| 1. |
- Abu-Omar, Mahdi M., et al.
(författare)
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Guidelines for performing lignin-first biorefining
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 14:1, s. 262-292
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Forskningsöversikt (refereegranskat)abstract
- The valorisation of the plant biopolymer lignin is now recognised as essential to enabling the economic viability of the lignocellulosic biorefining industry. In this context, the lignin-first biorefining approach, in which lignin valorisation is considered in the design phase, has demonstrated the fullest utilisation of lignocellulose. We define lignin-first methods as active stabilisation approaches that solubilise lignin from native lignocellulosic biomass while avoiding condensation reactions that lead to more recalcitrant lignin polymers. This active stabilisation can be accomplished by solvolysis and catalytic conversion of reactive intermediates to stable products or by protection-group chemistry of lignin oligomers or reactive monomers. Across the growing body of literature in this field, there are disparate approaches to report and analyse the results from lignin-first approaches, thus making quantitative comparisons between studies challenging. To that end, we present herein a set of guidelines for analysing critical data from lignin-first approaches, including feedstock analysis and process parameters, with the ambition of uniting the lignin-first research community around a common set of reportable metrics. These guidelines comprise standards and best practices or minimum requirements for feedstock analysis, stressing reporting of the fractionation efficiency, product yields, solvent mass balances, catalyst efficiency, and the requirements for additional reagents such as reducing, oxidising, or capping agents. Our goal is to establish best practices for the research community at large primarily to enable direct comparisons between studies from different laboratories. The use of these guidelines will be helpful for the newcomers to this field and pivotal for further progress in this exciting research area.
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| 2. |
- Aitola, Kerttu, et al.
(författare)
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Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells
- 2016
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:2, s. 461-466
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a high efficiency perovskite solar cell with a hybrid hole-transporting material-counter electrode based on a thin single-walled carbon nanotube (SWCNT) film and a drop-cast 2,2,7,-7-tetrakis(N, N-di-p-methoxyphenylamine)-9,90-spirobifluorene (Spiro-OMeTAD) hole-transporting material (HTM). The average efficiency of the solar cells was 13.6%, with the record cell yielding 15.5% efficiency. The efficiency of the reference solar cells with spin-coated Spiro-OMeTAD hole-transportingmaterials (HTMs) and an evaporated gold counter electrode was 17.7% (record 18.8%), that of the cells with only a SWCNT counter electrode (CE) without additional HTM was 9.1% (record 11%) and that of the cells with gold deposited directly on the perovskite layer was 5% (record 6.3%). Our results show that it is possible to manufacture high efficiency perovskite solar cells with thin film (thickness less than 1 mu m) completely carbon-based HTMCEs using industrially upscalable manufacturing methods, such as press-transferred CEs and drop-cast HTMs.
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| 3. |
- Akhtar, Farid, et al.
(författare)
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Strong and binder free structured zeolite sorbents with very high CO2-over-N-2 selectivities and high capacities to adsorb CO2 rapidly
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:6, s. 7664-7673
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Tidskriftsartikel (refereegranskat)abstract
- Mechanically strong monoliths of zeolite NaKA with a hierarchy of pores displayed very high CO2-over-N-2 selectivity. The zeolite monoliths were produced by pulsed current processing (PCP) without the use of added binders and with a preserved microporous crystal structure. Adsorption isotherms of CO2 and N-2 were determined and used to predict the co-adsorption of CO2 and N-2 using ideal adsorbed solution theory (IAST). The IAST predictions showed that monolithic adsorbents of NaKA could reach an extraordinarily high CO2-over-N-2 selectivity in a binary mixture with a composition similar to flue gas (15 mol% CO2 and 85 mol% N2 at 25 degrees C and 101 kPa). Structured NaKA monoliths with a K+ content of 9.9 at% combined a CO2-over-N-2 selectivity of >1100 with a high CO2 adsorption capacity (4 mmol g(-1)) and a fast adsorption kinetics (on the order of one minute). Estimates of a figure of merit (F) based on IAST CO2-over-N-2 selectivity, and time-dependent CO2 uptake capacity, suggest that PCP-produced structured NaKA with a K+ content of 9.9 at% offers a performance far superior to 13X adsorbents, in particular at short cycle times.
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| 4. |
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| 5. |
- Ardo, Shane, et al.
(författare)
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Pathways to electrochemical solar-hydrogen technologies
- 2018
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 11:10, s. 2768-2783
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Forskningsöversikt (refereegranskat)abstract
- Solar-powered electrochemical production of hydrogen through water electrolysis is an active and important research endeavor. However, technologies and roadmaps for implementation of this process do not exist. In this perspective paper, we describe potential pathways for solar-hydrogen technologies into the marketplace in the form of photoelectrochemical or photovoltaic-driven electrolysis devices and systems. We detail technical approaches for device and system architectures, economic drivers, societal perceptions, political impacts, technological challenges, and research opportunities. Implementation scenarios are broken down into short-term and long-term markets, and a specific technology roadmap is defined. In the short term, the only plausible economical option will be photovoltaic-driven electrolysis systems for niche applications. In the long term, electrochemical solar-hydrogen technologies could be deployed more broadly in energy markets but will require advances in the technology, significant cost reductions, and/ or policy changes. Ultimately, a transition to a society that significantly relies on solar-hydrogen technologies will benefit from continued creativity and influence from the scientific community.
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| 6. |
- Bartling, Andrew W., et al.
(författare)
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Techno-economic analysis and life cycle assessment of a biorefinery utilizing reductive catalytic fractionation
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 14:8, s. 4147-4168
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Tidskriftsartikel (refereegranskat)abstract
- Reductive catalytic fractionation (RCF) is a promising approach to fractionate lignocellulose and convert lignin to a narrow product slate. To guide research towards commercialization, cost and sustainability must be considered. Here we report a techno-economic analysis (TEA), life cycle assessment (LCA), and air emission analysis of the RCF process, wherein biomass carbohydrates are converted to ethanol and the RCF oil is the lignin-derived product. The base-case process, using a feedstock supply of 2000 dry metric tons per day, methanol as a solvent, and H-2 gas as a hydrogen source, predicts a minimum selling price (MSP) of crude RCF oil of $1.13 per kg when ethanol is sold at $2.50 per gallon of gasoline-equivalent ($0.66 per liter of gasoline-equivalent). We estimate that the RCF process accounts for 57% of biorefinery installed capital costs, 77% of positive life cycle global warming potential (GWP) (excluding carbon uptake), and 43% of positive cumulative energy demand (CED). Of $563.7 MM total installed capital costs, the RCF area accounts for $323.5 MM, driven by high-pressure reactors. Solvent recycle and water removal via distillation incur a process heat demand equivalent to 73% of the biomass energy content, and accounts for 35% of total operating costs. In contrast, H-2 cost and catalyst recycle are relatively minor contributors to operating costs and environmental impacts. In the carbohydrate-rich pulps, polysaccharide retention is predicted not to substantially affect the RCF oil MSP. Analysis of cases using different solvents and hemicellulose as an in situ hydrogen donor reveals that reducing reactor pressure and the use of low vapor pressure solvents could reduce both capital costs and environmental impacts. Processes that reduce the energy demand for solvent separation also improve GWP, CED, and air emissions. Additionally, despite requiring natural gas imports, converting lignin as a biorefinery co-product could significantly reduce non-greenhouse gas air emissions compared to burning lignin. Overall, this study suggests that research should prioritize ways to lower RCF operating pressure to reduce capital expenses associated with high-pressure reactors, minimize solvent loading to reduce reactor size and energy required for solvent recovery, implement condensed-phase separations for solvent recovery, and utilize the entirety of RCF oil to maximize value-added product revenues.
