3 Plasmonically Enhanced Dye-Sensitized Solar Cells
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Fig. 3.3 Optical Response of a Ag nanosphere coated with a TiO 2 capping layer of varying
thickness (0 nm – 12 nm). a The absorption efficiency (total particle cross-section divided by the
cross-sectional area of the silver core) showing the red-shift of the resonance. b The surfaceaveraged electric field enhancement (measured 0.25 nm from the TiO 2 surface). c The electric field
enhancement around the Ag/TiO 2 structure showing that the field enhancement around the particle
is lower for increased TiO 2 thickness. Light is polarized in the vertical direction and propagates left
to right in the figure. d The total cross-section of a monolayer of dyes absorbed to the structures in
(a) and (b). The cross-section of the isolated dye is 0.01 nm 2
C EF =
4.1eV
1.5eV
D(π)S(π)
|E(π)|
2
dπ.
(3.4)
With D and S as the dye absorption cross-section and AM 1.5 G solar spectrum,
respectively, normalized according to:
4.1eV
1.5eV
f (π)dπ = 1.
(3.5)
An example calculation of C EF is presented in Fig. 3.4. The normalized absorption
cross-section for the N3 dye was used for D, and the nanoparticle was a 30 nm
radius silver sphere coated with 10 nm of AgO and 2 nm of amorphous TiO 2 . The