The band edge luminescence of surface modified CdSe nanocrystallites: Probing the luminescing state

被引:581
作者
Kuno, M
Lee, JK
Dabbousi, BO
Mikulec, FV
Bawendi, MG
机构
[1] Department of Chemistry, Massachusetts Inst. of Technology, Cambridge, MA 02139
关键词
D O I
10.1063/1.473875
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We study the luminescence of surface modified CdSe nanocrystallites. There has been much speculation as to the origin of the band edge emission in these quantum confined structures. Because of their large surface to volume ratios it has been suggested that the emission originates from surface-related states. However, recent theory suggests that the band edge luminescence arises from an optically inactive fine structure state or ''dark'' exciton. To address this issue we modify the surface of CdSe nanocrystallites with a variety of organic and inorganic ligands. We then monitor the effect changing the surface has on the energetics of the band edge luminescence through photoluminescence and fluorescence line narrowing experiments. Our results are compared with theoretical predictions for the nonresonant and resonant luminescence. We find good agreement between experiment and theory for CdSe nanocrystallites passivated with trioctylphosphine oxide, ZnS, 4-picoline, 4-(trifluoromethyl)thiophenol, and tris(2-ethylhexyl)phosphate. The lack of dependence of our data on surface modification is consistent with a dark exciton description of the band edge luminescence. (C) 1997 American Institute of Physics.
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页码:9869 / 9882
页数:14
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