Structural and Morphological Characterization of Dye-sensitized Solar Cells Using Natural Dyes as Sensitizers
Daniel da Motta Sampaio1; Larissa Osório da Silva1; Patrick Terra Mendes1; Elumalai Thirumal1; Ana Lucia Ferreira de Barros1
1 Centro Federal de Educação Tecnológica Celso Suckow da Fonseca - CEFET/RJ
doi:10.20906/CPS/CON-2016-0332
Resumo
The search for alternative forms of energy turns out to be a crucial point for the development of a technologically advanced society committed to environmental sustainability. Amongst those, solar power is a particularly promising solution to the world's energy needs. Recent researches on finding an alternative energy resource for the next generation addresses the design of efficient photovoltaic cells. From the variety of such devices, we focus on the production of dye-sensitized solar cells (DSSC's). However, the construction of low cost, highly efficient and stable DSSC's defines a challenge for practical applications. At the Laboratory of Experimental and Applied Physics (LaFEA - CEFET/RJ) we have been able to produce DSSC's using organic dyes extracted from different fruits and vegetables to be used as sensitizers. Photo-anodes Titanium Dioxide (TiO2) films with different thicknesses were prepared in order to get proper morphological surface profile. The cathode films were composed by a thin layer of graphite, applied over a Transparent Conductive Oxide (TCO) Indium Tin Oxide (ITO) coated glass. The resulting films were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) measurements, and the composition and superficial characteristics of the films were also studied. The photovoltaic performance and electrochemical impedance studies were carried out to understand the effect of the variation of the thickness of photo-anode films for different dyes. In a comparison between solar cells with two different thicknesses, it was found that dye-sensitized solar cell prepared with the thick photo-anode film shows relatively more short-circuit current (Isc = 0.4 mA) and open-circuit voltage (Voc = 400 mV) than the solar cell designed using thin coating of photo-anode film (Isc = 0.3 mA, Voc = 225 mV). Also, the maximum short-circuit current of 4 mA was observed in a sample with 10 x 10 cm² of area, designed for large applications. As a ma
Palavras-chave: solar cells; organic dyes; thin films