Aluminum hydroxide nanoparticles, one of the essential luminescent materials for display technology, bio-imaging, and sensors due to their non-toxicity, affordable pricing, and rare-earth-free phosphors, are synthesized via a simple method at a reaction time of 10 min at a low temperature of 200 °C. By controlling the precursor's ratio of aluminum acetylacetonate to oleic acid, UV or blue light-emitting aluminum hydroxides with oxygen defects and carbonyl radicals can be synthesized. As a result, aluminum hydroxide (Al(OH)3-x ) nanoparticles overwhelmingly emit UVA light (390 nm) because of the oxygen defects in nanoparticles, and carbon-related radicals on the nanoparticles are responsible for the blue-light emission at 465 nm. Electrically driven light-emitting devices are applied using luminescent aluminum hydroxide as an emissive layer, that consists of a cost-efficient inverted bottom-emission structure as [ITO (cathode)/ZnO/emissive layers/2,2'-bis(4-(carbazol-9-yl)phenyl)-biphenyl (BCBP)/MoO3/Al (anode)]. The device with aluminum hydroxide as an emissive layer shows a maximum luminance of 215.48 cd m-2 and external quantum efficiency (EQE) of 0.12%. The new method for synthesizing UV-blue emitting aluminum hydroxides and their application to LEDs will contribute to developing the field of non-toxic optoelectronic material or UV-blue emitting devices.

To investigate the role of Zn precursor based on hard and soft acids and bases theory, we introduced Mn and Ca precursors along with Zn precursor. The synthesis of III-V cores with these three metal precursors revealed that the roles of Zn precursor are as a reaction suppressant, a size regulator, and a dopant. Furthermore, we discovered which role was primarily played by Zn precursor at different concentrations.

We present a method for gram-scale synthesis of colloidal quantum dots (CQDs) with a quantum yield of up to 80% at room temperature and a narrow full width at half-maximum (FWHM) (<35 nm) in a wide range of emission wavelengths (480-619 nm) using a green solvent, cooking oil, either fresh or recycled. Hydrolyzing edible cooking oils such as soybean oil or waste cooking oil (i.e., a low-cost ($1.69/500 mL) and eco-friendly solvent), all in one step can easily generate various fatty acids, serving as green solvents and coordinating surfactants. Adjusting the conditions of hydrolysis such as the ratio of water to oil, reaction time, and temperature, we can control the amount of fatty acids (acting as solvents and ligands) generated from the cooking oil. The method of gram-scale synthesis of R/G/B-CQDs with the structure of a core/chemical composition gradient shell by a single-step method using inexpensive and environmentally benign cooking oils, either fresh or waste, will greatly contribute to the field of full-color displays and solid-state lighting.

The ultrathin film of copper selenide with 50 nm in thickness by the home-made atomic layer deposition apparatus was deposited. Synthesized copper pivalate and bis(triethylsilyl) selenide precursors were used. The deposition rate at 160oC was 0.48 A per ALD cycle and the thickness was monitored by the in-situ ellipsometer and further analyzed by an AFM. The composition and structure of the film were found by XPS, Raman and XRD to be Cu1.16Se. The FTO/Cu1.16Se/tungsten wire memristor was fabricated and its memristive effect was investigated. The non-linear I - V curve and spike timing dependent plasticity of our Cu1.16Se memristor demonstrate that short-term potentiation and long-term potentiation occurring in a human brain can be realized by adjusting voltage pulse intervals. A memristor is the electrical equivalent to a synapse. Our memristor shows 1 ms of switching time, 400 s of retention time, Roff/on=2, and the reproducibility over 1000 cycles.

An ultrathin film of copper selenide 50 nm thick was deposited using a home-made atomic layer deposition apparatus. Synthesized copper pivalate and bis(triethylsilyl) selenide precursors were used. The deposition rate at 160 °C was 0.48 Å per atomic layer deposition cycle. The thickness was monitored by an in situ ellipsometer and further analyzed by an atomic force microscope. The composition and structure of the film were confirmed by x-ray photoelectron spectroscopy, Raman spectroscopy, and x-ray diffraction to be Cu1.16Se. The fluorine-doped tin oxide/Cu1.16Se/tungsten wire memristor was fabricated and its memristive effect was investigated. The non-linear I–V curve and spike-timing-dependent plasticity of our Cu1.16Se memristor demonstrate that the short-term and long-term potentiation that occurs in a human brain can be mimicked by adjusting voltage-pulse intervals. A memristor is the electrical equivalent of a synapse. Our memristor has a 1 ms switching time, a 400 s retention time, Roff/on = 2, and reproducibility over 1000 cycles.

