Perovskite quantum dots(PQDs)have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and ***,they exhibit l...
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Perovskite quantum dots(PQDs)have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and ***,they exhibit low moisture stability at room humidity(20-30%)owing to many surface defect sites generated by inefficient ligand exchange *** surface traps must be re-passivated to improve both charge transport ability and moisture *** address this issue,PQD-organic semiconductor hybrid solar cells with suitable electrical properties and functional groups might dramatically improve the charge extraction and defect *** organic semiconductors are typically low-dimensional(1D and 2D)and prone to excessive self-aggregation,which limits chemical interaction with *** this work,we designed a new 3D star-shaped semiconducting material(Star-TrCN)to enhance the compatibility with *** robust bonding with Star-TrCN and PQDs is demonstrated by theoretical modeling and experimental *** Star-TrCN-PQD hybrid films show improved cubic-phase stability of CsPbI_(3)-PQDs via reduced surface trap states and suppressed moisture *** a result,the resultant devices not only achieve remarkable device stability over 1000 h at 20-30%relative humidity,but also boost power conversion efficiency up to 16.0%via forming a cascade energy band structure.
In recent years,considerable attention has been focused on the development of sodium-ion batteries(SIBs)because of the natural abundance of raw materials and the possibility of low cost,which can alleviate the concern...
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In recent years,considerable attention has been focused on the development of sodium-ion batteries(SIBs)because of the natural abundance of raw materials and the possibility of low cost,which can alleviate the concerns of the limited lithium resources and the increasing cost of lithium-ion *** the growing demand for reliable electric energy storage devices,requirements have been proposed to further increase the comprehensive performance of ***,the low-temperature tolerance has become an urgent technical obstacle in the practical application of SIBs,because the low operating temperature will lead to sluggish electrochemical reaction kinetics and unstable interfacial reactions,which will deteriorate the performance and even cause safety *** the basis of the charge-storage mechanism of SIBs,optimization of the composition and structure of electrolyte and electrode materials is crucial to building SIBs with high performance at low *** this review,the recent research progress and challenges were systematically summarized in terms of electrolytes and cathode and anode materials for SIBs operating at low *** typical full-cell configurations of SIBs at low temperatures were introduced to shed light on the fundamental research and the exploitation of SIBs with high performance for practical applications.
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 coal fly ash(CFA)contains a high content of rare earth elements(REEs),the related extraction methods have limitations because of their low efficiencies,high levels of energy consumption,and other *** address ...
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Although coal fly ash(CFA)contains a high content of rare earth elements(REEs),the related extraction methods have limitations because of their low efficiencies,high levels of energy consumption,and other *** address these problems,in this study,we examined the coextraction of REEs and Al_(2)O_(3)from two types of Al_(2)O_(3)-rich CFA,pulverized CFA(PCFA)and circulating fluidized bed fly ash(CFBFA)using low-temperature calcination in the presence of K_(2)S_(2)O_(7).The total REEs,heavy REEs(HREEs),and light REEs(LREEs)extraction efficiencies were determined using different K_(2)S_(2)O_(7)/Al_(2)O_(3) molar ratios and calcination temperatures and correlated with the Al_(2)O_(3) extraction efficiency using Pearson correlation coefficient *** REEs are concentrated within CFA particles encapsulated in an aluminosilicate glass phase,and the REEs extraction efficiency is related to the form of Al in *** extraction efficiencies of Al_(2)O_(3) and REEs increase as the K_(2)S_(2)O_(7)/Al_(2)O_(3) molar ratio and calcination temperature increase,and the extraction selectivity of the more industrially valuable HREEs from CFBFA is *** high K_(2)S_(2)O_(7)/Al_(2)O_(3) molar ratios,the extraction of REEs from PCFA is more efficient than that from CFBFA with the regeneration of the highly active Al-O-Si bonds in *** Al_(2)O_(3) extraction efficiencies of PCFA as well as CFBFA correlate strongly with the total REEs,HREEs,and LREEs extraction *** developed extraction technology has the potential to promote CFA valorization and expand REEs resources,thus mitigating the bottlenecks of REEs procurement.
The phenomenon of oxygen adsorption induced surface restructuring is widespread across various metal-oxygen systems, yet its impact on initiating bulk oxide formation remains largely unexplored. Through in situ atomic...
