Res. Chem. Intermed.
, Vol. 33, No. 7, pp. 655–661 (2007)
Also available online - www.brill.nl/rci
Photo-induced interfacial electron transfer from CdSe
quantum dots to surface-bound p-benzoquinone and
DEWU LONG, GUOZHONG WU
, WENFENG WANG and SIDE YAO
Department of Nuclear Analysis, Shanghai Institute of Applied Physics,
Chinese Academy of Sciences, Shanghai, 201800, China
Received 28 September 1996; accepted 18 May 2007
Abstract—Here we report transient spectral red-shift and transient absorption enhancement of
p-benzoquinone radical in the presence of CdSe quantum dots after 355 nm pulse laser excitation. The
spectral shift was caused by surface-bound p-benzoquinone molecules while the transient absorption
increase was due to interfacial electron transfer from CdSe quantum dots to p-benzoquinone
molecules. In contrast, spectral shift and absorption increase were much less signiﬁcant for
anthraquinone in the presence of CdSe quantum dots due to their weak adsorption abilities.
Keywords: Spectral shift; p-benzoquinone; anthraquinone; quantum dots; absorption enhancement.
Semiconductor quantum dots have been widely investigated due to their remark-
able size-tunable emission properties [1– 3], their potential application in biological
luminescent labeling [4, 5] and advanced sensors [6–9]. In the synthesis proce-
dure, organic molecules are usually immobilized at the surface of semiconductor
nanoparticles to protect against their aggregation. Solvent molecules or other or-
ganic molecules can substitute for the sites where stabilizer is adsorbed and/or un-
occupied [10–13]. This interfacial binding process often causes some structural
change or spectral shift, as compared to the free molecules in bulk solution.
The study of photo-induced electron transfer between adsorbed molecules and
semiconductor quantum dots is very important as this may be applied in photo-
catalysis, solar cells and biosensors. Previous studies of this process by ultrafast
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