Thermochemical growth of Mn-doped CdS nanoparticles and study of luminescence evolution

We report a new method of growing Mn-doped CdS (CdS:Mn) nanoparticles in an aqueous solution at boiling temperature. The idea is to use precursors that react only at high temperature, in order to gain crystalline luminescent nanoparticles. CdSO(4), Mn(NO(3))(2) and Na(2)S(2)O(3) were used as the precursors, and thioglycerol was employed as the capping agent and also the reaction catalyst. Na(2)S(2)O(3) is thermally sensitive and it releases S(2-) ions upon heating. The CdS:Mn nanoparticles obtained are about 4 nm in size and show both cubic and hexagonal crystalline phases with a ratio of 35% to 65%. The luminescence of nanoparticles contains a peak at 580 nm, which is related to Mn(2+) ions. Prolonged reaction time results in a decrease of the Mn luminescence peak to about 35% of the maximum value. We discuss the possible causes of the Mn peak reduction and attribute it to preferential dissolution of Mn ions into the solution due to shape reconfiguration of the nanoparticles.