral and Anion Anchoring Groups for Dye-Sensitized Solar Cells

Journal of Nanoscience and Nanotechnology, 2015

Two simple organic dyes (J1 and J2) containing julolidine as the electron donor were synthesized.... more Two simple organic dyes (J1 and J2) containing julolidine as the electron donor were synthesized. The simple structure of julolidine attached to the cyanoacetic acid group formed two compounds (anion and neutral forms of E-CCVJ), which showed two different efficiencies when applied to dye-sensitized solar cells (DSSCs). Overall conversion efficiencies of 0.91% and 1.21% were obtained for DSSCs based on the cyanoacetic acid (J1) and cyanoacetate (J2) derived dyes, respectively. Compared to the cyanoacetic acid terminated dye, the current density, open circuit voltage and conversion efficiency of the solar cells based on cyanoacetate dye were increased by approximately 24%, 8% and 32%, respectively. The electrochemical impedance analysis showed that the better charge transfer of TiO2 (e-) and electron lifetime (τ(e)) for J2 dye as compared with J1. The power conversion efficiency was found to be quite sensitive to small structural changes to the anchoring moiety.

Research paper thumbnail of Mass transport effect on the photovoltaic performance of ruthenium-based quasi-solid dye sensitized solar cells using cobalt based redox couples

Research paper thumbnail of A comparison of the optical and photovoltaic properties of novel double branched organic dyes in dye sensitized solar cells

Research paper thumbnail of High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells

Journal of Chemical Sciences, 2011

Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyri... more Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyridyl) (4,4'-dicarboxy-2,2'-bipyridyl) (NCS 2 ) (H112) was synthesized and characterized by 1 H-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 (V OC ) = 0·631 V, short-circuit photocurrent density (J SC ) = 8·96 mA/cm 2 , fill factor (ff) = 0·430], while η values of 2·51% (V OC = 0·651 V, J SC = 9·41mA/cm 2 , ff = 0·410) and 2·74% (V OC = 0·705 V, J SC = 8·62 mA/cm 2 , 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 J SC .

Research paper thumbnail of A molecularly engineered fluorene-substituted Ru-complex for efficient mesoscopic dye-sensitized solar cells

Advances in Natural Sciences: Nanoscience and Nanotechnology, 2011

A new high molar extinction coefficient ruthenium(II) bipyridyl complex 'cis-Ru(L1)(2,2 -bipyridi... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex 'cis-Ru(L1)(2,2 -bipyridine-4,4 -dicarboxylic acid) (NCS) 2 , BDF', where L1 = 4,4-bis(9,9-dibutyl-9H-fluorene-2-yl)-[2,2] bipyridine, has been synthesized and characterized by Fourier transform infrared (FTIR), hydrogen nuclear magnetic resonance ( 1 H-NMR) and electrospray ionization mass (ESI-MASS) spectroscopes. The dye, upon anchoring onto mesoporous nano-crystalline TiO 2 solar cells, exhibited a broader photocurrent action spectrum, with a solar-to-electric energy conversion efficiency (η) of 6.58% (J SC = 14.66 mA cm −2 , V OC = 640 mV, fill factor = 0.71) under sunlight at air mass (AM) 1.5, larger than the reference Z907 sensitized solar cell fabricated under similar conditions, which exhibited an η-value of 4.65% (J SC = 11.52 mA cm −2 , V OC = 566 mV, fill factor = 0.72). Absorption measurements and time-dependent density functional theory (TDDFT) calculations show that the increased conjugation length by introducing 9,9-dibutyl-9H-fluorene moiety relatively enhances the spectral response of the ancillary ligand and the corresponding BDF complex. The calculated dipole moments for BDF and Z907 are 17.71 and 16.34 Debye, respectively. The first three highest occupied molecular orbitals (HOMOs) of BDF have a t 2g character, as observed in Z907, while HOMO-4 and HOMO-5 have considerable sizable mixing from Ru-NCS with π-orbitals of L1.

