Screening of Natural Dyes for Use in Dye Sensitized Solar Cells
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Date
2012-06
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Addis Ababa Universty
Abstract
Five natural dyes, extracted from natural materials such as flowers, were used as
sensitizers to fabricate dye-sensitized solar cells (DSSCs). Dye-sensitized solar cells
(DSSCs) were fabricated using natural dyes extracted from flowers Amaranthus
caudatus, Bougainvillea spectabilis, Delonix regia, Nerium oleander, Spathodea
companulata and a mixture of the extracts. The PEC performance of the DSSCs based
on these dyes showed that the fill factors of these DSSCs are mostly higher than 50%,
the open circuit voltages (VOC) varied from 0.45 to 0.55 V, and the short circuit
photocurrent densities (JSC) ranged from 0.013 to 1.82 mAcm−2. Specifically, a high
open circuit voltage (VOC = 0.55 V) and short circuit photocurrent density (JSC = 1.82
mAcm−2) were obtained from the DSSC sensitized by the ethanol extract of flower of
Amaranthus caudatus. The photon to electricity conversion efficiency of the dyesensitized
solar cell (DSSC) sensitized with the ethanol extract of flower of
Amaranthus caudatus reached 0.61%. The PEC performances of DSSCs using the
dye mixed solutions were also investigated. However, the mixed extract does not
show synergistic photosensitization compared to the individual extracts. Instead, the
cell sensitized by the flower of Amaranthus caudatus extract extracted with ethanol
alone showed the best sensitization. The devices showed that an incident
monochromatic photon to current conversion efficiencies (IPCE) varied from 4.7% to
52% illuminated from front side. The results from the IPCE data are consistent with
the results from the current density ‒ voltage (J − V) curves.
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Keywords
Dye Sensitized Solar Cells