0000000000490012
AUTHOR
Ilaria Citro
Nanostructured anatase TiO2 densified at high pressure as advanced visible light photocatalysts
This study reports on characterization and photoactivity of nanostructured TiO2 samples, which have been permanently densified under high pressures, up to 2.1 GPa. Commercial Mirkat 211 anatase has been used as a benchmark sample, in order to investigate the effect of unidirectional high pressure on structural, optical and photocatalytic properties of TiO2. Vibrational Raman spectroscopy shows that the treatment does not cause transitions among the different crystalline phases of titanium dioxide. UV-vis diffuse reflectance spectra reveal that increasing pressure gives rise to a shift of the absorption onset towards higher wavelength enhancing the photoactivity under visible radiation. Samp…
Investigation of recovery mechanisms in dye sensitized solar cells
Abstract We study the spontaneous recovery phenomenon displayed by solar cells sensitized with a ruthenium complex-based dye N719, which manifests with the increase over the time (from several minutes up to some days) of the short circuit current density J sc and the open circuit voltage V oc , during cell illumination. Under dark conditions the current decreases over time after the application of forward bias voltages. We investigate the effects of temperature and electrolyte composition by means of current–voltage measurements and electrochemical impedance spectroscopy, both under dark and illumination conditions. The main result is that the recovery of the performances depends on the cha…
Improvement of DSSC performance by voltage stress application
Dye-sensitized solar cells (DSSCs) are promising third generation photovoltaic devices given their potential low cost and high efficiency. Some factors still affect DSSCs performance, such structure of electrodes, electrolyte compositions, nature of the sensitizers, power conversion efficiency, long-term stability, etc. In this work we discuss the effect of electrical stresses, which allow to improve DSSC performance. We have investigated the outcomes of forward and reverse DC bias stress as a function of time, voltage, and illumination level in the DSSCs sensitized with the N719, Ruthenium complex based dye. We demonstrate that all the major solar cell parameters, i.e., open circuit voltag…