Research paper thumbnail of Highly conjugated electron rich thiophene antennas on phenothiazine and phenoxazine-based sensitizers for dye sensitized solar cells

Synthetic Metals, 2014

Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiop... more Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiophene derivatives as antennas and cyanoacrylic acid as acceptor, bridged by phenothiazine or phenoxazine were designed and synthesized for dye-sensitized solar cells applications. They were fully characterized with their photophysical, electrochemical properties, density functional theory (DFT), time dependent density DFT (TDDFT) and the light-harvesting properties of the new sensitizers were evaluated with nanocrystalline TiO 2 -based devices. Among the four diheteroanthracene based dyes, phenoxazine (CSORG7 and CSORG9) based devices afforded the best photovoltaic performance (Á) of 6% under standard AM 1.5G solar irradiation, whereas, N719 showed (Á) 6.4% under the similar fabrication and evolution conditions.

Research paper thumbnail of Novel 4′-functionalized 4,4′′-dicarboxyterpyridine ligands for ruthenium complexes: near-IR sensitization in dye sensitized solar cells

Dalton Trans., 2014

Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the blac... more Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the black dye (N749), have been evaluated as sensitizers for dye sensitized solar cells (DSSCs). The modification is carried out by attaching selected chromophores, with varying electron donating strength, covalently to the central ring of the ligand. The complexes, compared to the parent dye, show red shifted absorption covering visible and near IR regions and higher molar extinction coefficients. We report in this work synthesis of a series of these ruthenium complexes with chromophores such as tert-butyl phenyl, triphenylamine, bithiophene, phenoxazine and phenothiazine. Detailed experimental characterization using optical, electrochemical and photovoltaic techniques has been carried out and complemented by density functional theory studies. The fill factors (ff ) obtained for these dyes are larger than those of the parent black dye. In spite of these superior properties, the dyes show only moderate to good power conversion efficiencies. The possible reasons for this have been investigated and discussed. † Electronic supplementary information (ESI) available. See

Research paper thumbnail of Phenothiazine conjugated bipyridine as ancillary ligand in Ru(II)-complexes for application in dye sensitized solar cell

Synthetic Metals, 2011

A new high molar extinction coefficient ruthenium(II)-bipyridine complex "cis-Ru(4,4 -bis((E)-2-(... more A new high molar extinction coefficient ruthenium(II)-bipyridine complex "cis-Ru(4,4 -bis((E)-2-(10-decyl-10H-phenothiazin-3-yl)vinyl)-2,2 -bipyridine)(4,4 -dicarboxylic acid-2,2 -bipyridine)(NCS) 2 PTZ1 was synthesized through conjugation of phenothiazine unit with bipyridine and characterized by FT-IR, 1 H-NMR and ESI-MASS spectroscopes. Absorption measurements and time dependent-density functional theory (TD-DFT) calculations show increased spectral response for the ancillary ligand and the corresponding complex. The dye upon anchoring onto mesoporous nanocrystalline TiO 2 solar cells exhibited solar-to-electric energy conversion efficiency (Á) of 3.77% short-circuit photocurrent density (J SC ) = 7.79 mA/cm 2 , open-circuit voltage (V OC ) = 640 mV, fill factor = 0.750) under air mass 1.5 sunlight, the reference Z907 and HRS1sensitized solar cells, fabricated and evaluated under identical conditions exhibited Á-value of 7.02% (J SC = 15.25 mA/cm 2 , V OC = 650 mV, fill factor = 0.705) and 3.05% (J SC = 8.20 mA/cm 2 , V OC = 610 mV, fill factor = 0.620) respectively. The lower film absorption of PTZ1on TiO 2 surface could be probably due to larger molecular diameter and planarity of phenothiazine prone to aggregate in solution as well as on TiO 2 surface. The DFT calculations show that the first three HOMOs of PTZ1 have t2g character as observed in case of Z907, while HOMO-4 and HOMO-5 have -orbitals with major component on phenothiazine moieties of L1.

Research paper thumbnail of Novel ruthenium sensitizer with multiple butadiene equivalent thienyls as conjugation on ancillary ligand for dye-sensitized solar cells

Organic Electronics, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Research paper thumbnail of Carbazole based A-π-D-π-A dyes with double electron acceptor for dye-sensitized solar cell

Organic Electronics, 2014

and sharing with colleagues.

