7 research outputs found

    Electrolyte/dye/TiO2 interfacial structures of dye-sensitized solar cells revealed by in situ neutron reflectometry with contrast matching

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    The nature of an interfacial structure buried within a device assembly is often critical to its function. For example, the dye/TiO2 interfacial structure that comprises the working electrode of a dye-sensitized solar cell (DSC) governs its photovoltaic output. These structures have been determined outside of the DSC device, using ex situ characterization methods; yet, they really should be probed while held within a DSC since they are modulated by the device environment. Dye/TiO2 structures will be particularly influenced by a layer of electrolyte ions that lies above the dye self-assembly. We show that electrolyte/dye/TiO2 interfacial structures can be resolved using in situ neutron reflectometry with contrast matching. We find that electrolyte constituents ingress into the self-assembled monolayer of dye molecules that anchor onto TiO2. Some dye/TiO2 anchoring configurations are modulated by the formation of electrolyte/dye intermolecular interactions. These electrolyte-influencing structural changes will affect dye-regeneration and electron-injection DSC operational processes. This underpins the importance of this in situ structural determination of electrolyte/dye/TiO2 interfaces within representative DSC device environments

    What drives the vulnerability of pastoralists to global environmental change? A qualitative meta-analysis

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    The long-term viability of pastoralism has been a constant theme for discussions. The progress of knowledge on the sustainability of pastoralism under global environmental change has been notable in the last years. To better characterize this vulnerability, we have examined the existing scientific knowledge about the three dimensions of vulnerability, being exposure illustrated by the existing climate trends and non-climate transformations, sensitivity by the impacts of these on pastoral resources and pastoral land conversions, and adaptation by the adaptation strategies developed by the pastoral communities. A qualitative meta-analysis was conducted to explore patterns and trends across the literature. From this, six different pathways of vulnerability being followed by pastoral communities were identified: Encroachment, Re-greening, Customary, Polarization, Communal and No-alternative. The results point that the livelihood options of pastoralists are generally becoming narrower. Four major forces are identified as exerting determinant influence on the co-production of the vulnerability of pastoralism: (i) the double exposure to climate and non-climate transformations, (ii) the persistence of unfavorable development policies, (iii) the great vitality of adaptation, and (iv) the multifaceted role of markets. We point that it is crucial to distinguish between the component of vulnerability inherent in any economic activity devoted to the use of natural resources, which is the usual business of pastoralism, and the component of vulnerability linked to external forces that disturb the usual working of the pastoral production strategies

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