A novel P precursor with controllable reactivity and new metal complex precursors soluble in ODE are created and used for blue-emitting In1−xGaxP@ZnS QDs (PLQY: 65%; FWHM: 46 nm). The III–V-CQD based blue-QLED of the best EQE until now is reported.

We demonstrate the improvement in the efficiency of planar heterojunction perovskite solar cells by employing cadmium selenide tetrapods (CdSe TPs) as an electron extraction layer. The insertion of the CdSe TP layer between the titanium oxide (TiO2) and perovskite film facilitates electron transfer at the TiO2/perovskite interface, as indicated by the significantly quenched steady-state photoluminescence of the perovskite film. Furthermore, we observed a conductivity enhancement of the perovskite film by introducing the CdSe TP layer. The combination of both effects induced by the TPs leads to enhancement in the carrier extraction as well as decreased recombination losses in the perovskite solar cells. As a result, an efficiency of 13.5% (1 sun condition) is achieved in the perovskite solar cells that incorporate the CdSe TP layer, which is 10% higher than that of the device without the CdSe TP layer.

Magnesium oxysulfate (MOS) whisker is considered as a promising inorganic material recently attracting a great attention for being used as a reinforcing filler for polymer composites due to high aspect ratio and extremely-low bulk density. In this study, the MOS was treated with 3-methacryloyloxypropyl-trimethoxy silane (MPS) via sol-gel condensation reactions, which successfully allowed melt mixing with polypropylene (PP) up to 30 wt% of MOS. The tensile strength at yield and modulus of the MOS/PP composites were substantially increased by 50.8% and 362%, respectively, when compared with the pristine PP. As a novel finding, the flame retardancy of MOS was proved by identifying water evolution at elevated temperatures giving out 9 wt% of water in 250e320 degrees C and 14 wt% in 350-420 degrees C in two steps. This work demonstrated that the MOS could be an excellent filler for PP not only increasing the mechanical properties in a great extent but also imposing flame retarding capability. (C) 2018 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Magnesium oxysulfate (MOS) whisker is considered as a promising inorganic material recently attracting a great attention for being used as a reinforcing filler for polymer composites due to high aspect ratio and extremely-low bulk density. In this study, the MOS was treated with 3-methacryloyloxypropyl-trimethoxy silane (MPS) via sol-gel condensation reactions, which successfully allowed melt mixing with polypropylene (PP) up to 30wt% of MOS. The tensile strength at yield and modulus of the MOS/PP composites were substantially increased by 50.8% and 362%, respectively, when compared with the pristine PP. As a novel finding, the flame retardancy of MOS was proved by identifying water evolution at elevated temperatures giving out 9wt% of water in 250e320 C and 14wt% in 350e420 C in two steps. This work demonstrated that the MOS could be an excellent filler for PP not only increasing the mechanical properties in a great extent but also imposing flame retarding capability. © 2018 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The growth rate of TiO2 nanotubes depends on temperature, etchant concentration, and the strength of electric field. Under the typical fast hard anodization condition such as the strong electric field at 120 V, the flow of current is concentrated through the thin layer of TiO2, resulting in the bent or collapsed TiO2 nanotubes or a break-down, called 'burning'. To prevent the adverse effects, top etching and 'burning', we introduced formamide of a high dielectric constant as an additive in the electrolyte. The organic acids were electrochemically generated from the decomposition of formamide on TiO2. The organic acids rapidly stabilized anodization current and thus, the highly ordered 17 mu m-long TiO2 nanotube arrays were obtained just in 5 min anodization. During the anodization with pure formamide mixed with 1.3 vol % water under the strong electric field, cyanides, ammonium ions, and fatty acids, originated from the decomposition of formamide adsorbed on the TiO2, were found by ion chromatograph and gas chro-matographemass spectrometer (GC-MS) equipped with a pyrolyzer. The major roles of fatty acids such as oleic acids etc. generated from formamide are the current stabilization, the prevention of burning, and the delicate balancing of speed of etching with oxide layer growth. (C) 2018 Published by Elsevier Ltd.

