400
425
450
475
λ /nm
1
1.5
2
Absorbance /a.u
0 µM
32 µM
61 µM
80 µM
400
425
450
475
λ /nm
1
1.5
2
2.5
Absorbance /a.u
0 µM
91 µM
180 µM
230 µM
(a)
(b)
Fig. 4.26. Electronic absorption spectra of @5 nm Ag
nanoparticles showing changes accompanying the addition of
(a) Cu
2þ and (b) Fe
2þ ions. The concentrations of the ions are
indicated.
4.4 Emerging Applications 81
425
450
475
λ /nm
1
1.5
2
Absorbance /a.u
0 µM
32 µM
61 µM
80 µM
400
425
450
475
λ /nm
1
1.5
2
2.5
Absorbance /a.u
0 µM
91 µM
180 µM
230 µM
(a)
(b)
Fig. 4.26. Electronic absorption spectra of @5 nm Ag
nanoparticles showing changes accompanying the addition of
(a) Cu
2þ and (b) Fe
2þ ions. The concentrations of the ions are
indicated.
4.4 Emerging Applications 81