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International Journal of Photoenergy
Volume 2013 (2013), Article ID 871526, 8 pages
http://dx.doi.org/10.1155/2013/871526
Research Article

Fast TiO2Sensitization Using the Semisquaric Acid as Anchoring Group

1Center for Space Human Robotics @Polito, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Turin, Italy
2Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
3Chemistry Department and Nanostructured Interfaces and Surfaces Interdepartmental Center of Excellence, Università degli Studi di Torino, Via Giuria 7, 10125 Turin, Italy
4Cyanine Technologies S.p.A and Pianeta s.r.l., Via Giannone 3, 10036 Settimo Torinese, Italy

Received 20 July 2013; Revised 6 September 2013; Accepted 10 September 2013

Academic Editor: Jun-Ho Yum

Copyright © 2013 D. Pugliese et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Metal-free dye molecules for dye-sensitized solar cells application can avoid some of the typical drawbacks of common metal-based sensitizers, that are high production costs, relatively low molar extinction coefficient in the visible region, limited availability of precursors, and waste disposal issues. Recently we have proposed an innovative organic dye based on a simple hemi-squaraine molecule (CT1). In the present work, the effect of the sensitization time of the TiO2 photoelectrode in the dye solution is studied with the aim of optimizing the performance of CT1-based DSCs. Moreover, the addition of the chenodeoxycholic acid (CDCA) as coadsorbent in the dye solution at different concentrations is investigated. Both CT1-sensitized mesoporous TiO2 photoanodes and complete solar cells have been fully characterized in their electrical and absorption properties. We have found that the best photoconversion performances are obtained with 1 hour of impregnation time and a 1 mM CDCA concentration. The very fast kinetics in dye adsorption, with optimal sensitization steps almost 15 times faster than conventional Ru-based sensitizers, confirms the theoretical predictions and indicates a strong interaction of the semisquaric acid group with the anatase surface. This result suggests that this small molecule can be a promising sensitizer even in a continuous industrial process.