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In this report a new series of metal Schiff base complexes (MMePy, M = Pt, Pd and Cu) were synthesized and used as hole transport materials (HTMs) in perovskite solar cells (PSCs), as an attempt to realize the hole extraction and transport ability of these materials in PSCs. The energy levels of the materials can be easily tuned by changing the central metal, leading to a better alignment with the perovskite absorber. The well matching of energy level along with lower surface roughness and higher crystallinity of the thin film give rise to the highest PCE of 8.07 % for the CuMePy-based device among the MMePy-based devices. The result indicates the promising application of this series of metal complexes for the use as HTM in PSCs.

A new electrochemical sensor to determine Sunset yellow (SY) in foods has been developed. A composite consisting of highly dispersed polypyrrole (ppy) and single-walled carbon nanotube (ppy–SCNT) was synthesized as a modification via a facile method at room temperature. The ppy–SCNT composites were demonstrated to be highly sensitive for SY detection. The influences of pH value, amount of ppy–SCNT dispersion, accumulation time and scan rate on the signal enhancement of SY are discussed. Under optimal experimental conditions, the ppy–SCNT modified glass carbon electrode (ppy–SCNT/GCE) exhibited a wide linear response to SY ranging from 2.0 × 10−9 to 1.5 × 10−6 M with a high sensitivity of 91.53 μA μM−1 and a low detection limit of 3.0 × 10−10 M (S/N = 3). The novel ppy can prevent the aggregation of SCNT via π–π interaction, and enhance their electrochemical properties for the measurement of Sunset yellow in food samples. The novel sensor possesses following features: facile fabrication, easy operation and acceptable stability. The analysis of real sample drinks demonstrated that the electrode has excellent selectivity.

DOI: 10.1002/adma.201201195 Flash memories have recently attracted considerable attention as promising next-generation nonvolatile memories owing to their higher chip density, multi-bit per cell storage properties, and compatibility with the current complementary metal– oxide–semiconductor (CMOS) process. [ 1–4 ] The fl ash memories based on fi eld-effect transistors (FETs) with a fl oating gate architecture work on the variation of the threshold voltage ( V th ) by trapping/detrapping the charge carriers of the semiconductor under external gate bias. To meet the requirements of manipulating the trap levels (work functions of metal) and trap sites (directly related to memory window which can be controlled by varying the density of nanoparticles), employment of nanocrystals fl oating gate is considered to be an alternative approach to replace the planar fl oating gate for information storage. [ 5 , 6 ] Gold nanoparticles (Au NPs) are appropriate material to serve as fl gate due to their chemical stability and high work function. [ 7 ] The Au NPs charge trapping layer can be created by several methods including thermal evaporation, [ 8 , 9 ] chemical process such as electrostatic self-assembly

Regioregular poly(3-hexylthiophene) (RR-P3HT) nanotubes (200 nm in diameter) with tunable aspect ratios from 25 to 300 were prepared using a polymer melt wetting technique. Aspect-ratio tunability was achieved by controlling the wetting behavior of RR-P3HT melts in a template. The crystallinity and chain orientation of RR-P3HT were studied by grazing incidence X-ray diffraction, wide-angle X-ray diffraction, and polarized photoluminescence spectroscopy. Results suggest that RR-P3HT chains in the lamellar structure prefer to be perpendicular to the axis of the RR-P3HT nanotubes, forming a face-on conformation in the RR-P3HT nanotubes that leads to increased carrier mobility of RR-P3HT. Field-effect transistors were fabricated based on a single RR-P3HT nanotube and showed a carrier mobility of 0.14 ± 0.02 cm(2)/V·s.

The half-metallicity and electronic structures for the bulk, surfaces and interfaces of zinc blende (ZB) NiO are investigated by using full potential linearized augment plane wave method with the modified Becke and Johnson potential. Obtained results reveal ZB NiO is half-metallic ferromagnet with half-metallic gap 0.80 eV. Smaller energy difference between ZB and stable rocksalt phase, negative cohesive energy and heat of formation imply ZB NiO could obtain experimentally. Both Ni- and O-termianted (001) surfaces as well as interfaces GaN/NiO, AlN/NiO, and ZnO/NiO preserve half-metallicity, suggesting ZB NiO, when realized experimentally, would be a promising half-metallic ferromagnet for spintronics devices application.

A series of ionic complexes composed with ([Ni(qdt)2]2−) and alkyl substituted asymmetric viologen derivatives (AV+) as cations have been synthesized and characterized. A slight change in the length of the alkyl chain of AV+ alters the cation–anion packing and leads to different charge transport properties of these complexes. Here, we establish a structure–property relationship of Ni(qdt)2 complexes by structurally modifying the cations.

The development of high performance flexible electronics requires dielectrics possessing a high dielectric constant and enhanced mechanical stability. In this study, we report on novel polymer nanocomposite dielectrics based on n-octadecylphosphonic acid (ODPA) functionalized aluminum titanate (AT) nanoparticles as dopants in poly(4-vinylphenol) (PVP). The robust surface layer covering the nanoparticles induces improved dielectric properties of the resulting composite films due to better interfacial adhesion. The nanocomposite layer with tunable dielectric permittivity and low leakage current is highly compatible on flexible substrates and has been deposited via a simple solution process. The air-stable p-type and n-type transistors fabricated on the composite dielectric layer exhibited superior electrical performance than those on the pristine polymer dielectric layer. The complementary inverters made from these transistors possessed a large signal gain and sharp switching. We systematically studied the electrical performance of the capacitors, transistors and inverters under different applied strains on flexible substrates. From the flexibility test, all these devices were found to be mechanically stable and environmentally robust, demonstrating that the composite dielectric layer is an excellent candidate for the future development of conformable sensors, portable displays and other flexible electronic applications.

Metal-assisted chemical etching (MACE) was carried out to fabricate solid silicon nanowires (s-SiNWs) and mesoporous silicon nanowires (mp-SiNWs). Total reflection and transmission were measured using an integrated sphere to study optical properties of the MACE-generated silicon nanostructures. Without NW aggregation, mp-SiNWs vertically standing on a mesoporous silicon layer trap less light than s-SiNWs over a wavelength range of 400-800 nm, owing to porosification-enhanced optical scattering from the rough inner surfaces of the mesoporous silicon skeletons. Porosification substantially weakens the NW mechanical strength; hence the elongated mp-SiNWs aggregate after 30 min etching and deteriorate optical trapping.