Research paper thumbnail of Functionalized phenyl bipyridine ancillary ligand as double recombination inhibitor in ruthenium complex for dye solar cells

Dyes and Pigments, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Research paper thumbnail of Functionalized styryl bipyridine as a superior chelate for a ruthenium sensitizer in dye sensitized solar cells

Dalton Transactions, 2012

The new sensitizer 119 has been synthesized and the solar cell constructed with 0.25 cm(2) active... more The new sensitizer 119 has been synthesized and the solar cell constructed with 0.25 cm(2) active area photoelectrode in combination with an electrolyte composed of 0.6 M dimethylpropyl-imidazolium iodide (DMPII), 0.05 M I(2), 0.5 M TBP and 0.1 M LiI in acetonitrile achieved a solar to electric energy conversion efficiency (η) of 8.36% under Air Mass (AM) 1.5 sunlight, while the reference 719 sensitized solar cell exhibited η-value of 7.2%.

Research paper thumbnail of Substitution of Ethynyl-Thiophene Chromophores on Ruthenium Sensitizers: Influence on Thermal and Photovoltaic Performance of Dye-Sensitized Solar Cells

Advances in OptoElectronics, 2012

A new high molar extinction coefficient ruthenium(II) bipyridyl complex, "Ru(2,2-bipyridine-4,4 -... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex, "Ru(2,2-bipyridine-4,4 -dicarboxylic acid)(4,4 -bis((3hexylthiophen-2-yl)ethynyl)-2,2 -bipyridine)(NCS) 2 (N(C 4 H 9 ) 4 ), MC101" was synthesized and fully characterized by 1 H-NMR, ESI-MASS, FT-IR, UV-Vis., and fluorescence spectroscopes. The dye showed relatively high molar extinction coefficient of 25.0 × 10 3 M −1 cm −1 at λ maximum of 544 nm, while the reference C101 has shown 15.8 × 10 3 M −1 cm −1 at λ maximum 528 nm. The monochromatic incident photon-to-collected electron conversion efficiency of 44.1% was obtained for MC101 over the entire visible range, while the C101 sensitized solar cell fabricated and evaluated under identical conditions exhibited 40.1%. The DSSCs fabricated with 0.54 cm 2 active area TiO 2 electrodes and high efficient electrolyte (E01), from the sensitizers MC101 and C101 exhibited energy conversion efficiencies of 3.25% (short-circuit current density (J SC ) = 7.32 mA/cm 2 , V OC = 610 mV, ff = 0.725) and 2.94% (J SC = 6.60 mA/cm 2 ; V OC = 630 mV; ff = 0.709), respectively, under air mass of 1.5 sunlight.

Research paper thumbnail of High Molar Extinction Coefficient Ru(II)-Mixed Ligand Polypyridyl Complexes for Dye Sensitized Solar Cell Application

Advances in OptoElectronics, 2011

... Malapaka Chandrasekharam, 1 Ganugula Rajkumar, 2 Chikkam Srinivasa Rao, 1 Thogiti Suresh, 1 Y... more ... Malapaka Chandrasekharam, 1 Ganugula Rajkumar, 2 Chikkam Srinivasa Rao, 1 Thogiti Suresh, 1 Yarasi Soujanya, 3 and Paidi Yella Reddy 2. ... mm thickness, Libbey-Owens-Ford Industries) with TiCl 4 and further with a drop of H 2 PtCl 6 solution (2 mg of Pt in 1 mL of ethanol ...

Research paper thumbnail of Substitution of Carbazole Modified Fluorenes as π-Extension in Ru(II) Complex-Influence on Performance of Dye-Sensitized Solar Cells

