| 11. |
- Börjesson, Karl, 1982, et al.
(author)
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Efficiency Limit of Molecular Solar Thermal Energy Collecting Devices
- 2013
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In: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 1:6, s. 585-590
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Journal article (peer-reviewed)abstract
- As a larger fraction of energy is based on solar energy an other renewable energy sources, technologies for energy storage and conversion is becoming, increasingly important Molecular solar thermal (MOST) is a concept for long-term storage of solar energy in molecules and release of the energy as heat with full regeneration of the initial materials The process is inherently closed cycle and emission free. No assessment of the fundamental efficiency limits of the technology has been made. In this report, I efficiency limits and fundamental factors for molecular design of molecular solar thermal systems are discussed. Maximum efficiencies and potential temperature gradients are estimated using a number of basic assumptions on desired storage lifetimes and energy losses. The predicted maximum solar energy conversion efficiency is 10.6% at a S-1-S-0 gap of 1.89 eV. At this S-1-S-0 gap, the stored energy is able to create temperature differences of similar to 300 degrees C. Several existing systems have an energy storage density in line with the predicted maximum one but do so at larger than optimal S-1-S-0 gaps.
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| 12. |
- Börjesson, Karl, 1982, et al.
(author)
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Exploring the Potential of Fulvalene Dimetals as Platforms for Molecular Solar Thermal Energy Storage: Computations, Syntheses, Structures, Kinetics, and Catalysis
- 2014
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In: Chemistry - A European Journal. - : Wiley. - 1521-3765 .- 0947-6539. ; 20:47, s. 15587-15604
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Journal article (peer-reviewed)abstract
- A study of the scope and limitations of varying the ligand framework around the dinuclear core of FvRu(2) in its function as a molecular solar thermal energy storage framework is presented. It includes DFT calculations probing the effect of substituents, other metals, and CO exchange for other ligands on Delta H-storage. Experimentally, the system is shown to be robust in as much as it tolerates a number of variations, except for the identity of the metal and certain substitution patterns. Failures include 1,1',3,3'-tetra-tert-butyl (4), 1,2,2',3'-tetraphenyl (9), diiron (28), diosmium (24), mixed iron-ruthenium (27), dimolybdenum (29), and di-tungsten (30) derivatives. An extensive screen of potential catalysts for the thermal reversal identified AgNO3-SiO2 as a good candidate, although catalyst decomposition remains a challenge.
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| 13. |
- Börjesson, Karl, 1982, et al.
(author)
-
Fluorinated fulvalene ruthenium compound for molecular solar thermal applications
- 2014
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In: Journal of Fluorine Chemistry. - : Elsevier BV. - 0022-1139. ; 161, s. 24-28
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Journal article (peer-reviewed)abstract
- Molecular photoswitches, i.e. molecules capable of isomerizing between two states when submitted to light stimuli, has found applications in several areas such as molecular logic, molecular electronics, and, if the two isomers differ substantially in energy, molecular solar thermal (MOST) systems. In a MOST system the photoswitchable molecule absorbs a photon where after a photoinduced isomerisation to a high energy metastable photoisomer occurs. The photon energy is thus stored within the molecule. Fulvalenediruthenium compounds, has been suggested as a candidate in MOST systems thanks to the large difference in energy between the two isomers, its relative stability, and its ability to absorb sunlight. We here present a fluorinated fulvalene ruthenium derivative and show that its processing properties is remarkably different, while having retained photoisomerization efficiency, compared to its hydrocarbon analog. © 2014 The Authors.
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| 14. |
- Börjesson, Karl, 1982, et al.
(author)
-
Photon up-conversion and molecular solar thermal energy storage: New materials and devices
- 2014
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In: 2014 IEEE Photonics Conference, IPC 2014. ; , s. 445-446
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Conference paper (peer-reviewed)abstract
- In a future society with limited access to fossil fuels, technologies for efficient on demand delivery of renewable energy are highly desirable. In this regard, methods that allow for solar energy storage and on demand solar driven energy generation are particularly relevant since the sun is the most abundant energy source.
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| 15. |
- Börjesson, Karl, 1982, et al.
(author)
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Photon up-converting devices for solar fuels
- 2014
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In: SPIE Newsroom. - : SPIE-Intl Soc Optical Eng. - 1818-2259.
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Journal article (other academic/artistic)abstract
- Employing a molecular solution capable of triplet-triplet annihilation in a layered microfluidic device enables the solar spectrum to be locally modified toward the UV, increasing solar energy system efficiency.
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| 16. |
- Börjesson, Karl, 1982, et al.
