Accurate prediction of electronic and optical excitations in van der Waals(vdW)materials is a long-standing challenge for density functional *** recent Wannier-localized optimally-tuned screened range-separated hybrid...
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Accurate prediction of electronic and optical excitations in van der Waals(vdW)materials is a long-standing challenge for density functional *** recent Wannier-localized optimally-tuned screened range-separated hybrid(WOT-SRSH)functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for covalent and ionic ***,for vdW materials the tuning of the material-and structure-dependent functional parameters has only been attained ***,we present a non-empirical WOT-SRSH approach applicable to vdW materials,with the optimal functional parameters transferable between monolayer and *** apply this methodology to prototypical vdW materials:black phosphorus,molybdenum disulfide,and hexagonal boron nitride(in the latter case including zero-point renormalization).We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and many-body perturbation theory(MBPT)calculations for band structures and optical absorption spectra,both on its own and as an optimal starting point for MBPT calculations.
LiBH_(4)with high hydrogen storage density,is regarded as one of the most promising hydrogen storage ***,it suffers from high dehydrogenation temperature and poor reversibility for practical *** is effective in achiev...
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LiBH_(4)with high hydrogen storage density,is regarded as one of the most promising hydrogen storage ***,it suffers from high dehydrogenation temperature and poor reversibility for practical *** is effective in achieving low dehydrogenation temperature and favorable ***,graphene can serve as supporting materials for LiBH_(4)catalysts and also destabilize LiBH_(4)via interfacial ***,graphene has never been used alone as a frame material for nanoconfining LiBH_(4).In this study,graphene microflowers with large pore volumes were prepared and used as nanoconfinement framework material for LiBH_(4),and the nanoconfinement effect of graphene was *** loading 70 wt%of LiBH_(4) and mechanically compressed at 350 MPa,8.0 wt% of H2 can be released within 100 min at 320C,corresponding to the highest volumetric hydrogen storage density of 94.9 g H2 L^(-1)ever *** to the nanoconfinement of graphene,the rate-limiting step of dehydrogenation of nanoconfined LiBH_(4) was changed and its apparent activation energy of the dehydrogenation(107.3 kJ mol^(-1))was 42%lower than that of pure LiBH_(4).Moreover,the formation of the intermediate Li_(2)B_(12)H_(12) was effectively inhibited,and the stable nanoconfined structure enhanced the reversibility of LiBH_(4).This work widens the understanding of graphene's nanoconfinement effect and provides new insights for developing high-density hydrogen storage materials.
In this article, we harnessed biomedical applications in laser-assisted etching long-period fiber gratings (LLPFGs) sensors, subsequently deploying them within the realm of biomedical applications. The primary aim of ...
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CsSnI3 is widely studied as an environmentally friendly Pb-free perovskite material for optoelectronic device applications. To further improve material and device performance, it is important to understand the surface...
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CsSnI3 is widely studied as an environmentally friendly Pb-free perovskite material for optoelectronic device applications. To further improve material and device performance, it is important to understand the surface structures of CsSnI3. We generate surface structures with various stoichiometries, perform density functional theory calculations to create phase diagrams of the CsSnI3 (001), (110), and (100) surfaces, and determine the most stable surfaces under a wide range of Cs, Sn, and I chemical potentials. Under I-rich conditions, surfaces with Cs vacancies are stable, which lead to partially occupied surface states above the valence band maximum. Under I-poor conditions, we find the stoichiometric (100) surface to be stable under a wide region of the phase diagram, which does not have any surface states and can contribute to long charge-carrier lifetimes. Consequently, the I-poor (Sn-rich) conditions will be more beneficial to improve the device performance.
Although supramolecular chirality tuning is prosperous in systems with small molecular building blocks,these systems lack structural strength and have limited practical ***,polymer systems do not exhibit these drawbac...
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Although supramolecular chirality tuning is prosperous in systems with small molecular building blocks,these systems lack structural strength and have limited practical ***,polymer systems do not exhibit these drawbacks but suffer from topological chain entanglement,which often leads to large dynamic obstacles and therefore limits the tunability of supramolecular ***,we report that by manipulating stoichiometry and employing light to alter the H-bond crosslinking between a photoexcitation-induced aggregatable molecule and high molecular weight poly(L-lactic acids),supramolecular chirality tuning of the polymer gel systems can be achieved in different ways through a cooperative ***,the Cotton effects of the examined systems can be negatively tuned by varying their stoichiometry,while positive tuning can be realized by *** deexcitation,negative Cotton effect tuning occurs again spontaneously in some *** supramolecular chirality tuning is accompanied by rheological property tuning,demonstrating that our strategy can overcome polymer chain entanglement *** proposed strategy inspires further works on the precise control of polymer chirality and,hence,development of asymmetric materials with changeable optical activity and modulus.
We study the rheology of bidisperse non-Brownian suspensions using particle-based simulation, mapping the viscosity as a function of the size ratio of the species, their relative abundance, and the overall solid conte...
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We study the rheology of bidisperse non-Brownian suspensions using particle-based simulation, mapping the viscosity as a function of the size ratio of the species, their relative abundance, and the overall solid content. The variation of the viscosity with applied stress exhibits shear-thickening phenomenology irrespective of composition, though the stress-dependent limiting solids fraction governing the viscosity and its divergence point are nonmonotonic in the mixing ratio. Contact force data demonstrate an asymmetric exchange in the dominant stress contribution from large-large to small-small particle contacts as the mixing ratio of the species evolves. Combining a prior model for shear thickening with one for composition-dependent jamming, we obtain a full description of the rheology of bidisperse non-Brownian suspensions capable of predicting effects such as the viscosity reduction observed upon adding small particles to a suspension of large particles.
Piezoelectric materials that can effectively convert natural mechanical energy into electrical energy without time and space constraints have been widely applied for energy harvesting and *** piezocomposites with high...
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Piezoelectric materials that can effectively convert natural mechanical energy into electrical energy without time and space constraints have been widely applied for energy harvesting and *** piezocomposites with high piezoelectricity and flexibility have shown great promise for renewable electric energy generation that can power implantable and wearable *** minireview aims to summarize the recent progress of the piezocomposites with different composite structures,as well as the role of the theoretical understandings and designs in the development of new piezoelectric nanogenerator ***,the most common composite structural types(0-3,1-3,and 3-3)have been discussed *** strategies for high output performance of piezocomposites are also proposed on the basis of current experimental and simulation ***,the review concludes with perspectives on the future design of flexible piezoelectric nanocomposites for energy harvesters.
Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and ***,both the low room-temperature ionic conductivities and the small Li^(+)transference...
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Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and ***,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the ***,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer *** optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of ***,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.
The evolution of electronic systems towards small,flexible,portable and human-centered forms drives the demand for onbody power supplies with lightweight and high *** solar cells that can be integrated into soft and l...
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The evolution of electronic systems towards small,flexible,portable and human-centered forms drives the demand for onbody power supplies with lightweight and high *** solar cells that can be integrated into soft and lightweight textiles are considered as potential sustainable power sources for the next generation of wearable *** this end,they have been extensively investigated in the past decade aiming to improve their photovoltaic performances,but there is still a big gap between the high-performance devices and real ***,the key advances of configurations,fabrications and performances of fiber solar cells are highlighted and *** on the current progress,the latest ideas with regard to the remaining challenges and opportunities beyond the reach of the previous studies are presented.
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