Synthesis of type II CdTe/CdSe heterostructure tetrapod nanocrystals for PV applications

We report a facile one-pot synthetic method for the formation of CdTe/CdSe tetrapod nanocrystals with type II band alignment. The crystal growth kinetics can be controlled by changing the injection temperature, rate and concentration of the chalcogen precursor, allowing the structure of CdTe/CdSe tetrapod nanocrystals to be synthesized without changing the underlying chemistry. Only the multiple injection of Se precursor promotes epitaxial growth of a CdSe nanorod on the end of CdTe tetrapod arms. This synthesis shows that the mechanism of tetrapod nucleated growth may be generally applicable for creating other non-core/shell heterostructures. The heterostructure nanocrystals are composed of a CdTe tetrapod core and four CdSe nanorod tips, showing optical properties typical of type II heterostructures that are well suited for photovoltaic applications.