We consider the effects of external electric field and anisotropic long-range reactivity on the recombination dynamics of a geminate charge pair. A closed-form analytic expression for the ultimate separation probability of the pair is presented. In previous theories, analytic expressions for the separation probability were obtained only for the case where the recombination reaction can be assumed to occur at a contact separation. For this case, Noolandi and Hong obtained an exact solution, but their expression for the separation probability was too complicated to evaluate. Hence an approximate analytic expression proposed by Braun has been widely used. However, Braun’s expression overestimates the separation probability when the electric field is large. In this work, we present an approximate analytic expression that is accurate enough for all parameter values. In addition, the expression is also applicable when the interaction between the geminate charge pair is described by screened Coulombic potential, and the recombination reaction has an anisotropic and long-range reactivity. We also provide the expression for the separation probability when the initial separation between the geminate charge pair is larger than the contact distance.

Preparing samples with good homogeneity is one of the requirements for generating reproducible matrix-assisted laser desorption ionization (MALDI) spectra and for using them in analyte quantification. Thus far, we have not been successful in producing homogeneous solid samples from popular matrixes apart from -cyano-4-hydroxycinnamic acid (CHCA). In this work, we demonstrate the production of an outwardly homogeneous solid sample by loading a methanol solution of a matrix into a shallow reservoir on a coated MALDI sample plate and then vacuum-drying it. Out of ten popular matrixes tested, seven yielded homogeneous samples. These were 9-aminoacridine, 6-aza-2-thiothymine, CHCA, 2,5-dihydroxybenzoic acid, ferulic acid, sinapinic acid, and 2,4,6-trihydroxyacetophenone. For MALDI with these matrixes, linear calibration curves covering wide dynamic ranges were acquired. Performances of these matrixes in various aspects of analyte quantification have been investigated.

Fluorous liquid-soluble semiconductor nanocrystals enable the solution-casting of inorganic films on top of an organic small-molecular hole-transporting layer, providing stacked structures suitable for light-emitting diode fabrication.

We report on a sequential ligand exchange and elimination process for the fast and easy surface modification of CdSe quantum dots (QDs) in order to improve the electronic interaction between poly(3-hexylthiophene) (P3HT) and CdSe QDs in P3HT:CdSe hybrid solar cells. We systematically investigated the influence of surface treatment on the insulating ligand shell of CdSe QDs using (1)H-NMR analysis, and correlated their influence on the photovoltaic properties of P3HT:CdSe hybrid solar cells. A decrease in the average thickness of the ligand shells directly improved carrier transport properties. Moreover, the presence of remnant 1-hexylamine ligands provided efficient surface trap passivation. As a result, overall solar cell performance (especially fill factor and power conversion efficiency) was enhanced and the recombination mechanism was dominated by monomolecular recombination due to enhanced carrier collection length (l(C0)).

We report a unique nanostructured electron-selective interlayer comprising of In-doped ZnO (ZnO:In) and vertically aligned CdSe tetrapods (TPs) for inverted polymer:fullerene bulkheterojunction (BHJ) solar cells. With dimension-controlled CdSe TPs, the direct inorganic electron transport pathway is provided, resulting in the improvement of the short circuit current and fill factor of devices. We demonstrate that the enhancement is attributed to the roles of CdSe TPs that reduce the recombination losses between the active layer and buffer layer, improve the hole-blocking as well as electron-transporting properties, and simultaneously improve charge collection characteristics. As a result, the power conversion efficiency of PTB7:PC70BM based solar cell with nanostructured CdSe TPs increases to 7.55%. We expect this approach can be extended to a general platform for improving charge extraction in organic solar cells.

We report very efficient red, green, blue, and white light‐emitting diodes based on colloidal quantum dots (QLEDs) using an inverted device architecture. We also review recent research progress of QLEDs and discuss issues for realizing full‐color QLED displays.

Thin-film ultraviolet (UV) light-emitting diodes (LEDs) with emission wavelengths below 400 nm are emerging as promising light sources for various purposes, from our daily lives to industrial applications. However, current thin-film UV-emitting devices radiate not only UV light but also visible light. Here, we introduce genuine UV-emitting colloidal nanocrystal quantum dot (NQD) LEDs (QLEDs) using precisely controlled NQDs consisting of a 2.5-nm-sized CdZnS ternary core and a ZnS shell. The effective core size is further reduced during the shell growth via the atomic diffusion of interior Cd atoms to the exterior ZnS shell, compensating for the photoluminescence red shift. This design enables us to develop CdZnS@ZnS UV QLEDs with pure UV emission and minimal parasitic peaks. The irradiance is as high as 2.0-13.9 mW cm(-2) at the peak wavelengths of 377-390 nm, several orders of magnitude higher than that of other thin-film UV LEDs.