Henan Normal University

About: Henan Normal University is a education organization based out in Xinxiang, China. It is known for research contribution in the topics: Catalysis & Ionic liquid. The organization has 10863 authors who have published 11077 publications receiving 166773 citations.

π-Type halogen bonding enhanced the long-lasting room temperature phosphorescence of Zn(II) coordination polymers for photoelectron response applications

Abstract: The development of non-noble metal ions with potential organic phosphor ligands through strong coordination bonds can afford an effective platform for achieving persistent and tunable phosphorescence at room temperature. However, successful examples of coordination polymers (CPs) or metal–organic frameworks (MOFs) exhibiting long-lasting phosphorescence emission are still rarely explored. In this work, a new strategy has been used for the first time to achieve long-lasting phosphorescence via π-type halogen bonding in coordination polymers. By the selection of two isomers 5-BIPA and 4-BIPA with different Br atom substitution positions in isophthalic acid (IPA), two new Zn(II)-based coordination polymers exhibiting long-lasting phosphorescence emission up to the order of magnitude of millisecond (ms) were presented, which were further revealed by theoretical calculations. Optoelectronic measurements indicated that 1 showed a high photoelectron response because the delocalized π-type halogen bonding and long range order of π-conjugated chains afforded large electron channels for efficient charge transport.

Gutzwiller Density Functional Studies of FeAs-Based Superconductors: Structure Optimization and Evidence for a Three-Dimensional Fermi Surface

Abstract: A binary-component self-assembled monolayer (SAM) comprising tetrathiafulvalene (TTF) and n-tetradecane (n-C(14)H(30)) molecules has been investigated by a scanning tunneling microscope (STM) on a highly oriented pyrolytic graphite (HOPG) surface at room temperature. High-resolution STM images of the SAM reveal that the two different kinds of molecules spontaneously form periodic ordered strip-like phase separation structure on the HOPG substrate. The phenomenon can be qualitatively understood in terms of a phase field model, in which the interplay of three ingredients, including free energy of the binary component solution monolayer, phase boundary energy, and surface stress, is suggested to play an important role in determining the equilibrium sizes of strip-like domains of the TTF and n-C(14)H(30) in the ordered phase separation structure. In addition, scanning tunneling spectrum (STS) measurements have also been performed by operating an STM tip to locate on the individual TTF or n-C(14)H(30) molecule in the SAM on the HOPG substrate. The STS at the TTF molecule shows a distinct rectifying behavior, while at the n-C(14)H(30) molecule it shows an intrinsic small current increase with the change of bias voltage and a slight asymmetry.

Hybrid tapered silicon nanowire/PEDOT:PSS solar cells

Abstract: A tapered silicon nanowire array (TSiNWs)/poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) hybrid solar cell was obtained based on alkali treatment processing. TSiNWs are engineered by combining electroless etching and an alkali solution in which the morphology of the tapered nanowire can be controlled by changing the immersing time. The results show that the alkali treatment could taper the silicon nanowires so that the polymer could conformally infiltrate into SiNWs via spin-coating. The experimental results demonstrate that the length and morphology of the SiNWs are key factors for improving the cell performance. Compared to the SiNWs/polymer hybird device, the TSiNWs/polymer hybrid solar cell can achieve a high power conversion efficiency of 6.87% and short-circuit current density of 26.7 mA cm−2. Therefore, tapered silicon nanowires are promising structures for realizing economically viable hybrid solar cells based on a very simple, scalable, and low-cost solution route.

DNA-Functionalization Gold Nanoparticles based Fluorescence sensor for sensitive detection of Hg2+ in aqueous solution

Abstract: We have developed a sensitive, selective, and simple fluorescence spectrometric sensor for Hg 2+ detection in aqueous solution by using thiol-DNA-functionalized gold nanoparticles (Au NPs). This sensor is based on the Hg 2+ -induced conformational change of single-stranded DNA (ssDNA) with an enhanced fluorescence resonance energy transfer (FRET) process between the energy donor (fluorescein, FAM) and the energy acceptor (Au NPs). In the presence of Hg 2+ , a formation of a hairpin structure for ssDNA originates from thymine-Hg 2+ -thymine (T-Hg 2+ -T) coordination, resulting in notable fluorescence quenching in comparison to the random coil. In order to improve the stability and sensitivity of the sensor, we adopt short “helper” oligonucleotides to increase the density of DNA on the surface of Au NPs. The assay enables the detection limit for the detection of Hg 2+ is 8 nM, and is extremely specific for Hg 2+ even in the presence of high concentrations of other metal ions. Toward the goal for practical applications, this sensor was applied to monitor Hg 2+ in tap water samples and showed low matrix interference and high sensitivity.

Effects of Electric Field on the Electronic Structures of Broken-gap Phosphorene/Sn X 2 (X = S , Se ) van der Waals Heterojunctions

Abstract: Custom-made stacks of two-dimensional materials can be constructed to achieve specific optoelectronic properties in devices. This work uses density functional theory to investigate the electronic structures and transport properties of phosphorene--tin-dichalcogenide van der Waals heterostructures in an external electric field. The results show that these systems exhibit rare type-III (broken-gap) band alignment, which will facilitate the development of tunnel field-effect transistors. Moreover, the band alignment can be tuned effectively by the applied electric field.