title: Thermal stability of Mn2+ ion luminescence in Mn-doped core-shell quantum dots.
abstract: The thermal stability of luminescence is important for the application of quantum dots (QDs) in light-emitting devices. The temperature-dependent photoluminescence (PL) intensities and decay times of Mn-doped ZnS, ZnSe, and ZnSeS alloyed core-shell QD films were studied in the temperature range from 80 to 500 K by steady-state and time-resolved PL spectroscopy. It was found that the thermal stability of Mn-doped QD emissions was significantly dependent on the shell thickness and the host bandgap, which was higher than that of workhorse CdSe QDs. Nearly no PL quenching took place in Mn:ZnS QDs with a thick ZnS shell, which kept a high PL quantum yield (QY) of ~50% even at 500 K; and the thermally stable PL was also observed in highly luminescent Mn:ZnSe and Mn:ZnSeS QDs with a quenching temperature over 200 °C. Further, the stability of Mn-doped QDs with different shell thickness at high temperature was also examined through heating-cooling cycling experiments. The PL quenching in the thick shell-coated Mn-doped QDs was almost totally recovered. The PL quenching mechanisms of the Mn(2+) ion emissions were discussed.
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China. zhaojl@ciomp.ac.cn.
authors.forename: Xi
authors.initials: X
authors.lastname: Yuan
authors.forename: Jinju
authors.initials: J
authors.lastname: Zheng
authors.forename: Ruosheng
authors.initials: R
authors.lastname: Zeng
authors.forename: Pengtao
authors.initials: P
authors.lastname: Jing
authors.forename: Wenyu
authors.initials: W
authors.lastname: Ji
authors.forename: Jialong
authors.initials: J
authors.lastname: Zhao
authors.forename: Weiyou
authors.initials: W
authors.lastname: Yang
authors.forename: Haibo
authors.initials: H
authors.lastname: Li