Elnaggar, Mohamed M.Frolova, Lyubov A.Gordeeva, Alexandra M.Ustinova, Marina, I...
6页
查看更多>>摘要：Perovskite solar cells (PSCs) have attracted significant attention due to their high efficiency and potential for low-cost manufacturing, but their commercialization is strongly impeded by low operational stability. The engineering of charge-transport layer materials have been recognized as an effective strategy to improve both stability and performance of PSCs. Here, we introduce a pyrrolo[3,4-c]pyrrole-1,4-dione-based n-type copolymer as an electron transport material for perovskite solar cells. Using a composite of this polymer with the fullerene derivative [60]PCBM delivered an efficiency of 16.4% and enabled long-term operational stability of p-i-n perovskite solar cells.
查看更多>>摘要：Coating is considered to be a convenient and effective method for functionalization of textiles. However, the nonuniform dispersion of the functional particles and their tendency to flake off from the fabric's surface are not only detrimental to their functionality, but also cause problems of poor durability. In this study, graphene oxide (GO) and cuprous oxide (Cu2O), which have a synergistic antibacterial effect, are uniformly and firmly anchored to the surface of the polyethylene terephthalate (PET) fabric by means of the excellent adhesion of dopamine. The results show that GO provides a nucleation site for Cu2O while avoiding agglomeration, and is reduced to rGO during the reduction of Cu2O. The coated PET fabric exhibits strong antibacterial capabilities against S. aureus and E. coli, with antibacterial rates of more than 99.99% due to the synergistic action of rGO and Cu2O nano particles. Furthermore, the modified PET fabric offers superior washing resistance, with an antibacterial rate of 90% for S. aureus and 88% for E. coli after 40 washes. The resistivity of coated PET fabric is decreased to 7.16 x 10(8)& nbsp;omega cm from 2.64 x 10(15) omega cm of pure PET fabric. In addition, the modification can substantially improve the UV protection factor (UPF) of the PET fabric from 45 to 460, far exceeding the excellent UPF rating (50). Overall, these findings could open a new pathway to develop versatile textiles for applications in various fields.
查看更多>>摘要：Nanostructured hybrids of Co9S8 and polypyrrole (PPy) were grown on carbon cloth (CC) for battery-type supercapacitor electrode. Zeolitic imidazolate framework (ZIF-67) was first self-assembled on CC, which was further hydrothermally converted to Co9S8. After electrodeposition of PPy on the surface of CC/Co9S8, the electrochemical performances of the CC/Co9S8/PPy were greatly enhanced. After 2500 cycles of charge/ discharge, the capacity retention can remain 83.5%. The high cyclic stability of the CC/Co9S8/PPy might be due to the buffered volume change of Co9S8 during the redox process by the introduction of PPy shell.
Stanley, J. S. Santhosh JefersonGovind, LogeshMathivathanan, AriramanSindam, Bashaiah...
14页
查看更多>>摘要：The present study investigates the effect of reduced graphene oxide (r-GO) on the microstructure evolution, damping, and microwave absorption performance of the caproamine (CA) toughened epoxy /imidazole (m-CA/ ER/MI/r-GO) system. The X-ray diffraction analysis revealed good dispersion levels of r-GO featuring intercalation of r-GO into galleries of polymer chains. The effective role of r-GO in tuning the microstructure was confirmed from SEM, AFM and TEM analysis and the consequence of this is reflected in the dynamic mechanical characteristics. The m-CA/ER/3 wt% r-GO composites achieved an outstanding microwave absorption performance with a reflection loss of-51.6 dB (99.999% microwave absorption) at 9.51 GHz and an effective absorption bandwidth of 2.48 GHz when compared to m-CA/ER composite. The microwave performances are justified with the attenuation constant, impedance matching ratio, and the dielectric loss mechanisms operating in the composites. Hence, the developed m-CA/ER/r-GO will serve as a potential multifunctional composite with synergetic thermomechanical properties and excellent microwave absorption performance.
