Back to Search
Start Over
Exploring Mn2+-location-dependent red emission from (Mn/Zn)–Ga–Sn–S supertetrahedral nanoclusters with relatively precise dopant positions.
- Source :
- Journal of Materials Chemistry C; 11/28/2016, Vol. 4 Issue 44, p10435-10444, 10p
- Publication Year :
- 2016
-
Abstract
- Mn<superscript>2+</superscript>-Doped semiconductor nanocrystals or quantum dots have been extensively studied as potential yellow/orange/red phosphors due to the stable Mn<superscript>2+</superscript>-related emission tuned by its tetrahedral coordination environment in host lattices. However, it is still very difficult to objectively explore the location–performance relationship in conventional Mn<superscript>2+</superscript>-doped nanomaterials since the precise location information on Mn<superscript>2+</superscript> dopants is generally unavailable due to their random distribution in host lattices. Herein, we purposely selected a specific supertetrahedral-nanocluster-based molecular crystal (OCF-40-ZnGaSnS, composed of isolated supertetrahedral T4-ZnGaSnS nanoclusters (NCs) with the formula [Zn<subscript>4</subscript>Ga<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript>) as a host lattice, and effectively controlled the relatively precise position of Mn<superscript>2+</superscript> dopants in host lattices of T4-ZnGaSnS NCs by in situ substitution of Zn<superscript>2+</superscript> sites by Mn<superscript>2+</superscript> ions, and investigated the Mn<superscript>2+</superscript>-location-dependent red emission properties. The current study clearly indicates that a long-lifetime (∼170 μs) red emission centred at 625 nm at room temperature for lightly-doped [Zn<subscript>3</subscript>MnGa<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript> NCs with one Mn<superscript>2+</superscript> dopant in its surface centre is very sensitive to temperature and dramatically red-shifts to 645 nm at 33 K upon the excitation of 474 nm. However, heavily-doped OCF-40-MnGaSnS (composed of T4-MnGaSnS NCs with the formula [Mn<subscript>4</subscript>Ga<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript>, in which four Mn<superscript>2+</superscript> dopants are accurately located at its core in the form of Mn<subscript>4</subscript>S) gives the temperature-insensitive red emission with a longer wavelength (641 nm) and a shorter lifetime (42 μs) at room temperature. This phenomenon is pretty uncommon compared to other heavily Mn<superscript>2+</superscript>-doped semiconductors. Such differences in their PL properties are ascribed to Mn<superscript>2+</superscript>-location-induced lattice strain to different degrees in two Mn<superscript>2+</superscript>-doped supertetrahedral NCs. In addition, the Mn<superscript>2+</superscript>-related red emission of both samples can be predominantly induced by the direct excitation of Mn<superscript>2+</superscript> ions and secondarily by indirect excitation through exciton energy transfer from host lattices to Mn<superscript>2+</superscript> dopants. Consistently, the DFT calculations suggest that the emission of NCs originated from the transition from the low spin excited state of Mn<superscript>2+</superscript> (<superscript>4</superscript>T<subscript>1</subscript>) to its high spin ground state (<superscript>6</superscript>A<subscript>1</subscript>). The calculation results also revealed that the emission wavelength of lightly-doped [Zn<subscript>3</subscript>MnGa<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript> NCs is not obviously affected by the temperature-induced thermal effect, but by temperature-induced structural contraction, while that of heavily-doped [Mn<subscript>4</subscript>Ga<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript> NCs is affected by both effects. The total temperature cooling effect on the emission of [Zn<subscript>3</subscript>MnGa<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript> NCs is the red-shift, while that on the emission of [Mn<subscript>4</subscript>Ga<subscript>14</subscript>Sn<subscript>2</subscript>S<subscript>35</subscript>]<superscript>12−</superscript> NCs is negligible, which is akin to the experimental results. This research opens up a new perspective and provides a feasible method to explore the location–performance relationship of other Mn<superscript>2+</superscript>-doped NCs. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507526
- Volume :
- 4
- Issue :
- 44
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry C
- Publication Type :
- Academic Journal
- Accession number :
- 119387793
- Full Text :
- https://doi.org/10.1039/c6tc03844a