We have studied the mechanism of photoluminescence (PL) from MnS/ZnS core/shell quantum dots (QDs) synthesized via hot solution phase chemistry using a nucleation-doping strategy. Efficient PL of the Mn2+ ions with a quantum yield (QY) of over 35% is demonstrated in the resulting QDs coated with a thick ZnS shell oil the MnS core. The MnS/ZnS core/shell QDs with a thick shell exhibit PL enhancement with increasing temperature in the range between 140 and 300 K, resulting from the thermal activation of charge carriers localized at the interface between the MnS core and the ZnS shell. The PL decays of the Mn2+ ions in the core/shell QDs consist of three exponential components with time constants oil the scales of 1-2 ms, hundreds of mu s, and tens of mu s. Surprisingly, the PL lifetimes of Mn2+, ions show a very weak dependence on the shell thickness, which is clearly different from that of the PL QY of the QDs. The experimental results indicate that the mechanism for improving the PL QY in MnS/ZnS QDs can be understood in terms of a significantly enhanced energy transfer from the ZnS shell to Mn2+ ions and a slightly decreased nonradiative relaxation rate from Mn2+ ions to surface states/traps of the ZnS shell by the surface passivation of the QDs with a thick ZnS shell.
Zheng J. J.,Yuan X.,Ikezawa M.,et al. Efficient Photoluminescence of Mn2+ Ions in MnS/ZnS Core/Shell Quantum Dots[J]. Journal of Physical Chemistry C,2009,113(39):16969-16974.
APA
Zheng J. J..,Yuan X..,Ikezawa M..,Jing P. T..,Liu X. Y..,...&Masumoto Y..(2009).Efficient Photoluminescence of Mn2+ Ions in MnS/ZnS Core/Shell Quantum Dots.Journal of Physical Chemistry C,113(39),16969-16974.
MLA
Zheng J. J.,et al."Efficient Photoluminescence of Mn2+ Ions in MnS/ZnS Core/Shell Quantum Dots".Journal of Physical Chemistry C 113.39(2009):16969-16974.
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