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| 7. |
- Beckmann, K., et al.
(författare)
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Formation of stoichiometrically O-18-labelled oxygen from the oxidation of O-18-enriched water mediated by a dinuclear manganese complex : a mass spectrometry and EPR study
- 2008
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 1:6, s. 668-676
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen formation was detected for the oxidations of various multinuclear manganese complexes by oxone (HSO5-) in aqueous solution. To determine to what extent water was the source of the evolved O-2, (H2O)-O-18 isotope-labelling experiments coupled with membrane inlet mass spectrometry (MIMS) were carried out. We discovered that during the reaction of oxone with [Mn-2(OAc)(2)(bpmp)](+) (1), stoichiometrically labelled oxygen (O-18(2)) was formed. This is the first example of a homogeneous reaction mediated by a synthetic manganese complex where the addition of a strong chemical oxidant yields O-18(2) with labelling percentages matching the theoretically expected values for the case of both O-atoms originating from water. Experiments using lead acetate as an alternative oxidant supported this finding. A detailed investigation of the reaction by EPR spectroscopy, MIMS and Clark-type oxygen detection enabled us to propose potential reaction pathways.
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| 8. |
- Bertoni, M. I., 1967-, et al.
(författare)
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Nanoprobe X-ray fluorescence characterization of defects in large-area solar cells
- 2011
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4, s. 4252-4257
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Tidskriftsartikel (refereegranskat)abstract
- The performance of centimeter-sized energy devices is regulated by inhomogeneously distributednanoscale defects. To improve device efficiency and reduce cost, accurate characterization of thesenanoscale defects is necessary. However, the multiscale nature of this problem presentsa characterization challenge, as non-destructive techniques often specialize in a single decade of lengthscales, and have difficulty probing non-destructively beneath the surface of materials with sub-micronspatial resolution. Herein, we push the resolution limits of synchrotron-based nanoprobe X-rayfluorescence mapping to 80 nm, to investigate a recombination-active intragranular defect in industrialsolar cells. Our nano-XRF measurements distinguish fundamental differences between benign anddeleterious dislocations in solar cell devices: we observe recombination-active dislocations to containa high degree of nanoscale iron and copper decoration, while recombination-inactive dislocationsappear clean. Statistically meaningful high-resolution measurements establish a connection betweencommercially relevant materials and previous fundamental studies on intentionally contaminatedmodel defect structures, pointing the way towards optimization of the industrial solar cell process.Moreover, this study presents a hierarchical characterization approach that can be broadly extended toother nanodefect-limited energy systems with the advent of high-resolution X-ray imaging beamlines
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| 9. |
- Boot-Handford, M. E., et al.
(författare)
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Carbon capture and storage update
- 2014
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 7:1, s. 130-189
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Forskningsöversikt (refereegranskat)abstract
- In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coat (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
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| 10. |
- Bounioux, C., et al.
(författare)
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Thermoelectric composites of poly(3-hexylthiophene) and carbon nanotubes with a large power factor
- 2013
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 6:3, s. 918-925
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Tidskriftsartikel (refereegranskat)abstract
- Composite films of poly(3-hexylthiophene) and single- as well as multi-walled carbon nanotubes are demonstrated to offer a competitive thermoelectric performance. The power factor significantly exceeds values obtained with either constituent alone provided that the conjugated polymer is sufficiently p-doped. The use of single-walled carbon nanotubes consistently results in a higher electrical conductivity with a maximum value above 10(3) S cm(-1) and thus gives rise to a power factor of 25 +/- 6 mu W m(-1) K-2 for a filler content of only 8 wt% and a maximum 95 +/- 12 mu W m(-1) K-2 for 42-81 wt%. Moreover, a carbon nanotube content of 8-10 wt% does not compromise the low bulk thermal conductivity of the polymer matrix, which promises a high figure of merit of at least ZT > 10(-2) at room-temperature. All samples are cast on plastic substrates, emphasising their suitability for large-area, flexible thermoelectric applications.
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| 11. |
- Bubnova, Olga, et al.
(författare)
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Towards polymer-based organic thermoelectric generators
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 5:11, s. 9345-9362
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Tidskriftsartikel (refereegranskat)abstract
- In response to the thread of environmental and ecological degradation along with projected fossil fuel depletion the active search for efficient renewable energy conversion technologies has been attempted in various research areas including the field of thermoelectrics. Despite the availability of considerable amounts of waste and natural heat stored in warm fluids (andlt;250 degrees C) a lack of environmentally friendly materials with high natural abundance, low manufacturing cost and high thermoelectric efficiency impedes the widespread use of thermoelectric generators for energy harvesting on a large scale. In this perspective, we examine the possibility of using organic conducting polymers in thermoelectric applications. We provide an overview of the background and the key concepts of organic thermoelectrics and illustrate some of the first prototypes of polymer-based organic thermoelectric generators.
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| 12. |
- Carrod, Andrew J., 1994, et al.
(författare)
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Recent advances in triplet-triplet annihilation upconversion and singlet fission, towards solar energy applications
- 2022
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 15, s. 4982-5016
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Forskningsöversikt (refereegranskat)abstract
- Solar energy is an ample renewable energy resource, with photovoltaic (PV) technology enabling a direct route from light to electricity. Currently, PVs are limited in photon conversion efficiency, due in major part to spectral losses. Mitigation of these losses is therefore important, economically and environmentally. Two processes that aim to increase solar light utilisation are described herein. The first is triplet-triplet annihilation upconversion (TTA-UC), through which two incoherent photons of low energy can produce one of higher energy, reducing below bandgap losses. Secondly, singlet fission (SF), through which two triplet states may be obtained from one initial singlet excited state, in theory allowing two electrons per photon in a PV, reducing thermalisation losses. These fields are often covered seperately, despite being the reverse processes of one another. This work aims to consolidate research in the two fields and highlight their similarities and common challenges, specifically those relevant to PV applications. Herein, we cover systems primarily based on organic small molecules (anthracene, rubrene, tetracene, pentacene), and detail the fabrication of functional materials containing them (MOFs, gels, SAMs on TiO2, thin evaporated and solution cast films, and cavities). We further offer our recommendations for the focus of future work in both the TTA and SF fields, and discuss the need to address current limitations such as poor triplet diffusion, limited charge injection to PVs, and material stability. Specifically, one could do this by cherry picking ideas from other research fields, for example photosensitisers for photodynamic therapy could be used as TTA sensitisers, and molecules having a considerable excited state aromaticity could be considered as SF materials. We hope this review may aid development towards the end goal of an efficient PV, incorporating either, or both, SF and TTA-UC materials.
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| 13. |
- Caspeta-Guadarrama, Luis, 1974, et al.
