%0 Journal Article %A Sil, Manik Chandra %A Sudhakar, Vediappan %A Kavungathodi, Munavvar Fairoos Mele %A Punitharasu, Vellimalai %A Nithyanandhan, Jayaraj %D 2017 %T Orthogonally Functionalized Donor/Acceptor Homo- and Heterodimeric Dyes for Dye-Sensitized Solar Cells: An Approach to Introduce Panchromaticity and Control the Charge Recombination %U https://acs.figshare.com/articles/journal_contribution/Orthogonally_Functionalized_Donor_Acceptor_Homo-_and_Heterodimeric_Dyes_for_Dye-Sensitized_Solar_Cells_An_Approach_to_Introduce_Panchromaticity_and_Control_the_Charge_Recombination/5459227 %R 10.1021/acsami.7b09010.s001 %2 https://ndownloader.figshare.com/files/9440866 %K TiO 2 surface %K chromophore %K monomeric D 1 %K π- framework forms %K attenuated charge recombination %K TiO 2 film %K power conversion efficiency %K PCE %K Charge Recombination Organic dyes %K Dye-Sensitized Solar Cells %K D 2 %K D 1 %K V oc %K TiO 2 %K DSSC %K spiroBiProDOT π- spacer %K J sc %K FT-IR %K homodimeric spiro-dye D 1 %X Organic dyes possessing conjugated π-framework forms closely packed monolayers on photoanode in dye-sensitized solar cell (DSSC), because of the limitation to control the orientation and the extend of intermolecular π–π interaction, self-aggregation of dyes leads to reduced cell performance. In this report, a series of homodimeric (D1-D1 and D2-D2) and heterodimeric (D1-D2 and D2-D4) donor/acceptor (D/A) dyes containing spiroBiProDOT π-spacer were designed and synthesized by utilizing Pd-catalyzed direct arylation reaction and correlates the device performance with monomeric dyes (D1 and D2). Both the thiophenes (π-spacer) of spiroBiProDOT were functionalized with same or different donor groups which led to homodimeric and heterodimeric chromophores in a single sensitizer. The homodimeric spiro-dye D1-D1 showed higher power conversion efficiency (PCE), of 7.6% with a Voc and Jsc of 0.672 V and 16.16 mA/cm2, respectively. On the other hand, the monomeric D1 exhibited a PCE of 3.2% (Voc of 0.64 V and Jsc of 7.2 mA/cm2), which is lower by 2.4 fold compared to dimeric analogue. The spiro-unit provides flexibility between the incorporated chromophores to orient on TiO2 due to four sp3-centers, which arrest the molecular motions after chemisorption. This study shows a new molecular approach to incorporate two chromophores in the dimeric dye possessing complementary absorption characteristics toward panchromatic absorption. The attenuated charge recombination at TiO2/Dye/redox couple interface in case of D1-D1, owing to better passivation of TiO2 surface, was elucidated through impedance analysis. The FT-IR spectrum of D1-D1 adsorbed on TiO2 film indicated both the carboxylic units were involved in chemisorption which makes strong coupling between dye and TiO2. %I ACS Publications