Preparation and photoluminescence properties of Mn Doped Zn-In-S quantum dots

Mn doped Zn-In-S quantum dots (QDs) were prepared and the effect of Zn/In molar ratio and reaction temperature on their photoluminescence properties were studied. A 600 nm photoluminescence band was observed in the doped QDs. The absorption band of the doped QDs could be tuned from 3.76 eV (330 nm) to 2.82 eV (440 nm) by changing the Zn/In ratio while the photoluminescence band around 600 nm only slightly shifted. The longest photoluminescence lifetime in the doped QDs reached up to 2.14 ms. When the reaction temperature increased to 230℃ from 200℃, the photoluminescence intensity of doped QDs increased and reached the maximum. When the temperature increased to 260℃, the photoluminescence intensity rapidly deceased. Further the temperature-dependent photoluminescence spectra of Mn doped Zn-In-S QDs were measured. It was found that the photoluminescence intensity significantly decreased, the photoluminescence peak slightly shifted to higher energy, and the linewidth of the photoluminescence increased with the increasing of temperature. It can be concluded that the emission in Mn doped Zn-In-S QDs originates from the radiative recombination of Mn2+ ions between 4T1 and 6A1 energy states. ©, 2015, Chines Academy of Sciences. All right reserved.