查看更多>>摘要：Transparent conducting oxides (TCOs), such as indium-tin oxide (ITO) and indium gallium zinc oxide (IGZO), are essential components in the design of flexible optoelectronic devices. However, it is still a challenge to prepare low-cost flexible transparent conductive film for achieving the flexible functionality together with high optical transparency and electrical conductivity. Herein, fluorphlogopite (mica) is selected as the bendable and transparent substrate for the fabrication of low-cost perovskite CaVO3 TCO epitaxial film. Benefitting from thin mica substrate with high Young's modulus of 200 GPa, flexible CaVO3 TCO epitaxial film exhibits high mechanical stability in terms of electrical conductivity and optical transparency after bending up to 105 cycles. The change of resistance can reflect the bending curvature and strain state. Our results provide a new pathway to design superior mechanical flexibility and stability CaVO3 TCO films for application in flexible, light-weight, and portable smart optoelectronic devices.
查看更多>>摘要：The development of high efficiency catalysts is of pivotal importance. By introducing heteroatom phosphorus into the core-shell structure, it can optimize the electronic structure, improve the catalyst performance for direct ethylene glycol fuel cells (DEGFCs). In this study, a phosphating etched-PtCox-alloy pseudo-core-shell electrocatalyst (P-(PtCox@Pt)/C, x = 2, 4, 6, 8) is fabricated by a combined phosphating and etching method. Among as-prepared catalysts, the optimal P-(PtCo4@Pt)/C exhibits high catalytic activity for ethylene glycol electrooxidation. Furthermore, after 3000 s chronoamperometry test, its residual current density is also higher than others, indicating its good stability. Importantly, the P-(PtCo4@Pt)/C assembled-DEGFCs has an open circuit potential of 0.675 V, and peak power density of 14.48 mW cm?2. This P-(PtCo4@Pt)/C would be a good choice to developing DEGFCs technology.
查看更多>>摘要：In this work, ZnFe2O4: 1 wt% Ce3+/Carbon fibers composite-based adsorbent with high adsorption capacity was synthesized using electrospinning as well as solvothermal approaches. Then, the produced compounds were characterized by XRD, SEM, FE-SEM, EDS and BET methods. Adsorption behavior was studied by using Congo Red (CR) solution. The effects of pH, initial dye concentration, as well as contact time on removal behavior were investigated. The results showed that, at the acidic environment, the removal of contamination due to the negatively charged surface of adsorbent would be enhanced. The investigation of contact time revealed that, with increasing time, the rate of removal efficiency increased up to its maximum value at the equilibrium time. The BET analysis revealed that the specific surface area of the mesoporous structure composite is as high as 93.7 m2/g and it provides a high surface area to the adsorption contaminate. In this work, Langmuir and Freundlich models were employed to investigate the mechanism of interaction between adsorbent and adsorbate, and the obtained results indicated that the Langmuir model is predominant for this adsorption system with the maximum adsorption capacity of 265.2 mg/g.
查看更多>>摘要：Mechanochemical synthesis of MgAl-layered double hydroxides (MgAl-LDH) with molar ratio MgAl = 3 was performed. The effect of the acceleration of milling bodies (500 and 1000 m s-2), activation time (5–90 min), and water addition on the phase composition of obtained samples, their structural parameters, as well as on the process of formation of mixed oxides, prepared after LDH calcination was studied. The conditions for the preparation of single-phase LDH were established. It was shown the possibility of the textural properties regulation of mixed oxides by change of the mechanochemical synthesis parameters of corresponding layered double hydroxides.
查看更多>>摘要：Carbon nanofibers are widely used for electromagnetic wave (EMW) absorption. However, it is still worthy attention for rationally optimizing their permittivity. Herein, a satisfactory EMW absorber of few-layer BN nanosheets decorated N-doped carbon nanofibers (BNNS-CNFs) was successfully prepared by electrospinning-assisted synthetic technology. The permittivity of CNFs can be adjusted by introducing of BNNS and N-doped in carbon matrix. As a EMW absorber, BNNS-CNFs/paraffin hybrid with a low filling ratio of 10 wt% shows excellent absorption performances. The minimum reflection loss (RL) is about ?58.41 dB at a thickness of 1.6 mm and the widest absorption bandwidth (RL<?10 dB) of 5.76 GHz can be obtained at 1.75 mm. The significant enhancement of EMW absorption performance is mainly attributed to the improvement of impedance match and multiple polarizations after introduction of BNNS and more defects by N-doped. Thus, BNNS-CNFs with lightweight and wide-band at low load content would be utilized as a high-efficiency EMW absorber.
