Synthesis and characterization of transition metal doped ZnSe/ZnS nanocrystals by a rapid photochemical method

In the present work, a one pot, rapid and room temperature photochemical Synthesis of transition metal (TM; Cu, Mn, Cr)-doped ZnSe/ZnS core/shell nanocrystals (NCs) was reported. FT-IR spectrum confirmed the capping of ZnSe by thioglycolic acid. XRD and TEM analysis demonstrated zinc blende phase NCs with an average size of around 3 and 5 nm for TM:ZnSe and TM:ZnSe/ZnS NCs, respectively. PL spectra of ZnSe NCs showed a broad emission with two peaks located at 380 and 490 nm related to exitonic and trap states emission, respectively. For ZnSe:Cu NCs, exitonic emission disappeared completely and PL intensity of trap states emission increased. For ZnSe:Mn and ZnSe:Cr NCs, the exitonic emission decreased gradually with the increase in the impurity concentration whereas trap state emission increased. Moreover a peak about 580 nm was appeared from 4T1-6A1 transition of the Mn impurity. ZnS Shell increased photoluminescence and stability of all of TM-doped ZnSe NCs.