(författare)
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The role of biofuels in the future energy supply
- 2013
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 6:4, s. 1077-1082
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Forskningsöversikt (refereegranskat)abstract
- In recent years several different arguments have been raised against the use of biofuels and their role in our future energy supply. These arguments can be divided into issues related to costs, food versus fuel, and lack of sustainability. Here we address these three points and argue that biofuels represent an essential contribution to our future energy supply and more importantly will contribute to a reduction in carbon dioxide emissions.
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| 14. |
- Chen, Jingxuan, et al.
(författare)
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Emerging perovskite quantum dot solar cells : feasible approaches to boost performance
- 2021
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Ingår i: Energy & Environmental Science. - CAMBRIDGE ENGLAND : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:1, s. 224-261
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Forskningsöversikt (refereegranskat)abstract
- Lead halide perovskite quantum dots (PQDs), also called perovskite nanocrystals, are considered as one of the most promising classes of photovoltaic materials for solar cells due to their prominent optoelectronic properties and simple preparation techniques. Remarkable achievements in PQD solar cells (PQDSCs) have been made. In particular, the power conversion efficiency of PQDSCs has been largely pushed from 10.77% to 17.39% (certified 16.6%) by finely controlling the surface chemistry of PQDs and the device physics of PQDSCs. In this review, we summarize the latest advances of emerging PQDSCs and discuss various strategies applied to improve the device performance of PQDSCs, including the synthesis methods, compositional engineering and surface chemistry of PQDs. Moreover, the device operation of PQDSCs is discussed to highlight the effect of device architecture on the photovoltaic performance of PQDSCs. Facing the practical applications of the PQDSCs under ambient conditions, device stability is also highlighted. Finally, conclusions and perspectives are presented along with the possible challenges and opportunities to promote development steps of PQDSCs with higher photovoltaic performance and robust stability.
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| 15. |
- Chen, Lin, et al.
(författare)
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A super-efficient cobalt catalyst for electrochemical hydrogen production from neutral water with 80 mV overpotential
- 2014
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 7:1, s. 329-334
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembled molecular iron and cobalt catalysts (MP4N2, M = Fe, Co) bearing a multihydroxy-functionalized tetraphosphine ligand electrocatalyze H-2 generation from neutral water on a mercury electrode at -1.03 and -0.50 V vs. NHE, respectively. Complex CoP4N2 displays extremely low overpotential (E-onset = 80 mV) while maintaining high activity and good stability. Bulk electrolysis of CoP4N2 in a neutral phosphate buffer solution at -1.0 V vs. NHE produced 9.24 x 10(4) mol H-2 per mol cat. over 20 h, with a Faradaic efficiency close to 100% and without apparent deactivation.
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| 16. |
- Chen, W., et al.
(författare)
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Operando structure degradation study of PbS quantum dot solar cells
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 14:6, s. 3420-3429
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Tidskriftsartikel (refereegranskat)abstract
- PbS quantum dot (QD) solar cells demonstrate great potential in solar energy conversion with a broad and flexible spectral response. Even though long-term storage stabilities of QD solar cells were reported in literature, the operation stability from a more practical aspect, to date, has been not yet investigated. Herein, we observe the structure degradation process of a PbS QD-ink based solar cell during the device operation. Simultaneously to probing the solar cell parameters, the overall structure evolutions of the QDs in both, active layer and hole transport layer of the solar cell are studied with grazing-incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS). We find a spontaneous decrease of the QD inter-dot distance with an increase in the spatial disorder in the active layer (PbX2-PbS QDs, X = I, and Br) during the operation induced degradation. Consequently, the structure disorder-induced broadening of the energy state distribution is responsible for the decrease in open-circuit voltageVocleading to the device degradation. These findings elucidate the origin of light-soaking as well as the structure degradation of QD ink-based solar cells and indicate that the stability of the device can be realized by the positional stabilization of the QDs in the QD solid.
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| 17. |
- Cheng, Ming, et al.
(författare)
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Efficient dye-sensitized solar cells based on an iodine-free electrolyte using L-cysteine/L-cystine as a redox couple
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:4, s. 6290-6293
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Tidskriftsartikel (refereegranskat)abstract
- A new iodine-free electrolyte based on amino acids L-cysteine/L-cystine as a redox couple has been designed and synthesized. DSSCs fabricated with the conventional I-/I-3(-) redox couple gave efficiencies of 8.1% and 6.3% under optimized experimental conditions based on ruthenium dye, N719, and metal-free organic dye, TH202, respectively. Based on the same dyes, the DSSCs employing the new L-cysteine/L-cystine redox couple showed comparable efficiencies of 7.7% and 5.6%, respectively. However, higher incident-photon-to-electron (IPCE) conversion efficiencies and larger J(sc) values were found for devices with the L-cysteine/L-cystine redox couple than with I-/I-3(-). From an electrochemical impedance spectroscopic study, we found that the charge recombination between the conduction band electrons in the TiO2 film and the electrolyte containing the L-cysteine/L-cystine redox couple is restrained.
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| 18. |
- Cong, Jiayan, et al.
(författare)
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Iodine/iodide-free redox shuttles for liquid electrolyte-based dye-sensitized solar cells
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 5:11, s. 9180-9194
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Forskningsöversikt (refereegranskat)abstract
- Dye-sensitized solar cells have attracted intense academic interest over the past two decades. For a long time, the development of new redox systems has fallen far behind that of the sensitizing dyes and other materials. However, the field has received renewed attention recently. In particular, in 2011, the Gratzel group published a record DSC efficiency of 12.3% by using a new Co-complex-based electrolyte. In this review, we will provide an overview of iodine/iodide-free redox systems for liquid electrolytes, and reveal that the design of an efficient redox system should combine with appropriate sensitizing dyes which is the pivotal challenge for highly efficient DSCs.
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| 19. |
- Cui, Daqing, et al.
(författare)
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Environmental behaviors of spent nuclear fuel and canister materials
- 2011
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4:7, s. 2537-2545
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Tidskriftsartikel (refereegranskat)abstract
- The world's first spent nuclear fuel repository concept (Swedish KBS-3) is illustrated and the results of experiments on environmental behaviors of spent fuel and canister materials under a potential canister breaching at early stage of disposal are reported. In a deoxygenated synthetic groundwater (2 mM NaHCO(3)) under radiation (gamma 0.9 Gy h(-1)), inventory fraction leaching rates of fission-products ((137)Cs, (90)Sr and (99)Tc) and actinides ((238)U, (237)Np) from a spent fuel segment were found to be around 10(-6) and 10(-7) per day, respectively. A cast-iron canister surface was found to be able to immobilize (238)U, (90)Sr, (99)Tc and (237)Np dissolved from spent fuel, but a copper surface could not. In the presence of the oxidative species generated from water radiolysis, the corrosion rates of waste canister materials, copper and cast-iron were found to be 1 and 30 mm per year, respectively. The observation of insignificant dissolution of spent fuel in the leaching solution equilibrated with 0.1 atm H(2) is explained by the reducing effects of H(2) in the presence of fission-product alloy particles (Mo-Tc-Ru-Rh-Pd) as catalysts and dissolved Fe(II) in groundwater. The coating effect of ferric precipitates on spent nuclear fuel dissolution is also discussed.
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| 20. |
- Dagys, Marius, et al.
