Well‐organized Si‐Cu nanocables are directly anchored on a current collector to promote the cycling stability and high rate capability of Si as a superior anode in lithium‐ion batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Self‐wound nanomembranes out of functional multilayered structures were designed to improve lithium storage performance. The intrinsic strain is relaxed by rolling; the composite components are ...uniformly dispersed; the micro/nanohierarchical structure assumes a mixed ion/electron conduction network; and conventional nanomembrane deposition techniques allow for various materials combinations, suitable to meet different demands of lithium ion batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Carbon-based materials are the most common and important supercapacitor electrode materials, and have been attracting much attention for researchers. Although much work has focused on increasing the ...gravimetric capacitance of carbon materials, it is highly needed to obtain high volumetric capacitance for real compact device application. Therefore, a finely tuned carbon material structure with both optimal gravimetric and volumetric capacitances has been becoming a considerable challenge. In this work, we synthesized free-standing boron and oxygen co-doped carbon nanofiber (BO-CNF) films for the first time. Both high gravimetric and volumetric capacitances (192.8Fg−1 and 179.3Fcm−3 at 1Ag−1) can be obtained by an optimized design with regulating the heteroatom content and packing density. Meanwhile, the BO-CNF film with a relatively high packing density exhibits an excellent rate capability (78.5% capacitance retention from 1 to 100Ag−1), which is due to the formation of continuous electrolyte ion diffusion network as well as good electrical conductivity. Such BO-CNF film provides an excellent platform for depositing polyaniline active materials and the boron dopant can be recycled to reduce the cost for the possibly scalable application.
High volumetric capacitance and outstanding rate capability supercapacitor performances based on free-standing boron and oxygen co-doped carbon nanofiber (BO-CNF) films have been finely tuned by an optimal trade-off between gravimetric capacitance and packing density. Display omitted
•Free-standing boron and oxygen co-doped carbon nanofiber (BO-CNF) films are prepared by a very simple casting and pyrolysis process.•The BO-CNF films exhibit high gravimetric and volumetric capacitances (192.8Fg−1 and 179.3Fcm−3 at 1Ag−1).•A volumetric capacitance of 140.7Fcm−3 at 100Ag−1 can be maintained, delivering an excellent rate capability with 78.5% from 1Ag−1 to 100Ag−1.•Polyaniline nanoparticles can be anchored on the BO-CNF film to obtain a higher volumetric capacitance. The recycling of boron source is highly possible with a recovery ratio of about 50%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Spin–orbit charge transfer intersystem crossing (SOCT-ISC) is a promising approach to develop heavy-atom-free triplet photosensitizers. However, designing a strong visible-light harvesting ...heavy-atom-free triplet photosensitizer with efficient ISC ability in various solvents is still challenging. Most of the SOCT-ISC triplet photosensitizers exhibit efficient ISC only in solvent of particular polarity. To address this challenge, herein, two triads (BDP-AN-C-CZ and BDP-AN-N-CZ), composed of carbazole (CZ), anthracene (AN), and bodipy (BDP) moieties, were devised. In these triads, the distance, relative orientation, and position of CZ with respect to the AN moiety were varied to study the effect on photophysical properties, especially on SOCT-ISC efficiency. Electrochemical studies, steady-state, and time-resolved spectroscopies confirmed a sequential photoinduced electron transfer (PET) process in the triads. The fluorescence of the BDP moiety is quenched and a red-shifted CT emission band is observed in the triads, due to the enhanced PET effect, compared to the reference BDP-AN dyad. We observed that the SOCT-ISC yield can be enhanced taking advantage of sequential electron transfer. The triad BDP-AN-C-CZ, in which the CZ moiety was directly linked to the AN moiety, shows an efficient ISC ability both in low-polarity and high-polarity solvents, and unity triplet quantum yield (ΦT) was observed in dichloromethane. Femtosecond transient absorption spectroscopy confirmed the fast charge separation process (1.8 ps) in BDP-AN-C-CZ as compared to the other triad BDP-AN-N-CZ (4.8 ps) and the reference BDP-AN dyad (7.7 ps). The triads were used as triplet photosensitizers for triplet–triplet annihilation (TTA) upconversion, and high upconversion quantum yield (ΦUC = 18%) was observed. Interestingly, long-lived (τDF = 118 μs) and solvent-dependent color-tunable TTA delayed fluorescence was observed in the case of BDP-AN-C-CZ.
