[en] Full text: The oxides most explored in solar cells researches are TiO₂ and ZnO, however, few studies are found in literature using Nb₂O₅ as photoelectrode. However, they are good candidates for this application due to their properties such as band gap values of 3,9 eV, it is 0.3 eV greater than the band gap of TiO₂ anatase and also the possibility to obtain easily transparent films [1]. Furthermore, Brazil has the largest reserves of this metal, which makes researches with niobium attractives [2] . So, in this work we present the synthesis and characterization of Nb₂O₅ film for solar cells application. The film were synthetized by sol gel technique and characterized by thermogravimetry analyses (TG/DTA), XDR and scanning electronic microscopy (SEM). The sol-gel solution was prepared in two steps. Firstly, sodium butoxide was prepared by dissolution of NaOH in n-butanol, under stirring. In the second step, NbCl₅ was dissolved in sodium butoxide solution, product of first step. The process led to the formation of Nb(OBu_n )₅ and NaCl. The NaCl was separated by centrifugation. Finally, was added glacial acetic acid (CH₃ COOH), resulting in a sol stable at room temperature [3]. The results of TG showed the temperature of Nb₂O₅ phase crystallization and DTA shows the temperature where occurs the endothermic and exothermic processes. X-rays analyses showed the peaks related to the crystallization of pentoxide of niobium. SEM images showed the thin film composed of particles with nanometric sizes. References: [1]. SAYAMA, K.; H. SUGIHARA; ARAKAWA, H. Photoelectrochemical Properties of a Porous Nb₂O₅ Electrode Sensitized by a Ruthenium Dye. Chemistry of Materials, 1998. 10(12): p. 3825-3832. [2]. JÚNIOR P. F. R.; DNPM, Sumário Mineral 2010. Found in:www.sistemas.dnpm.gov.br [3]. AEGERTER M. A.; Institut fur Neue Materialien, Im Stadtwald, Gebaude 43, D 66-123 Saarbrucken, Germany; Two methods of obtaining sol-gel Nb₂O₅ thin films for electrochromic devices. (author)