Quantum Dot-Sensitized Solar Cells - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 103

Fig. 9 SEM images of (a) untreated (b) DMF treated and (c) THF vapor-treated TiO 2 fibers;
d current-voltage (J-V) measurements and (f) IPCE spectra of QDSSCs using different surface
treated TiO 2 fibers electrodes. The electrode thickness is 2.4 lm. (Sudhagar et al. [ 63 ] reprint
permission from RSC publishers)
photocurrent. The observed higher performance in THF vapor-treated cells may
attribute to the improved physical adhesion of fibers with the TCO substrate. The
recombination parameters of this system have been studied and found that
chemical vapor treatment offer high charge recombination resistance to the elec-
trodes. Interestingly, these TiO 2 fibrous membranes afford high feasibility in
altering their Fermi level under post-doping process. Under the post-doping of
fluorine ion (in Fig. 9 d, THF+F) results upward Fermi level shift in TiO 2 con-
duction band. This Fermi level upward shift promotes the V oc as well as fill factor
(FF) of the device. We found that the combined pretreatment (THF) and post-
treatment (F ion doping and ZnS QDs decoration on CdS/CdSe QDs) the 3-D TiO 2
fibrous photoanode yielded a device performance of 3.2 % with a remarkable
V oc = 0.69 V compared with most of the reports existing in the literature.
Yet another attempt on improving the electrical contact between fibrous elec-
trode with TCO substrates has been demonstrated by Samadpour et al. [ 107 ].