Biomedical Engineering Reference
In-Depth Information
Table 9.1
Photoluminescence properties of Au MPCs
Core size
(nm)
Quantum
yield
max
a
Ligand
λ
em
Assignment Ref.
1 × 10
−6
3 × 10
−5
0.8 (Au
12
)DMSA
DMSA-TOA
630 (395)
643 (404)
T
1
→
S
0
T
1
→
S
0
50
1.1 (Au
38
) Mixed ligands:
phenylethanethiolate
and PEG
135
SH
902 (680)
1025
(680)
1.2 × 10
−2
sp
→
sp
(HOMO-
LUMO)
51
Au
13
Mixed ligands:
triphenylphosphine
and dodecanethiol
~1000
(718)
1.3 × 10
−3
sp
→
sp
(HOMO-
LUMO)
52
1.1 (Au
38
) Dodecanethiol
~1200
(1064)
—
sp
→
sp
(HOMO-
LUMO)
53
1.7
(Au
147
)
Dodecanethiol
~1200
(1064)
4.4 × 10
−5
sp
→
sp
(HOMO-
LUMO)
53
0.8
Dodecanethiol
840 (680) <3 × 10
−7
—
54
1.8
(Au
201
)
Tiopronin
770 (451) (3 ± 1)
×10
−3
sp
→
d
55
0.9 (Au
28
) Glutathione
830 (500)
1080
(514)
(3.5 ± 1.0)
× 10
−3
sp
→
d or
(S
1
→
S
0
)
sp
→
sp
(HOMO-
LUMO) or
(T
1
→
S
0
)
56
a
Wavelengths of emission maxima. Numbers in parentheses represent excitation wavelengths (nm).
Key issues in the study of the optical properties of very small NPs
are their size and shape effects and the contributions from surface
characteristics. These issues are interrelated because the surface-
to-volume ratio increases as the size decreases. To precisely assign
the luminescence peaks that allow study of size dependence of the
optical properties of NCs, solutions containing monodisperse NPs are
essential. Luminescence becomes broad when the size distribution
of the NPs is large. Polyacrylamide gel electrophoresis and ESI
mass spectrometry are powerful tools for characterizing small Au
NCs; for example, spectroscopic measurements of a fractionated
series of Au
n
NCs (
n
= 10-39) protected by GSH ligands [Au
10
(SG)
10
,
Au
15
(SG)
13
, Au
18
(SG)
14
, Au
22
(SG)
16
, Au
22
(SG)
17
, Au
25
(SG)
18
,
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