Bridging energy harvesting and storage through self-charging photo-supercapacitors: Achievements, innovations, challenges, and future horizons

The increasing global demand for renewable energy has spurred extensive research into efficient and reliable energy storage systems, with solar energy emerging as a dominant solution despite inherent fluctuations caused by location, diurnal cycles, and weather conditions. This challenge has emphasized the importance of integrating energy harvesting and storage technologies to enable electricity generation from direct sunlight, diffuse light, and even indoor illumination. This review delves into the advancements and potential of photo-supercapacitors (PSCs), a cutting-edge hybrid technology combining dye-sensitized solar cells (DSSCs) or quantum dot-sensitized solar cells (QDSSCs) with supercapacitors (SCs). Unlike existing reviews that treat DSSCs, QDSSCs, or SCs in isolation, this article uniquely focuses on their hybridization, highlighting the simultaneous energy harvesting and storage capabilities of PSCs. It provides a comprehensive analysis of key components - such as dyes, photoactive metal oxides, counter electrodes, redox electrolytes, and conducting polymers - offering a strategic roadmap for optimizing PSC performance. Additionally, the review explores innovative developments, including compact layer designs, electrolyte-free configurations, and emerging technologies like hole-conductor and perovskite solar cells (PSSCs). By consolidating recent progress and identifying critical challenges, this work serves as a valuable reference for advancing energy conversion and storage efficiencies, pushing the boundaries of traditional energy storage solutions.