Due to their excellent optoelectronic properties and extremely high carrier mobility, single-walled carbon nanotubes (SWCNTs) show immense potential for solar cell applications. In silicon/carbon heterojunction solar cells, they can act as a high-performance transparent conductive electrode, effectively improving carrier collection efficiency and enhancing device flexibility. For perovskite solar cells, SWCNTs can serve as either a highly stable hole transport layer or a composite electrode, significantly increasing the device's photothermal stability. In the field of organic photovoltaics (OPVs), they can simultaneously function as both the photoactive layer and the charge transport channel, which effectively promotes exciton separation and electron conduction. Their inherent flexibility and solution-processability make SWCNTs an ideal material for flexible and wearable solar cells, providing an energy solution for the next generation of portable electronic devices.