查看更多>>摘要：A novel type ternary GO/PANI/CuCo2O4 composite for electrode material was successfully synthesized and ensured by different characterizations such as XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), FE-SEM (Field emission scanning electron microscopy), and EDS (Energy-dispersive X-ray spectroscopy). The interconnected morphology of ternary GO/PANI/CuCo2O4 indicates superior electrochemical performance. Ternary GO/PANI/CuCo2O4 displayed the maximum specific capacitance of 741.39 F/g at 1 mV/s scan rate and 312.72 F/g at 1 A/g current density using three-electrode and symmetric two-electrode system, respectively. The ternary GO/PANI/CuCo2O4 electrode based symmetric device had specific energy of 62.54 Wh/kg at 1 A/g current density and specific power of 5997.61 W/kg at 20 A/g. The systems have a wide potential window of 1.2 V, which is beneficial for the energy density. The ternary material electrode also has the lowest value of charge transfer resistance (R-ct) as 12.23 omega and relatively good specific capacitance of 84.25% after 5000 cycles. The excellent electrochemical nature of ternary GO/PANI/CuCo2O4 is mainly because of the synergistic effect which has brought this material to the spotlight for the supercapacitor application.
Ali, Muhammad ZeshanIshak, Ku Marsilla KuZawawi, Mohamad Adzhar MdJaafar, Mariatti...
9页
查看更多>>摘要：Organic thermoelectric materials are of great interest for development of flexible thermoelectric devices. Two crucial parameters namely conductivity and Seebeck coefficient apparently display a trade-off effect towards optimization of thermoelectric (TE) properties. Dopants normally increase the conductivity of PEDOT:PSS but Seebeck coefficient remains unaffected at around 15-18 mu V K-1. In this work, pre-treatment using triflic acid to PEDOT:PSS solution is employed displaying simultaneous increase in conductivity of 1686 S cm(-1) and Seebeck coefficient of 23.6 mu V K-1. Mechanism of improvements are attributed to the increased order of long-range crystal packing as well as hopping between newly generated DOS. HRTEM and XRD data substantiated the improved crystallinity. Acid treatment induced change of conformation from coil like benzoid to linear quinoid structure as observed by Raman spectra, with increasing level of oxidation based on Raman and UV-vis-NIR spectra. The carrier concentration and mobility increased leading to the power factor of 94 mu W m(-1) K-2. Flexible thermoelectric generator (TEG) device is developed on PET film which generate thermovoltage of 2.0 mV at temperature difference of 15 K.& nbsp;
查看更多>>摘要：Two alternating polymers (P3 and P4) based on side-chain modified benzo[1,2-b:4,5-b']dithiophene as the electron-donating unit and fluorinated benzothiadiazole derivatives as the electron-withdrawing segment were adopted as donor materials to blend with a main-chain twisted non-fullerene acceptor (i-IEICO-4 F) for bulk heterojunction polymer solar cells (PSCs). The effects of the two types of side-chain substitutions on the UV-Vis absorptive characteristics, frontier molecular orbitals, and photovoltaic performances of the polymers were systematically probed. Both two polymers have medium-bandgaps, 1.75 eV for P3 and 1.71 eV for P4, respectively, guaranteeing the complementary absorption with i-IEICO-4 F. Among these polymers, the device of polymer P3, which has 2,3-octylthienyl side-chain, shows enhanced dielectric constant, suppressed trap-assisted recombination, promoted hole mobility with more balanced carrier mobility, and suitable phase separation, thus successfully achieving an efficiency of 10.67%. While the alkoxylphenyl substituted polymer P4 has slightly deepened molecular energy level and bathochromic-shifted absorption spectrum and achieved enhanced open circuit voltage, improved electron mobility, and inhibitive bimolecular recombination in the device, thus acquiring a slightly reduced efficiency of 10.19%. This work not only elaborates the applicability of benzothiadiazole-based medium bandgap polymer donors with main-chain twisted acceptors but also reveals the importance of the side-chain modification of the polymer donors on the performances of the fabricated PSCs.
