Nanocrystalline titanium dioxide sensitised with natural dyes for eco-friendly solar cell application

Figures & data

Figure 1. Schematic representation of a dye-sensitised solar cell.

Figure 2. XRD pattern of anatase TiO₂ nanoparticles deposited on FTO glass by electrophoresis.

Figure 3. FESEM images of TiO₂ nanoparticles deposited on FTO glass by electrophoresis. (a) Morphology of TiO₂ nanoparticles. (b) Cross section of TiO₂ nanoparticles with FTO.

Figure 4. Molecular structures of main pigments of natural dyes. (a) Chlorophyll a and chlorophyll b. (b) Anthocyanin.

Figure 5. FTIR spectra of natural dyes. (i) Neem, (ii) poinsettia and (iii) cocktail.

Figure 6. Thermogravimetric analysis of Neem and poinsettia extracts.

Figure 7. UV–visible absorption spectra of Neem, poinsettia and cocktail dyes.

Figure 8. (Colour online) UV–visible absorption spectra of pure TiO₂ nanoparticles (black line), Neem extract adsorbed TiO₂ nanoparticles (green line), poinsettia extract adsorbed TiO₂ nanoparticles (red line) and cocktail adsorbed TiO₂ nanoparticles (blue).

Table 1. Photoelectrochemical parameters of the fabricated DSSCs.

Dye	Voc (mV)	Jsc (mA/cm^2)	Fill factor (%)	Efficiency (%)
Neem	404	0.43	40.1	0.72
Poinsettia	406	0.30	45.8	0.56
Cocktail	396	0.52	46.7	0.96

Figure 9. Current density–voltage characteristics of DSSC based on different natural dyes.

Table 2. Comparison of photoelectrochemical properties of dye-sensitised solar cells based on natural extracts.

Dye	Voc (mV)	Jsc (mA/cm^2)	Fill factor (%)	Counter electrode	Reference
Neem	404	0.43	40.1	Graphite	This work
Poinsettia	406	0.30	45.8	Graphite	This work
Cocktail	396	0.52	46.7	Graphite	This work
Spinach	550	0.46	51	Platinum	[8]
Pomegranate leaves	560	2.05	52	Platinum	[9]
Sicilian orange	340	3.84	50	Platinum	[23]
Skin of eggplant	350	3.40	40	Platinum	[23]
Rosella	404	1.63	57	Platinum	[21]
Blue pea	372	0.37	33	Platinum	[21]
Black rice	551	1.14	52	Platinum	[24]

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