| 31. |
- Inganäs, Olle, et al.
(författare)
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Solar energy for electricity and fuels.
- 2016
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Ingår i: Ambio: a Journal of Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45:Suppl 1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy conversion into electricity by photovoltaic modules is now a mature technology. We discuss the need for materials and device developments using conventional silicon and other materials, pointing to the need to use scalable materials and to reduce the energy payback time. Storage of solar energy can be achieved using the energy of light to produce a fuel. We discuss how this can be achieved in a direct process mimicking the photosynthetic processes, using synthetic organic, inorganic, or hybrid materials for light collection and catalysis. We also briefly discuss challenges and needs for large-scale implementation of direct solar fuel technologies.
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| 32. |
- Jiang, Haiying, et al.
(författare)
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A Highly Crystalline Wide-Band-Gap Conjugated Polymer toward High-Performance As-Cast Nonfullerene Polymer Solar Cells
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:41, s. 36061-36069
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Tidskriftsartikel (refereegranskat)abstract
- A new wide-band-gap conjugated polymer PBODT was successfully synthesized that showed high crystallinity and was utilized as, the active material in nonfullerene bulk-heterojunction, polymer solar cells (PSCs). The photovoltaic devices based on the as-cast blend films of PBODT with ITIC and IDIC acceptors showed notable power conversion efficiencies (PCEs) of 7.06% and 9:09%, with high open-circuit voltages of 1.00 and 0.93 V that correspond to low energy losses of 0.59 and 0.69 eV, respectively. In the case of PBODT:ITIC, lower exciton quenching efficiency and monomolecular recombination are found for devices with small driving force. On the other hand, the relatively higher driving force and suppressed monomolecular recombination for PBODT:IDIC devices are identified to be the reason for their higher short-circuit current density (J(sc)) and higher PCEs. In addition, when processed with the nonchlorinated solvent 1,2,4-trimethylbenzene, a good, PCE of 8.19% was still, achieved for the IDIC-based device. Our work shows that such wide-band-gap polymers have great potential for the environmentally friendly fabrication of highly efficient PSCs.
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| 33. |
- Johansson, Patrik, et al.
(författare)
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Electronic polymers in lipid membranes
- 2015
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 5:11242
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Tidskriftsartikel (refereegranskat)abstract
- Electrical interfaces between biological cells and man-made electrical devices exist in many forms, but it remains a challenge to bridge the different mechanical and chemical environments of electronic conductors (metals, semiconductors) and biosystems. Here we demonstrate soft electrical interfaces, by integrating the metallic polymer PEDOT-S into lipid membranes. By preparing complexes between alkyl-ammonium salts and PEDOT-S we were able to integrate PEDOT-S into both liposomes and in lipid bilayers on solid surfaces. This is a step towards efficient electronic conduction within lipid membranes. We also demonstrate that the PEDOT-S@alkyl-ammonium: lipid hybrid structures created in this work affect ion channels in the membrane of Xenopus oocytes, which shows the possibility to access and control cell membrane structures with conductive polyelectrolytes.
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| 34. |
- Karuthedath, Safakath, et al.
(författare)
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Thermal annealing reduces geminate recombination in TQ1:N2200 all-polymer solar cells
- 2018
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 6:17, s. 7428-7438
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Tidskriftsartikel (refereegranskat)abstract
- combination of steady-state and time-resolved spectroscopic measurements is used to investigate the photophysics of the all-polymer bulk heterojunction system TQ1:N2200. Upon thermal annealing a doubling of the external quantum efficiency and an improved fill factor (FF) is observed, resulting in an increase in the power conversion efficiency. Carrier extraction is similar for both blends, as demonstrated by time-resolved electric-field-induced second harmonic generation experiments in conjunction with transient photocurrent studies, spanning the ps-mu s time range. Complementary transient absorption spectroscopy measurements reveal that the different quantum efficiencies originate from differences in charge carrier separation and recombination at the polymer-polymer interface: in as-spun samples similar to 35% of the charges are bound in interfacial charge-transfer states and recombine geminately, while this pool is reduced to similar to 7% in thermally-annealed samples, resulting in higher short-circuit currents. Time-delayed collection field experiments demonstrate a field-dependent charge generation process in as-spun samples, which reduces the FF. In contrast, field-dependence of charge generation is weak in annealed films. While both devices exhibit significant non-geminate recombination competing with charge extraction, causing low FFs, our results demonstrate that the donor/acceptor interface in all-polymer solar cells can be favourably altered to enhance charge separation, without compromising charge transport and extraction.
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| 35. |
- Kroon, Renee, 1982, et al.