(author)
-
Photon upconversion facilitated molecular solar energy storage
- 2013
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In: Journal of Materials Chemistry. - 1364-5501 .- 0959-9428. ; 1, s. 8521-8524
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Journal article (peer-reviewed)abstract
- Photon upconversion is used to facilitate the production of a solar fuel. This is done by collocating a triplet–triplet annihilation upconversion system in a microfluidic device with a molecular solar thermal energy storage system. Incoherent truncated white light is used to drive the reaction and the green part of the spectrum is upconverted to blue light, which in turn is absorbed by the solar fuel.
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| 17. |
- Gray, Victor, 1988, et al.
(author)
-
Diaryl-substituted norbornadienes with red-shifted absorption for molecular solar thermal energy storage
- 2014
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In: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1364-548X .- 1359-7345. ; 50:40, s. 5330-5332
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Journal article (peer-reviewed)abstract
- Red-shifting the absorption of norbornadienes (NBDs), into the visible region, enables the photo-isomerization of NBDs to quadricyclanes (QCs) to be driven by sunlight. This is necessary in order to utilize the NBD-QC system for molecular solar thermal (MOST) energy storage. Reported here is a study on five diaryl-substituted norbornadienes. The introduced aryl-groups induce a significant red-shift of the UV/vis absorption spectrum of the norbornadienes, and device experiments using a solar-simulator set-up demonstrate the potential use of these compounds for MOST energy storage. © the Partner Organisations 2014.
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| 18. |
- Gray, Victor, 1988, et al.
(author)
-
Triplet-triplet annihilation photon-upconversion: Towards solar energy applications
- 2014
-
In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 16:22, s. 10345-10352
-
Research review (peer-reviewed)abstract
- Solar power production and solar energy storage are important research areas for development of technologies that can facilitate a transition to a future society independent of fossil fuel based energy sources. Devices for direct conversion of solar photons suffer from poor efficiencies due to spectrum losses, which are caused by energy mismatch between the optical absorption of the devices and the broadband irradiation provided by the sun. In this context, photon-upconversion technologies are becoming increasingly interesting since they might offer an efficient way of converting low energy solar energy photons into higher energy photons, ideal for solar power production and solar energy storage. This perspective discusses recent progress in triplet-triplet annihilation (TTA) photon-upconversion systems and devices for solar energy applications. Furthermore, challenges with evaluation of the efficiency of TTA-photon-upconversion systems are discussed and a general approach for evaluation and comparison of existing systems is suggested.
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| 19. |
- Gschneidtner, Tina, 1985, et al.
(author)
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A photolabile protection strategy for terminal alkynes
- 2013
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In: Tetrahedron Letters. - : Elsevier BV. - 0040-4039 .- 1873-3581. ; 54:40, s. 5426-5429
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Journal article (peer-reviewed)abstract
- We present a strategy for photolabile protection of terminal alkynes. Several photo-caged alcohols were synthesized via mild copper(II)-catalyzed substitution between tertiary propargylic alcohols and 2-nitrobenzyl alcohol to build up robust, base stable o-nitrobenzyl (NB) photo-cleavable compounds. We compare the new photolabile protecting group with the commonly used alkyne protecting group, 2-methyl-3-butyn-2-ol and the results show that NB ethers are stable under the cleaving conditions for the cleavage of methylbutynol protected alkynes. Additionally, we present the synthesis of photo-cleavable NB derivatives containing thiol groups that can serve as agents for photoinduced surface functionalization reactions.
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| 20. |
- Gschneidtner, Tina, 1985, et al.
(author)
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Toward Plasmonic Biosensors Functionalized by a Photoinduced Surface Reaction
- 2013
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:28, s. 14751-14758
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Journal article (peer-reviewed)abstract
- We present a method for efficient coupling of amine nucleophilic molecules of choice to a nanostructured gold surface via photoinduced surface chemistry. The method is based on photoactive self-assembled monolayers and can be used to functionalize localized surface plasmon resonance (LSPR) based biosensors with biorecognition motifs while reducing nonspecific binding via introduction of hydrophilic units. The photoactive linker molecule, 5-bromo-7-nitroindoline, couples nucleophilic molecules such as biotin ethylenediamine to a surface when exposed to UV-light. The specific, noncovalent recognition between biotin and streptavidin is used for demonstration of a simple biorecognition assay based on the LSPR sensing principle. By doing so, one can envision that the binding of any streptavidin fusion protein, being attached to specific spots at the gold surface, is monitored by an LSPR peak shift. Since the surface functionalization is based on a photoinduced reaction, this method can be used to functionalize the surface in a local and site-specific way, and biomedical applications such as drug-screening platforms, microarrays, solid support protein synthesis, and even single molecule experiments can be envisioned.
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