Chemistry Reference
In-Depth Information
d
n
3
r
4
n
g
|
4
Figure 8.14 TiO
2
nanostructures of different RFs and their DSSCs performance. The
DSSC e
ciency ratio is in quite good agreement with the RF ratio.
Reproduced from ref. 10.
130). However, the former shows worse PEC properties, which is attributed
to factors other than the surface area.
32
Also, thick electrode layers have
higher RF values; however, charge recombination tends to increase in a thick
layer and is deleterious to the cell eciency. Therefore, it makes more sense
to use the RF value as a parameter of PEC cells comprising nanostructure
layers of the same or similar thickness. For this reason, some literature have
adopted the modified RF, which is defined as the total surface area over
projected one per unit length of the film thickness with its dimension of
[length
1
].
75-77
.
8.6 Examples of Hierarchical Nanostructures for PEC
Cell Applications
Representative examples of hierarchical structure photoelectrodes for PEC
cell applications are provided in Table 8.1. Overall, the solution-phase route
(hydrothermal) and vapor-phase route (VLS and evaporation) are two major
processes used to build backbone or trunk nanostructures from various
kinds of materials, while anisotropic etching prevails for Si backbone gen-
eration. The hydrothermal method is the most widely implemented route to
generate branch nanostructures attached to the backbone. PEC cells
adopting hierarchical structures show considerably enhanced performance
compared with those with unbranched or non-hybridized electrodes.
Search WWH ::
Custom Search