Abstract. Hybrid solar cells have been constructed by using nanocrystalline titania and hole-transporting polymers. Titania was deposited on fluorine-doped tin-oxide transparent electrodes in three layers: a blocking layer and two nanostructured layers, giving densely packed or open structures. Open structures produced higher currents due to better polymer penetration and larger oxide–polymer interface. Cells based on the dithiophene-unit-containing polymer gave higher open-circuit voltage. Efficient cells could be made only in the presence of a dye sensitizer and a lithium salt. Cells were neither sealed nor encapsulated and their components were deposited under ambient conditions except for the metal back electrode, which was deposited under vacuum. Cells demonstrated a transient behavior in two stages: initially an increase of both current and voltage followed by an increase in voltage and a drop in current. Both quantities were stabilized at values approximately established within a few days. These values remained stable for several months when the cells were stored in the dark.

Print publication: Issue 49 (9 December 2009)
Received 15 September 2009, in final form 19 October 2009
Published 6 November 2009