Search

Diatomaceous earth has been used as a nonorganic carrier to prepare a sodium humate modified diatomaceous space using the sol‐gel method. X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscope, the Brunauer–Emmett–Teller (BET) method, and other methods were used to characterize its physio‐chemical properties. The effects of sodium humate/diatomite on the pH of tetracycline in water, the dosage of adsorbent, and pollutant temperature on the adsorption effect were studied. The results show that after alkali modification, the porous structure of diatomite remains undamaged, and the specific surface area of the modified sample is increased to 12.712 m2/g, and the average pore diameter is reduced to 146.19 nm. Adding 20‐mg sodium humate/diatomite into 100‐mL tetracycline wastewater with an initial concentration of 20 mg/L, and pH of 5 at a temperature of 55°C, the adsorption capacity reaches 75.1 mg/L, and the removal rate reaches 78.3%. The quasi‐second‐order kinetic model was fitted by regression and found to have R2 > 0.99, indicating that the adsorption process was one of surface adsorption. It is a process that involves initially rapid adsorption and then slowly reaching equilibrium. As an adsorption thermodynamics model, the Temkin, Redlich‐Peterson and Koble‐Corrigan models can explain humic acid sodium/diatomite behavior in the adsorption of tetracycline in water (each with R2 ≥ 0.99), and the effects of surface behavior in multilayer adsorption and electrostatic attraction on uneven heterogeneous adsorption. [ABSTRACT FROM AUTHOR]

Resistive random access memory (RRAM) crossbar arrays require the highly nonlinear selector with high current density to address a specific memory cell and suppress leakage current through the unselected cell. 3D monolithic integration of RRAM array requires selector devices with a small footprint and low‐temperature processing for ultrahigh‐density data storage. Here, an ultrathin two‐terminal n‐p‐n selector with 2D transition metal dichalcogenides (TMDs) is designed by a low‐temperature transfer method. The van der Waals contact between transferred Au electrodes and TMDs reduces the Fermi level pinning and retains the intrinsic transport behavior of TMDs. The selector with a single type of TMD exhibits a trade‐off between current density and nonlinearity depending on the barrier height. By tuning the Schottky barrier height and controlling the thickness of p‐type WSe2 in MoS2/WSe2/MoS2 n‐p‐n selector for a punch‐through transport, the selector shows high nonlinearity (≈ 230) and high current density (2 × 103 A cm−2) simultaneously. The n‐p‐n selectors are further integrated with a bipolar hexagonal boron nitride memory and calculate the maximum crossbar size of the 2D material‐based one‐selector one‐resistor according to a 10% read margin, which offers the possible realization of future 3D monolithic integration. [ABSTRACT FROM AUTHOR]

Nonvolatile memory is distinguished for the application in many electronic products due to its excellent charge storage ability. Nevertheless, as the device dimensions are scaled down, floating gate memory encounters various challenges: the increasing leakage current leading to a serious reliability issue and the decreasing of charge density. Hence, metal nanoparticle‐based floating gate memory has been proposed and become a promising candidate for nonvolatile memories due to its outstanding operation speed, excellent scalability, and favorable reliability. This review briefly introduces the classification of memory devices. The operation mechanisms, fabrication and characterization of metal nanoparticle‐based floating gate memory are discussed based on research activities reported in recent years. [ABSTRACT FROM AUTHOR]

High‐yield wavelength conversion is one of the key requirements for efficient photon energy harvesting. Attempts to realize efficient conversion by simply stacking layers of chromophores have failed so far, even when using highly crystalline assemblies and employing the recently discovered long‐range (>100 nm) Förster resonance energy transfer (LR‐FRET). Optical conversion efficiency is drastically improved using chromophoric metal–organic framework heterolayers fabricated layer‐by‐layer in connection with an "antenna doping" strategy. Systematic investigations reveal that the LR‐FRET mechanism, reported previously in chromophoric aggregates, is highly anisotropic for neat materials but can be made more isotropic by employing doping strategies. Using optimized fabrication parameters and dopant concentrations, a three‐layer, two‐step cascade with an overall optical conversion efficiency of ≈75% is realized. [ABSTRACT FROM AUTHOR]

Since metal electrode is an important component in the perovskite solar cells, which can be used as back contact, transparent electrode, and the transparent interlayer of tandem devices, the corrosion of metal electrode by perovskite film, should be understood. Here, the corrosion of conventional reagents of organic–inorganic perovskite material, i.e., CH3NH3X (MAX) and PbX2, X = I, Br, and Cl, against silver nanowire (AgNW) based transparent electrode are investigated under four different environments, i.e., nitrogen protection, light irradiation, oxygen exposure, and moisture exposure, separately. The corrosion process is inspected by monitoring the time‐dependent resistance variation of the electrode coated by the film of precursor reagent. In addition, the perovskite film of CH3NH3PbI3 (MAPbI3) is also coated on the silver nanowire electrode without or with the hole transporting layer of poly(3,4‐ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) or nanostructured CuSCN for understanding the corrosion process under different environmental conditions. The experimental results presented in this paper would be helpful to the understanding of metal electrode stability in perovskite solar cells. [ABSTRACT FROM AUTHOR]

Several photophysical properties of chromophores depend crucially on intermolecular interactions. Thermally‐activated delayed fluorescence (TADF) is often influenced by close packing of the chromophore assembly. In this context, the metal‐organic framework (MOF) approach has several advantages: it can be used to steer aggregation such that the orientation within aggregated structures can be predicted using rational approaches. We demonstrate this design concept for a DPA‐TPE (diphenylamine‐tetraphenylethylene) chromophore, which is non‐emissive in its solvated state due to vibrational quenching. Turning this DPA‐TPE into a ditopic linker makes it possible to grow oriented MOF thin films exhibiting pronounced green electroluminescence with low onset voltages. Measurements at different temperatures clearly demonstrate the presence of TADF. Finally, this work reports that the layer‐by‐layer process used for MOF thin film deposition allows the integration of the TADF‐DPA‐TPE in a functioning LED device. [ABSTRACT FROM AUTHOR]