The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching.

We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm.

Zener Tunneling and Photoresponse of a WS2/Si van der Waals Heterojunction.

Van der Waals heterostructures built from two-dimensional materials on a conventional semiconductor offer novel electronic and optoelectronic properties for next-generation information devices. Here we report that by simply stacking a vapor-phase-synthesized multilayer n-type WS2 film onto a p-type Si substrate, a high-responsivity Zener photodiode can be achieved. We find that above a small reverse threshold voltage of 0.

Isomeric Thermally Activated Delayed Fluorescence Emitters for Color Purity-Improved Emission in Organic Light-Emitting Devices.

To improve the color purity of thermally activated delayed fluorescence (TADF) emitters, two isomeric compounds, oPTC (5'-(phenoxazin-10-yl)-[1,1':3',1″-terphenyl]-2'-carbonitrile) and mPTC (2'-(phenoxazin-10-yl)-[1,1':3',1″-terphenyl]-5'-carbonitrile), were designed and synthesized with same skeleton but different molecular restrictions. Both compounds exhibit similar highest occupied molecular orbital and lowest unoccupied molecular orbital distributions and energy levels, photophysical properties in nonpolar cyclohexane solution, and high external quantum efficiencies (19.9% for oPTC and 17.

Toward Efficient Thick Active PTB7 Photovoltaic Layers Using Diphenyl Ether as a Solvent Additive.

The development of thick organic photovoltaics (OPV) could increase absorption in the active layer and ease manufacturing constraints in large-scale solar panel production. However, the efficiencies of most low-bandgap OPVs decrease substantially when the active layers exceed ∼100 nm in thickness (because of low crystallinity and a short exciton diffusion length). Herein, we report the use of solvent additive diphenyl ether (DPE) that facilitates the fabrication of thick (180 nm) active layers and triples the power conversion efficiency (PCE) of conventional thienothiophene-co-benzodithiophene polymer (PTB7)-based OPVs from 1.

Examining the Contributions of Image-Charge Forces to Charge Reversal: Discrete Versus Continuum Modeling of Surface Charges.

The effects of both repulsive and attractive image-charge forces on the structure of electric double layers are addressed by Monte Carlo determination, based on a primitive model of electrolytes in contact with two types of identically charged surfaces: one with a homogeneously smeared-out charge density and the other with discrete interfacial groups. It is shown that the behavior of ions is closely related to surface charge distributions. Moreover, charge reversal in the absence of image charges witnesses an initial enhancement and then follows a fast suppression with increasing valence of the interfacial groups.

Remote Evaluation of Rotational Velocity Using a Quadrant Photo-Detector and a DSC Algorithm.

This paper presents an approach to remotely evaluate the rotational velocity of a measured object by using a quadrant photo-detector and a differential subtraction correlation (DSC) algorithm. The rotational velocity of a rotating object is determined by two temporal-delay numbers at the minima of two DSCs that are derived from the four output signals of the quadrant photo-detector, and the sign of the calculated rotational velocity directly represents the rotational direction. The DSC algorithm does not require any multiplication operations.

Narrow Red Emission Band Fluoride Phosphor KNaSiF6:Mn(4+) for Warm White Light-Emitting Diodes.

Red phosphors AMF6:Mn(4+) (A = Na, K, Cs, Ba, Rb; M = Si, Ti, Ge) have been widely studied due to the narrow red emission bands around 630 nm. The different emission of the zero-phonon line (ZPL) may affect the color rendering index of white light-emitting diodes (WLED). The primary reason behind the emergence and intensity of ZPL, taking KNaSiF6:Mn(4+) as an example, was investigated here.

THz Transmittance and Electrical Properties Tuning across IMT in Vanadium Dioxide Films by Al Doping.

Due to the insulator-metal transition (IMT) performance covering the full terahertz (THz) band, VO2 films were extensively investigated as an excellent candidate for modulating, switching, and memory devices. However, some remarkable absorption peaks owing to the infrared-active phonon modes suppressed the films' modulation ability and restricted the films' application in high THz frequency. Here we prepared Al-doped VO2 films on (111) directional silicon substrate, which rapidly counteracted the absorption peak and exhibited widely modulating properties.

A novel method of artery stenosis diagnosis using transfer function and support vector machine based on transmission line model: A numerical simulation and validation study.

Background And Objective: Transfer function (TF) is an important parameter for the analysis and understanding of hemodynamics when arterial stenosis exists in human arterial tree. Aimed to validate the feasibility of using TF to diagnose arterial stenosis, the forward problem and inverse problem were simulated and discussed.

Methods: A calculation method of TF between ascending aorta and any other artery was proposed based on a 55 segment transmission line model (TLM) of human artery tree.

Unraveling the formation mechanism of graphitic nitrogen-doping in thermally treated graphene with ammonia.

Nitrogen-doped graphene (N-graphene) has attractive properties that has been widely studied over the years. However, its possible formation process still remains unclear. Here, we propose a highly feasible formation mechanism of the graphitic-N doing in thermally treated graphene with ammonia by performing ab initio molecular dynamic simulations at experimental conditions.

High performance NiFe layered double hydroxide for methyl orange dye and Cr(VI) adsorption.

The NiFe layered double hydroxides (LDHs) with different mole ratio of Ni/Fe (4:1, 3:1, 7:3 and 1:1) were prepared by a simple coprecipitation method. The adsorption performance were evaluated by the removal of methyl orange (MO) dye and hexavalent chromium(VI) heavy metal ion. It is found that Ni4Fe1-LDH can remove more than 92% of MO in 10 min at the 10 mg/L MO initial concentration, and 97% of Cr(VI) in 1 h at 4 mg/L Cr2O7(2-) initial concentration.

