Environmental Engineering Reference
In-Depth Information
Fig. 5 Schematic diagram illustrating the three step electrochemical/chemical (E/C) synthesis of
epitaxial CdS nanocrystals [Anderson et al. [ 94 ] Reprint permission from ACS]
Fig. 6 SEM images of low and high magnification of CdSe-free mesoporous film of TiO 2
(a) and for different CdSe electrodeposition times from 30 to 300 mC cm 2 (b)-(f). [Sauvage et al.
[ 183 ], reprint permission from IOP publishers]. (g)-(i) CdSe QDs electrodeposited TiO 2 ruitle
nanowires [Kamat et al. [ 184 ], reprint permission from Wiley VCH]
In sensitizer-type solar cells, the photoanode should have high surface area to
accommodate more amount of sensitizer loading to enhance light harvesting.
However, the recombination process is proportional to the electrode surface area.
The open-circuit potential (V oc ) in sensitized solar cells is significantly affected by
the recombination process. A balance between recombination and light harvesting
is therefore needed to maximize sensitized solar cell performance. With these
considerations on mind inorganic semiconductors are extremely attractive due to
their high extinction coefficient, in many cases, see Fig. 7 .
In Fig. 7 , a comparison of the extinction coefficients of one of the most
employed dyes in DSSCs, N719, with the inorganic semiconductor Sb 2 S 3 .This
implied that the effective surface area of QDSSCs covered with QDs may not need
as much increase as in DSSCs for achieving high light harvesting. In this sense,
QDSCs can take advantage of the development of new electrode structures to
control the recombination process with lower effective area and consequently
lower
recombination.
In
addition,
despite
the
high
extension
coefficient
of
Search WWH ::




Custom Search