16 p-Type Dye Sensitized Solar Cells …
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increased, photovoltage was increased due to the positive shift in fermi level of the
semiconductor (NiO/MgO); however, the generated photocurrent drops with increasing the concentration of Mg
2+ . Still they were able to show that a constitution of 5%
MgO could balance the increased photo voltage and decreased photo current owning a large pore volume in both meso and macropore range (BET surface area of
35 m
2 g
−1 ). The power conversion efficiency obtained by incorporating 5% MgO
was higher than using NiO alone (V OC = 123 mV; J SC = 5.09 mA cm
−2 ; FF = 0.32;
η = 0.2%) (Zannotti et al. 2015).
Muhammad Awais et al. have revealed, that in addition to electrochemical parameters of individual components, the deposition method of NiO nanoparticles on indium
tin oxide (ITO) substrate could affect the performance of p-DSCs. They have chosen spray deposition followed by sintering of nickel oxide nanoparticles to acquire a
large surface area. A comparison of the J–V performance with NiO samples prepared
using sol–gel method exemplified an enhanced performance in the NiO sample prepared using spray deposition due to higher mesoporosity obtained with this method
(Awais et al. 2013).
Plasma-assisted microwave sintering (or rapid-discharge sintering, RDS) is a
novel technique that was being employed by Awais et al. for the preparation of NiO
thin films which can be used to fabricate photoactive electrodes in p-DSCs (Awais
et al. 2014). The novelty of this method is the application of plasma bombardment
treatment prior to the step of spray-deposition and heating of the FTO substrate.
During the spray deposition, heating is controlled by the energy of microwaves. This
method could ensure more efficient charge collection due to improved adhesion and
electrical contact at the FTO/NiO interface. For comparison, they have used NiO
nanoparticles synthesised by conventional sintering in furnace or through sol–gel
procedures which are screen printed. They were able to produce NiO samples with
better performance using RDS method when applied to p-DSCs sensitized with erythrosine B (Awais et al. 2014; Novelli et al. 2015) .
Current p-type semiconductor materials have been maneuvered towards a novel
category of chemicals called delafossites. They belong to a family of transparent
conducting oxides. Low electrical resistivity (high conductivity), high transparency,
wide band gap, high energy conversion efficiency and low fabrication cost motivate
their use as the semiconductor material in p-DSCs. More recognition is given to Cu
(1) based CuMO 2 (M = Al, Cr, Ga, Cr, B, In) delafossites. Strong hybridization of
3d orbitals of Cu with 2p orbitals of O facilitate the delocalization of hole charge
carriers, increasing the hole mobility (Ahmed et al. 2014; Jiang et al. 2016; Xu et al.
2014).
Yu et al. reported the first application of CuGaO 2 delafossite into pDSCs. The
VB edge of CuGaO 2 is +0.6 V v.s. NHE and they have achieved V OC of 357 mV
by using Co
3+/2+ (dtb-bpy) as the electrolyte (1 Sun AM 1.5 illumination). Increasing
the illumination enhanced the V OC up to 464 mV, which is known as the saturation
photovoltage. Nano plates of CuGaO 2 that are stable up to to 350 °C have been made
with an average diameter of 200 nm and thickness of 45 nm using a hydrothermal
method. Since there is an off white colour in these nano plates, no competition exists
against the sensitizer for capturing sunlight (Yu et al. 2012). Another research based
333
increased, photovoltage was increased due to the positive shift in fermi level of the
semiconductor (NiO/MgO); however, the generated photocurrent drops with increasing the concentration of Mg
2+ . Still they were able to show that a constitution of 5%
MgO could balance the increased photo voltage and decreased photo current owning a large pore volume in both meso and macropore range (BET surface area of
35 m
2 g
−1 ). The power conversion efficiency obtained by incorporating 5% MgO
was higher than using NiO alone (V OC = 123 mV; J SC = 5.09 mA cm
−2 ; FF = 0.32;
η = 0.2%) (Zannotti et al. 2015).
Muhammad Awais et al. have revealed, that in addition to electrochemical parameters of individual components, the deposition method of NiO nanoparticles on indium
tin oxide (ITO) substrate could affect the performance of p-DSCs. They have chosen spray deposition followed by sintering of nickel oxide nanoparticles to acquire a
large surface area. A comparison of the J–V performance with NiO samples prepared
using sol–gel method exemplified an enhanced performance in the NiO sample prepared using spray deposition due to higher mesoporosity obtained with this method
(Awais et al. 2013).
Plasma-assisted microwave sintering (or rapid-discharge sintering, RDS) is a
novel technique that was being employed by Awais et al. for the preparation of NiO
thin films which can be used to fabricate photoactive electrodes in p-DSCs (Awais
et al. 2014). The novelty of this method is the application of plasma bombardment
treatment prior to the step of spray-deposition and heating of the FTO substrate.
During the spray deposition, heating is controlled by the energy of microwaves. This
method could ensure more efficient charge collection due to improved adhesion and
electrical contact at the FTO/NiO interface. For comparison, they have used NiO
nanoparticles synthesised by conventional sintering in furnace or through sol–gel
procedures which are screen printed. They were able to produce NiO samples with
better performance using RDS method when applied to p-DSCs sensitized with erythrosine B (Awais et al. 2014; Novelli et al. 2015) .
Current p-type semiconductor materials have been maneuvered towards a novel
category of chemicals called delafossites. They belong to a family of transparent
conducting oxides. Low electrical resistivity (high conductivity), high transparency,
wide band gap, high energy conversion efficiency and low fabrication cost motivate
their use as the semiconductor material in p-DSCs. More recognition is given to Cu
(1) based CuMO 2 (M = Al, Cr, Ga, Cr, B, In) delafossites. Strong hybridization of
3d orbitals of Cu with 2p orbitals of O facilitate the delocalization of hole charge
carriers, increasing the hole mobility (Ahmed et al. 2014; Jiang et al. 2016; Xu et al.
2014).
Yu et al. reported the first application of CuGaO 2 delafossite into pDSCs. The
VB edge of CuGaO 2 is +0.6 V v.s. NHE and they have achieved V OC of 357 mV
by using Co
3+/2+ (dtb-bpy) as the electrolyte (1 Sun AM 1.5 illumination). Increasing
the illumination enhanced the V OC up to 464 mV, which is known as the saturation
photovoltage. Nano plates of CuGaO 2 that are stable up to to 350 °C have been made
with an average diameter of 200 nm and thickness of 45 nm using a hydrothermal
method. Since there is an off white colour in these nano plates, no competition exists
against the sensitizer for capturing sunlight (Yu et al. 2012). Another research based