Flexible devices have demonstrated great potential in a wide range of applications including wearable devices for fitness and health care. Flexible plastic substrates, such as polyimide, or transparent conductive polyester are used to fabricate flexible devices that increase the comfort when they are worn by users or patients. Flexible fiber solar cells are wire-shaped solar cells which are a type of photovoltaic cells fabricated on wire-like substrates. These type devices, including inorganic, organic, dye-sensitized and perovskite solar cells have made great progress in the recent years. In the case of flexible dye-sensitized solar cells the energy conversion efficiency of has increased from 0.5% to 9%.