• Energy Research
• Open Source close
• Embargo close
• natural sciences close
• DE close
• GB close
• IT close

Organic solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate organic solar cell blends with highest occupied molecular orbital energy-level offsets (∆EHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ∆EHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quantitatively describe this finding via the Boltzmann stationary-state equilibrium between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ∆EHOMO. Moreover, the Boltzmann equilibrium quantitatively describes the major reduction in non-radiative voltage losses at a very small ∆EHOMO. Ultimately, highly luminescent near-infrared emitters with very long exciton lifetimes are suggested to enable highly efficient organic solar cells. Donor–acceptor systems with low energy-level offset enable high power efficiency in organic solar cells yet it is unclear what drives charge generation. Classen et al. show that long exciton lifetimes enable efficient exciton splitting and thus generation of free charges while also suppressing voltage losses.

Seaweed fibre is usually discarded as biomass waste after extraction of useful ingredients from seaweed. However this seaweed fibre, a natural abundant cellulose material with uniform dimensions 10 times smaller than other plant-based fibre can be utilized as electrode material for energy storage. In this work, we converted seaweed fibre into conductive carbon electrodes by a thermal carbonisation method. The morphology, chemical composition and conductivity are highly influenced by the carbonisation temperature. In comparison to other biomass sources such as cotton pulp, seaweed fibre is finer, smoother and more conductive at low carbonisation temperature. These carbonized seaweeds were then used as a supercapacitor, giving a high supercapacitance (226.3 Fg−1) at the carbonisation temperature of 900°C, and good stability within 2400 cycles. This specific capacitance is significantly higher than values obtained from filter paper or cotton pulp.

Revolutionary catalyst protection by single layer graphene capping, tremendous catalyst lifetime longevity and activity enhancement towards oxygen reduction reaction.

A one-pot fuel cell for specific, enzyme-catalysed organic synthesis, with continuous monitoring of rate and reaction progress, combines an electrode catalysing rapid, reversible and diffusion-controlled interconversion of NADP+ and NADPH with a Pt electrode catalysing 2H+/H2 interconversion.

AbstractThe Homeless Heritage project took place across two English cities (Bristol and York) between 2010 and 2014. The project sought to use a range of participatory heritage practices to engage contemporary homeless people in documenting their perspectives on each city. Drawing on data gathered over three and a half years this paper reflects on how collaborative cultural heritage practices can be useful in recording diverse stakeholder perspectives which can become catalysts for social change. It is further argued that two interactive exhibitions that resulted from the Homeless Heritage project contributed to the democratisation of knowledge, aiding negotiation of the complicated politics of contemporary homelessness in valuable ways.

Moisture availability is a strong determinant of decomposition rates in forests worldwide. Climate models suggest that many terrestrial ecosystems are at risk from future droughts, suggesting moisture limiting conditions will develop across a range of forests worldwide. The impacts of increasing drought conditions on forest carbon (C) fluxes due to shifts in organic matter decay rates may be poorly characterised due to limited experimental research. To appraise this question, we conducted a meta-analysis of forest drought experiment studies worldwide, examining spatial limits, knowledge gaps and potential biases. To identify limits to experimental knowledge, we projected the global distribution of forest drought experiments against spatially modelled estimates of (i) future precipitation change, (ii) ecosystem total above-ground C and (iii) soil C storage. Our assessment, involving 115 individual experimental study locations, found a mismatch between the distribution of forest drought experiments and regions with higher levels of future drought risk and C storage, such as Central America, Amazonia, the Atlantic Forest of Brazil, equatorial Africa and Indonesia. Decomposition rate responses in litter and soil were also relatively under-studied, with only 30 experiments specifically examining the potential experimental impacts of drought on C fluxes from soil or litter. We propose new approaches for engaging experimentally with forest drought research, utilising standardised protocols to appraise the impacts of drought on the C cycle, while targeting the most vulnerable and relevant forests.

AbstractThe preparation of nanomaterials for energy applications such as intercalation batteries and materials that can act as substrates for water oxidation is a subject of major interest nowadays. In this work, we report the deposition of Prussian blue (PB) and its cobalt analogue (CoPBA) on mesoporous titania thin films (MTTF) using the successive ionic layer adsorption reaction (SILAR) technique under soft conditions. A bifunctional ligand, 1,10‐phenanthroline‐5,6‐dione (pd), was used to functionalize the titania surface and promote the growth of PB and CoPBA. The resulting PB@MTTF and CoPBA@MTTF nanocomposites were characterized using several techniques and it was determined that PB and CoPBA grow in a controlled and sequential manner, maintaining the mesoporous architecture. Both PB@MTTF and CoPBA@MTTF demonstrated very good electroactive properties, while CoPBA@MTTF exhibited water oxidation capabilities. The flexibility of this PBA@MTTF platform allows the incorporation of any labile transition metal ion or fragment into the structure of the coordination polymer embedded into a mesoporous matrix, opening the door for (photo)electrochemical devices and catalysts.

This paper assesses the capacity of Whitehouse, Jamaica to adapt to climate change. A community-based vulnerability assessment was conducted that employed semi-structured interviews with community members within or related to the tourism, fisheries and agricultural sectors. The results were analysed using the Local Adaptive Capacity (LAC) framework, which characterises adaptive capacity based on five elements: asset base; institutions and entitlements; knowledge and information; innovation; and flexible forward-looking decision-making and governance. This paper contributes to the literature in three ways. First, it argues that many elements of the LAC framework correspond with an evolutionary perspective on adaptive capacity. Second, it offers an in-depth case study of the capacity of Whitehouse to adapt to climate change. Third, it offers a critical assessment of whether the LAC framework fully captures the important elements of adaptive capacity.