(författare)
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Oxygen electroreduction catalysed by laccase wired to gold nanoparticles via the trinuclear copper cluster
- 2017
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 10:2, s. 498-502
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Tidskriftsartikel (refereegranskat)abstract
- Specific wiring of biocatalysts par excellence, viz. redox enzymes, to an electrode can be exploited in the fabrication of high-performance bioelectronic devices. Here we report oxygen electroreduction catalysed by Didymocrea sp. J6 laccase wired to gold nanoparticles via the trinuclear copper cluster. Bypassing the intramolecular electron transfer, which under certain conditions is the rate-limiting step of oxygen bioelectroreduction, has resulted in the fabrication of a high current density biocathode based on high-redox-potential laccase, which is able to operate in electrolytes with a broad pH range in the presence of high fluoride concentrations.
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| 21. |
- Datta, Shuvo Jit, et al.
(författare)
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Removal of Sr-90 from highly Na+-rich liquid nuclear waste with a layered vanadosilicate
- 2019
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 12:6, s. 1857-1865
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Tidskriftsartikel (refereegranskat)abstract
- Capture of trace amounts (parts per trillion or ppt level) of Sr-90 from highly Na+-rich (5 M or 115 000 parts per million) liquid wastes produced from reprocessing of spent nuclear fuel rods is crucial for continuous operation of nuclear power plants. However, no sorbents have shown such abilities. We now report that a novel layered vanadosilicate, SGU-7, with the unit cell parameters of a = 23.58 A, b = 30.04 A, c = 12.31 A, b = 100.28, and space group of P12(1)/a1, can effectively capture Sr-90 from a 5 M Na+ solution containing 6.2 ppt of Sr-90. It also effectively captures 1-ppb level Ra-226 from 2 M NaCl solution, and Cs+ and Sr2+ from groundwater, demonstrating that it can be immediately used to remedy groundwater and soil contaminated with Ra-226, Sr-90, and Cs-137.
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| 22. |
- De La Fuente Durán, Ana, et al.
(författare)
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Origins of hydrogen peroxide selectivity during oxygen reduction on organic mixed ionic-electronic conducting polymers
- 2023
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 16:11, s. 5409-5422
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical reduction of atmospheric oxygen provides carbon emission-free pathways for the generation of electricity from chemical fuels and for the distributed production of green chemical oxidants like hydrogen peroxide. Recently, organic mixed ionic-electronic conducting polymers (OMIECs) have been reported as a new class of active electrode materials for the oxygen reduction reaction. This work sets out to identify the operative oxygen reduction mechanism of OMIECs through a multi-faceted experimental and theoretical approach. Using a combination of pH-dependent electrochemical characterization, operando UV-Vis and Raman spectroscopy, and ab initio calculations, we find that the n-type OMIEC, p(NDI-T2 P75), displays pH-dependent activity for the selective reduction of oxygen to the 2-electron hydrogen peroxide product. We use microkinetic simulations of the electrochemical behavior to rationalize our experimental observations through a polaron-mediated, non-adsorptive pathway involving chemical reduction of oxygen to the 1-electron superoxide intermediate followed by pH-dependent catalytic disproportionation to hydrogen peroxide. Finally, this pathway is applied to understand the experimental oxygen reduction reactivity across several n- and p-type OMIECs.
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| 23. |
- Delannoy, Louis, et al.
(författare)
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Emerging consensus on net energy paves the way for improved integrated assessment modeling
- 2024
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 17:1, s. 11-26
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Extracting, processing, and delivering energy requires energy itself, which reduces the net energy available to society and yields considerable socioeconomic implications. Yet, most mitigation pathways and transition models overlook net energy feedbacks, specifically related to the decline in the quality of fossil fuel deposits, as well as energy requirements of the energy transition. Here, we summarize our position across 8 key points that converge to form a prevailing understanding regarding EROI (Energy Return on Investment), identify areas of investigation for the Net Energy Analysis community, discuss the consequences of net energy in the context of the energy transition, and underline the issues of disregarding it. Particularly, we argue that reductions in net energy can hinder the transition if demand-side measures are not implemented and adopted to limit energy consumption. We also point out the risks posed for the energy transition in the Global South, which, while being the least responsible for climate change, may be amongst the most impacted by both the climate crisis and net energy contraction. Last, we present practical avenues to consider net energy in mitigation pathways and Integrated Assessment Models (IAMs), emphasizing the necessity of fostering collaborative efforts among our different research communities.
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| 24. |
- Dossow, Marcel, et al.
(författare)
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Electrification of gasification-based biomass-to-X processes - a critical review and in-depth assessment
- 2024
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 17:3, s. 925-973
-
Forskningsöversikt (refereegranskat)abstract
- To address the impacts of climate change, it is imperative to significantly decrease anthropogenic greenhouse gas emissions. Biomass-based chemicals and fuels will play a crucial role in substituting fossil-based feedstocks and reducing emissions. Gasification-based biomass conversion processes with catalytic synthesis producing chemicals and fuels (Biomass-to-X, BtX) are an innovative and well-proven process route. Since biomass is a scarce resource, its efficient utilization by maximizing product yield is key. In this review, the electrification of BtX processes is presented and discussed as a technological option to enhance chemical and fuel production from biomass. Electrified processes show many advantages compared to BtX and electricity-based processes (Power-to-X, PtX). Electrification options are classified into direct and indirect processes. While indirect electrification comprises mostly the addition of H2 from water electrolysis (Power-and-Biomass-to-X, PBtX), direct electrification refers to power integration into specific processing steps by converting electricity into the required form of energy such as heat, electrochemical energy or plasma used (eBtX). After the in-depth review of state-of-the-art technologies, all technologies are discussed in terms of process performance, maturity, feasibility, plant location, land requirement, and dynamic operation. H2 addition in PBtX processes has been widely investigated in the literature with process simulations showing significantly increased carbon efficiency and product yield. Similar studies on direct electrification (eBtX) are limited in the literature due to low technological maturity. Further research is required on both, equipment level technology development, as well as process and system level, to compare process options and evaluate performance, economics, environmental impact and future legislation.
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| 25. |
- Dreos, Ambra, 1987, et al.
(författare)
-
Exploring the potential of a hybrid device combining solar water heating and molecular solar thermal energy storage
- 2017
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:3, s. 728-734
-
Tidskriftsartikel (refereegranskat)abstract
- A hybrid solar energy system consisting of a molecular solar thermal energy storage system (MOST) combined with a solar water heating system (SWH) is presented. The MOST chemical energy storage system is based on norbornadiene- quadricyclane derivatives allowing for conversion of solar energy into stored chemical energy at up to 103 kJ mol(-1) (396 kJ kg(-1)). It is demonstrated that 1.1% of incoming solar energy can be stored in the chemical system without significantly compromising the efficiency of the solar water heating system, leading to efficiencies of combined solar water heating and solar energy storage of up to 80%. Moreover, prospects for future improvement and possible applications are discussed.
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| 26. |
- Duan, Lele, et al.
