Dye-sensitized solar cells (DSSC) have received much attention as an alternative to silicon-based solar cells, due to various advantages. Zinc oxide (ZnO) is an n-type semiconductor employed as photoanode on DSSC. The decrease of charge recombination is an efficient strategy capable of improving the photovoltaic performance of the device. In this perspective, Nb₂O₅ was added on ZnO solar cells. The oxides were characterized by the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and X-ray fluorescence (XRF). The photovoltaic parameters were obtained through J-V plots and photocronoamperometry. The results showed that the niobium oxide obtained presented orthorhombic crystal structure and DSSC with the addition of niobium oxide showed better efficiency, of 1.42% when compared the device with only ZnO.

Hybrid solar cells show an increasing number in researches due to its low cost and easy of production. They are composed by and organic material and a semiconductor oxide. The aim of this paper was to synthesis and characterize zinc oxide by coprecipitation and apply it in a hybrid solar cell that uses a P3HT/P3OT copolymer as charge carrier. The cell was assembled in "sandwich" form using FTO/ZnO/P3HT-P3OT as work electrode, (Pt/FTO) as conter electrode and I/I-3 redox couple as electrolyte. Through the X-ray diffractogram the formation of a single ZnO wutzite hexagonal phase was observed. The morphology obtained for the oxide was spherical. The results of photochronoamperometry showed current density values of jP3HT/P3OT =0.55 mA.cm^-2 for the cell in the presence of the copolymer and the curve jxV showed an efficiency of 0.16% for the studied cell, demonstrating that the polymer was a satisfactory sensitizer.

The development of dye-sensitized solar cells (DSSCs) has gained prominence as an economical alternative for photovoltaic energy conversion. This work investigates the synthesis of niobium pentoxide (Nb₂O₅) by the Pechini method, followed by calcination at different temperatures (500 °C, 600 °C and 700 °C) to evaluate its structural, morphological, and electrochemical properties as a photoanode material in DSSCs. SEM and XRD analyses revealed that calcination at 600 °C produced a material with optimized particle size (642.17 ± 37 nm) and adequate crystalline structure, favoring dye adsorption and electronic transport. Electrochemical characterization, including open-circuit potential and impedance spectroscopy, indicated that the sample at 600 °C presented superior photovoltaic performance, achieving a power conversion efficiency of 1.39% and electron lifetime equal to 0.159 s. These findings suggest that Nb₂O₅, under controlled calcination conditions, may act as a promising alternative to TiO₂ substitution in DSSC applications.

Purpose: The purpose of this paper is to evaluate the protection against corrosion of carbon steel SAE 1020 promoted by a niobium- and titanium-based coating produced from a resin obtained by the Pechini method. Design/methodology/approach: A resin was prepared with ammonium niobium oxalate as niobium precursor and K₂TiF₆ as titanium precursor. Carbon Steel SAE 1020 plates were dip coated in the resin and calcinated for 1 h at 600 ºC. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to characterize the coating morphologically and structurally. Open circuit potential, electrochemical impedance spectroscopy, anodic potentiodynamic polarization and scanning vibrating electrode technique were used to evaluate the corrosion protection of the coating. Findings: The electrochemical analyses evidence slight protection against corrosion of the coating by itself; however, the needle-like crystal structure obtained may potentially provide a good anchorage site, suggesting the coating could be used as a pretreatment that may present similar application to phosphating processes, generating lower environmental impacts. Originality/value: Due to increasingly restrictive environmental laws, new environmentally friendlier surface treatments must be researched. This paper approaches this matter using a combination of niobium- and titanium-based coating, produced by a cleaner process, the Pechini method.