Investigation of the properties of niobium pentoxide for use in dye‐sensitized solar cells

Abstract

This work demonstrates the obtention of Nb2O5 nanoparticles by the microwave‐assisted hydrothermal synthesis method in a fast way and with the use of low temperatures. The heat treatment applied on the samples promotes the phase change in Nb2O5 from pseudohexagonal to orthorhombic as the temperature increases, with a particle size between 7.3 and 32.6 nm. The band gap of the samples decreases with increasing temperature, obtaining a minimum value of 3.04 eV at 800°C. Dye‐sensitized solar cells (DSSC) were assembled using the Doctor Blade coating technique. The photovoltaic parameters of open‐circuit voltage (Voc) and short‐circuit current density (Jsc) were evaluated. The cells showed a photovoltaic response, demonstrating that Nb2O5 has a semiconductive potential. The DSSC have different characteristics regarding Jsc and Voc, showing that according to the temperature increase in the semiconductor sample, there is a decrease in the photovoltaic parameters of the cells.

Multi-Photonic behavior of Nb2O5 and its correlation with synthetic methods

“…The DSSC assembly was performed in different steps. First, for the photoanode, the conductive glass substrate FTO (fluorine-doped tin oxide, 7 X sq -1 , Sigma-Aldrich) was cleaned as previously described [11,24]. Nb 2 O 5 pastes were prepared using 300 mg of Nb 2 O 5 from each synthesis (CR, SG, PP, MAH), 18 lL of ethylene glycol, 15 lL of Triton-X, and an amount of ethanol between 75 and 150 lL.…”

“…Microwave-assisted hydrothermal synthesis is considered by many researchers to be an advantageous technique in relation to the other synthesis methods since it is easy to perform, completed in a relatively short synthesis time, and conducted at a lower temperature range, making it efficient for crystallization [43][44][45]. In a previous work, we demonstrated that Nb 2 O 5 obtained by this method presented good optical properties and photovoltaic responses [24].…”

“…Even though Nb 2 O 5 has a high application capacity in these devices, the characteristics of the oxide used as a semiconductor can affect the final performance of the DSSC and photocatalytic degradation [24]. Nb 2 O 5 presents in different crystalline phases depending on temperature [24,25].…”

“…Even though Nb 2 O 5 has a high application capacity in these devices, the characteristics of the oxide used as a semiconductor can affect the final performance of the DSSC and photocatalytic degradation [24]. Nb 2 O 5 presents in different crystalline phases depending on temperature [24,25]. Therefore, it is necessary that the synthesis process is controlled since the reaction time, temperature of the heat treatment, and other synthesis parameters can affect the crystalline structure and the morphology of the final ceramic material, thus affecting their photovoltaic and photocatalytic properties.…”

Properties of zinc titanates synthesized by microwave assisted hydrothermal method

“…The adoption of this synthesis method allows simplicity, speed and low cost in obtaining zinc titanates. The same method has already been used in other works involving the synthesis of titanium oxides [ 13 ] and other metals [ 14 , 15 ] as well as the manufacture of components for DSSC's [ 16 ] with excellent results related to electrical properties.…”