(författare)
-
Visible light-driven water oxidation-from molecular catalysts to photoelectrochemical cells
- 2011
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4:9, s. 3296-3313
-
Tidskriftsartikel (refereegranskat)abstract
- This perspective article reports the most significant advances in the field of water oxidation-from molecular water oxidation catalysts (WOCs) to photoelectrochemical cells. Different series of catalysts that can be applied in visible light-driven water oxidation catalysis are discussed in details and several key aspects of their catalytic mechanisms are introduced. In order to construct a water oxidation electrode from molecular catalysts, proper immobilization methods have to be employed. Herein, we present one section about how to attach catalysts onto an electrode/material surface. Finally, the state of the art photoelectrochemical cells that achieve visible light-driven water splitting are described.
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| 27. |
- Eriksson, Ola, et al.
(författare)
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Plastic waste as a fuel - CO2-neutral or not?
- 2009
-
Ingår i: Energy and Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 2:9, s. 907-914
-
Tidskriftsartikel (refereegranskat)abstract
- Municipal solid waste (MSW) is not only a societal problem addressed with environmental impact, it is also a resource that can be used for energy supply. In Northern Europe combustion of MSW ( incineration with energy recovery) in combination with district heating systems is quite common. In Sweden, about 47% of the household waste is treated by incineration with energy recovery. Most incineration plants are CHP, summing up to 0.3% of the total electricity generation. MSW is to a high extent a renewable fuel, but plastic, rubber etc. can amount to 50% of the carbon content in the waste. Recycling of plastic is in general environmentally favourable in comparison to landfill disposal or incineration. However, some plastic types are not possible to recycle and some plastic is of such low quality that it is not suitable for recycling. This paper focuses on the non-renewable and non-recyclable plastic in MSW. A CO2 assessment has been made for non-recyclable plastic where incineration with energy recovery has been compared to landfill disposal. In the assessment, consideration has been taken of alternative fuel in the incinerator, emissions from waste treatment and avoided emissions from heat and power supply. For landfill disposal of plastic the emissions of CO2 amounts to 253 g kg(-1) plastic. For incineration, depending on different discrete choices, the results vary from -673 g kg(-1) to 4605 g kg(-1). Results indicate that for typical Swedish and European conditions, incineration of plastics has net emissions of greenhouse gases. These emissions are also in general higher for incineration than for landfill disposal. However in situations where plastics are incinerated with high efficiency and high electricity to heat ratios, and the heat and the electricity from incineration of plastics are replacing heat and electricity in non-combined heat and power plants based on fossil fuels, incineration of plastics can give a net negative contribution of greenhouse gases. The results suggest that efforts should be made to increase recycling of plastics, direct incineration of plastics in places where it can be combusted with high efficiency and high electricity-to-heat ratios where it is replacing fossil fuels, and reconsider the present policies of avoiding landfill disposal of plastics.
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| 28. |
- Fan, Qunping, 1989, et al.
(författare)
-
Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation
- 2020
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 13:12, s. 5017-5027
-
Tidskriftsartikel (refereegranskat)abstract
- Obtaining both high open-circuit voltage (V-oc) and short-circuit current density (J(sc)) has been a major challenge for efficient all-polymer solar cells (all-PSCs). Herein, we developed a polymer acceptor PF5-Y5 with excellent optical absorption capability (onset extending to similar to 880 nm and maximum absorption coefficient exceeding 105 cm(-1) in a film), high electron mobility (3.18 x 10(3) cm(2) V-1 s(-1)) and high LUMO level (-3.84 eV) to address such a challenge. As a result, the PBDB-T:PF5-Y5-based all-PSCs achieved a high power conversion efficiency of up to 14.45% with both a high Voc (0.946 V) and a high Jsc (20.65 mA cm(-2)), due to the high and broad absorption coverage, small energy loss (0.57 eV) and efficient charge separation and transport in the device, which are among the best values in the all-PSC field. In addition, the all-PSC shows a similar to 15% improvement in PCE compared to its counterpart small molecule acceptor (Y5)-based device. Our results suggest that PF5-Y5 is a very promising polymer acceptor candidate for applications in efficient all-PSCs.
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| 29. |
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| 30. |
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| 31. |
- Felekidis, Nikolaos, et al.
(författare)
-
Open circuit voltage and efficiency in ternary organic photovoltaic blends
- 2016
-
Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:1, s. 257-266
-
Tidskriftsartikel (refereegranskat)abstract
- Organic bulk heterojunction solar cells based on ternary blends of two donor absorbers and one acceptor are investigated by experiments and modeling. The commonly observed continuous tunability of the open circuit voltage VOC with the donor1: donor2 ratio can quantitatively be explained as quasi-Fermi level splitting due to photocreated charges filling a joint density of states that is broadened by Gaussian disorder. On this basis, a predictive model for the power conversion efficiency that accounts for the composition-dependent absorption and the shape of the current-voltage characteristic curve is developed. When all other parameters, most notably the fill factor, are constant, we find that for state-of-the-art absorbers, having a broad and strong absorption spectrum, ternary blends offer no advantage over binary ones. For absorbers with a more narrow absorption spectrum ternary blends of donors with complementary absorption spectra, offer modest improvements over binary ones. In contrast, when, upon blending, transport and/or recombination kinetics are improved, leading to an increased fill factor, ternaries may offer significant advantages over binaries.
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| 32. |
- Finegan, Donal P., et al.
(författare)
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Spatial dynamics of lithiation and lithium plating during high-rate operation of graphite electrodes
- 2020
-
Ingår i: Energy and Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 13:8, s. 2570-2584
-
Tidskriftsartikel (refereegranskat)abstract
- The principal inhibitor of fast charging lithium ion cells is the graphite negative electrode, where favorable conditions for lithium plating occur at high charge rates, causing accelerated degradation and safety concerns. The local response of graphite, both at the electrode and particle level, when exposed to fast charging conditions of around 6C is not well understood. Consequently, the conditions that lead to the onset of lithium plating, as well as the local dynamics of lithium plating and stripping, have also remained elusive. Here, we use high-speed (100 Hz) pencil-beam X-ray diffraction to repeatedly raster along the depth of a 101 µm thick graphite electrode in 3 µm steps during fast (up to 6C) charge and discharge conditions. Consecutive depth profiles from separator to current collector were each captured in 0.5 seconds, giving an unprecedented spatial and temporal description of the state of the electrode and graphite's staging dynamics during high rate conditions. The electrode is preferentially activated near the separator, and the non-uniformity increases with rate and is influenced by free-energy barriers between graphite's lithiation stages. The onset of lithium plating and stripping was quantified, occurring only within the first 15 µm from the separator. The presence of lithium plating changed the behavior of the underlying graphite, such as causing co-existence of LiC6 and graphite in the fully discharged state. Finally, the staging behavior of graphite at different rates was quantified, revealing a high dependency on rate and drastic hysteresis between lithiation and delithiation.
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| 33. |
- Freitag, Marina, et al.
(författare)
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High-efficiency dye-sensitized solar cells with molecular copper phenanthroline as solid hole conductor
- 2015
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 8:9, s. 2634-2637
-
Tidskriftsartikel (refereegranskat)abstract
- Copper phenanthroline complexes in the solid phase can act as efficient molecular hole transporting material (HTM) for hybrid solar cells. We prepared solid-state dye-sensitized solar cells with the organic dye LEG4 and bis(2,9-dimethyl-1,10-phenanthroline)copper(I/II) (Cu(dmp)(2)) and achieved power conversion efficiencies of more than 8% under 1000 W m(-2) AM1.5G illumination, with open-circuit potentials of more than 1.0 V. The successful application of a copper-complex based HTM paves the way for low-cost and efficient hybrid solar cells, as well as for other opto-electronic devices.
