Monte Carlo study on the self-assembly of nanoparticles into a nanorod structure

It is well known that semiconductor nanoparticles (NPs) can assemble into a range of low dimensional structures, such as nanowires, nanorods and nanosheets. In this study, we investigate the self-assembly of CdTe NPs by using Monte Carlo simulation. Using a simple model for the anisotropic interaction of NPs, the present Monte Carlo simulation demonstrated that NPs with large dipole moments assemble spontaneously into a nanorod even if the short range interactions among NPs is isotropic. Interestingly, we found that the present nanorod grew by forming a transient structure which looks similar to a double ring. For NPs similar to CdTe, the dipole-dipole interaction had a dominant effect over van der Waals attractions and steric repulsion on the final structure of the NP aggregates. The simulated rods are similar to those observed in the experimental self-assembly of CdTe NPs. The NPs with relatively small electric dipole moments aggregated into more or less isotropic structures.