Photoluminescence properties and energy transfer processes from excitons to Mn2+ ions in Mn2+-doped CdS quantum dots prepared by a reverse-micelle method
Photoluminescence properties and energy transfer processes from excitons to Mn2+ ions in Mn2+-doped CdS quantum dots prepared by a reverse-micelle method
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DOI：
10.1063/1.2363238
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发表时间：
2006-11
影响因子：
3.2
通讯作者：
Daegwi Kim;M. Miyamoto;M. Nakayama
中科院分区：
文献类型：
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作者：
Daegwi Kim;M. Miyamoto;M. Nakayama
研究了反胶束法制备的Mn ~（2+）掺杂CdS（CdS：Mn ~（2+））量子点的光致发光（PL）特性。在~ 2.1eV处清晰地观察到一个源于四面体配位的Mn ~（2+）离子的胞内跃迁（即所谓的d-d跃迁）的PL带，表明Mn ~（2+）离子完全掺杂在CdS量子点内部。通过用Cd（OH）2层进行表面改性，与Mn 2+相关的PL带的强度与未改性的相比增加了约10倍，并且观察到带边PL带的强烈增强。表面修饰的CdS：Mn 2+量子点的带边光致发光的衰减曲线比未掺杂的CdS量子点的带边光致发光的衰减曲线快得多;这种缩短的衰减时间源于从基质量子点的激子到Mn 2+离子的有效能量转移过程。PL衰减曲线的基础上，包括暗激子态和能量转移过程的三能级模型进行了定量解释。
We investigated the photoluminescence (PL) properties of Mn2+-doped CdS (CdS:Mn2+) quantum dots (QDs) prepared by a reverse-micelle method. A PL band which originates from the intracation transition, the so-called d‐d transition, of tetrahedrally coordinated Mn2+ ions, is clearly observed at ∼2.1eV, indicating that Mn2+ ions are thoroughly doped inside CdS QDs. By surface modification with a Cd(OH)2 layer, the intensity of the Mn2+-related PL band is increased approximately ten times compared with that without modification, and strong enhancement of the band-edge PL band is observed. The decay profile of the band-edge PL in surface-modified CdS:Mn2+ QDs is much faster than that in undoped CdS QDs; this shortened decay time originates from the effective energy transfer process from the excitons of host QDs to Mn2+ ions. The PL decay profiles are quantitatively explained on the basis of a three-level model including both the dark-exciton state and the energy transfer process.