The possibility of producing bioethanol from the biomass of finger millet straw was studied. The ... more The possibility of producing bioethanol from the biomass of finger millet straw was studied. The effects of temperature, acid concentration, hydrolysis time, and substrate concentration were investigated. The result showed that a maximum sugar content of 79.04 and 82.01 %w/w was achieved using phenol-sulfuric acid and Fehling method, respectively, from hydrolysis of 10 % biomass concentration at 2 % sulfuric acid, 35 o C reaction temperature, and 4 days of hydrolysis time. The optimized hydrolyzate sample was fermented at optimized pH 6.0, 4 g/L yeast concentration, 32.5 o C reaction temperature, 4 days of fermentation time, and maximum of 7.28 %w/v of ethanol content was obtained using Pycnometer measurement. In general, the bioethanol achieved from FMS (7.28 %) at optimized conditions were highly promising and hence, it can be employed as an alternative lignocellulosic feedstock for bioethanol production rather than using food crops such as corn, sugarcane, etc.
In this paper, quasi-solid-state dye-sensitized solar cell has been constructed based on natural ... more In this paper, quasi-solid-state dye-sensitized solar cell has been constructed based on natural photo-sensitizers extracted from the bracts of Bougainvillea spectabilis and the leaves of Euphorbia cotinifolia using acidified (0.1 M HCl) distilled water and ethanol separately. The absorption spectra of the extracts were performed in the spectral range from 395 to 750 nm. The cells were assembled using commercial TiO 2 powder film and PEDOT coated FTO glasses as working and counter electrodes , respectively, and also the quasi-solid electrolyte sandwiched in between. The Photovoltaic parameters such as short circuit current density (J sc), open circuit voltage (V oc), fill factor (FF), and overall conversion efficiency (g) for the as-prepared DSSC were determined under 100 mW/ cm 2 illuminations. The highest open circuit voltage (V oc = 0.549 V) and short circuit current density (J sc = 0.592 mA/cm 2) were obtained from the DSSCs assembled by natural dye extracted with the acidified ethanol of Bougainvillea spectabilis bracts and the leaves of Euphorbia cotinifolia, respectively. The highest power conversation efficiency (g) of the as-prepared DSSC assembled with natural dye extracted from Bougainvillea spectabilis bracts using acidified ethanol as extracting solvent was 0.175 %. The use of Bougainvillea spectabilis and Euphorbia cotinifolia pigments as natural sensitizers along with the use of quasi-solid electrolyte and PEDOT coated FTO counter electrodes could be a possible alternative for the production of low-cost and environment friendly DSSCs.
The possibility of producing bioethanol from the biomass of finger millet straw was studied. The ... more The possibility of producing bioethanol from the biomass of finger millet straw was studied. The effects of temperature, acid concentration, hydrolysis time, and substrate concentration were investigated. The result showed that a maximum sugar content of 79.04 and 82.01 %w/w was achieved using phenol-sulfuric acid and Fehling method, respectively, from hydrolysis of 10 % biomass concentration at 2 % sulfuric acid, 35 o C reaction temperature, and 4 days of hydrolysis time. The optimized hydrolyzate sample was fermented at optimized pH 6.0, 4 g/L yeast concentration, 32.5 o C reaction temperature, 4 days of fermentation time, and maximum of 7.28 %w/v of ethanol content was obtained using Pycnometer measurement. In general, the bioethanol achieved from FMS (7.28 %) at optimized conditions were highly promising and hence, it can be employed as an alternative lignocellulosic feedstock for bioethanol production rather than using food crops such as corn, sugarcane, etc.
In this paper, quasi-solid-state dye-sensitized solar cell has been constructed based on natural ... more In this paper, quasi-solid-state dye-sensitized solar cell has been constructed based on natural photo-sensitizers extracted from the bracts of Bougainvillea spectabilis and the leaves of Euphorbia cotinifolia using acidified (0.1 M HCl) distilled water and ethanol separately. The absorption spectra of the extracts were performed in the spectral range from 395 to 750 nm. The cells were assembled using commercial TiO 2 powder film and PEDOT coated FTO glasses as working and counter electrodes , respectively, and also the quasi-solid electrolyte sandwiched in between. The Photovoltaic parameters such as short circuit current density (J sc), open circuit voltage (V oc), fill factor (FF), and overall conversion efficiency (g) for the as-prepared DSSC were determined under 100 mW/ cm 2 illuminations. The highest open circuit voltage (V oc = 0.549 V) and short circuit current density (J sc = 0.592 mA/cm 2) were obtained from the DSSCs assembled by natural dye extracted with the acidified ethanol of Bougainvillea spectabilis bracts and the leaves of Euphorbia cotinifolia, respectively. The highest power conversation efficiency (g) of the as-prepared DSSC assembled with natural dye extracted from Bougainvillea spectabilis bracts using acidified ethanol as extracting solvent was 0.175 %. The use of Bougainvillea spectabilis and Euphorbia cotinifolia pigments as natural sensitizers along with the use of quasi-solid electrolyte and PEDOT coated FTO counter electrodes could be a possible alternative for the production of low-cost and environment friendly DSSCs.
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Papers by Abebe Reda
Akenchira (Striga hermonthica) flower as the natural dyes for a dye-sensitized solar cell (DSSC).
The electrodes, electrolyte (I−∕I3
−), and dyes were assembled into a cell and illuminated by a
light with an intensity 100 mW∕cm2 to measure the photoelectrochemical parameters of the
prepared DSSCs. According to the experimental results, the maximum conversion efficiency
of the DSSCs prepared from anthocyanin dyes of Morus atba Lam fruit extract is 0.42%,
with an open-circuit voltage (Voc) of 0.54 V, a short circuit current density (Jsc) of
1.38 mA∕cm2, and a fill factor (FF) of 0.56. The maximum conversion efficiency of the
DSSCs prepared by anthocyanin dye from the flower of S. hermonthica extract is 0.304%
with a Voc of 0.52 V, Jsc of 1.01 mA∕cm2, and an FF of 0.58. © 2014 Society of Photo-
Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.JPE.4.043091]
Keywords: natural dyes; anthocyanin; solar cells; titanium dioxide.
Akenchira (Striga hermonthica) flower as the natural dyes for a dye-sensitized solar cell (DSSC).
The electrodes, electrolyte (I−∕I3
−), and dyes were assembled into a cell and illuminated by a
light with an intensity 100 mW∕cm2 to measure the photoelectrochemical parameters of the
prepared DSSCs. According to the experimental results, the maximum conversion efficiency
of the DSSCs prepared from anthocyanin dyes of Morus atba Lam fruit extract is 0.42%,
with an open-circuit voltage (Voc) of 0.54 V, a short circuit current density (Jsc) of
1.38 mA∕cm2, and a fill factor (FF) of 0.56. The maximum conversion efficiency of the
DSSCs prepared by anthocyanin dye from the flower of S. hermonthica extract is 0.304%
with a Voc of 0.52 V, Jsc of 1.01 mA∕cm2, and an FF of 0.58. © 2014 Society of Photo-
Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.JPE.4.043091]
Keywords: natural dyes; anthocyanin; solar cells; titanium dioxide.