Hot-Injection Synthesis of HgTe Nanoparticles: Shape Control and Growth Mechanisms

Different planesof HgTe nanoparticles have different unsaturatedbonds of Hg to combine the -NH2 of OAm. Thus, OAmcan passivate the crystal planes anisotropically. Meanwhile, the bindof Hg and OAm can be broken by increasing the reaction temperaturegradually. Hence, HgTe nanoparticles show different shapes under differentreaction temperatures. Understanding the growth mechanisms of HgTe nanoparticles(NPs)with varied shapes is crucial for their applications in infrared photodetection.Here, we investigated the growth mechanisms of HgTe NPs with nanorod,sphere, and tetrahedral shapes in depth. The HgTe NPs with a nanorodshape are obtained at low reaction temperatures and formed by breakingtetrapod branches, while HgTe NPs with sphere and tetrahedron shapeshave been further achieved at increased reaction temperatures. Thesystematic crystal analyses demonstrate this effective shape controlis related to the synergic effect among the anisotropic passivationof oleylamine, surface free energy, and reaction temperatures. Ourfindings have deepened the understanding of shape control of the HgTeNPs and inspired a growing passion in the design and engineering ofinfrared photodetectors using HgTe NPs.

Automated summary

HgTe nanoparticles have different shapes depending on the planes and the reaction temperature, due to the combination of Hg unsaturated bonds and -NH2 of OAm. The understanding of their growth mechanisms is crucial for their applications in infrared photodetection. The shape control of HgTe nanoparticles is achieved through the synergistic effect of anisotropic passivation, surface free energy, and reaction temperatures.