Photoluminescence Enhancement of ZnS:Mn2+ Nanocrystal Phosphors: Comparison of Organic and Inorganic Surface Modifications
Photoluminescence Enhancement of ZnS:Mn2+ Nanocrystal Phosphors: Comparison of Organic and Inorganic Surface Modifications
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DOI：
10.1143/jjap.44.922
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发表时间：
2005-02
影响因子：
1.5
通讯作者：
Hayato Takahashi;T. Isobe
中科院分区：
文献类型：
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作者：
Hayato Takahashi;T. Isobe
通过透射电子能谱分析，在直径为3nm的ZnS:Mn2+纳米晶体表面包覆二氧化硅，形成了直径为20±4 nm的核壳颗粒。对于二氧化硅修饰的ZnS:Mn2+纳米晶体，由于Mn2+的d-d跃迁引起的光致发光（PL）强度随着正硅酸四乙酯（TEOS）用量的增加而增加，从而随着二氧化硅外壳厚度的增加而增加。这归因于表面缺陷的钝化和量子限制效应。相反，磷酸十二烷基（HLP）和二氧化硅改性的ZnS:Mn2+纳米晶体的发光强度随着TEOS用量的增加而降低。31P CP/MAS NMR表明，磷酸基团与ZnS:Mn2+之间的化学相互作用被二氧化硅壳打断。这些结果表明，从PL增强的角度来看，HLP在ZnS:Mn2+纳米晶体周围的表面改性比形成二氧化硅壳更有效。
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:Mn2+ 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:Mn2+ 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.