Quantum Dots-Enabled Downshifting and Downconversion Strategies for Enhanced Photovoltaics

The photovoltaic (PV) efficiency of a solar cell is limited by the Shockley–Queisser limit, stemming from the mismatch between the cell’s bandgap and the solar spectrum. This issue can be addressed by integrating a downconverter layer that transforms high-energy ultraviolet (UV) photons into visible/near-infrared ones, which the solar cell can absorb more effectively. Quantum dots (QDs), with their tunable bandgap, high quantum yield, large Stokes shift, and multiexciton generation, show strong potential for such applications. However, an in-depth review of quantum-dot-based downconverters, including the selection of appropriate semiconductor QDs based on key downconversion/downshifting properties, and their integration challenges remains largely unexplored. This account presents a comprehensive overview of recent developments in QD-based downconverters for advanced photovoltaic systems, highlighting their advantages over conventional materials. To elucidate the topic, fundamental strategies for harvesting solar UV photons were discussed, particularly through downshifting and downconversion processes. Furthermore, this review addressed the key challenges associated with QD-based downconverter materials and their integration into existing photovoltaic systems, while also outlining a roadmap for future research. Finally, this review presents innovative strategies to improve the efficiency of QD-based downconverters, emphasizing advancements in material design and device architecture. By outlining these key strategies, the article seeks to drive transformative advancements in QD-based downconverter technology, aiming to maximize solar energy harvesting and surpass the photovoltaic efficiency limits set by the Shockley–Queisser threshold.