Fabrication of efficient solar cells on plastic substrates using binder-free ball milled titania slurries

Mechanically stable, well adhered TiO2 films based on nanocrystalline P-25 TiO2 slurries were developed using ball milling as a part of the processing stage, without the need for binders or high temperature annealing. The strength of the TiO2 films was examined by a novel nano-scratch technique which was developed to assess inter-particle adhesion. Interfacial and photovoltaic properties of flexible dye sensitized solar cells with a ruthenium dye involving two tetra-butyl-ammonium carboxylate groups (N719) were studied. The maximum power conversion efficiency of 4.2% is obtained under illumination of 100 mW cm−2, for the electrodes fabricated using 20 h milled slurry, shorter or longer milling times were less optimal.