**Acknowledgements**

*Transition Metal Compounds - Synthesis, Properties, and Application*

the estimate of the relative concentrations of Mn2 + ions for samples containing Cd1-xMnxTe USQDs with x = 0.010, 0.050 and 0.100. It is observed that the increase in the concentration of manganese results in an increase in the concentration of Mn2+ ions inserted in the CdTe USQDs. Therefore, these results confirm the growth

*(a) Optical absorption spectra (b, c) AFM images, (d) Luminescence spectra, (e) Energy Diagram (f) EPR spectra, (g) Mn2+ ions Concentration of samples containing Cd1-xMnxTe UPNCs, with Mn-concentrations* 

Therefore, this chapter shows how the incorporation of transition metals in nanocrystals can change their physical, chemical, and biological properties. In addition, depending on the application, these nanocrystals may be in powder or host glass systems. Interestingly, the doping with iron ions in the ZnO NCs did not change for malachite green degradation in relation of ZnO NCs. However, the doping with copper ions in ZnO NCs improved in the biocompatibility of ZnO NCs. Regarding physical properties, the incorporation of transition metals in semiconductors, allows the emergence of the magneto-optical properties as shown in nanocrystals doped with manganese, chromium or nickel ions, and their manipulation depend on the concentration and heat treatment when embedded

**92**

of Cd1-xMnxTe USQDs.

*ranging from x = 0.000 to x = 0.100.*

**2. Conclusion**

**Figure 5.**

in glass matrices.

This work was supported by grants of CNPq, CAPES, and FAPEMIG.
