DESENVOLVIMENTO E CARACTERIZAÇÃO DE CÉLULA SOLAR SENSIBILIZADA POR CORANTES COMPOSTA DE TiO2 e Nb2O5

Abstract

Solar energy as a source of renewable energy has grown exponentially with regard to the development of technology and installation of photovoltaic systems, much due to the wide availability of this source coupled with innovative technologies. The dye-sensitized cells are embedded in the array of device options that convert solar energy into electrical energy, with the advantage of being made of biocompatible materials and presenting unparalleled versatility. The main objective of this thesis was to study the insertion of niobium pentoxide in TiO2 cells in order to improve energy conversion efficiency. The Nb2O5 particles were obtained by the Pechini method and the synthesis conditions established by experimental design using the software Design Expert. The results indicated that obtaining spherical particles with a hydrodynamic diameter of 105 nm is possible by employing the molar ratio of ethylene glycol: citric acid of 13: 1 and citric acid: metal 1: 0.1. The characterization by XRD and FTIR proved that the structure obtained was pseudohexagonal. The films were produced using commercial anatase TiO2 and various proportions of Nb2O5 and deposited by doctor blading. The characterization by XRD indicated that the Nb was inserted in the structure of TiO2 which led to the decrease of band gap values as evidenced by UV-Vis.. The IXV curves indicated that cells containing 2 and 5% of Nb2O5 had the best results of conversion efficiency. The results of the Intensity Modulated Photocurrent Spectroscopy and Intensity Modulated Photovoltage Spectroscopy curves indicated that the collection efficiency was higher for TiO2 cells containing 2% Nb2O5.