Chlorophyll and Betalain as Light-Harvesting Pigments for Nanostructured TiO2 Based Dye-Sensitized Solar Cells
Eli Danladi,
Philip Musa Gyuk,
Ezra Bako Danladi
Issue:
Volume 5, Issue 5, October 2016
Pages:
53-58
Received:
7 August 2016
Accepted:
15 August 2016
Published:
2 September 2016
Abstract: Chlorophyll and betalain pigments extracted from scent leaves and flower of Bougainvillea Spectabilis were used as sensitizers for nanostructured TiO2 based dye-sensitized solar cells (DSSCs), and their perfomances were investigated systematically. The light harvesting pigments have shown absorption in broad range of the visible region of the solar spectrum and appreciable adsorption onto the semiconductor surface. The photovoltaic (PV) parameters such as short circuit current density (JSC ), open circuit voltage (VOC), fill factor (FF), and overall solar conversion efficiency (η) were determined under 100 mAcm-2. The DSSC fabricated with betalains pigment from Bougainvillea Spectabilis was found to be superior to that obtained from chlorophyll pigment of scent leave (Ocimum Gratissimum). The DSSC gave a short circuit current density of 0.093 mAcm-2, open circuit voltage of 0.433 V, fill factor of 0.550, and an overall solar conversion efficiency of 0.040%. The cell sensitized with betalains pigment exhibits: (i) ~ 1.90 times improvement in conversion efficiency, (ii) ~ 2.11 times enhancement in photocurrent density, and (iii) ~ 1.38 times improvement in fill factor compared to the results obtained with the chlorophyll sensitized solar cell. The sensitization performance related to interaction between the dye and TiO2 surface is discussed.
Abstract: Chlorophyll and betalain pigments extracted from scent leaves and flower of Bougainvillea Spectabilis were used as sensitizers for nanostructured TiO2 based dye-sensitized solar cells (DSSCs), and their perfomances were investigated systematically. The light harvesting pigments have shown absorption in broad range of the visible region of the solar...
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The Spatial-Temporal Distribution of the Coupling between Urbanization and Farmland Resources in the Mainland of China
Xiang Gao,
Lei Cao,
Xiaohua Ma,
Hao Zhao
Issue:
Volume 5, Issue 5, October 2016
Pages:
59-66
Received:
20 September 2016
Accepted:
2 October 2016
Published:
31 October 2016
Abstract: An evaluation index system was constructed for the coupling between urbanization and farmland resources, based on data from 31 provinces in the mainland of China. Using the Grey Relational Analysis method, the spatial-temporal variations of the coupling between them can be revealed. The conclusions of this study were: (1) the stress of urbanization on farmland resources is dominated by economic urbanization, while this kind of constraint also produces the strongest influence on the status (endowment) of the arable resources; (2) viewed over time, the coupling degree in Chinese provinces between urbanization and farmland resources shows volatility and internal differences: East > West > Central regions, and the causes for these differences are also discussed; (3) The interaction between them is spatially strong, and the coupling degree is relatively close and high, showing the coexisting features of complexity and specificity. Combining the coupling with the urban level the 31 provinces can be categorized into four types: Low-level Coupled Mode, Antagonism Mode, Transition Mode and Coordination Mode.
Abstract: An evaluation index system was constructed for the coupling between urbanization and farmland resources, based on data from 31 provinces in the mainland of China. Using the Grey Relational Analysis method, the spatial-temporal variations of the coupling between them can be revealed. The conclusions of this study were: (1) the stress of urbanization...
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