Advances in OptoElectronics, 2011

A new high molar extinction coefficient ruthenium(II) bipyridyl complex "cis-Ru(4,4 -bis(9,9-dibu... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex "cis-Ru(4,4 -bis(9,9-dibutyl-7-(3,6-di-tert-butyl-9Hcarbazol-9-yl)-9H-fluoren-2-yl)-2,2 -bipyridine)(2,2 -bipyridine-4,4 -dicarboxylic acid)(NCS) 2 , BPFC" has been synthesized and characterized by FT-IR, 1 H-NMR, and ESI-MASS spectroscopes. The sensitizer showed molar extinction coefficient of 18.5 × 10 3 M −1 cm −1 , larger as compared to the reference N719, which showed 14.4 × 10 3 M −1 cm −1 . The test cells fabricated using BPFC sensitizer employing high performance volatile electrolyte, (E01) containing 0.05 M I 2 , 0.1 M LiI, 0.6 M 1,2-dimethyl-3-n-propylimidazolium iodide, 0.5 M 4-tert-butylpyridine in acetonitrile solvent, exhibited solar-to-electric energy conversion efficiency (η) of 4.65% (short-circuit current density (J SC ) = 11.52 mA/cm 2 , open-circuit voltage (V OC ) = 566 mV, fill factor = 0.72) under Air Mass 1.5 sunlight, lower as compared to the reference N719 sensitized solar cell, fabricated under similar conditions, which exhibited η-value of 6.5% (J SC = 14.3 mA/cm 2 , V OC = 640 mV, fill factor = 0.71). UV-Vis measurements conducted on TiO 2 films showed decreased film absorption ratios for BPFC as compared to those of reference N719. Staining TiO 2 electrodes immediately after sonication of dye solutions enhanced film absorption ratios of BPFC relative to those of N719. Timedependent density functional theory (TD-DFT) calculations show higher oscillation strengths for 4,4 -bis(9,9-dibutyl-7-(3,6di-tert-butyl-9H-carbazol-9-yl)-9H-fluoren-2-yl)-2,2 -bipyridine relative to 2,2 -bipyridine-4,4 -dicarboxylic acid and increased spectral response for the corresponding BPFC complex.

Research paper thumbnail of Effect of Iodine Concentration in the Quasi-Solid State Electrolyte on the Photovoltaic Performance of Dye-Sensitized Solar Cells

Molecular Crystals and Liquid Crystals, 2015

Research paper thumbnail of Comparison of triphenylamine based single and double branched organic dyes in dye-sensitized solar cells

Electronic Materials Letters, 2015

Research paper thumbnail of Influence of Thermal and Solvent Annealing on the Morphology and Photovoltaic Performance of the Solution Processed, D-A-D type Small Molecules-Based Bulk Heterojunction Solar Cells

Research paper thumbnail of Julolidine—Based Organic Dyes with Neutral and Anion Anchoring Groups for Dye-Sensitized Solar Cells

Journal of Nanoscience and Nanotechnology, 2015

Two simple organic dyes (J1 and J2) containing julolidine as the electron donor were synthesized.... more Two simple organic dyes (J1 and J2) containing julolidine as the electron donor were synthesized. The simple structure of julolidine attached to the cyanoacetic acid group formed two compounds (anion and neutral forms of E-CCVJ), which showed two different efficiencies when applied to dye-sensitized solar cells (DSSCs). Overall conversion efficiencies of 0.91% and 1.21% were obtained for DSSCs based on the cyanoacetic acid (J1) and cyanoacetate (J2) derived dyes, respectively. Compared to the cyanoacetic acid terminated dye, the current density, open circuit voltage and conversion efficiency of the solar cells based on cyanoacetate dye were increased by approximately 24%, 8% and 32%, respectively. The electrochemical impedance analysis showed that the better charge transfer of TiO2 (e-) and electron lifetime (τ(e)) for J2 dye as compared with J1. The power conversion efficiency was found to be quite sensitive to small structural changes to the anchoring moiety.

Research paper thumbnail of Mass transport effect on the photovoltaic performance of ruthenium-based quasi-solid dye sensitized solar cells using cobalt based redox couples

Research paper thumbnail of A comparison of the optical and photovoltaic properties of novel double branched organic dyes in dye sensitized solar cells

Research paper thumbnail of High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells

Journal of Chemical Sciences, 2011

Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyri... more Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyridyl) (4,4'-dicarboxy-2,2'-bipyridyl) (NCS 2 ) (H112) was synthesized and characterized by 1 H-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 (V OC ) = 0·631 V, short-circuit photocurrent density (J SC ) = 8·96 mA/cm 2 , fill factor (ff) = 0·430], while η values of 2·51% (V OC = 0·651 V, J SC = 9·41mA/cm 2 , ff = 0·410) and 2·74% (V OC = 0·705 V, J SC = 8·62 mA/cm 2 , 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 J SC .

