Water-based route to colloidal Mn-doped ZnSe and core/shell ZnSe/ZnS quantum dots.
Relatively monodisperse and highly luminescent Mn(2+)-doped zinc blende ZnSe nanocrystals were synthesized in aqueous solution at 100 °C using the nucleation-doping strategy. The effects of the experimental conditions and of the ligand on the synthesis of nanocrystals were investigated systematically. It was found that there were significant effects of molar ratio of precursors and heating time on the optical properties of ZnSe:Mn nanocrystals. Using 3-mercaptopropionic acid as capping ligand afforded 3.1 nm wide ZnSe:Mn quantum dots (QDs) with very low surface defect density and which exhibited the Mn(2+)-related orange luminescence. The post-preparative introduction of a ZnS shell at the surface of the Mn(2+)-doped ZnSe QDs improved their photoluminescence properties, resulting in stronger emission. A 2.5-fold increase in photoluminescence quantum yield (from 3.5 to 9%) and of Mn(2+) ion emission lifetime (from 0.62 to 1.39 ms) have been observed after surface passivation. The size and the structure of these QDs were also corroborated by using transmission electron microscopy, energy dispersive spectroscopy, and X-ray powder diffraction.
Laboratoire Réactions et Génie des Procédés (LRGP), UPR 3349, Nancy-University, CNRS, 1 rue Grandville, 54001 Nancy Cedex, France.
Abdelhay
A
Aboulaich
Malgorzata
M
Geszke
Lavinia
L
Balan
Jaafar
J
Ghanbaja
Ghouti
G
Medjahdi
Raphaël
R
Schneider
D003102:Colloids / Q000737:chemistry; D006358:Hot Temperature; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
D003102:Colloids; D049408:Luminescent Agents; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D014867:Water; D008345:Manganese; C031238:zinc sulfide; C044696:zinc selenide