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AbstractRevolutionary changes in energy storage technology have put forward higher requirements on next‐generation anode materials for lithium‐ion battery. Recently, a new class of materials with complex stoichiometric ratios, high‐entropy oxide (HEO), has gradually emerging into sight and embracing the prosperity. The ideal elemental adjustability and attractive synergistic effect make HEO promising to break through the integrated performance bottleneck of conventional anodes and provide new impetus for the design and development of electrochemical energy storage materials. Here, the research progress of HEO anodes is comprehensively reviewed. The driving force behind phase stability, the role of individual cations, potential mechanisms for controlling properties, as well as state‐of‐the‐art synthetic strategies and modification approaches are critically evaluated. Finally, we envision the future prospects and related challenges in this field, which will bring some enlightening guidance and criteria for researchers to further unlock the mysteries of HEO anodes.image

AbstractThis work reports the synthesis, characterization, photophysical, and photovoltaic properties of five new thieno[3,2‐b][1]benzothiophene isoindigo (TBTI)‐containing low bandgap donor–acceptor conjugated polymers with a series of comonomers and different side chains. When TBTI is combined with different electron‐rich moieties, even small structural variations can have significant impact on thin film morphology of the polymer:phenyl C70 butyric acid methyl ester (PCBM) blends. More importantly, high‐resolution electron energy loss spectroscopy is used to investigate the phase‐separated bulk heterojunction domains, which can be accurately and precisely resolved, enabling an enhanced correlation between polymer chemical structure, photovoltaic device performance, and morphology.

Abstract Polymer light emitting diodes (PLEDs) may revolutionize lighting and display industries. PLEDs would enable printing of display or lighting panels on large area substrates that could substantially reduce fabrication costs by avoiding expensive vacuum processes presently used in OLED technologies. PVK is one of the most popular hosts for blue PLEDs. However, PVK has very poor electron transport properties and oxadiazole based electron dopants, e.g. PBD or OXD-7, are used to improve charge transport. This is generally ascribed to capture and transport of electrons on the PBD or OXD-7. Here we show that this is not necessarily the only reason for improved efficiency upon PVK doping. We demonstrate that devices with PVK doped with PBD or OXD-7 have emission lasting up to 1 ms which in some cases may be greater than prompt emission from excitons formed initially on the dopant. This long-lived emission is arising mainly due to formation of an exciplex between the PVK and PBD/OXD-7. This exciplex state then repopulates dopant iridium complexes over a long period of time giving very long-lived emission. We also note that this exciplex-fed long-lived emission from heavy metal complexes is observed in several PLEDs with PBD and PVK (and also OXD-7) doped with blue or green iridium phosphors indicating this to be a general phenomenon.

AbstractHigh‐performance dye‐sensitized solar cell (DSSC) devices rely on photoanodes that possess excellent light‐harvesting capabilities and high surface areas for sufficient dye adsorption. In this work, morphologically controlled SnO2 microstructures were synthesized and used as an efficient light‐backscattering layer on top of a nanocrystalline TiO2 layer to prepare a double‐layered photoanode. By optimizing the thickness of both the TiO2 bottom layer and the SnO2 top layer, a high power conversion efficiency (PCE) of 7.8 % was achieved, an enhancement of approximately 38 % in the efficiency compared with that of a nanocrystalline TiO2‐only photoanode (5.6 %). We attribute this efficiency improvement to the superior light‐backscattering capability of the SnO2 microstructures.

AbstractErbium doped silicon-rich silica offers broad band and very efficient excitation of erbium photoluminescence (PL) due to a sensitization effect attributed to silicon nanocrystals (Si-nc), which grow during thermal treatment. PL decay lifetime measurements of sensitised Er3+ ions are usually reported to be stretched or multi exponential, very different to those that are directly excited, which usually show a single exponential decay component.In this paper, we report on SiO2 thin films doped with Si-nc's and erbium. Time resolved PL measurements reveal two distinct 1.54μm Er decay components; a fast microsecond component, and a relatively long lifetime component (10ms). We also study the structural properties of these samples through TEM measurements, and reveal the formation of Er clusters. We propose that these Er clusters are responsible for the fast μs decay component, and we develop rate equation models that reproduce the experimental transient observations, and can explain some of the reported transient behaviour in previously published literature.

