Influence of loadings of single-walled carbon nanotubes on the performance of ZnO nanorod-based dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are a promising low-cost alternative to silicon-based photovoltaic solar cells. Thus, this study was initiated with the aim of combining the unique physical and chemical properties of both SWCNTs and metal oxide nanostructures (such as ZnO-NR) for assembling novel building blocks for solar cells and light energy harvesting devices. DSSCs based on ZnO nanorods/single-walled carbon nanotubes (ZnO-NR/SWCNT) nanocomposite were prepared by the hydrothermal and spin coating method. The photoelectric performances of the DSSCs with various SWCNT loadings up to 1.00 wt% were compared. A gradual increase in the power conversion efficiency (η) was observed up to SWCNT loading of 0.50 wt%, at which the power conversion efficiency of fabricated cells increased to 3.4% compared to 1.97% without SWCNTs. However, further increases in SWCNTs loadings significantly reduced cell performance. Furthermore, the maximum dye absorption intensity was attained at the SWCNT loading of 0.50 wt%. Compared to the DSSC with ZnO-NR electrode, the photocurrent–voltage (J–V) characteristics of the DSSC with 0.50 wt% SWCNTs loading showed an increase in the short-circuit photocurrent (J_sc) of 38% leading to an increase in (η) by a factor of approximately 1.7.