Effect of flower extracts on the photoconversion efficiency of dye sensitized solar cells fabricated with Sn-doped TiO 2 S. G. Ansari 1 • Fatima Tuz-Zehra 1 • H. Fouad 2,3 • Azza S. Hassenein 3 • Z. A. Ansari 1 Received: 18 March 2015 / Accepted: 4 April 2015 Ó Springer Science+Business Media New York 2015 Abstract Extensive efforts are being made in enhancing the photoconversion efficiency of TiO 2 based dye sensi- tized solar cells (DSSC) using different approaches. In this work, the Sn-doped TiO 2 nanopowder was sensitized with flower extracts of Dahlia Violet (DV), Rabbit flower (RF) and their mixed extract separately other than the com- mercial N719 dye and DSSC characteristics were studied. Hydrothermal method was used to synthesize Sn-doped TiO 2 for 48 h at 150 °C. X-ray diffraction, UV–Vis, FTIR and Raman scattering were used to characterize the syn- thesized powder. DSSCs of the synthesized powder was fabricated using conventional sandwich type technique sealed with Surlyn Ò polymer film. The photocurrent–volt- age characteristics were measured under solar simulated light using source-meter. It is interesting to note that the flower extract resulted in comparable photoconversion ef- ficiency as that of N719 dye. When the powder was sen- sitized with N719, 1.66 % efficiency was achieved while mixed extract resulted in 1.28 %, DV in 0.99 % and RF in 0.52 % efficiency. The results of various analysis tech- niques and cell characteristics are correlated. 1 Introduction Since Gra ¨tzel reported dye sensitized solar cell (DSSC) using combination of nanostructured electrodes and charge injection dyes [1], extensive efforts have been put to de- velop DSSCs with various combination such as varied material composition/properties, dimensional variation in materials, liquid/gel electrolyte and different combinations of synthetic dyes [1–6]. Apart from these efforts, natural photosynthesis and colour pigments inspired researchers to explore for their possible use in DSSCs in combination with nanomaterials. Metal oxides received greater attention owing to their simple synthesis and flexibility in shape and dimensional control resulting in better adsorption of dye molecules. The work of Kasuga et al. [7] on Titanium dioxide and/or titanate nanotubes paved further way in realizing the much awaited cheap alternate source of en- ergy which resulted in large number of reports [8–14]. However, the thirst of exploring new material led to the use of composite metal oxides as a suitable material for pho- toconversion. For example, Li et al. [15] have tailored the bandgap of TiO 2 nanoparticles using Nd 3? ions by -0.55 eV for a doping of 1.5 at%. Zhou Xiufeng and co- workers doped TiO 2 with Sn and studied its photocatalytic properties and found that tin doping improved the photo- catalytic activity [16]. Yandong Duan and co-workers varied Sn content from 0.25 to 1 mol % to TiO 2 to fabri- cate DSSC and could find the effect of Sn on the conver- sion efficiencies [17]. Additionally, there are several reports on the doping of metal ion/anion such as N, S, V 4? , Zr 4? , Cr 3? , Mn 5? , Zn 2? for tailoring the absorption spec- trum [18–21]. Besides the material tuning, the attempts were also made to use extract of fruits, green peas and some of the flowers [22–25] instead of ruthenium based commercial dyes. The & Z. A. Ansari zaansari@jmi.ac.in 1 Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India 2 Department of Applied Medical Science, Community College King Saud University, Riyadh 11437, Saudi Arabia 3 Biomedical Engineering Department, Faculty of Engineering, Helwan University, Helwan 11792, Egypt 123 J Mater Sci: Mater Electron DOI 10.1007/s10854-015-3047-7