398
S. Datta and S. Roy
by professor Michael Graetzel and it showed new direction (Ludin et al. 2014). This
DSSC technology has attracted many researchers due to low-cost, easy fabrication
process (Nair et al. 2012). Typically, a DSSC consists of one working electrode, dye,
electrolyte, and a counter electrode. Titanium dioxide (TiO 2 ) is commonly used for
layering on the working electrode and a sensitized adsorbed into the TiO 2 used to trap
the sunlight and excite the TiO 2 molecules. An electrolyte containing iodide/triiodide
is used as a redox mediator between two electrodes. TiO 2 is used in layering on the
working electrode as it is chemically stable, nontoxic, and abundantly available.
But TiO 2 has high bandgap (e.g. 3.6 eV) and absorbs a small fraction of solar light
spectrum (Ye et al. 2015). Bandgap reduction is possible by adding other lower
bandgap material with TiO 2 . The main objective of this research is to improve the
efficiency of DSSC by adding KMnO 4 with TiO 2 on the active layer of the working
electrode.
In this paper, different weight percentages of KMnO 4 in TiO 2 composite films
were prepared and deposited on the conductive side of the FTO glass by the doctor
blade method. Optical properties, surface morphology, and crystal structure were
investigated by UV–vis spectroscope, scanning electron microscope (SEM), and Xray diffraction (XRD). Moreover, the performance of the DSSC was tested under
AM 1.5G solar illumination of having light intensity 100 mW/cm
2 .
2 Experimental Details
2.1 Materials
All the chemicals used in this experiment were purchased from Sigma-Aldrich, India.
2.2 Preparation of Natural Dye
Fresh Mirabilis Jalapa flower of 5 g was placed in 50 ml of ethanol and the mixed
solution was heated up to 80 °C for 10 min to extract light-sensitive dye molecules.
The liquor was then strained through a filter paper (200 nm) to obtain pure dye.
2.3 Preparation of the Working Electrodes
FTO glass having an area of 2 × 1 cm
2 was washed with deionized water and
then with ethanol. KMnO 4 –TiO 2 composite layer around 2000 nm was prepared by
adding TiO 2 paste containing 20 wt% titanium dioxide, 65 wt% benzyl alcohol, and
15 wt% deionized water with KMnO 4 and deposited on the conductive side of the
S. Datta and S. Roy
by professor Michael Graetzel and it showed new direction (Ludin et al. 2014). This
DSSC technology has attracted many researchers due to low-cost, easy fabrication
process (Nair et al. 2012). Typically, a DSSC consists of one working electrode, dye,
electrolyte, and a counter electrode. Titanium dioxide (TiO 2 ) is commonly used for
layering on the working electrode and a sensitized adsorbed into the TiO 2 used to trap
the sunlight and excite the TiO 2 molecules. An electrolyte containing iodide/triiodide
is used as a redox mediator between two electrodes. TiO 2 is used in layering on the
working electrode as it is chemically stable, nontoxic, and abundantly available.
But TiO 2 has high bandgap (e.g. 3.6 eV) and absorbs a small fraction of solar light
spectrum (Ye et al. 2015). Bandgap reduction is possible by adding other lower
bandgap material with TiO 2 . The main objective of this research is to improve the
efficiency of DSSC by adding KMnO 4 with TiO 2 on the active layer of the working
electrode.
In this paper, different weight percentages of KMnO 4 in TiO 2 composite films
were prepared and deposited on the conductive side of the FTO glass by the doctor
blade method. Optical properties, surface morphology, and crystal structure were
investigated by UV–vis spectroscope, scanning electron microscope (SEM), and Xray diffraction (XRD). Moreover, the performance of the DSSC was tested under
AM 1.5G solar illumination of having light intensity 100 mW/cm
2 .
2 Experimental Details
2.1 Materials
All the chemicals used in this experiment were purchased from Sigma-Aldrich, India.
2.2 Preparation of Natural Dye
Fresh Mirabilis Jalapa flower of 5 g was placed in 50 ml of ethanol and the mixed
solution was heated up to 80 °C for 10 min to extract light-sensitive dye molecules.
The liquor was then strained through a filter paper (200 nm) to obtain pure dye.
2.3 Preparation of the Working Electrodes
FTO glass having an area of 2 × 1 cm
2 was washed with deionized water and
then with ethanol. KMnO 4 –TiO 2 composite layer around 2000 nm was prepared by
adding TiO 2 paste containing 20 wt% titanium dioxide, 65 wt% benzyl alcohol, and
15 wt% deionized water with KMnO 4 and deposited on the conductive side of the