Effect of LiF/metal electrodes on the performance of plastic solar cells

Abstract
The insertion of thin interlayers of LiF under the negative metal electrode (Al and Au) of bulk heterojunctionsolar cells significantly enhances the fill factor and stabilizes high open circuit voltages. Compared to devices without the LiF interfacial layer, the white light efficiencies increase by over 20% up to η eff ∼3.3%. Substitution of the LiF by another insulating interlayer SiO x results in lower overall efficiencies. In the case of a LiF/Au electrode, substantial efficiency enhancement is observed compared to a pristine Auelectrode and white light efficiencies up to η eff ∼2.3% are reported.