Optimized TiO2 nanoparticle packing for DSSC photovoltaic applications

• Different synthesis protocols have been developed to control TiO2 nanoparticle packing.
• It is demonstrated that the TiO2 nanoparticles packing influences the performance of DSSC.
• The higher energy conversion efficiency of 4.3% was achieved using TiO2 aggregates with a size of about 90 nm.
• The role of cracks on decreasing the energy conversion efficiency was illustrated.

Different synthesis protocols have been developed to control TiO2 anatase nanoparticle packing. The diameter of TiO2 packing aggregate varies from 13 nm to a few 100 nm. Efficiency of dye-sensitized solar cells (DSSC) fabricated with the obtained TiO2 packing aggregate films was reported to depend on the size of the packing aggregate. It increases with the increase of the aggregate size (number of TiO2 nanoparticles) to a maximum of 4.3% and then it decreases. This effect was discussed in terms of a balance between the incident light scatterings, adsorbing amount of dye molecules, cracks free and the efficiency of electron transfer (reduction of recombination process).