Research paper thumbnail of A molecularly engineered fluorene-substituted Ru-complex for efficient mesoscopic dye-sensitized solar cells

Advances in Natural Sciences: Nanoscience and Nanotechnology, 2011

A new high molar extinction coefficient ruthenium(II) bipyridyl complex 'cis-Ru(L1)(2,2 -bipyridi... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex 'cis-Ru(L1)(2,2 -bipyridine-4,4 -dicarboxylic acid) (NCS) 2 , BDF', where L1 = 4,4-bis(9,9-dibutyl-9H-fluorene-2-yl)-[2,2] bipyridine, has been synthesized and characterized by Fourier transform infrared (FTIR), hydrogen nuclear magnetic resonance ( 1 H-NMR) and electrospray ionization mass (ESI-MASS) spectroscopes. The dye, upon anchoring onto mesoporous nano-crystalline TiO 2 solar cells, exhibited a broader photocurrent action spectrum, with a solar-to-electric energy conversion efficiency (η) of 6.58% (J SC = 14.66 mA cm −2 , V OC = 640 mV, fill factor = 0.71) under sunlight at air mass (AM) 1.5, larger than the reference Z907 sensitized solar cell fabricated under similar conditions, which exhibited an η-value of 4.65% (J SC = 11.52 mA cm −2 , V OC = 566 mV, fill factor = 0.72). Absorption measurements and time-dependent density functional theory (TDDFT) calculations show that the increased conjugation length by introducing 9,9-dibutyl-9H-fluorene moiety relatively enhances the spectral response of the ancillary ligand and the corresponding BDF complex. The calculated dipole moments for BDF and Z907 are 17.71 and 16.34 Debye, respectively. The first three highest occupied molecular orbitals (HOMOs) of BDF have a t 2g character, as observed in Z907, while HOMO-4 and HOMO-5 have considerable sizable mixing from Ru-NCS with π-orbitals of L1.

Research paper thumbnail of Highly conjugated electron rich thiophene antennas on phenothiazine and phenoxazine-based sensitizers for dye sensitized solar cells

Synthetic Metals, 2014

Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiop... more Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiophene derivatives as antennas and cyanoacrylic acid as acceptor, bridged by phenothiazine or phenoxazine were designed and synthesized for dye-sensitized solar cells applications. They were fully characterized with their photophysical, electrochemical properties, density functional theory (DFT), time dependent density DFT (TDDFT) and the light-harvesting properties of the new sensitizers were evaluated with nanocrystalline TiO 2 -based devices. Among the four diheteroanthracene based dyes, phenoxazine (CSORG7 and CSORG9) based devices afforded the best photovoltaic performance (Á) of 6% under standard AM 1.5G solar irradiation, whereas, N719 showed (Á) 6.4% under the similar fabrication and evolution conditions.

Research paper thumbnail of Novel 4′-functionalized 4,4′′-dicarboxyterpyridine ligands for ruthenium complexes: near-IR sensitization in dye sensitized solar cells

Dalton Trans., 2014

Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the blac... more Novel ruthenium complexes (MC113-MC117), obtained by modifying the terpyridine ligand of the black dye (N749), have been evaluated as sensitizers for dye sensitized solar cells (DSSCs). The modification is carried out by attaching selected chromophores, with varying electron donating strength, covalently to the central ring of the ligand. The complexes, compared to the parent dye, show red shifted absorption covering visible and near IR regions and higher molar extinction coefficients. We report in this work synthesis of a series of these ruthenium complexes with chromophores such as tert-butyl phenyl, triphenylamine, bithiophene, phenoxazine and phenothiazine. Detailed experimental characterization using optical, electrochemical and photovoltaic techniques has been carried out and complemented by density functional theory studies. The fill factors (ff ) obtained for these dyes are larger than those of the parent black dye. In spite of these superior properties, the dyes show only moderate to good power conversion efficiencies. The possible reasons for this have been investigated and discussed. † Electronic supplementary information (ESI) available. See

