CdSe nanocrystals, including quantum dots and quantum rods, are a research hotspot in nanomaterials. Recently, it has been found that two-dimensional CdSe semiconductor nanobelts show a unique quantum confinement effect… Click to show full abstract
CdSe nanocrystals, including quantum dots and quantum rods, are a research hotspot in nanomaterials. Recently, it has been found that two-dimensional CdSe semiconductor nanobelts show a unique quantum confinement effect owing to their homogeneous nanoscale thickness. In this study, a series of (CdSe) n·monoamine ( n = 1, 2, and 4, monoamine = butylamine, hexylamine, and octylamine) layered inorganic/organic hybrid nanobelts was synthesized by the solvothermal method. These hybrids have a lamellar structure with a few inorganic [CdSe] layers and monoamine layers alternatively stacked along the c axis of their crystallites, which exhibit the typical preferred orientation for layered crystallites and isomorphous [CdSe] layers according to their X-ray diffraction patterns. The [CdSe] layer is a contracted (110) superlattice cell of wurtzite (WZ)-type CdSe with unit cell parameter relations of a ≈ √3 aWZ and b ≈ cWZ, and a lamellar nanobelt morphology with the [010] growth direction. These ordered hybrids exhibit prominent split exciton absorption peaks and sharp band edge luminescence owing to the homogeneous thickness of the [CdSe] layers within the hybrids, all of which are comparable with reported WZ-type CdSe colloidal nanosheets and exhibit a prominent two-dimensional exciton quantum confinement effect. The solvothermal reaction was systematically investigated. The multiple stage amine de-intercalation topotactic process was revealed for the WZ-type CdSe nanobelts with the (CdSe) n·monoamine ( n = 1, 2, and 4) hybrids as the intermediate phases. The solvothermal synthesis method (70-150 °C) is facile and milder than the traditional hot injection method (>200 °C). Therefore, these hybrids can be considered to be intermediate phases or precursors of WZ-type CdSe nanosheets with a topotactic intralayer [CdSe] structure and also a type of multiple quantum well with extremely thin [CdSe] layers orderly stacked among the monoamine insulating blocking layers.
               
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