The integration of flexible dye-sensitized solar cells and storage devices towards wearable self-charging power systems: A review

Due to the outstanding high power conversion efficiency and mechanical robustness, photovoltaic systems have become a perfect alternative to traditional sources of energy. This helps in fulfilling the human demand for renewable, inexpensive and compact electricity sources. The production of highly efficient flexible dye-sensitized solar cells (FDSSCs) has sparked a lot of attention in recent years. These FDSSCs are promising energy sources for battery-free and self-powered electronics, which have application in different sectors, including the Internet of Things. Due to the intermittent and unpredictable nature of solar radiation, photoelectric conversion devices fail to satisfy the criteria of constant power output. Owing to the emergence of rechargeable electric energy storage devices, the integration of FDSSCs and rechargeable electric energy storage systems has become a promising approach in solving this problem. This review focused on the recent developments in terms of the materials used to fabricate FDSSCs along with the working principle, challenges in FDSSCs and improvements made in photoanode, sensitizer, electrolytes and counter electrode materials. In addition, some of the general characterization methods for newly prepared flexible/rigid dye-sensitized solar cell materials and the device are summarized. The evolution of many forms of mainstream flexible integrated photorechargeable energy storage systems, prospects for the development of highly effective, reliable FDSSCs and their integrated devices have also been demonstrated.