Effect of TiO₂ layer thickness on the energy conversion efficiency of dye-sensitized solar cells

The past two decades have seen the unprecedentedly rapid emergence of dye-sensitized solar cells that are efficient, inexpensive, and eco-friendly. However, a systematic study of the dependence on active layer thickness into energy conversion efficiency (ECE) of solar cells has not been reported often. In this study, we synthesized the TiO2 nanoparticles with various particle sizes and fabricated TiO2 nanoparticle-based dye-sensitized solar cells with different thickness of the TiO2 active layers. Then, a systematic study was carried out to enhance the ECE and found that as the thickness of TiO2 active layers increases, the ECE could improve from 3.77% to 5.10%. This is an enhancement of as much as 26%. Therefore, it can be concluded that the optimal TiO2 layer thickness in dye-sensitized solar cells (DSSC) depends on the particle size due to back scattering and charge transport properties.