Fuente: Materials The global energy demand is projected to grow by nearly 30% between 2020 and 2040, necessitating a rapid transition to renewable sources like solar power, which has surpassed 1000 GW of installed capacity. However, the efficiency and cost-effectiveness of conventional solar cells remain critical barriers. This chapter comprehensively reviews how nanocomposites materials engineered with nanoscale components such as carbon nanotubes (CNTs), quantum dots (QDs), and plasmonic nanoparticles are revolutionizing photovoltaic (PV) technology. These materials enable remarkable performance enhancements: antireflection coatings boost silicon cell efficiency by 31.25%; CNT integration improves organic PV (OPV) performance by 20–50%; and QDs cells now achieve certified efficiencies exceeding 16%. Furthermore, nanocomposites are pivotal in record-breaking tandem cells, with perovskite-silicon architectures reaching 33.9% efficiency. The chapter details the mechanisms behind these gains, including light absorption enhancement, charge transport improvement, and recombination loss reduction. It also explores innovative applications in flexible and transparent solar cells, while critically addressing persistent challenges in stability, scalability, and cost where CNTs can add $0.15–0.25/W to module costs and environmental impact. By synthesizing the latest advances and hurdles, this analysis highlights the pivotal role of nanocomposites in developing the next generation of high-efficiency, versatile, and commercially viable solar technologies.