Highly asymmetric phthalocyanine-sensitized solar cells: The effect of coadsorbent and adsorption temperature of phthalocyanine

Highly asymmetric zinc phthalocyanine derivative (Zn-tri-PcNc) containing tribenzonaphtho-condensed porphyrazine with one carboxyl and three tert-butyl (t-Bu) substituent groups is used as a sensitizer to fabricate dye-sensitized solar cells (DSSCs), and the effects of chenodeoxycholic acid (CDCA) as a coadsorbent and the dye adsorption temperature on the solar cell's performance are investigated. It is found that CDCA coadsorption can hinder the dye aggregation, which is beneficial for improving the electron injection efficiency and retarding the charge recombination, and thus resulting in the enhancement of the short-circuit current density and open-circuit photovoltage. Moreover, the dye adsorption temperature on electrode also shows a significant impact on the photovoltaic performance of-the solar cell, and an optimal dye adsorption condition of the TiO2 electrode is found to be 5 x 10(-5) M Zn-tri-PcNc ethanol solution containing 7.5 mM CDCA at 5 degrees C, which can contribute to the maximum conversion efficiency of 2.89% with short-circuit current density of 9.42 mA cm(-2) and open-circuit photovoltage of 0.48 V, improved by 47% as compared to the solar cell fabricated with TiO2 electrode sensitized by the zinc phthalcoyanine in absence of CDCA. (C) 2013 Elsevier Ltd. All rights reserved.ElectrochemistrySCI(E)4ARTICLE344-35011