Tuning Temperature Dependence of Dopant Luminescence via Local Lattice Strain in Core/Shell Nanocrystal Structure

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• 作者：Hsiang-Yun Chen ; Sourav Maiti ; Cory A. Nelson ; Xiaoyang Zhu ; Dong Hee Son
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 8, 2012
• 年：2012
• 卷：116
• 期：44
• 页码：23838-23843
• 全文大小：339K
• 年卷期：v.116,no.44(November 8, 2012)
• ISSN：1932-7455

文摘

We report the tunable temperature dependence of Mn luminescence spectral characteristics (peak position and bandwidth) in Mn-doped CdS/ZnS core/shell nanocrystals via controlled local lattice strain at the dopant site that affects the local vibronic coupling and local thermal expansion. The lattice mismatch at the core/shell interface creates a gradient of lattice strain in the shell along the radial direction that allows varying the local lattice strain at the Mn²⁺ site via the controlled radial doping location. Increasing the local lattice strain at the Mn²⁺ site results in the stronger temperature broadening of Mn luminescence bandwidth due to the increasing softening of the vibrational mode coupled to Mn²⁺ ligand field transition. Larger local lattice strain also causes a stronger temperature dependence of the luminescence peak, which indicates the enhanced local thermal expansion at the dopant site.