Structure Direction of II−VI Semiconductor Quantum Dot Binary Nanoparticle Superlattices by Tuning Radius Ratio
We report a nanoparticle radius ratio dependent study of the formation of binary nanoparticle superlattices (BNSLs) of CdTe and CdSe quantum dots. While keeping all other parameters identical in the system, the effective nanoparticle radius ratio, γeff, was tuned to allow the formation of five different BNSL structures, AlB2, cub-NaZn13, ico-NaZn13, CaCu5, and MgZn2. For each structure, γeff is located close to a local maximum of its space-filling factor, based on a model for space filling principles. We demonstrate the ability to select specific BNSLs based solely on γeff, highlighting the role of entropic forces as a driver for self-assembly.