Photoluminescence enhancement of ZnS: Mn2+ nanocrystal phosphors: Comparison of organic and inorganic surface modifications

Hayato Takahashi, Tetsuhiko Isobe

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16 Citations (Scopus)

Abstract

ZnS:Mn2+ nanocrystals of 3 nm in diameter were coated with silica to form 20 ± 4 nm core/shell particles, as observed by transmission electron spectroscopy. For ZnS:Mn2+ nanocrystals modified with silica, the intensity of photoluminescence (PL) due to the d-d transition of Mn2+ increases with increasing tetraethyl orthosilicate (TEOS) amount and hence with increasing the thickness of silica shell. This is attributed to the passivation of surface defects and the quantum confinement effect. On the contrary, the PL intensity of the ZnS:Mn 2+ nanocrystals modified by both lauryl phosphate (HLP) and silica decreases with increasing TEOS amount. 31P CP/MAS NMR spectroscopy reveals that the chemical interaction between phosphate groups and ZnS:Mn 2+ is interrupted by the silica shell. These results suggest that the surface modification of HLP around the ZnS:Mn2+ nanocrystals is more effective than the formation of the silica shell from the viewpoint of PL enhancement.

Original languageEnglish
Pages (from-to)922-925
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume44
Issue number2
DOIs
Publication statusPublished - 2005 Feb

Fingerprint

Phosphors
Nanocrystals
phosphors
Surface treatment
Photoluminescence
nanocrystals
Silica
silicon dioxide
photoluminescence
augmentation
tetraethyl orthosilicate
phosphates
Phosphates
Quantum confinement
Electron spectroscopy
Surface defects
surface defects
Passivation
Nuclear magnetic resonance spectroscopy
passivity

Keywords

  • Nanocrystal
  • Phosphor
  • Photoluminescence
  • Quantum confinement effect
  • Surface modification
  • ZnS:Mn

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

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title = "Photoluminescence enhancement of ZnS: Mn2+ nanocrystal phosphors: Comparison of organic and inorganic surface modifications",
abstract = "ZnS:Mn2+ nanocrystals of 3 nm in diameter were coated with silica to form 20 ± 4 nm core/shell particles, as observed by transmission electron spectroscopy. For ZnS:Mn2+ nanocrystals modified with silica, the intensity of photoluminescence (PL) due to the d-d transition of Mn2+ increases with increasing tetraethyl orthosilicate (TEOS) amount and hence with increasing the thickness of silica shell. This is attributed to the passivation of surface defects and the quantum confinement effect. On the contrary, the PL intensity of the ZnS:Mn 2+ nanocrystals modified by both lauryl phosphate (HLP) and silica decreases with increasing TEOS amount. 31P CP/MAS NMR spectroscopy reveals that the chemical interaction between phosphate groups and ZnS:Mn 2+ is interrupted by the silica shell. These results suggest that the surface modification of HLP around the ZnS:Mn2+ nanocrystals is more effective than the formation of the silica shell from the viewpoint of PL enhancement.",
keywords = "Nanocrystal, Phosphor, Photoluminescence, Quantum confinement effect, Surface modification, ZnS:Mn",
author = "Hayato Takahashi and Tetsuhiko Isobe",
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T2 - Mn2+ nanocrystal phosphors: Comparison of organic and inorganic surface modifications

AU - Takahashi, Hayato

AU - Isobe, Tetsuhiko

PY - 2005/2

Y1 - 2005/2

N2 - ZnS:Mn2+ nanocrystals of 3 nm in diameter were coated with silica to form 20 ± 4 nm core/shell particles, as observed by transmission electron spectroscopy. For ZnS:Mn2+ nanocrystals modified with silica, the intensity of photoluminescence (PL) due to the d-d transition of Mn2+ increases with increasing tetraethyl orthosilicate (TEOS) amount and hence with increasing the thickness of silica shell. This is attributed to the passivation of surface defects and the quantum confinement effect. On the contrary, the PL intensity of the ZnS:Mn 2+ nanocrystals modified by both lauryl phosphate (HLP) and silica decreases with increasing TEOS amount. 31P CP/MAS NMR spectroscopy reveals that the chemical interaction between phosphate groups and ZnS:Mn 2+ is interrupted by the silica shell. These results suggest that the surface modification of HLP around the ZnS:Mn2+ nanocrystals is more effective than the formation of the silica shell from the viewpoint of PL enhancement.

AB - ZnS:Mn2+ nanocrystals of 3 nm in diameter were coated with silica to form 20 ± 4 nm core/shell particles, as observed by transmission electron spectroscopy. For ZnS:Mn2+ nanocrystals modified with silica, the intensity of photoluminescence (PL) due to the d-d transition of Mn2+ increases with increasing tetraethyl orthosilicate (TEOS) amount and hence with increasing the thickness of silica shell. This is attributed to the passivation of surface defects and the quantum confinement effect. On the contrary, the PL intensity of the ZnS:Mn 2+ nanocrystals modified by both lauryl phosphate (HLP) and silica decreases with increasing TEOS amount. 31P CP/MAS NMR spectroscopy reveals that the chemical interaction between phosphate groups and ZnS:Mn 2+ is interrupted by the silica shell. These results suggest that the surface modification of HLP around the ZnS:Mn2+ nanocrystals is more effective than the formation of the silica shell from the viewpoint of PL enhancement.

KW - Nanocrystal

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KW - Quantum confinement effect

KW - Surface modification

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