Semiconductor Nanocrystal Heterostructures: Near-Infrared Emitting PbSe-Tipped CdSe Tetrapods

We report on a near-infrared (NIR)-emitting semiconductor nanocrystal (NC) heterostructure with tunable optical properties. This heterostructure is built of two different semiconductor sections in the same NC combining various absorption/emission properties of each constituent part. In our approach, PbSe NCs of different sizes are grown on the tips of CdSe tetrapods (TPs) serving as seeds. In these structures, the CdSe TP acts as an efficient light-harvesting antenna, which can transfer the energy to the PbSe NCs heterogeneously grown on the tips. In turn, the PbSe domains receive the transferred energy from CdSe and perform as NIR light emitters. By adjusting the reaction parameters, we achieved precise control of the optical properties of these PbSe-tipped CdSe TPs, resulting in the fine-tuning of their emission maxima over a wide range from 1000 nm to more than 2000 nm. The obtained results demonstrate the potential and functionality of these heterostructures as novel NIR emitting nanomaterials, which makes them promising candidates to be used in the field of optoelectronics, for example, in NIR light-emitting diodes.