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Dye-sensitized solar cells (DSSC) are devices to solar energy conversion, which present low production costs and high photoelectrochemical stability. The aim of this study was to investigate the synthesis of TiO2 by Pechini methodology, using C12H28O4Ti and TiCl3 as precursors, and their application in solar cell sensitized by N719 dye. The characterization techniques employed were Scanning Electron Microscopy (SEM), UV-VIS Spectroscopy, X-ray diffraction (XRD), photochronoamperometry, j-V Curves and EIS plots. The results demonstrated a high crystallinity and surface area to particles obtained with C12H28O4Ti as precursor. The highest photoconversion energy efficiency reached was to TiO2 using C12H28O4Ti with PCE= 4.17±0.13% with photoelectrochemical parameters of jsc= 5.53 ±0.08, Voc= 0.78±0.07 FF=0.58±0.05 and less resistive to charge transport with τe= 53 ms. DOI: http://dx.doi.org/10.17807/orbital.v13i2.1446

Renewable energy methodologies are the key to a sustainable future. PV technology has been raised as one of the most promisor alternatives for energy conversion, due to the use of an inexhaustible source. The third generation of solar devices, present in composition a semiconductor oxide, that work as electron transport material (ETL), receiving and transporting the electron from a photosensitive molecule. TiO2 performs with efficiency the role of ETL in solar devices, nevertheless, since of the higher cost, other oxides have been studied, as Nb2O5. This work aims to synthetized Nb2O5 by Pechini methodology and applied it as ETL in a solar device. The techniques performed in particle characterization were Scanning Electronic Microscopy (SEM) and X-ray diffraction (XRD). To verify the capability of transport electrons, the electrochemical measurements were applied to Voc/Jsc decay, j-V curves, Electrochemical Impedance Spectroscopy (EIS), and Intensity Modulate Photovoltage Spectroscopy (IMVS). The results showed Nb2O5 synthesized in orthorhombic phase able to produce a photosensitive dye-solar device with j = 4.18 mA cm−2, V = 825 mV, FF = 0.4, PCE = 1.38% with slow recombination rate when compare to TiO2 dye-solar cell. The IMVS and EIS technique present the same accuracy to electron lifetime determination which is confirmed by the t-test performed.

Mix of oxides is an alternative method to enhance the photoelectrochemical parameters of solar devices. Nb inserted in TiO2 was prepared successfully by Pechini methodology and the oxide was used as electron transport material in P3HT organic solar device. TiO2 anatase/rutile was confirmed by XRD measurement and band gap determination combined with cyclic voltammetry measurement indicated the Nb sub states creation above TiO2 conduction band. IMVS and OCP decay diagram showed an increasing in electron lifetime of 0.4758 s–0.6645 s to the cell containing Niobium. The energy conversion efficiency to the cell based in 5% of Nb presented an improving about 25% when compared to bared TiO2, proving that this methodology is a promisor route to produce enhanced electron transport materials.

Investment in renewable energy sources has increased in recent decades because of the environmental impact caused by the non-renewable energy sources burning. Regarding to the available renewable energy technologies, the conversion of solar energy into electrical energy using photovoltaic devices, especially dye-sensitized solar cells (DSSC), stands out. In this study, we investigated the recombination reactions of DSSCs containing ZnO and Nb2O5 using electrochemical impedance spectroscopy, intensity modulated photovoltage spectroscopy, intensity modulated photocurrent spectroscopy, and charge extraction. The addition of Nb2O5 to the ZnO cells reduced recombination effects, and the 5% Nb2O5 cell presented the best photovoltaic parameters, having an electron lifetime of 0.18 s, collection time of 0.01 s, and efficiency of 2.39%.

Natural dyes can be used in dye sensitized solar cells (DSSCs) to generate low-cost devices, although with low light harvesting because of energy losses from the recombination process. This study investigates recombination reactions in DSSCs with natural dyes extracted from eggplants, plums, and hibiscus flowers. Titanium dioxide films were coated on a fluorine-doped tin oxide glass conductor substrate by the doctor blading method and impregnated in a dye solution for 24 h. Electrodeposited platinum was used as the cathode, and I3–/I– as the redox couple. The techniques employed were: intensity modulated photovoltage spectroscopy, intensity modulated photocurrent spectroscopy, electrochemical impedance spectroscopy, charge extraction, and cyclic voltammetry. The results show that cells containing plum dye exhibited the best photovoltaic parameters, with high values of gap, charge extraction, and potential, being less resistive to charge transfer with an electron lifetime of 0.51 s, collection time of 8.54 ms, and charge efficiency collection of 0.99.