Abstract The harvesting of energy from ambient environments is an emerging technology with potential for numerous applications, including portable electronic devices for renewable energy. Most of the current research activities refer to classical piezoelectric ceramic materials but more recently the development of electrostrictive polymers has generated novel opportunities for high-strain actuators. At present, the investigation of using electrostrictive polymers for energy harvesting (a conversion of mechanical to electrical energy) is beginning to show potential for this application. Basically, the relative energy gain depends on the current induced by the mechanical strain and frequency. The aim of this work was to determine the optimum operating range for improved electro-mechanical conversion efficiency of electrostrictive polymer composite by the effect of mechanical parameters (mechanical frequency and the amplitude strain) that leads to an increase in the generated current and improve the output power in relation to the injected power. It was also found that the trend of the experimental data is in good accordance with that of the theoretical prediction. Finally, the results indicated that the frequency and the amplitude of mechanical excitation were the critical parameters for the best electromechanical conversion.

The increasing demand for energy and commodities has led to escalating greenhouse gas emissions, the chief of which is represented by carbon dioxide (CO2). Blue hydrogen (H2), a low-carbon hydrogen produced from natural gas with carbon capture technologies applied, has been suggested as a possible alternative to fossil fuels in processes with hard-to-abate emission sources, including refining, chemical, petrochemical and transport sectors. Due to the recent international directives aimed to combat climate change, even existing hydrogen plants should be retrofitted with carbon capture units. To optimize the process economics of such retrofit, it has been proposed to remove CO2 from the pressure swing adsorption (PSA) tail gas to exploit the relatively high CO2 concentration. This study aimed to design and numerically investigate a vacuum pressure swing adsorption (VPSA) process capable of capturing CO2 from the PSA tail gas of an industrial steam methane reforming (SMR)-based hydrogen plant using NaX zeolite adsorbent. The effect of operating conditions, such as purge-to-feed ratio and desorption pressure, were evaluated in relation to CO2 purity, CO2 recovery, bed productivity and specific energy consumption. We found that conventional cycle configurations, namely a 2-bed, 4-step Skarstrom cycle and a 2-bed, 6-step modified Skarstrom cycle with pressure equalization, were able to concentrate CO2 to a purity greater than 95% with a CO2 recovery of around 77% and 90%, respectively. Therefore, the latter configuration could serve as an efficient process to decarbonize existing hydrogen plants and produce blue H2.

Small band gap molecular semiconductors are of interest for the development of transparent electronics. Here we report two near-infrared (NIR), n-type small molecule semiconductors, based upon an acceptor-donor-acceptor (A-D-A) approach. We show that the inclusion of molecular spacers between the strong-electron-accepting end group, 2,1,3-benzothiadiazole-4,5,6-tricarbonitrile, and the donor core affords semiconductors with very low band gaps down to 1 eV. Both materials were synthesized by a one-pot, 6-fold nucleophilic displacement of a fluorinated precursor by cyanide. Significant differences in solid-state ordering and charge carrier mobility are observed depending on the nature of the spacer, with a thiophene spacer resulting in solution processed organic field-effect transistors (OFETs) exhibiting excellent electron mobility up to 1.1 cm2 V-1 s-1. The use of silver nanowires as the gate electrode enables the fabrication of a semitransparent OFET device with an average visible transmission of 71% in the optical spectrum. ; The authors thank the Engineering and Physical Sciences Research Council (EPSRC) (EP/L016702/1 and EP/T028513/1), Global Research Laboratory Program of the National Research Foundation (NRF-2017K1A1A2013153), the Royal Society, and the Wolfson Foundation (Royal Society Wolfson Fellowship) for funding. M.I.N., M.H., and T.D.A. acknowledge funding from the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award Nos. OSR-2018-CARF/CCF-3079 and OSR-2020-CRG8-4095. F.E. thanks EPSRC for support via a Doctoral Prize Fellowship.