336
S. Peiris et al.
0.46, η = 0.42%) due to high dye adsorption capability. They also verified factors
such as the thickness of prepared Cu 2 O(2) film, uniformity and the grain size of
material Cu 2 O, affects the electrode performances (Du et al. 2014).
Daniel Ursu et al. have synthesized different morphologies of cuprous oxide,
such as porous truncated octahedrons, and 3D hierarchical structures consisting of
the micrometer dendritic rods, employing copper (II) acetate and ethyl cellulose as
reactants. They have observed nearly 15% increase in V OC and J SC in the porous
structure over the 3D hierarchical structure due to high dye loading capacity and the
reduced recombination process at the oxide/dye/electrolyte interfaces (Ursu et al.
2018).
Despite the fact that attention given for the improvement of counter electrode is
not very prominent, Mirko Congiu et al. have studied a novel application of transparent thin film of cobalt sulfide (CoS) as an anodic counter electrode in place of
a Pt electrode. CoS is preferred over Pt due to low cost of the starting material and
easier deposition. They have implemented a typical p-type cathode incorporated with
mesoporous NiO-deposited via discharge sintering, erythrosin B as the photo sensitizer and I
− /I 3
− as the redox mediator along with the CoS anodic counter electrode.
They report similar efficiency, J SC , FF, and V OC values to those obtained for DSCs
with the Pt counter electrode (V OC = 74 V, J SC = −1.051 mA cm
−2 , FF = 0.325,
η = 0.026%). Electrochemical impedance spectroscopy of CoS anodes in p-DSCs
have shown higher electrocatalytic efficiency and lower charge-transfer resistance in
comparison to platinized FTO anodes (Congiu et al. 2016).
The work done by Matteo Bonomo et al. has shown the limits on using cobalt
sulfide as the anode of p-DSCs by employing a film of CoS of thickness <10 μm as
the counter electrode with NiO photoactive cathode and I
− /I 3
− redox mediator. In
comparison with Pt in the counter electrode CoS is unable to sustain photocurrent
densities generated by NiO at a given potential, due to slower kinetics of iodide
oxidation at the CoS anode. This could create 30 times larger charge transfer resistance of CoS with respect to Pt-FTO (130 vs. 4.5 ). Furthermore, the behavior of
CoS like a p-type semiconductor without a degeneracy, could induce the reverse bias
of the photoelectrochemical cell. This displays a lower photoconversion efficiency
(V OC = 128 mV, J SC = −1.70 mA cm
−2 , FF = 0.317, η = 0.07%) that is about 35%
less than that of the analogous p-DSC with Pt-FTO anode (0.07 vs. 0.11%). However,
there is no significant effect identified on the open circuit potential (130 mV) or the
FF based on the nature of the anodic material (Bonomo et al. 2017a).
16.10 Solid State Dye Sensitized Solar Cells
One of the challenges encountered in liquid state DSCs is the instability of conventional liquid electrolytes due to volatilization. This affects the durability and
the performance of solar cells. Consequently, scientists paid their attention towards
employing solid or quasi solid hole conducting materials in place of liquid electrolytes like I
− /I 3
− . Both n-DSCs and p-DSCs are candidates for replacement of
S. Peiris et al.
0.46, η = 0.42%) due to high dye adsorption capability. They also verified factors
such as the thickness of prepared Cu 2 O(2) film, uniformity and the grain size of
material Cu 2 O, affects the electrode performances (Du et al. 2014).
Daniel Ursu et al. have synthesized different morphologies of cuprous oxide,
such as porous truncated octahedrons, and 3D hierarchical structures consisting of
the micrometer dendritic rods, employing copper (II) acetate and ethyl cellulose as
reactants. They have observed nearly 15% increase in V OC and J SC in the porous
structure over the 3D hierarchical structure due to high dye loading capacity and the
reduced recombination process at the oxide/dye/electrolyte interfaces (Ursu et al.
2018).
Despite the fact that attention given for the improvement of counter electrode is
not very prominent, Mirko Congiu et al. have studied a novel application of transparent thin film of cobalt sulfide (CoS) as an anodic counter electrode in place of
a Pt electrode. CoS is preferred over Pt due to low cost of the starting material and
easier deposition. They have implemented a typical p-type cathode incorporated with
mesoporous NiO-deposited via discharge sintering, erythrosin B as the photo sensitizer and I
− /I 3
− as the redox mediator along with the CoS anodic counter electrode.
They report similar efficiency, J SC , FF, and V OC values to those obtained for DSCs
with the Pt counter electrode (V OC = 74 V, J SC = −1.051 mA cm
−2 , FF = 0.325,
η = 0.026%). Electrochemical impedance spectroscopy of CoS anodes in p-DSCs
have shown higher electrocatalytic efficiency and lower charge-transfer resistance in
comparison to platinized FTO anodes (Congiu et al. 2016).
The work done by Matteo Bonomo et al. has shown the limits on using cobalt
sulfide as the anode of p-DSCs by employing a film of CoS of thickness <10 μm as
the counter electrode with NiO photoactive cathode and I
− /I 3
− redox mediator. In
comparison with Pt in the counter electrode CoS is unable to sustain photocurrent
densities generated by NiO at a given potential, due to slower kinetics of iodide
oxidation at the CoS anode. This could create 30 times larger charge transfer resistance of CoS with respect to Pt-FTO (130 vs. 4.5 ). Furthermore, the behavior of
CoS like a p-type semiconductor without a degeneracy, could induce the reverse bias
of the photoelectrochemical cell. This displays a lower photoconversion efficiency
(V OC = 128 mV, J SC = −1.70 mA cm
−2 , FF = 0.317, η = 0.07%) that is about 35%
less than that of the analogous p-DSC with Pt-FTO anode (0.07 vs. 0.11%). However,
there is no significant effect identified on the open circuit potential (130 mV) or the
FF based on the nature of the anodic material (Bonomo et al. 2017a).
16.10 Solid State Dye Sensitized Solar Cells
One of the challenges encountered in liquid state DSCs is the instability of conventional liquid electrolytes due to volatilization. This affects the durability and
the performance of solar cells. Consequently, scientists paid their attention towards
employing solid or quasi solid hole conducting materials in place of liquid electrolytes like I
− /I 3
− . Both n-DSCs and p-DSCs are candidates for replacement of