Journal of Porphyrins and Phthalocyanines J. Porphyrins Phthalocyanines 2014; 18: 1–17 DOI: 10.1142/S108842461450117X Published at http://www.worldscinet.com/jpp/ Copyright © 2014 World Scientific Publishing Company INTRODUCTION Among the various types of solar cells, dye sensitized solar cells (DSSCs) with are considered to be very promising, since due to their low cost and are considered Donor-π-acceptor, triazine-linked porphyrin dyads as sensitizers for dye-sensitized solar cells Ganesh D. Sharma* a , Galateia E. Zervaki b , Kalliopi Ladomenou b , Emmanuel N. Koukaras c , Panagiotis P. Angaridis e and Athanassios G. Coutsolelos* c,d◊ a R&D Center for Engineering and Science, JEC Group of Colleges, Jaipur Engineering College, Kukas, Jaipur (Raj.) 303101, India b Laboratory of Bioinorganic Chemistry, Department of Chemistry, University of Crete, Voutes Campus, P. O. Box 2208, 71003 Heraklion, Crete, Greece c Institute of Chemical Engineering Sciences, Foundation for Research & Technology Hellas (FORTH/ICE-HT), Stadiou Str. Platani, Patras 26504, Greece d Molecular Engineering Laboratory, Department of Physics, University of Patras, Patras, 26500, GR, Greece e Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece Dedicated to Professor Shunichi Fukuzumi on the occasion of his retirement Received 27 October 2014 Accepted 6 November 2014 ABSTRACT: Two porphyrin dyads with the donor-π-acceptor molecular architecture, namely (ZnP)- [triazine-gly]-(H 2 PCOOH) and (ZnP)-[triazine-Npip]-(H 2 PCOOH), which consist of a zinc-metalated porphyrin unit and a free-base porphyrin unit covalently linked at their peripheries to a central triazine group, substituted either by a glycine in the former or a N-piperidine group in the latter, have been synthesized via consecutive amination substitution reactions of cyanuric chloride. The UV-vis absorption spectra and cyclic-voltammetry measurements of the two dyads, as well as theoretical calculations based on Density Functional Theory, suggest that they have suitable frontier orbital energy levels for use as sensitizers in dye-sensitized solar cells. Dye-sensitized solar cells based on (ZnP)-[triazine-gly]-(H 2 PCOOH) and (ZnP)-[triazine-Npip]-(H 2 PCOOH) have been fabricated, and they were found to exhibit power conversion efficiency values of 5.44 and 4.15%, respectively. Photovoltaic measurements (J–V curves) and incident photon to current conversion efficiency spectra of the two solar cells suggest that the higher power conversion efficiency value of the former solar cell is a result of its enhanced short circuit current, open circuit voltage, and fill factor values, as well as higher dye loading. This is ascribed to the existence of two carboxylic acid anchoring groups in (ZnP)-[triazine-gly]-(H 2 PCOOH), compared to one carboxylic acid group in (ZnP)-[triazine-Npip]- (H 2 PCOOH), which leads to a more effective binding onto the TiO 2 photoanode. Electrochemical impedance spectra show evidence that the (ZnP)-[triazine-gly]-(H 2 PCOOH) based solar cell exhibits a longer electron lifetime and more effective suppression of charge recombination reactions between the injected electrons and electrolyte. KEYWORDS: DSSC, porphyrin dyad, triazine, piperidine, glycine. ◊ SPP full member in good standing *Correspondence to: Athanassios G. Coutsolelos, email: coutsole@chemistry.uoc.gr; Ganesh D. Sharma, email: gdsharma273@gmail.com 1450117.indd 1 2/10/2015 1:53:58 PM J. Porphyrins Phthalocyanines Downloaded from www.worldscientific.com by Mr, Dr Athanassios Coutsolelos on 03/04/15. For personal use only.