ZnO Nanoparticles/Reduced Graphene Oxide Bilayer Thin Films for Improved NH3-Sensing Performances at Room Temperature.

ZnO nanoparticles and graphene oxide (GO) thin film were deposited on gold interdigital electrodes (IDEs) in sequence via simple spraying process, which was further restored to ZnO/reduced graphene oxide (rGO) bilayer thin film by the thermal reduction treatment and employed for ammonia (NH3) detection at room temperature. rGO was identified by UV-vis absorption spectra and X-ray photoelectron spectroscope (XPS) analyses, and the adhesion between ZnO nanoparticles and rGO nanosheets might also be formed. The NH3-sensing performances of pure rGO film and ZnO/rGO bilayer films with different sprayed GO amounts were compared.

Charge reversal at a planar boundary between two dielectrics.

Despite the ubiquitous character and relevance of the electric double layer in the entire realm of interface and colloid science, very little is known of the effect that surface heterogeneity exerts on the underlying mechanisms of ion adsorption. Herein, computer simulations offer a perspective that, in sharp contrast to the homogeneously charged surface, discrete groups promote multivalent counterion binding, leading to charge reversal but possibly having not a sign change of the electrophoretic mobility. Counterintuitively, the introduction of dielectric images yields a significantly greater accumulation of counterions, which further facilitates the magnitude of charge reversal.

Suppression and promotion of charge inversion in the presence of multivalent coions.

We report charge inversion using Monte Carlo calculations for a negatively charged surface in aqueous solutions involving coions of different charges and monovalent counterions. It is shown that a rise in the valence of coions at moderate concentrations can substantially promote charge inversion for the surface charge values of biological relevance, regardless of the representation of surface charges but dependent in a nontrivial way on polarization effects resulting from dielectric discontinuity. These obtained characteristics challenge the traditional belief that the coions are generally considered to suppress charge inversion and expose the important role of coions of higher valence in tailoring the effective interactions of biomolecules with the cell membrane.

Ammonia gas sensors based on poly (3-hexylthiophene)-molybdenum disulfide film transistors.

In this work, in order to enhance the recovery performance of organic thin film transistors (OTFTs) ammonia (NH3) sensors, poly (3-hexylthiophene) (P3HT) and molybdenum disulfide (MoS2) were combined as sensitive materials. Different sensitive film structures as active layers of OTFTs, i.e.

Reactive Sputter Deposition of WO3/Ag/WO3 Film for Indium Tin Oxide (ITO)-Free Electrochromic Devices.

Functioning both as electrochromic (EC) and transparent-conductive (TC) coatings, WO3/Ag/WO3 (WAW) trilayer film shows promising potential application for ITO-free electrochromic devices. Reports on thermal-evaporated WAW films revealed that these bifunctional WAW films have distinct EC characteristics; however, their poor adhesive property leads to rapid degradation of coloring-bleaching cycling. Here, we show that WAW film with improved EC durability can be prepared by reactive sputtering using metal targets.

Comparing object recognition from binary and bipolar edge features.

Edges derived from abrupt luminance changes in images carry essential information for object recognition. Typical binary edge images (black edges on white background or white edges on black background) have been used to represent features (edges and cusps) in scenes. However, the polarity of cusps and edges may contain important depth information (depth from shading) which is lost in the binary edge representation.

Highly Efficient Organic Solar Cells with Improved Vertical Donor-Acceptor Compositional Gradient Via an Inverted Off-Center Spinning Method.

A novel, yet simple solution fabrication technique to address the trade-off between photocurrent and fill factor in thick bulk heterojunction organic solar cells is described. The inverted off-center spinning technique promotes a vertical gradient of the donor-acceptor phase-separated morphology, enabling devices with near 100% internal quantum efficiency and a high power conversion efficiency of 10.95%.

High mobility emissive organic semiconductor.

The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.

Synthesis and photoluminescence of novel red-emitting ZnWO₄: Pr³⁺, Li⁺ phosphors.

Zn0.997WO4: Pr(3+)(0.003) and different concentrations (0.

Improved Crystallization of Perovskite Films by Optimized Solvent Annealing for High Efficiency Solar Cell.

Organic-inorganic halide perovskite-based thin film solar cells show excellent light-to-power conversion efficiency. The high performance for the devices requires the preparation of well-crystallized perovskite absorbers. In this paper, we used the postannealing process to treat the perovskite films under different solvent vapors and observed that the solvent vapors have a strong effect on the film growth.

Chemical structures and physical properties of vanadium oxide films modified by single-walled carbon nanotubes.

A series of vanadium oxide (VOx)-single-walled carbon nanotube (SWCNT) composite films with different SWCNT concentrations were prepared and systematically investigated. The results reveal that after SWCNT addition, the optical absorption and electrical conductivity of VOx are enhanced, but the crystallinity and temperature coefficient of resistance (TCR) are weakened. Consequently, either too low or too high CNT loading will lead to the degradation of the comprehensive properties.

Correction: Large-area synthesis of monolayer WS₂ and its ambient-sensitive photo-detecting performance.

Correction for 'Large-area synthesis of monolayer WS2 and its ambient-sensitive photo-detecting performance' by Changyong Lan et al., Nanoscale, 2015, 7, 5974-5980.

Self-Assembled Asymmetric Block Copolymer Membranes: Bridging the Gap from Ultra- to Nanofiltration.

The self-assembly of block copolymers is an emerging strategy to produce isoporous ultrafiltration membranes. However, thus far, it has not been possible to bridge the gap from ultra- to nanofiltration and decrease the pore size of self-assembled block copolymer membranes to below 5 nm without post-treatment. It is now reported that the self-assembly of blends of two chemically interacting copolymers can lead to highly porous membranes with pore diameters as small as 1.