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The phenomenon of oxygen adsorption induced surface restructuring is widespread across various metal-oxygen systems, yet its impact on initiating bulk oxide formation remains largely unexplored. Through in situ atomic-resolution electron microscopy observations of surface oxidation of Cu(110) and Cu85Au15(110), we unveil intermittent oxide-film growth modulated by oxygen-induced surface restructuring. This modulation is evidenced by repeated pinning of the Cu2O growth front at isolated Cu columns of the c(6×2)-O reconstruction, owing to required long-range diffusion of Cu and O atoms to the Cu2O growth front. We reveal that Cu vacancies, generated at the Cu2O growth front, are injected into the Cu2O/Cu interface, inducing hill and valley undulation of the Cu2O film. In contrast, atomic vacancies produced during the Cu85Au15(110) oxidation preferentially migrate into interfaces between Au-rich and Au-poor regions in the bulk, resulting in a flat and adherent Cu2O film. These findings demonstrate the critical role of oxygen-induced surface restructuring in modulating oxide film growth kinetics and the manipulability of the fate of injected vacancies by alloying, thereby offering insights applicable to a broader range of metal-oxygen systems for fine-tuning oxidation kinetics and enhancing oxide/metal interfacial adhesion.
This study investigates the influence of waste characteristics,especially zeta potential,on the properties of cement pastes and *** focus is to evaluate the impact of the zeta potential of cement particles and waste m...
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This study investigates the influence of waste characteristics,especially zeta potential,on the properties of cement pastes and *** focus is to evaluate the impact of the zeta potential of cement particles and waste materials on the sedimentation speed,rheology,and hardening time of stabilized cement *** Cement II F 40,retarder additive,silica,and fly ash were used in the *** pastes were prepared,and during the stabilization period,their rheological properties and pH were *** zeta potential and sedimentation speed of the cement and waste particles were measured at the pH that the pastes presented during the entire stabilization *** the stabilization period,the pastes were subjected to the hardening time *** zeta potential analyses revealed diverse values for the different powder types,with the cement particles exhibiting a zeta potential of−3.0 mV,the silica particles exhibiting−10.5 mV,and the fly ash particles exhibiting−20.3 *** influence of the high zeta potential modulus was observed on the sedimentation speed,with the solution containing fly ash exhibiting a speed of 40.01μm/s,whereas the solution containing only cement exhibited a speed of 99.38μm/*** the pastes,the results indicate that the presence of fly ash particles with a significantly negative zeta potential led to a 16%reduction in hardening time compared to particles with a lower modulus of zeta *** tests showed that the inclusion of fly ash particles prevented the formation of *** the zeta potential influenced agglomerate formation and hardening time,it was found to have no effect on yield stress or viscosity.
Laser powder bed fusion(LPBF)combined with reaction bonding(RB)of Al particles is an effective method for preparing high-performance 3D Al_(2)O_(3) ceramic ***,the indistinct microstructure evolution hinders the regul...
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Laser powder bed fusion(LPBF)combined with reaction bonding(RB)of Al particles is an effective method for preparing high-performance 3D Al_(2)O_(3) ceramic ***,the indistinct microstructure evolution hinders the regulation of pore features and the improvement of synthetic ***,the microstructure evolution of the Al_(2)O_(3) ceramic foams during the LPBF/RB process is clarified by various characterization methods,and the corresponding mechanical property modulation is realized by optimizing LPBF parameters,organic binder(E12 epoxy resin)content,heating rate,sintering time,and coral-like Al_(2)O_(3) *** expansion from Al_(2)O_(3) outward growth and Al granule precipitation counteracts the shrinkage from E12 decomposition and Al_(2)O_(3) sintering,resulting in an ultra-low shrinkage of 0.94%–3.01%.The pore structures of particle packing pores,hollow spheres,and microporous structures allow a tunable porosity of 52.6%–73.7%.The in-situ formation of multi-scale features including hollow spheres,flaky grains,whiskers,nanofibers,and bond bridges brings about a remarkably high bending strength of 6.5–38.3 ***findings reveal the relationship between microstructure evolution and property optimization of high-performance ceramic foams,with potential significance for microstructure design and practical application.
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.
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