2% ZnO increases the conversion efficiency of TiO2 based dye sensitized solar cells by 12%

• Conversion efficiency improvement of 12% for TiO2 DSSCs is realized by adding just 2% of ZnO.
• Charge recombination is reduced by the formation of energy barrier.
• A rather simple strategy is used to accomplish the competing requirements.

High efficiency dye sensitized solar cells requires hierarchical photoanodes of large surface areas for effective light scattering and harvesting, rapid electron transfer and transport, and reduced charge recombination. In this work, we report a rather simple strategy to accomplish these competing requirements. By adding just 2% of ZnO into TiO2 based photoanodes, we observe that the dye adsorption is increased, the light scattering is enhanced, and electron transfer is improved, all accomplished without compromising large surface areas afforded by TiO2 nanoparticles. As a result, conversion efficiency of 9.53% is realized, which is 12% higher than TiO2 photoanodes without ZnO addition.