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| 34. |
- Gao, Feng, et al.
(författare)
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The renaissance of hybrid solar cells : progresses, challenges, and perspectives
- 2013
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 6:7, s. 2020-2040
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Forskningsöversikt (refereegranskat)abstract
- Solution-processed hybrid solar cells, a blend of conjugated polymers and semiconducting nanocrystals, are a promising candidate for next-generation energy-conversion devices. The renaissance of this field in recent years has yielded a much deeper understanding of optoelectronic interactions in organic–inorganic hybrid systems. In this article, we review the state-of-the-art progress in hybrid bulk heterojunction solar cells, covering new materials design, interfacial interaction, and processing control. Furthermore, critical challenges that determine photovoltaic performance and prospects for future directions are discussed.
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| 35. |
- Gusak, Viktoria, 1983, et al.
(författare)
-
Diffusion and adsorption of dye molecules in mesoporous TiO2 photoelectrodes studied by indirect nanoplasmonic sensing
- 2013
-
Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 6:12, s. 3627-3636
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we used Hidden Interface-Indirect Nanoplasmonic Sensing (HI-INPS) for real time monitoring of dye impregnation (adsorption-diffusion process) of mesoporous TiO2 electrodes of the kind used in dye-sensitized solar cells. We measured the dye percolation time (i.e. the time to diffuse to the bottom of a TiO2 photoelectrode film) for dye Z907 in a 1 : 1 volume mixture of acetonitrile and tert-butanol for different dye concentrations and for different thicknesses of the TiO2 film, while the total amount of adsorbed dye was simultaneously measured by optical absorption spectroscopy. The experimental data for the impregnation process were analyzed by employing a diffusion-front model, combining diffusion and Langmuir type adsorption, which allows extraction of the effective diffusion coefficient for the system. The latter value is about 15 mu m(2) s(-1) for the combined adsorption-diffusion movement of dye molecules through the TiO2 structure, which is an order of magnitude or more smaller than that for "free" diffusion of dye molecules in bulk solvents.
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| 36. |
- Hammarström, Leif, et al.
(författare)
-
Proton-coupled electron transfer of tyrosines in Photosystem II and model systems for artificial photosynthesis : the role of a redox-active link between catalyst and photosensitizer
- 2011
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 4:7, s. 2379-2388
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Tidskriftsartikel (refereegranskat)abstract
- Water oxidation in Photosystem II is dependent on a particular amino acid residue, Tyrosine(Z). This is a redox intermediate in steady state oxygen evolution and transfers electrons from the water splitting CaMn4 cluster to the central chlorophyll radical P-680(+). This Perspective discusses the functional principles of Tyrosine(Z) as a proton-coupled redox active link, as well as mechanistic studies of synthetic model systems and implications for artificial photosynthesis. Experimental studies of temperature dependence and kinetic isotope effects are important tools to understand these reactions. We emphasize the importance of proton transfer distance and hydrogen bond dynamics that are responsible for variation in the rate of PCET by several orders of magnitude. The mechanistic principles discussed and their functional significance are not limited to tyrosine and biological systems, but are important to take into account when constructing artificial photosynthetic systems. Of particular importance is the role of proton transfer management in water splitting and solar fuel catalysis.
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| 37. |
- Hieulle, Jeremy, et al.
(författare)
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Understanding and decoupling the role of wavelength and defects in light-induced degradation of metal-halide perovskites
- 2024
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 17:1, s. 284-295
-
Tidskriftsartikel (refereegranskat)abstract
- Light-induced degradation in metal halide perovskites is a major concern that can potentially hamper the commercialization of perovskite optoelectronic devices. The phenomena viz. ion migration, phase segregation, and defect intolerance are believed to be the factors behind the degradation. However, a detailed mechanistic understanding of how and why light reduces the long-term stability of perovskites is still lacking. Here, by combining multiscale characterization techniques and computational studies, we uncover the role of white light in the surface degradation of state-of-the-art FAPbI3-rich perovskite absorbers (reaching up to 22% PCE in solar cells). We unravel the degradation kinetics and found that white light triggers the chemical degradation of perovskite into secondary phases with higher work function and metallic I–V characteristics. Furthermore, we demonstrate that perovskite degradation is triggered by a combined mechanism involving both light and the presence of defects. We employ surface passivation to understand the role of defect intolerance in the degradation process. Moreover, by using filtered light we uncover the wavelength dependency of the light-induced perovskite degradation. Based on our findings, we infer some strategies for material engineering and device design that can expedite the path toward stable perovskite optoelectronic devices.
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| 38. |
- Horn, M. R., et al.
(författare)
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Polyoxometalates (POMs) : From electroactive clusters to energy materials
- 2021
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:4, s. 1652-1700
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Tidskriftsartikel (refereegranskat)abstract
- Polyoxometalates (POMs) represent a class of nanomaterials, which hold enormous promise for a range of energy-related applications. Their promise is owing to their "special"structure that gives POMs a truly unique ability to control redox reactions in energy conversion and storage. One such amazing capability is their large number of redox active sites that arises from the complex three-dimensional cluster of metal-oxide ions linked together by oxygen atoms. Here, a critical review on how POMs emerged from being molecular clusters for fundamental studies, to next-generation materials for energy applications is provided. We highlight how exploiting the versatility and activity of these molecules can lead to improved performance in energy devices such as supercapacitors and batteries, and in energy catalyst applications. The potential of POMs across numerous fields is systematically outlined by investigating structure-property-performance relationships and the determinant factors for energy systems. Finally, the challenges and opportunities for this class of materials with respect to addressing our pressing energy-related concerns are identified. This journal is © The Royal Society of Chemistry.
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| 39. |
- House, Robert A., et al.
(författare)
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Lithium manganese oxyfluoride as a new cathode material exhibiting oxygen redox
- 2018
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 11:4, s. 926-932
-
Tidskriftsartikel (refereegranskat)abstract
- The quantity of charge stored in transition metal oxide intercalation cathodes for Li or Na batteries is not limited by transition metal redox reactions but can also access redox reactions on O; examples include Li1.2Ni0.13Mn0.54Co0.13O2, Li2Ru0.75Sn0.25O3, Li1.2Nb0.3Mn0.4O2, Na2RuO3 and Na2/3Mg0.28Mn0.72O2. Here we show that oxyfluorides can also exhibit charge storage by O-redox. We report the discovery of lithium manganese oxyfluoride, specifically the composition, Li1.9Mn0.95O2.05F0.95, with a high capacity to store charge of 280 mA h g(-1) (corresponding to 960 W h kg(-1)) of which almost half, 130 mA h g(-1), arises from O-redox. This material has a disordered cubic rocksalt structure and the voltage-composition curve is significantly more reversible compared with ordered Li-rich layered cathodes. Unlike lithium manganese oxides such as the ordered layered rocksalt Li2MnO3, Li1.9Mn0.95O2.05F0.95 does not exhibit O loss from the lattice. The material is synthesised using a simple, one-pot mechanochemical procedure.
