Near-Infrared Emission from CdSe-Based Nanoplatelets Induced by Ytterbium Doping

Cadmium selenide (CdSe) nanoplatelets (NPLs) have attracted significant attention thanks to their favorable optical properties, including narrow emission linewidths, reduced Auger recombination, and a high absorption cross section. However, the photoluminescence (PL) quantum yield (QY) in the near-infrared (NIR) region is poor as compared to that in the visible region. Doping of metal ions is proven to be a successful strategy for inducing Stokes-shifted NIR emission. Here, we report the first account of the successful doping of ytterbium (Yb) into CdSe NPLs by a modified seeded-growth method. The successful incorporation of divalent Yb ions into CdSe NPLs resulted in an additional NIR emission apart from their excitonic emission. By optimizing the dopant concentration, we observed an impressive PL QY of similar to 55% for these Yb-doped NPLs. Detailed elemental and optical characterizations were conducted to understand the emerging photophysical properties of these Yb-doped NPLs. These NIR-emitting lanthanide-doped CdSe NPLs might have applications in the next-generation bioimaging, night vision, and photodetection.