Visible to Near-Infrared Sensitization of Silicon Substrates <italic>via</italic> Energy Transfer from Proximal Nanocrystals: Further Insights for Hybrid Photovoltaics

H arvesting solar energy is an important objective to fulfill the evergrowing energy demand. As a result, several new types of solar cells (SCs) have been introduced and discussed over the last two decades based onmaterials and principles that are quite different from the original crystalline Si p-n junction cell. 4 The quest for higher efficiency and lower production cost SCs with extended lifetime and versatile applications is driving the research. Despite much progress, many of these new approaches are yet to reach conceptual and operational maturity. The actual photovoltaic (PV) module production nowadays continues to overwhelmingly rely on Si technology. While some singleand multi-junction devices exhibit record efficiencies, the efficiencies of most of the manufactured SCs remain in the 10 18% range, well below the thermodynamic limits for the photovoltaic conversion. Hence, there is a well-recognized need and continuing effort to explore more opportunities to improve different aspects and/or achieve certain goals of SC performance and operation. According to an interesting recent viewpoint, such opportunities may lie not only within the realm of the so-called thirdgeneration photovoltaics (multiple-carrier generation, upand down-conversion, etc.) but also within a more familiar framework of a single-band-gap SC when combined with modern advances in the control of light and material processing. Nanostructured materials attract considerable attention as candidates for PV devices. Among them, inorganic colloidal nanocrystal quantumdots (NQDs) have gained large popularity as photon absorbers owing to their * Address correspondence to [email protected].