Hybrid titanium dioxide/sericite light scattering layer to enhance light harvesting of dye-sensitized solar cells

Abstract

Intensification of light harvesting is an imperative strategy to improve the photovoltaic performance of dye-sensitized solar cells (DSSCs). The typical way is to employ a light scattering layer on top of the photoanode to augment the photon scattering of incident light for light harvesting of dye sensitizers. In this study, we have designed a new light scattering layer consisting of micro-sized sericite flakes and TiO2 nanoparticles, and material optimization is performed by using two sizes of TiO2 nanoparticles (P25-TiO2 of 20-30 nm and B-TiO2 of 30-100 nm) as the matrix to dope sericite flakes. This hybrid scattering layer gives rise to an enhancement of power conversion efficiency of DSSC under 1 sun and low-intensity illuminations. Maximum cell efficiencies of 8.667 % and 8.963 % are recorded for the DSSCs employing P25-TiO2/5 wt% sericite and B-TiO2/25 wt% sericite scattering layer, respectively, at 1 sun illumination, which outperforms that employing pure TiO2 scattering layer (8.2 %). Maximum cell efficiencies of 22.936 % and 23.121 % are optimized at 6,000 lux following the same TiO2/sericite hybrid systems. Such addition of sericite in the scattering layer indeed enhances the light harvesting performance and offers a new pathway to prepare more efficient light scattering layer.