Anthocyanin from Vitis labrusca grape used as sensitizer in DSSC solar cells Rodrigo Szostak • Eder Carlos Ferreira de Souza • Sandra Regina Masetto Antunes • Christiane Philippini Ferreira Borges • Andre ´ Vitor Chaves de Andrade • Paulo Roge ´rio Pinto Rodrigues • Augusto Celso Antunes Received: 25 September 2014 / Accepted: 6 January 2015 Ó Springer Science+Business Media New York 2015 Abstract Dye sensitized solar cells or ‘‘Gra ¨tzel’’ cells are electrochemical devices capable of performing the direct conversion of light into electricity and are less expensive than traditional silicon solar cells. The most efficient dyes for Gra ¨tzel cells are those composed by the coordination compounds of ruthenium ions, which have high cost due to the shortage of ruthenium (Ru) element in the Earth’s crust. Thus, the study of dyes with lower cost is crucial for the viability of this technology on a large scale. Natural dyes are easily extracted in addition to being environmentally friendly and presenting reduced cost. Anthocyanins are the most important pigments of vascular plants, providing color to the flowers and fruits. In grapes, anthocyanins are found exclusively in the skin and can be easily extracted with ethanol at room temperature. In this work we used the ethanolic extract of anthocyanins from Vitis labrusca grape in the sensitization of TiO 2 electrodes and production of a Gra ¨tzel cell. The prepared Gra ¨tzel cell presents a short- circuit current of 0.045 mA/cm 2 , above that of the cell sensitized with commercial N719 dye, which was 0.032 mA/cm 2 . However, the open circuit voltage was 0.293 V, lower than that sensitized with N719 (0.335 V). The fill factor of the anthocyanin sensitized cell was 46.19 %, higher than that of the N719 sensitized cell, 42.72 %. These results are consistent with the greater absorption of light radiation observed in the cell with grape anthocyanins in comparison with the cells sensitized with N719 dye. 1 Introduction The access to renewable energy sources which are eco- nomically viable is essential for the development of a globally sustainable society. The global average con- sumption of energy was 13 TW (terawatts = 10 12 W) in the year 2000, and with the expected increase in popula- tion, a demand of 28 TW is foreseen in 2,050. Solar energy presents great potential to satisfy the need for global renewable energy. Around 1.7 9 10 5 TW solar energy reaches our planet surface, but the practical energy potential is estimated to be 600 TW. Using cells with 10 % conversion efficiency, around 60 TW of energy could be generated, in reply to the global need for energy [1]. Since the invention of the first dye sensitized solar cell (DSSC) or Gra ¨tzel cell [2], these cells have called attention of researchers. The DSSCs present some advantages when compared to the traditional silicon photovoltaic devices such as the construction of transparent modules, better performance on a broader radiation band, lower sensitivity to the incidence angle and opacity conditions, preparation from non-toxic materials with a certain level of purity that is not as high as that required by the silicon cells. The dye in a DSSC absorbs the solar radiation pumping the elec- trons to the semiconductor conduction band. On the other R. Szostak  E. C. F. de Souza (&)  S. R. M. Antunes  C. P. F. Borges  A. C. Antunes Chemistry Department, Universidade Estadual de Ponta Grossa (UEPG), 4748 Carlos Cavalcanti Avenue, Uvaranas, Ponta Grossa, Parana ´ 84030-900, Brazil e-mail: souza.eder@gmail.com A. V. C. de Andrade Physics Department, Universidade Estadual de Ponta Grossa (UEPG), 4748 Carlos Cavalcanti Avenue, Uvaranas, Ponta Grossa, Parana ´ 84030-900, Brazil P. R. P. Rodrigues Chemistry Department, Universidade Estadual do Centro-Oeste (UNICENTRO), 03 Simea ˜o Camargo Varela de Sa ´ Street, Carli, Guarapuava, Parana ´ 85040-080, Brazil 123 J Mater Sci: Mater Electron DOI 10.1007/s10854-015-2678-z