Research paper thumbnail of Phenothiazine conjugated bipyridine as ancillary ligand in Ru(II)-complexes for application in dye sensitized solar cell

Synthetic Metals, 2011

A new high molar extinction coefficient ruthenium(II)-bipyridine complex "cis-Ru(4,4 -bis((E)-2-(... more A new high molar extinction coefficient ruthenium(II)-bipyridine complex "cis-Ru(4,4 -bis((E)-2-(10-decyl-10H-phenothiazin-3-yl)vinyl)-2,2 -bipyridine)(4,4 -dicarboxylic acid-2,2 -bipyridine)(NCS) 2 PTZ1 was synthesized through conjugation of phenothiazine unit with bipyridine and characterized by FT-IR, 1 H-NMR and ESI-MASS spectroscopes. Absorption measurements and time dependent-density functional theory (TD-DFT) calculations show increased spectral response for the ancillary ligand and the corresponding complex. The dye upon anchoring onto mesoporous nanocrystalline TiO 2 solar cells exhibited solar-to-electric energy conversion efficiency (Á) of 3.77% short-circuit photocurrent density (J SC ) = 7.79 mA/cm 2 , open-circuit voltage (V OC ) = 640 mV, fill factor = 0.750) under air mass 1.5 sunlight, the reference Z907 and HRS1sensitized solar cells, fabricated and evaluated under identical conditions exhibited Á-value of 7.02% (J SC = 15.25 mA/cm 2 , V OC = 650 mV, fill factor = 0.705) and 3.05% (J SC = 8.20 mA/cm 2 , V OC = 610 mV, fill factor = 0.620) respectively. The lower film absorption of PTZ1on TiO 2 surface could be probably due to larger molecular diameter and planarity of phenothiazine prone to aggregate in solution as well as on TiO 2 surface. The DFT calculations show that the first three HOMOs of PTZ1 have t2g character as observed in case of Z907, while HOMO-4 and HOMO-5 have -orbitals with major component on phenothiazine moieties of L1.

Research paper thumbnail of Novel ruthenium sensitizer with multiple butadiene equivalent thienyls as conjugation on ancillary ligand for dye-sensitized solar cells

Organic Electronics, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Research paper thumbnail of Carbazole based A-π-D-π-A dyes with double electron acceptor for dye-sensitized solar cell

Organic Electronics, 2014

and sharing with colleagues.

Research paper thumbnail of Functionalized phenyl bipyridine ancillary ligand as double recombination inhibitor in ruthenium complex for dye solar cells

Dyes and Pigments, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Research paper thumbnail of Functionalized styryl bipyridine as a superior chelate for a ruthenium sensitizer in dye sensitized solar cells

Dalton Transactions, 2012

The new sensitizer 119 has been synthesized and the solar cell constructed with 0.25 cm(2) active... more The new sensitizer 119 has been synthesized and the solar cell constructed with 0.25 cm(2) active area photoelectrode in combination with an electrolyte composed of 0.6 M dimethylpropyl-imidazolium iodide (DMPII), 0.05 M I(2), 0.5 M TBP and 0.1 M LiI in acetonitrile achieved a solar to electric energy conversion efficiency (η) of 8.36% under Air Mass (AM) 1.5 sunlight, while the reference 719 sensitized solar cell exhibited η-value of 7.2%.

Research paper thumbnail of Substitution of Ethynyl-Thiophene Chromophores on Ruthenium Sensitizers: Influence on Thermal and Photovoltaic Performance of Dye-Sensitized Solar Cells