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| 40. |
- Hu, Liangbing, et al.
(författare)
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Transparent and conductive paper from nanocellulose fibers
- 2013
-
Ingår i: Energy & Environmental Science. - 1754-5692 .- 1754-5706. ; 6:2, s. 513-518
-
Tidskriftsartikel (refereegranskat)abstract
- Here we report on a novel substrate, nanopaper, made of cellulose nanofibrils, an earth abundant material. Compared with regular paper substrates, nanopaper shows superior optical properties. We have carried out the first study on the optical properties of nanopaper substrates. Since the size of the nanofibrils is much less than the wavelength of visible light, nanopaper is highly transparent with large light scattering in the forward direction. Successful depositions of transparent and conductive materials including tin-doped indium oxide, carbon nanotubes and silver nanowires have been achieved on nanopaper substrates, opening up a wide range of applications in optoelectronics such as displays, touch screens and interactive paper. We have also successfully demonstrated an organic solar cell on the novel substrate.
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| 41. |
- Huang, Ivy, et al.
(författare)
-
High performance dual-electrolyte magnesium-iodine batteries that can harmlessly resorb in the environment or in the body
- 2022
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 15:10, s. 4095-4108
-
Tidskriftsartikel (refereegranskat)abstract
- Batteries represent the dominant means for storing electrical energy, but many battery chemistries create waste streams that are difficult to manage, and most possess toxic components that limit their use in biomedical applications. Batteries constructed from materials capable of complete, harmless resorption into the environment or into living organisms after a desired period of operation bypass these disadvantages. However, previously reported eco/bioresorbable batteries offer low operating voltages and modest energy densities. Here, we introduce a magnesium-iodine chemistry and dual (ionic liquid/aqueous) electrolyte to overcome these limitations, enabling significant improvements in voltage, areal capacity, areal energy, areal power, volumetric energy, and volumetric power densities over any alternative. Systematic studies reveal key materials and design considerations. Demonstrations of this technology include power supplies for cardiac pacemakers, wireless environmental monitors, and thermal sensors/actuators. These results suggest strong potential for applications where commercial battery alternatives pose risks to the environment or the human body.
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| 42. |
- Jacobsson, Jesper, 1984-
(författare)
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Photoelectrochemical water splitting : an idea heading towards obsolescence?
- 2018
-
Ingår i: Energy & Environmental Science. - : ROYAL SOC CHEMISTRY. - 1754-5692 .- 1754-5706. ; 11:8, s. 1977-1979
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Forskningsöversikt (refereegranskat)abstract
- The production of hydrogen from water and sunlight is a way to address the intermittency in renewable energy production, while simultaneously generating a versatile fuel and a valuable chemical feedstock. Photoelectrochemical water splitting is one possible approach to accomplish this that has been researched since the early seventies. It has for a long time held the promise of having the potential to become the best, cheapest, and most efficient way to convert solar energy into chemical energy in the form of hydrogen, but in this paper, I argue that the time window where this could have happened has now come to an end. With the rapid development of both PV-technology and earth-abundant electrocatalysis, it will be tremendously difficult, even in the best-case scenario, for a classical photoelectrochemical water splitting device to compete with what PV-driven electrolysers can already do today. This is an insight that should influence the future of solar fuel research.
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| 43. |
- Jacobsson, Jesper, et al.
(författare)
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Sustainable Solar Hydrogen Production : From Photo-Electrochemical Cells to PV-Electrolysis and Back Again
- 2014
-
Ingår i: Energy & Environmental Science. - 1754-5692 .- 1754-5706.
-
Tidskriftsartikel (refereegranskat)abstract
- Sustainable hydrogen production could, in principle, be accomplished along several different routes, where some of the most promising approaches involve utilization of solar energy. Photoelectrochemical cells (PEC-cells) and PV-electrolyzers for solar hydrogen production are here analyzed and compared. The analysis is performed by theoretically designing a number of intermediate devices, successively going from PEC-cells to PV-electrolyzers. The main physical processes: absorption, charge carrier separation, charge carrier transport, and catalysis are analyzed in the different devices. This demonstrates how the two concepts are related, and how one could easily be transformed and converted into the other. The awareness of the close relationship between PEC-cells and PV-electrolyzers is not as widely recognized as it should be. Traditionally, these two approaches have often been considered as fundamentally different, and are far too seldom analyzed in the same context. We argue that the different device designs for solar hydrogen production are best seen as essentially equivalent approaches, and as topological variations of the same basic theme, and can in many cases be unified under the acronym photo driven catalytic (PDC) devices. We further argue that much is to gain by acknowledging the similarities between PEC water splitting and PV-electrolysis, and that one concept alone should not be considered without also considering the other. The analysis and discussion presented could potentially lead to an increased fruitful crossbreeding of the accumulated knowledge in the respective sub-discipline, and aid in realizing solar hydrogen production as a sustainable and economically compatible energy alternative.
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| 44. |
- Jacobsson, Jesper T., et al.
(författare)
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A monolithic device for solar water splitting based on series interconnected thin film absorbers reaching over 10% solar-to-hydrogen efficiency
- 2013
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 6:12, s. 3676-3683
-
Tidskriftsartikel (refereegranskat)abstract
- Efficient production of hydrogen from solar energy is anticipated to be an important component in a future sustainable post-carbon energy system. Here we demonstrate that series interconnected absorbers in a PV-electrolysis configuration based on the compound semiconductor CIGS, CuInxGa1-xSe2, are a highly interesting concept for solar water splitting applications. The band gap energy of CIGS can be adjusted to a value close to optimum for efficient absorption of the solar spectrum, but is too low to drive overall water splitting. Therefore we connect three cells in series, into a monolithic device, which provides sufficient driving force for the full reaction. Integrated with a catalyst this forms a stable PV/photo-electrochemical device, which when immersed in water reaches over 10% solar-to-hydrogen efficiency for unassisted water splitting. The results show that series interconnected device concepts, which enable use of a substantial part of the solar spectrum, provide a simple route towards highly efficient water splitting and could be used also for other solar absorbers with similar electro-optical properties. We discuss how the efficiency could be increased for this particular device, as well as the general applicability of the concepts used in this work. We also briefly discuss advantages and disadvantages of photo-electrochemical cells in relation to PV-electrolysis with respect to our results.
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| 45. |
- Jacobsson, T. Jesper, et al.