查看更多>>摘要：Herein, VO2 (D) compound is supplemented with graphitic carbon nitride or g-C3N4. In this discourse, authors have reported afresh, facile hydrothermal synthesis of VO2 (D) and g-C(3)N(4)composites by using vanadium pentoxide as a precursor and citric acid monohydrate as a reducing agent. Thus, the obtained phase of VO2 is supported by X-ray powder diffraction observations (XRD). Fourier transform infrared spectroscopy (FT-IR) is performed for further validation of thereby prepared chemical composition. Field emission scanning electron microscopy (FESEM) complemented with EDS was used for analyzing the morphology of the surface and confirmation of elementary composition. Transmission electron microscopy (TEM) is performed to check the distribution of VO2 (D) over the surface of g-C3N4. Thermo-gravimetric analysis (TGA) is also performed to thermal stability. Electrochemical performances are analyzed by cyclic voltammetry (CV), galvanostatic charge discharge (GCD), Nyquist plots. After the holistic analysis of the new composite, it has been found that 3VO(2)/gC(3)N(4) yielding 1416 F/g as a high specific capacitance at 2 mV/s scan rate with appealing cyclic stability (106.1%). This also agrees with GCD findings. The solution resistance (R-s), charge transfer resistance (R-ct) of 3VO(2)/g-C3N4 are 2.8 and 0.75 omega respectively.
查看更多>>摘要：Electrocatalysts have received enormous attention for use in applications related to the electrochemical sensing of hydrogen peroxide (H2O2). In this work, we synthesized a graphite-like carbon nitride (g-C3N4)/reduced graphene oxide (rGO) composite (g-C3N4/rGO) using a hydrothermal approach and characterized it by powder Xray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive electron microscopy, and X-ray photoelectron spectroscopy. The synthesized material (g-C3N4/rGO) was deposited on a screen-printed carbon electrode (SPE) to investigate its performance as an H(2)O(2 & nbsp;)sensor. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were adopted to evaluate the H2O2 detection properties of the g-C3N4/rGO composite-modified SPE (g-C3N4/rGO/SPE). The g-C3N4/rGO composite material exhibited excellent H2O2 detection ability with a detection limit as low as 0.09 mu M and sensitivity of 10.34 mu A/mu Mcm(2) using LSV. The C3N4/rGO/SPE also showed good selectivity, stability and excellent repeatability for H2O2 detection. These properties make the fabricated material an ideal candidate for practical applications that may be explored in future research.
Lezaic, Aleksandra JanosevicPasti, IgorGledovic, AnaAntic-Stankovic, Jelena...
13页
查看更多>>摘要：Novel electroactive PANI-GA micro/nanostructured functional copolymers/co-oligomers were synthesized by the oxidative copolymerization of aniline and gallic acid (GA) in an aqueous solution, using ammonium peroxydisulfate (APS) as an oxidant and different initial mole ratios of GA to aniline ([GA]/[aniline]=0.1, 0.25, 0.5 and 1.0). It was found that the yield, molecular structure, morphology, electrical conductivity, electrochemical behavior, antioxidant and antimicrobial properties of PANI-GA strongly depend on [GA]/[aniline] ratio. The highest conductivity (3.8 x 10(-3) S cm(-1)) showed PANI-GA with dominant polyaniline (PANI) emeraldine salt segments and nanorod morphology, synthesized at [GA]/[aniline] = 0.1. FTIR spectroscopy confirmed the presence of covalently bonded GA and PANI-type structural segments in PANI-GA. The antioxidant activity of PANI-GA was explored by the spectrophotometric 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay and electrochemical test for superoxide anion radical, O-center dot(2)-. All protonated PANI-GA showed good scavenging activity toward ABTS(center dot+) and O-center dot(2)- radicals, whereby the highest activity exhibited PANI-GA produced at [GA]/[aniline] = 1. The radical scavenging activity of protonated PANI-GA samples toward ABTS(center dot+) was much higher than that of PANI. The antimicrobial properties of the PANI-GA against bacteria S. aureus and E. coli, as well as against fungus C. albicans were evaluated. All synthesized protonated PANI-GA were more effective as S. aureus growth inhibitors than pristine GA and PANI. Highest effectiveness against E. coli and C. albicans, higher than that of pristine GA and PANI, showed conductive PANI-GA synthesized at [GA]/[aniline]= 0.1. Based on the obtained experimental results the mechanism of GA and aniline oxidative copolymerization is proposed.
NSTL
Elsevier