| 1. |
- Fan, Qunping, 1989, et al.
(författare)
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Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation
- 2020
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 13:12, s. 5017-5027
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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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| 2. |
- 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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| 3. |
- Dreos, Ambra, 1987, et al.
(författare)
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Exploring the potential of a hybrid device combining solar water heating and molecular solar thermal energy storage
- 2017
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:3, s. 728-734
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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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| 4. |
- Ma, Z. F., et al.
(författare)
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Structure-Property Relationships of Oligothiophene-Isoindigo Polymers for Efficient Bulk-Heterojunction Solar Cells
- 2014
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 7:1, s. 361-369
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Tidskriftsartikel (refereegranskat)abstract
- A series of alternating oligothiophene (nT)–isoindigo (I) copolymers (PnTI) were synthesized to investigate the influence of the oligothiophene block length on the photovoltaic (PV) properties of PnTI:PCBM bulk-heterojunction blends. Our study indicates that the number of thiophene rings (n) in the repeating unit alters both polymer crystallinity and polymer–fullerene interfacial energetics, which results in a decreasing open-circuit voltage (Voc) of the solar cells with increasing n. The short-circuit current density (Jsc) of P1TI:PCBM devices is limited by the absence of a significant driving force for electron transfer. Instead, blends based on P5TI and P6TI feature large polymer domains, which limit charge generation and thus Jsc. The best PV performance with a power conversion efficiency of up to 6.9% was achieved with devices based on P3TI, where a combination of a favorable morphology and an optimal interfacial energy level offset ensures efficient exciton separation and charge generation. The structure–property relationship demonstrated in this work would be a valuable guideline for the design of high performance polymers with small energy losses during the charge generation process, allowing for the fabrication of efficient solar cells that combine a minimal loss in Voc with a high Jsc.
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| 5. |
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| 6. |
- Tung, Cao, et al.
(författare)
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Capture of iodine and organic iodides using silica zeolites and the semiconductor behaviour of iodine in a silica zeolite
- 2016
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 9:3, s. 1050-1062
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Tidskriftsartikel (refereegranskat)abstract
- During the reprocessing of spent nuclear fuel rods, a highly moist off-gas mixture containing various volatile radioactive species, such as iodine (I-2), organic iodides and nitric acid, is produced. Efforts have been made to devise materials, which can effectively capture radioactive iodine (I-2) and organic iodides from the off-gas mixture without being damaged by moisture, nitric acid, and I-2. In the investigation described herein, we observed that all-silica zeolites, such as silicalite-1 and Si-BEA, are stable in 5 M nitric acid and adsorb I-2, CH3I, and CH3CH2I from highly acidic off-gas mixture to much greater extents than activated carbon does. In particular, the hydrophobicity-intensified silicalite-1 performs best. We further found that I-2 forms a unique semiconducting three-dimensional supramolecular network within the silicalite-1 channels. The conductivity of the fully I-2 loaded silicalite-1 is observed to be ca. 10(4) S m(-1), which is ca. 10(8)-fold higher than that of solid I-2.
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| 7. |
- Younesi, S. R., et al.
(författare)
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Lithium salts for advanced lithium batteries: Li-metal, Li-O2, and Li-S
- 2015
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 8:7, s. 1905-1922
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Forskningsöversikt (refereegranskat)abstract
- Presently lithium hexafluorophosphate (LiPF6) is the dominant Li-salt used in commercial rechargeable lithium-ion batteries (LIBs) based on a graphite anode and a 3-4 V cathode material. While LiPF6 is not the ideal Li-salt for every important electrolyte property, it has a uniquely suitable combination of properties (temperature range, passivation, conductivity, etc.) rendering it the overall best Li-salt for LIBs. However, this may not necessarily be true for other types of Li-based batteries. Indeed, next generation batteries, for example lithium-metal (Li-metal), lithium-oxygen (Li-O2), and lithium-sulfur (Li-S), require a re-evaluation of Li-salts due to the different electrochemical and chemical reactions and conditions within such cells. This review explores the critical role Li-salts play in ensuring in these batteries viability.
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| 8. |
- 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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| 9. |
- Sun, Fengbo, et al.
(författare)
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1,5-Diiodocycloctane: a cyclane solvent additive that can extend the exciton diffusion length in thick film organic solar cells
- 2024
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Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 17:5, s. 1916-1930
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Tidskriftsartikel (refereegranskat)abstract
- The short exciton diffusion length associated with most state-of-the-art organic semiconductors used in organic solar cells (OSCs) imposes severe limits on the exciton transport in the larger donor/acceptor domains and the exciton dissociation at the interface, which hinder further improvements in the power conversion efficiencies (PCE) of the thick-film devices. In this study, a new cyclane, 1,5-diiodocycloctane (DICO), was employed as a solvent additive to effectively extend the exciton LD within the bulk-heterojunction blend, which can function with the multiple photovoltaic materials system. Due to the great enhancement of molecular stacking and exclusively large domain sizes of photovoltaic materials with the assistance of the DICO additive, the trap density in devices is significantly reduced, thereby nearly doubling the LD in the thick film OSCs. Notably, the DICO-processed PM6/L8-BO-based OSC showed high thickness tolerance for the bulk-heterojunction (BHJ) layer, delivering a high PCE of 19.1% in the case of a 110 nm thick film and still maintaining an excellent PCE of 17.2% in the case of a 300 nm thick film. Crucially, a noticeably increased stability of the multiple materials system was observed in the DICO-processed OSCs. These findings enrich the additive family with new cyclane systems to extend the exciton LD in thick film OSCs with high performance.
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| 10. |
- Li, Zhaojun, 1989, et al.
(författare)
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9.0% power conversion efficiency from ternary all-polymer solar cells
- 2017
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Ingår i: Energy and Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 10:10, s. 2212-2221
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Tidskriftsartikel (refereegranskat)abstract
- Integration of a third component into a single-junction polymer solar cell (PSC) is regarded as an attractive strategy to enhance the performance of PSCs. Although binary all-polymer solar cells (all-PSCs) have recently emerged with compelling power conversion efficiencies (PCEs), the PCEs of ternary all-PSCs still lag behind those of the state-of-the-art binary all-PSCs, and the advantages of ternary systems are not fully exploited. In this work, we realize high-performance ternary all-PSCs with record-breaking PCEs of 9% and high fill factors (FF) of over 0.7 for both conventional and inverted devices. The improved photovoltaic performance benefits from the synergistic effects of extended absorption, more efficient charge generation, optimal polymer orientations and suppressed recombination losses compared to the binary all-PSCs, as evidenced by a set of experimental techniques. The results provide new insights for developing high-performance ternary all-PSCs by choosing appropriate donor and acceptor polymers to overcome limitations in absorption, by affording good miscibility, and by benefiting from charge and energy transfer mechanisms for efficient charge generation.
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