(författare)
-
Comparison of selenophene and thienothiophene incorporation into pentacyclic lactam-based conjugated polymers for organic solar cells
- 2015
-
Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 6:42, s. 7402-7409
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we compare the effect of incorporating selenophene versus thienothiophene spacers into pentacyclic lactam-based conjugated polymers for organic solar cells. The two cyclic lactam-based copolymers were obtained via a new synthetic method for the lactam moiety. Selenophene incorporation results in a broader and red-shifted optical absorption while retaining a deep highest occupied molecular orbital level, whereas thienothienophene incorporation results in a blue-shifted optical absorption. Additionally, grazing-incidence wide angle X-ray scattering data indicates edge- and face-on solid state order for the selenophene-based polymer as compared to the thienothiophene-based polymer, which orders predominantly edge-on with respect to the substrate. In polymer : PC71BM bulk heterojunction solar cells both materials show a similar open-circuit voltage of similar to 0.80-0.84 V, however the selenophene-based polymer displays a higher fill factor of similar to 0.70 vs. similar to 0.65. This is due to the partial face-on backbone orientation of the selenophene-based polymer, leading to a higher hole mobility, as confirmed by single-carrier diode measurements, and a concomitantly higher fill factor. Combined with improved spectral coverage of the selenophene-based polymer, as confirmed by quantum efficiency experiments, it offers a larger short-circuit current density of similar to 12 mA cm(-2). Despite the relatively low molecular weight of both materials, a very robust power conversion efficiency similar to 7% is achieved for the selenophene-based polymer, while the thienothiophene-based polymer demonstrates only a moderate maximum PCE of similar to 5.5%. Hence, the favorable effects of selenophene incorporation on the photovoltaic performance of pentacyclic lactam-based conjugated polymers are clearly demonstrated.
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| 36. |
- Li, Wei, et al.
(författare)
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One-Step Synthesis of Precursor Oligomers for Organic Photovoltaics: A Comparative Study between Polymers and Small Molecules
- 2015
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:49, s. 27106-27114
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Tidskriftsartikel (refereegranskat)abstract
- Two series of oligomers TQ and rhodanine end-capped TQ-DR were synthesized using a facile one-step method. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated and compared. The TQ series of oligomers were found to be amorphous, whereas the TQ-DR series are semicrystalline. For the TQ oligomers, the results obtained in solar cells show that as the chain length of the oligomers increases, an increase in power conversion efficiency (PCE) is obtained. However, when introducing 3-ethylrhodanine into the TQ oligomers as end groups, the PCE of the TQ-DR series of oligomers decreases as the chain length increases. Moreover, the TQ-DR series of oligomers give much higher performances compared to the original amorphous TQ series of oligomers owing to the improved extinction coefficient (epsilon) and crystallinity afforded by the rhodanine. In particular, the highly crystalline oligomer TQ5-DR, which has the shortest conjugation length shows a high hole mobility of 0.034 cm(2) V-1 s(-1) and a high PCE of 3.14%, which is the highest efficiency out of all of the six oligomers. The structure-property correlations for all of the oligomers and the TQ1 polymer demonstrate that structural control of enhanced intermolecular interactions and crystallinity is a key for small molecules/oligomers to achieve high mobilities, which is an essential requirement for use in OPVs.
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| 37. |
- Li, Yongxi, et al.
(författare)
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Non-fullerene acceptor with low energy loss and high external quantum efficiency: towards high performance polymer solar cells
- 2016
-
Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 4:16, s. 5890-5897
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Tidskriftsartikel (refereegranskat)abstract
- A non-fullerene electron acceptor bearing a fused 10-heterocyclic ring (indacenodithiophenoindacenodithiophene) with a narrow band gap (similar to 1.5 eV) was designed and synthesized. It possesses excellent planarity and enhanced effective conjugation length compared to previously reported fused-ring electron acceptors. When this acceptor was paired with PTB7-Th and applied in polymer solar cells, a power conversion efficiency of 6.5% was achieved with a high open circuit voltage of 0.94 V. More significantly, an energy loss as low as 0.59 eV and an external quantum efficiency as high as 63% were obtained simultaneously.
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| 38. |
- Li, Zhaojun, 1989, et al.
(författare)
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High Performance All-Polymer Solar Cells by Synergistic Effects of Fine-Tuned Crystallinity and Solvent Annealing.
- 2016
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 138:34, s. 10935-44
-
Tidskriftsartikel (refereegranskat)abstract
- Growing interests have been devoted to the design of polymer acceptors as potential replacement for fullerene derivatives for high-performance all polymer solar cells (all-PSCs). One key factor that is limiting the efficiency of all-PSCs is the low fill factor (FF) (normally
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| 39. |
- Lin, Yuze, et al.
(författare)
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Mapping Polymer Donors toward High-Efficiency Fullerene Free Organic Solar Cells
- 2017
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 29:3
-
Tidskriftsartikel (refereegranskat)abstract
- Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.
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| 40. |
- Liu, Jing, et al.
(författare)
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Fast charge separation in a non-fullerene organic solar cell with a small driving force
- 2016
-
Ingår i: NATURE ENERGY. - : NATURE PUBLISHING GROUP. - 2058-7546. ; 1
-
Tidskriftsartikel (refereegranskat)abstract
- Fast and efficient charge separation is essential to achieve high power conversion efficiency in organic solar cells (OSCs). In state-of-the-art OSCs, this is usually achieved by a significant driving force, defined as the offset between the bandgap (E-gap) of the donor/acceptor materials and the energy of the charge transfer (CT) state (E-CT), which is typically greater than 0.3 eV. The large driving force causes a relatively large voltage loss that hinders performance. Here, we report non-fullerene OSCs that exhibit ultrafast and efficient charge separation despite a negligible driving force, as E-CT is nearly identical to E-gap. Moreover, the small driving force is found to have minimal detrimental effects on charge transfer dynamics of the OSCs. We demonstrate a non-fullerene OSC with 9.5% efficiency and nearly 90% internal quantum efficiency despite a low voltage loss of 0.61V. This creates a path towards highly efficient OSCs with a low voltage loss.
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