Detrimental effect of inert atmospheres on hybrid solar cells based on semiconductor oxides

We report the improvement observed in J(sc), V-oc, and current-voltage (I-V) curves when hybrid solar cells (HSCs) are transferred from inert conditions to ambient atmosphere. The effect is observed regardless of the semiconductor oxide applied and has been attributed to the reversible incorporation of oxygen from the atmosphere into the semiconductor oxide surface during illumination. The HSCs were prepared as bilayers of thin-film semiconductor oxides (TiO2, Nb2O5, and ZnO) made by the sol-gel technique and the polymer poly[(2-methoxy-5-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), applying a final device configuration of the type indium tin oxide/oxide(thin film)/MEH-PPV/Ag. The photovoltaic response was studied in terms of inert atmosphere by recording the initial values of open-circuit voltage (V-oc) and current density (J(sc)). Solar decay curves, I-V curves, the effect of filter and resting time, as well as photophysical analyses were also carried out for each type of device. (c) 2007 The Electrochemical Society.