A set of DSSC were fabricated with pure

A set of DSSC were fabricated with pure TiO2
and Au:TiO2 photoanodes for comparison. Fluorine-doped
tin oxide (FTO; 8W/square, Pilkington, USA) coated glass was used as a substrate for both the working and
counter electrode. FTO substrates were cleaned using soap solution, Type 1
water and ethanol in an ultrasonic bath for 15 minutes each. The working
electrode preparation method: the cleaned electrodes with dimensions of
15 ´ 15
mm2 were refluxed in 40 mM TiCl4 in isopropyl alcohol at
for 30 minutes, followed by calcined at 450°C for 30 min. to form a
transparent layer. The homogeneous suspension of Au:TiO2
nanocomposite slurry was dispensed on the
transparent layer by doctor blade method which was calcined at 450°C for 30 minutes to obtain a semi-transparent layer. The active
area of the cell is 0.25 cm2. Again the substrate was refluxed in 1
mM titanium tetra isoporpoxide (TTIP) in isopropyl alcohol (IPA) then calcined and cooled to 120°C
which leads to the formation of a thin TiO2 shell over the Au:TiO2
nanocomposite photoanodic material. The thin TiO2 shell formed over
the AuNPs resulting in some kind of thin core-shell structure which prevents
the corrosion of AuNPs while it is exposed to the iodide-triiodide redox
species. But as we have not performed any long term stability studies, we
reserve our comments over the stability of this thin titania shell in the long
run compared to proper core-shell nanostructures. The substrate was loaded with
dye by immersing it in 0.3 mM solution of N719 (from dyesol, Queanbeyan NSW,
Australia) dye in ethanol for 24 h.  The
dye adsorbed electrode was withdrawn from the dye solution and immediately
cleaned with ethanol.  These
pre-assembled parts was integrated as a solar cell with platinum sputtered (~100
nm thickness) FTO glass counter electrode, wherein cathode/anode pair was
combined with a 25 mm thick surlyn (SolaronixSA, Aubonne,
Switzerland) polymer film. Further, the electrolyte containing 0.6 M
1-methyl-3-propylimidazolium iodide (PMII; Sigma-Aldrich), 0.03 M I2 (LR,
Thomas Baker), 0.1 M guanidinium thiocyanate, 0.5 M tert-butylpyridine (TBP; Sigma-Aldrich) in acetonitrile and
valeronitrile (Merck and Co., Germany) (85:15) was finally injected into the
DSSC. The active area of the cell is 0.25 cm2. The same experimental
procedure was followed for pure TiO2 film based DSSC wherein pure
TiO2 slurry was used instead of Au:TiO2 nanocomposite