查看更多>>摘要：Metal-organic frameworks (MOFs) have drawn numerous attention as precursors to fabricate porous materials owing to their inherent highly controllable composition and tunable porosities. Nevertheless, the construction of an efficient and low cost anode material derived from zeolitic imidazole framework-67 (ZIF-67) to pursue enhance rate capability and specific capacity remains attractive and challenging. Herein, the fabrication of the Co3O4-based hierarchical carbon fiber composites with the ZIF-67/Co2+ ions derivatives embedded (Co3O4@CNF) by a facile electrospinning technique and a two-step annealing is reported. When evaluate as a binder-free anode for SIBs, the resultant electrode delivers a superior sodium-ion storage capacity of 380 mAh g?1 after 150 cycles at 100 mA g?1, a remarkable rate performance and an outstanding long-cycling stability of 129 mAh g?1 after 500 cycles at 3.2 A g?1, which is better than other MOFs-derived free-standing anode materials for SIBs reported previously. The 1D carbon fibers can serve as a buffer framework to ensure the structural stability. In addition, the conductive matrix formed by the interleaving of carbon fibers can facilitate electronic transport along their 1D geometry. Furthermore, the dispersed ZIF-67/Co2+ ions derivatives in fibers provide the composite with high surface exposure to the electrolyte, which is conducive to chemical reactions.
查看更多>>摘要：The preparation of high-quality perovskite films with low defect density and long carrier lifetime is a precondition for achieving high-efficiency perovskite solar cells (PSCs). In this work, we successfully incorporated Y3+ ions into perovskite films to enhance the photovoltaic performance of hole-transport-layer-free (HTL-free) carbon-based MAPbBr3 PSCs in ambient atmosphere. The perovskite films exhibit better crystallinity, lower trap density, and longer carrier lifetime after the introduction of Y3+ ions. By optimizing the doping dosage, a maximal power conversion efficiency (PCE) of 8.313% (open-circuit voltage (VOC) = 1.562 V) is achieved for MAPb0.98Y0.02Br3 PSCs. Moreover, the unencapsulated device also shows remarkable long-term stability over 80 days under dry condition with 20–30% relative humidity (RH) at 20–25 °C, which even maintains 95% of its initial PCE when stored in harsh environment (80 °C and 40–70% RH) over 72 h.
查看更多>>摘要：Graphene quantum dots (GQDs) hybrid compositions have aroused wide attention with regard to their application in energy storage; however, complex procedures for their separation, purification and functionalization hinder their practical application. The present study put forward a facile and environmentally friendly coprecipitation approach to prepare Fe3O4@CTP QDs composites using coal tar pitch (CTP) as “natural GQDs” for the first time. When used as anode in lithium ion batteries (LIBs), the Fe3O4@CTP QDs-2 composite demonstrates high reversible capacity of 810 mAh g?1 over 200 cycles at the current density of 100 mA g?1. Moreover, at a high current density of 2000 mA g?1, the reversible capacity reaches 547 mAh g?1, which is 6 times that of pure Fe3O4 (91 mAh g?1). The marked ameliorated electrochemical performance is attributed to the fact that the successful coupling between Fe3O4 and CTP QDs can not only improves the overall conductivity but also effectively help preserving the structural integrity during cycling. This facile method does not require any cost precursor, harsh reagents, and complicated synthesis processes and can be developed into an eco-friendly way to large-scale production of CTP QDs hybrid materials for applications in energy storage.
查看更多>>摘要：Recently, SnO2 is widely used as an attractive electron transport layer in n-i-p planar perovskite solar cells (PSCs) due to its wide bandgap, high transmission, high carrier mobility, favorable band alignment and low annealing temperature. However, a commercial SnO2 colloid solution suffers from soft agglomerate under long-term storage. Produced film pinholes and oxygen vacancy defect can increase non-radiative recombination at the perovskite/SnO2 interface limiting the power conversion efficiency (PCE) and stability. Here, amino acid (glycine and alanine) and ammonium salt (ammonium titanium fluoride) are employed to modify SnO2 nanocrystals and passivate perovskite defects at SnO2/perovskite film. The PCE of glycine (GLY) modified device was 19.71% and hysteresis was suppressed compared with that of 16.21% for control device. After 15-day aging at 85% relative humidity (RH), the encapsulated GLY modified device and control device retain 83.58% and 74.52% of their initial efficiency, respectively. Finally a perspective on how to modify SnO2 with functional molecules toward efficient and stable PSCs is provided.
查看更多>>摘要：Antimony-based electrode materials with conventional slurry-casting process still face great challenges such as tedious preparation process and unsatisfying cycling stability for sodium ion batteries (SIBs). Therefore, the design and fabrication of integrated electrodes with binder-free and even current collector-free are highly significant. Herein, we fabricated flexible Sb/Sb2O3-C nanofibers (NFs) films utilizing a facile combination of electrospinning technique and carbonization. Sb/Sb2O3 nanoparticles are well embedded in carbon NFs with a fiber diameter of ca. 340 nm. The fabricated NFs films can be directly used as binder and current collector-free anodes for SIBs and exhibited high-capacity and long-lifetime cycles (385.6 mAh g?1 over 500 cycles). Ex situ SEM and TEM observations re-appear their intact fibrous network morphology and stable one-dimensional composite structures after hundreds of discharging-charging cycles, demonstrating that Sb/Sb2O3-C NFs film is a promising binder-free electrode for SIBs.
NSTL
Elsevier