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IJS, KILJ, NUK, PNG, UL, UM
Four novel transition metal complexes, Zn
2
(Bpz*eaT)
2
(HBTC)
2
·(CH
3
OH)
3
(
1
), Co(Bpz*eaT)(HBTC)·(CH
3
CH
2
OH)
0.5
·(H
2
O)
0.5
(
2
), Zn(Bpz*eaT)(H
2
BTA)(pz*H) (
3
) and Cu
4
(Mpz*T-O
2
)
4
...(BTA)(H
2
O)
8
·4H
2
O (
4
) (Bpz*eaT, 2,4-bis(3,5-dimethyl-1
H
-pyrazol-1-yl)-6-diethylamino-1,3,5-triazine; Mpz*T-O
2
, 6-(3,5-dimethyl-1
H
-pyrazol-1-yl)-1,3,5-triazine-2,4(1
H
,3
H
)-dione; pz*H, 3,5-dimethyl-1
H
-pyrazole; H
3
BTC, benzene-1,3,5-tricarboxylic acid; and H
4
BTA, 1,2,4,5-benzenetetracarboxylic acid), were synthesized by the reaction of metal salts (ZnSO
4
·7H
2
O, CoCl
2
·6H
2
O or CuCl
2
·2H
2
O), pincer N-heterocyclic triazine derivatives and aromatic polycarboxylate ligands. All the complexes were characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, thermal gravimetric analysis and single-crystal X-ray diffraction. Structural analysis reveals that complexes
1
and
2
are 2-D layers and complex
4
is a 3-D network structure with hydrogen bonding. In addition, the photocatalytic performances of complexes
1–4
were studied under UV irradiation at room temperature and their photocatalytic activity was also discussed. The result showed that complex
1
possessed higher photocatalytic activity.
A phototransistor with a field-effect transistor configuration was fabricated using a single zinc octaethylporphyrin (ZnOEP) nanorod; the device showed ability in signal amplification and reversible ...light-controlled switching.
Single-crystal submicrometer rods and tubes of C60 with highly uniform size and shape were produced from a solvent-induced and surfactant assisted self-assembly technique. The length and ...length-to-width ratio of both rods and tubes were tunable by controlling the concentration of C60 in the stock solution. The transformation from rod to tube was achieved by simply varying the volume ratio of two solvents. Fourier-transform infrared and Raman spectroscopy, X-ray diffraction and high-resolution transmission electron microscopy revealed the detailed structures of the rods and tubes. We proposed a concentration profile based growth model to describe the self-assembly process of C60 subunits. This study may contribute to better understanding of chemistry of fullerenes in solutions and extend the surfactant-assisted self-organization of inorganic system to fullerene system.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract Typical weak signal search experiments rely on resonant effects, where the resonance frequency is scanned over a broad range, resulting in significant time consumption. In this study, we ...demonstrate an accelerated strategy that surpasses the typical resonance-bandwidth limited scan step without compromising sensitivity. We apply this method to an alkali-noble-gas spin system, achieving an approximately 30-fold increase in scanning step size. Additionally, we obtain an ultrahigh sensitivity of 1.29 fT ⋅ Hz −1/2 at around 5 Hz, corresponding to an energy resolution of approximately 1.8 × 10 −23 eV ⋅ Hz −1/2 , which is among the highest quantum energy resolutions reported. Furthermore, we use this sensor to search for axion-like particles, setting stringent constraints on axion-like particles (ALPs) in the 4.5–15.5 Hz Compton-frequency range coupling to neutrons and protons, improving on previous limits by several-fold. This accelerated strategy has potential applications in other resonant search experiments.
A vapor transfer deposition method was developed to fabricate metal (metal = Co, Ni, Cu, Zn, Mg) octaethylporphyrin (MOEP) nanowire arrays in large area on a variety of substrates. The formation ...process of MOEP nanowire arrays was investigated by time-dependently terminating deposition at various stages, based on which, a vaporization−condensation−recrystallization (VCR) mechanism was proposed to understand the formation of nanowires and thus guide the synthesis of three-dimensional (3D) sea urchin-like nanowire assemblies and two-dimensional (2D) nanowire networks. As application examples of these porphyrin nanostructures, the porphyrin nanowires demonstrated a good field emission property and the photoelectric device based on the 2D MOEP nanowire network was fabricated, showing a good light-induced signal amplification behavior.
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