Nano-based technology has emerged as a transformative approach in energy conversion applications, offering unprecedented opportunities to enhance efficiency, sustainability, and scalability. This comprehensive review explores the multifaceted utilization of nano-based technology across various energy conversion platforms, spanning from solar cells to fuel cells and beyond. Beginning with an overview of nanostructured materials, including nanoparticles, nanowires, and nanotubes, the review highlights their pivotal role in enhancing energy conversion processes. These nanostructures facilitate improved catalysis, charge transport, and light absorption, thus unlocking new frontiers in energy conversion efficiency. Next, the review delves into the application of nano-based technology in solar energy conversion, focusing on advancements such as quantum dots, perovskite materials, and plasmonic nanoparticles. These nano-enabled solar cells offer higher efficiencies, greater durability, and lower manufacturing costs, driving the widespread adoption of solar energy worldwide.