Mn2+-doping

Many approaches have been taken to prepare colloidal doped semiconductor nanocrystals. For example, hot-injection methods have been used to synthesize colloidal Mn2+-doped CdSe (47, 48), ZnSe (49), and PbSe (50) colloidal nanocrystals. Colloidal ZnO DMS-QDs doped with Co2+, Ni2+, and Mn2+ have been prepared by low-temperature hydrolysis and condensation (51-54). Sol-gel methods have been used to prepare colloidal doped TiC>2 (55-57) and Sn02 (58-62) nanocrystals. Inverted micelle methods have been used for preparation of a range of doped II-VI sulfide DMS-QDs at low temperatures (63-68). A high-temperature lyothermal single-source method was used to synthesize Co2+- and Eu3+-doped CdSe nanocrystals (69, 70). Autoclaving has occasionally been used to induce crystallization at lower temperatures than reached under atmospheric pressures while retaining colloidal properties, for... 

The sensitivity of EPR to multiple coordination environments has been demonstrated in studies of Mn2+-doped CdS nanocrystals (63). In Mn2+ CdS nanocrystalline powders prepared by inverted micelle synthesis, four distinct resonances were observed and deconvoluted by varying experimental parameters including microwave power, microwave frequency, and temperature. The deconvoluted signals are shown in Fig. 18. Four distinct manganese species were detected through this experiment. A six line spectrum characteristic of isolated paramagnetic Mn2+ was observed at 300 K and below [multiline... 

Mn2+ CdS nanocrystals prepared by this method. A similar approach has been applied to colloidal Mn2+ -doped ZnSe nanocrystals (90) prepared via a singlesource precursor method (Section II.A), which showed evidence for both a disordered surface-bound or near-surface Mn2+ and an internal substitutional Mn2+. In both of these studies, this information was then applied in the analysis of energy-transfer processes involving the near-surface Mn2+ ions. 

The synthesis of Mn2+-doped CdS nanocrystals has been studied by several groups. In one such study (82), the doped CdS nanocrystals were prepared by simple mixing of ethylene glycol solutions of cadmium and manganese acetate with a solution of sodium sulfide, followed by washing with methanol and thermal treatment in triethyl phosphate to deagglomerate the particles. Mean... 

In one recent study, Mn2+-doped CdS nanocrystals grown with a ZnS passivating shell were used as the recombination centers in direct current (dc) electroluminescent devices (104). The Mn2+ CdS/ZnS nanocrystals were prepared by the inverse micelle procedure (102) (see Section II.C) and these colloids were incorporated into a multilayer device structure by spin-coat... 

Panel (d) shows two juxtaposed CL images of Mn2+-doped hydroxyapatite on a Ti6Al4V substrate (see also Figure 7.21) (Gotze, 2000 Gotze ef al., 2001). 

Figure 7.21 Cathodoluminescence images of Mn2+-doped hydroxyapatite powder (top), an as-sprayed coating (a), and coatings incubated in r-SBF (SBF-H, Table 7.8) for 1 day (b),...

Figure 7.22 Cathodoluminescence emission spectra of Mn2+ doped plasma-sprayed hydroxyapatite coatings in the as-sprayed state (KT) and immersed in HBSS for 7 (7KT) and 28 (28KT) days (Gotze, 2000).

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