| 1. |
- Chen, Haiyang, et al.
(författare)
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A guest-assisted molecular-organization approach for >17% efficiency organic solar cells using environmentally friendly solvents
- 2021
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Ingår i: Nature Energy. - : NATURE PORTFOLIO. - 2058-7546. ; 6:11, s. 1045-1053
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiencies (PCEs) of laboratory-sized organic solar cells (OSCs), usually processed from low-boiling-point and toxic solvents, have reached high values of over 18%. However, there is usually a notable drop of the PCEs when green solvents are used, limiting practical development of OSCs. Herein, we obtain certificated PCEs over 17% in OSCs processed from a green solvent paraxylene (PX) by a guest-assisted assembly strategy, where a third component (guest) is employed to manipulate the molecular interaction of the binary blend. In addition, the high-boiling-point green solvent PX also enables us to deposit a uniform large-area module (36 cm(2)) with a high efficiency of over 14%. The strong molecular interaction between the host and guest molecules also enhances the operational stability of the devices. Our guest-assisted assembly strategy provides a unique approach to develop large-area and high-efficiency OSCs processed from green solvents, paving the way for industrial development of OSCs. Organic solar cells processed from green solvents are easier to implement in manufacturing yet their efficiency is low. Chen et al. devise a guest molecule to improve the molecular packing, enabling devices with over 17% efficiency.
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| 2. |
- Chen, Xiaobin, et al.
(författare)
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Interlayer interactions in graphites
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 3046-
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Tidskriftsartikel (refereegranskat)abstract
- Based on ab initio calculations of both the ABC- and AB-stacked graphites, interlayer potentials (i.e., graphene-graphene interaction) are obtained as a function of the interlayer spacing using a modified Mobius inversion method, and are used to calculate basic physical properties of graphite. Excellent consistency is observed between the calculated and experimental phonon dispersions of AB-stacked graphite, showing the validity of the interlayer potentials. More importantly, layer-related properties for nonideal structures (e.g., the exfoliation energy, cleave energy, stacking fault energy, surface energy, etc.) can be easily predicted from the interlayer potentials, which promise to be extremely efficient and helpful in studying van der Waals structures.
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| 3. |
- Fan, Qunping, 1989, et al.
(författare)
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Mechanically Robust All-Polymer Solar Cells from Narrow Band Gap Acceptors with Hetero-Bridging Atoms
- 2020
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 4:3, s. 658-672
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Tidskriftsartikel (refereegranskat)abstract
- We developed three narrow band-gap polymer acceptors PF2-DTC, PF2-DTSi, and PF2-DTGe with different bridging atoms (i.e., C, Si, and Ge). Studies found that such different bridging atoms significantly affect the crystallinity, extinction coefficient, electron mobility of the polymer acceptors, and the morphology and mechanical robustness of related active layers. In all-polymer solar cells (all-PSCs), these polymer acceptors achieved high power conversion efficiencies (PCEs) over 8.0%, while PF2-DTSi obtained the highest PCE of 10.77% due to its improved exciton dissociation, charge transport, and optimized morphology. Moreover, the PF2-DTSi-based active layer showed excellent mechanical robustness with a high toughness value of 9.3 MJ m−3 and a large elongation at a break of 8.6%, which is a great advantage for the practical applications of flexible devices. As a result, the PF2-DTSi-based flexible all-PSC retained >90% of its initial PCE (6.37%) after bending and relaxing 1,200 times at a bending radius of ∼4 mm.
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| 4. |
- Sun, Ruirui, et al.
(författare)
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Experimental and theoretical study on the dissociative photoionization of methyl methacrylate
- 2017
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 50:23
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Tidskriftsartikel (refereegranskat)abstract
- The photoionization of methyl methacrylate and dissociation of its cation have been investigated by tunable vacuum ultraviolet synchrotron radiation coupled with time-of-flight mass spectrometer in the photon energy region of 9.0-15.5 eV. The ionization energy of methyl methacrylate and the appearance energies (AEs) for major fragments, C5H7O2+, C5H6O+, C4H5O2+,C4H5O+, C3H3O+ (C4H7+), C3H5+, C3H4+, C2H3O2+, and CH3+ are determined to be 9.76, 10.30, 10.66, 10.51, 11.17, 10.51, 10.74, 12.88, 12.73, 12.52, and 12.82 eV, respectively, by measurement of the photoionization efficiency curves. Possible formation pathways of the major fragments are proposed based on comparison of experimental AEs and energies predicted by ab initio G3B3 calculations. Transition states and intermediates involved in the dissociation channels are also located. The majority of the proposed channels occur through isomerization prior to dissociation. Hydrogen shift and ring closing/opening are found to be the dominant processes during photofragmentaion of methyl methacrylate.
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| 5. |
- Zhang, Xin, et al.
(författare)
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High-Performance All-Small-Molecule Organic Solar Cells Enabled by Regio-Isomerization of Noncovalently Conformational Locks
- 2022
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 32:19
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Tidskriftsartikel (refereegranskat)abstract
- The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have surpassed 19% thanks to the innovation of polymer donors and molecular acceptors. However, the batch-to-batch variations in polymer materials are detrimental to the reproducibility of the device performance. In comparison, small-molecule donors (SMDs) possess some unique advantages, such as well-defined molecular weights, easy purification, and excellent batch-to-batch repeatability. Herein, a pair of regioisomeric SMDs (BT-O1 and BT-O2) has been synthesized with alkoxy groups as S center dot center dot center dot O noncovalently conformational locks (NoCLs) at the inner and outer position, respectively. Theoretical and experimental results reveal that the regioisomeric effect has a significant influence on the light-harvest ability, energy levels, molecular geometries, internal reorganization energy, and packing behaviors for the two SMDs. As a result, BT-O2-based binary device shows an impressive PCE of 13.99%, much higher than that of BT-O1 based one (4.07%), due to the better-aligned energy level, more balanced charge transport, less charge recombination, lower energy loss, and more favorable phase separation. Furthermore, the fullerene derivative PC71BM is introduced into BT-O2:H3 as the third component to achieve a notable PCE of 15.34% (certified 14.6%). Overall, this work reveals that NoCLs is a promising strategy to achieve high-performance SMDs for all-small-molecule OSCs.
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