Advances in OptoElectronics, 2012

A new high molar extinction coefficient ruthenium(II) bipyridyl complex, "Ru(2,2-bipyridine-4,4 -... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex, "Ru(2,2-bipyridine-4,4 -dicarboxylic acid)(4,4 -bis((3hexylthiophen-2-yl)ethynyl)-2,2 -bipyridine)(NCS) 2 (N(C 4 H 9 ) 4 ), MC101" was synthesized and fully characterized by 1 H-NMR, ESI-MASS, FT-IR, UV-Vis., and fluorescence spectroscopes. The dye showed relatively high molar extinction coefficient of 25.0 × 10 3 M −1 cm −1 at λ maximum of 544 nm, while the reference C101 has shown 15.8 × 10 3 M −1 cm −1 at λ maximum 528 nm. The monochromatic incident photon-to-collected electron conversion efficiency of 44.1% was obtained for MC101 over the entire visible range, while the C101 sensitized solar cell fabricated and evaluated under identical conditions exhibited 40.1%. The DSSCs fabricated with 0.54 cm 2 active area TiO 2 electrodes and high efficient electrolyte (E01), from the sensitizers MC101 and C101 exhibited energy conversion efficiencies of 3.25% (short-circuit current density (J SC ) = 7.32 mA/cm 2 , V OC = 610 mV, ff = 0.725) and 2.94% (J SC = 6.60 mA/cm 2 ; V OC = 630 mV; ff = 0.709), respectively, under air mass of 1.5 sunlight.

Research paper thumbnail of High Molar Extinction Coefficient Ru(II)-Mixed Ligand Polypyridyl Complexes for Dye Sensitized Solar Cell Application

Advances in OptoElectronics, 2011

... Malapaka Chandrasekharam, 1 Ganugula Rajkumar, 2 Chikkam Srinivasa Rao, 1 Thogiti Suresh, 1 Y... more ... Malapaka Chandrasekharam, 1 Ganugula Rajkumar, 2 Chikkam Srinivasa Rao, 1 Thogiti Suresh, 1 Yarasi Soujanya, 3 and Paidi Yella Reddy 2. ... mm thickness, Libbey-Owens-Ford Industries) with TiCl 4 and further with a drop of H 2 PtCl 6 solution (2 mg of Pt in 1 mL of ethanol ...

Research paper thumbnail of Substitution of Carbazole Modified Fluorenes as π-Extension in Ru(II) Complex-Influence on Performance of Dye-Sensitized Solar Cells

Advances in OptoElectronics, 2011

A new high molar extinction coefficient ruthenium(II) bipyridyl complex "cis-Ru(4,4 -bis(9,9-dibu... more A new high molar extinction coefficient ruthenium(II) bipyridyl complex "cis-Ru(4,4 -bis(9,9-dibutyl-7-(3,6-di-tert-butyl-9Hcarbazol-9-yl)-9H-fluoren-2-yl)-2,2 -bipyridine)(2,2 -bipyridine-4,4 -dicarboxylic acid)(NCS) 2 , BPFC" has been synthesized and characterized by FT-IR, 1 H-NMR, and ESI-MASS spectroscopes. The sensitizer showed molar extinction coefficient of 18.5 × 10 3 M −1 cm −1 , larger as compared to the reference N719, which showed 14.4 × 10 3 M −1 cm −1 . The test cells fabricated using BPFC sensitizer employing high performance volatile electrolyte, (E01) containing 0.05 M I 2 , 0.1 M LiI, 0.6 M 1,2-dimethyl-3-n-propylimidazolium iodide, 0.5 M 4-tert-butylpyridine in acetonitrile solvent, exhibited solar-to-electric energy conversion efficiency (η) of 4.65% (short-circuit current density (J SC ) = 11.52 mA/cm 2 , open-circuit voltage (V OC ) = 566 mV, fill factor = 0.72) under Air Mass 1.5 sunlight, lower as compared to the reference N719 sensitized solar cell, fabricated under similar conditions, which exhibited η-value of 6.5% (J SC = 14.3 mA/cm 2 , V OC = 640 mV, fill factor = 0.71). UV-Vis measurements conducted on TiO 2 films showed decreased film absorption ratios for BPFC as compared to those of reference N719. Staining TiO 2 electrodes immediately after sonication of dye solutions enhanced film absorption ratios of BPFC relative to those of N719. Timedependent density functional theory (TD-DFT) calculations show higher oscillation strengths for 4,4 -bis(9,9-dibutyl-7-(3,6di-tert-butyl-9H-carbazol-9-yl)-9H-fluoren-2-yl)-2,2 -bipyridine relative to 2,2 -bipyridine-4,4 -dicarboxylic acid and increased spectral response for the corresponding BPFC complex.