Comparison of HgI2 nanostructures obtained in suspension in ODE and ODE/ODA

Mercuric iodide is a vast studied semiconductor because of its properties as photoconductor. One of its main applications is as material for ionizing radiation detection. Moreover, the inclusion of HgI₂ nanostructures in hybrid solar cells can be visualized as a new application. In the present work, mercuric iodide nanostructures were synthesized by the suspension method in 1-octadecene (ODE) from Hg(NO₃)₂.H₂O and I₂; and in 1-octadecene/octadecylamine (ODA) from HgO and I₂. The obtained products were centrifuged and washed with heptane. X-ray diffraction (XRD) was performed to nanostructures to confirm HgI₂ identity. Nanostructures size, morphology and crystallinity were determined by XRD, transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Nanoparticles were also observed by scanning electron microscopy (SEM). Crystalline nanostructures were obtained in ODE; they grow with their planes perpendicular to the [1 1 2] and [2 1 2] directions and have sizes between 40 and 300 nm depending on the synthesis time. HgI₂ nanostructures obtained in ODE/ODA showed a different morphology, grow with their planes perpendicular to the [1 0 2] and [1 1 2] directions, planes and have sizes between 10 and 70 nm. Results show that nanostructures morphology and size are influenced by the ODA and this fact can be used to control HgI₂ nanostructures properties for several applications including ionizing radiation imaging and hybrid solar cells development.