(författare)
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Exploration of the compositional space for mixed lead halogen perovskites for high efficiency solar cells
- 2016
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:5, s. 1706-1724
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Tidskriftsartikel (refereegranskat)abstract
- Lead halide perovskites have attracted considerable interest as photoabsorbers in PV-applications over the last few years. The most studied perovskite material achieving high photovoltaic performance has been methyl ammonium lead iodide, CH3NH3PbI3. Recently the highest solar cell efficiencies have, however, been achieved with mixed perovskites where iodide and methyl ammonium partially have been replaced by bromide and formamidinium. In this work, the mixed perovskites were explored in a systematic way by manufacturing devices where both iodide and methyl ammonium were gradually replaced by bromide and formamidinium. The absorption and the emission behavior as well as the crystallographic properties were explored for the perovskites in this compositional space. The band gaps as well as the crystallographic structures were extracted. Small changes in the composition of the perovskite were found to have a large impact on the properties of the materials and the device performance. In the investigated compositional space, cell efficiencies, for example, vary from a few percent up to 20.7%. From the perspective of applications, exchanging iodide with bromide is especially interesting as it allows tuning of the band gap from 1.5 to 2.3 eV. This is highly beneficial for tandem applications, and an empirical expression for the band gap as a function of composition was determined. Exchanging a small amount of iodide with bromide is found to be highly beneficial, whereas a larger amount of bromide in the perovskite was found to cause intense sub band gap photoemission with detrimental results for the device performance. This could be caused by the formation of a small amount of an iodide rich phase with a lower band gap, even though such a phase was not observed in diffraction experiments. This shows that stabilizing the mixed perovskites will be an important task in order to get the bromide rich perovskites, which has a higher band gap, to reach the same high performance obtained with the best compositions.
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| 46. |
- Jain, Sagar Motilal, et al.
(författare)
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Frustrated Lewis pair-mediated recrystallization of CH3NH3PbI3 for improved optoelectronic quality and high voltage planar perovskite solar cells
- 2016
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:12, s. 3770-3782
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Tidskriftsartikel (refereegranskat)abstract
- Films of the hybrid lead halide perovskite CH3NH3PbI3 were found to react with pyridine vapor at room temperature leading to complete bleaching of the film. In dry air or nitrogen atmosphere recrystallization takes place, leading to perovskite films with markedly improved optical and photovoltaic properties. The physical and chemical origin of the reversible bleaching and recrystallization mechanism was investigated using a variety of experimental techniques and quantum chemical calculations. The strong Lewis base pyridine attacks the CH3NH3PbI3. The mechanism can be understood from a frustrated Lewis pair formation with a partial electron donation of the lone-pair on nitrogen together with competitive bonding to other species as revealed by Raman spectroscopy and DFT calculations. The bleached phase consists of methylammonium iodide crystals and an amorphous phase of PbI2( pyridine)(2). After spontaneous recrystallization the CH3NH3PbI3 thin films have remarkably improved photoluminescence, and solar cell performance increased from 9.5% for as-deposited films to more than 18% power conversion efficiency for recrystallized films in solar cells with planar geometry under AM1.5G illumination. Hysteresis was negligible and open-circuit potential was remarkably high, 1.15 V. The results show that complete recrystallization can be achieved with a simple room temperature pyridine vapor treatment of CH3NH3PbI3 films leading to high quality crystallinity films with drastically improved photovoltaic performance.
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| 47. |
- Juarez-Perez, Emilio J., et al.
(författare)
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Thermal degradation of CH3NH3PbI3 perovskite into NH3 and CH3I gases observed by coupled thermogravimetry-mass spectrometry analysis
- 2016
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 9:11, s. 3406-3410
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Tidskriftsartikel (refereegranskat)abstract
- Thermal gravimetric and differential thermal analysis (TG-DTA) coupled with quadrupole mass spectrometry (MS) and first principles calculations were employed to elucidate the chemical nature of released gases during the thermal decomposition of CH3NH3PbI3. In contrast to the common wisdom that CH3NH3PbI3 is decomposed into CH3NH2 and HI, the major gases were methyliodide (CH3I) and ammonia (NH3). We anticipate that our findings will provide new insights into further formulations of the perovskite active material and device design that can prevent methylammonium decomposition and thus increase the long-term stability of perovskite-based opto-electronic devices.
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| 48. |
- Khanna, Namita, et al.
(författare)
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In vivo activation of an [FeFe] hydrogenase using synthetic cofactors
- 2017
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:7, s. 1563-1567
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Tidskriftsartikel (refereegranskat)abstract
- [FeFe] hydrogenases catalyze the reduction of protons, and oxidation of hydrogen gas, with remarkable efficiency. The reaction occurs at the H-cluster, which contains an organometallic [2Fe] subsite. The unique nature of the [2Fe] subsite makes it dependent on a specific set of maturation enzymes for its biosynthesis and incorporation into the apo-enzyme. Herein we report on how this can be circumvented, and the apo-enzyme activated in vivo by synthetic active site analogues taken up by the living cell.
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| 49. |
- Kim, Shi Hyeong, et al.
(författare)
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Harvesting temperature fluctuations as electrical energy using torsional and tensile polymer muscles
- 2015
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 8, s. 3336-3344
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Tidskriftsartikel (refereegranskat)abstract
- Diverse means have been deployed for harvesting electrical energy from mechanical actuation produced by low-grade waste heat, but cycle rate, energy-per-cycle, device size and weight, or cost have limited applications. We report the electromagnetic harvesting of thermal energy as electrical energy using thermally powered torsional and tensile artificial muscles made from inexpensive polymer fibers used for fishing line and sewing thread. We show that a coiled 27 μm-diameter nylon muscle fiber can be driven by 16.7 °C air temperature fluctuations to spin a magnetic rotor to a peak torsional rotation speed of 70 000 rpm for over 300 000 heating–cooling cycles without performance degradation. By employing resonant fluctuations in air temperature of 19.6 °C, an average output electrical power of 124 W per kg of muscle was realized. Using tensile actuation of polyethylene-based coiled muscles and alternating flows of hot and cold water, up to 1.4 J of electrical energy was produced per cycle. The corresponding per cycle electric energy and peak power output, per muscle weight, were 77 J kg−1 and 28 W kg−1, respectively.
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| 50. |
- Klug, Matthew T., et al.
(författare)
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Tailoring metal halide perovskites through metal substitution: influence on photovoltaic and material properties
- 2017
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Ingår i: Energy & Environmental Science. - : ROYAL SOC CHEMISTRY. - 1754-5692 .- 1754-5706. ; 10:1, s. 236-246
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Tidskriftsartikel (refereegranskat)abstract
- We present herein an experimental screening study that assesses how partially replacing Pb in methylammonium lead triiodide perovskite films with nine different alternative, divalent metal species, B = {Co, Cu, Fe, Mg, Mn, Ni, Sn, Sr, and Zn}, influences photovoltaic performance and optical properties. Our findings indicate the perovskite film is tolerant to most of the considered homovalent metal species with lead-cobalt compositions yielding the highest power conversion efficiencies when less than 6% of the Pb2+ ions are replaced. Through subsequent materials characterisation, we demonstrate for the first time that partially substituting Pb2+ at the B-sites of the perovskite lattice is not restricted to Group IV elements but is also possible with at least Co2+. Moreover, adjusting the molar ratio of Pb: Co in the mixed-metal perovskite affords new opportunities to tailor the material properties while maintaining stabilised device efficiencies above 16% in optimised solar cells. Specifically, crystallographic analysis reveals that Co2+ incorporates into the perovskite lattice and increasing its concentration can mediate a crystal structure transition from the cubic to tetragonal phase at room-temperature. Likewise, Co2+ substitution continually modifies the perovskite work function and band edge energies without either changing the band gap or electronically doping the intrinsic material. By leveraging this orthogonal dimension of electronic tunability, we achieve remarkably high open-circuit voltages up to 1.08 V with an inverted device architecture by shifting the perovskite into a more favourable energetic alignment with the PEDOT: PSS hole transport material.
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