Enhanced light extraction efficiency of GaN-based green micro-LED modulating by a thickness-tunable SiO2 passivation structure.

Green micro-light emitting diodes (micro-LEDs) is one of the three primary color light sources as full-color display, which serves as a key research object in the field of micro-LED display. As the micro-LED size decreases, the surface-area-to-volume ratio of the device increases, leading to more serious damage on the sidewall by inductively coupled plasma (ICP) etching. The passivation process of SiO2 provides an effective method to reduce sidewall damage caused by ICP etching. In this work, green rectangular micro-LEDs with passivation layer thickness of 0∼600 nm was designed using the finite-difference time-domain (FDTD) simulation. In order to verify the simulation results, the micro-LED array was fabricated by parallel laser micro-lens array (MLA) lithography in high speed and large area. The effect of the SiO2 passivation layer thickness on the performance of the green micro-LED was analyzed, which shows that the passivation layer thickness-light extraction efficiency curve fluctuates periodically. For the sample with 90 nm thickness of SiO2 passivation layer, there exists a small leakage current and higher operating current density, and the maximum external quantum efficiency (EQE) is 2.8 times higher than micro-LED without SiO2 passivation layer.

Hierarchical CdS/Ni3S4/Ni2P@C Photocatalyst for Efficient H2 Evolution under Visible-Light Irradiation.

Structural and morphological modulations play a crucial role in increasing the surface active sites of semiconductor photocatalysts for visible-light-driven water splitting. To fabricate a novel CdS/Ni3S4/Ni2P@C heterostructure, we first prepared carbon-encapsulated Ni3S4/Ni2P (Ni3S4/Ni2P@C) with a high surface area by sequential carbonization and phosphorization of a Ni-metal-organic framework (MOF) precursor. Combined characterization and photoelectrochemical measurement results reveal that the assembly of CdS nanowires and highly porous Ni3S4/Ni2P@C can enhance the visible-light response capability of the CdS/Ni3S4/Ni2P@C heterostructure catalyst by reducing the forbidden band gap of CdS. The hydrogen production rate of 21.56 mmol h-1 g-1 for CdS/Ni3S4/Ni2P@C with a Ni3S4/Ni2P@C mass fraction of 10 wt % was 26 times higher than that of CdS in a photolytic aquatic hydrogen system. A possible mechanism for the photocatalytic enhancement of the Ni3S4/Ni2P@C co-catalyst was systematically investigated and discussed. This research opens a new strategy for constructing ternary heterojunction photocatalysts via MOF precursors.

Cytotoxicity and DNA binding property of the dimers of triphenylethylene-coumarin hybrid with one amino side chain.

Novel dimers of triphenylethylene-coumarin hybrid containing one amino side chain were designed and synthesized by the condensation of four dicarboxylic acids with the amino monomeric hybrids catalyzed by HATU and DIPEA at room temperature. The adding order of the reactants had a significant effect on the condensation reaction when the malonic acid was used. The dimeric compounds 7a and 7b linked by the malonic acid, showed a broad-spectrum and good anti-proliferative activity against four tumor cells and low cytotoxicity in osteoblast. UV-vis, fluorescence, and circular dichroism (CD) spectroscopies and thermal denaturation exhibited that compounds 7b, 8b, 9b, and 10b had significant interactions with Ct-DNA by the intercalative mode of binding. Both the DNA binding properties and the anti-proliferative activities would be enhanced by dimerization of the monomeric hybrid with one amino side chain, and were significantly affected by the length of the linker (dicarboxylic acids).

Cytotoxicity and DNA binding property of triphenylethylene-coumarin hybrids with two amino side chains.

Novel triphenylethylene-coumarin hybrids containing two amino side chains were designed and synthesized. Some of these 3,4-diphenyl coumarins, 7b-c (the double chains at 4-position on 3-,4-phenyl, respectively), and 13b-f (the double chains at 4-position on 3-phenyl and 7-position, respectively), showed a broad-spectrum and good anti-proliferative activity against five tumor cells and low cytotoxicity in osteoblast. UV-vis, fluorescence, and circular dichroism (CD) spectroscopies and thermal denaturation exhibited that compounds 7b (R=piperidinyl), 7e (R=NEt2), and 7f (R=4-methylpiperazinyl) had significant interactions with Ct-DNA by the intercalative mode of binding. Structure activity relationships (SARs) analysis suggested that the location of the two amino alkyl chains would play an important role both in the compounds against tumor cells proliferation and their interactions with DNA.

Design, synthesis, and anti-tumor activities of novel triphenylethylene-coumarin hybrids, and their interactions with Ct-DNA.

Novel triphenylethylene-coumarin hybrid derivatives containing different amounts of amino side chains were designed and synthesized in good yields under microwave radiation. The derivatives 5b-d which possessed two amino side chains (except morpholinyl) showed a broad-spectrum and good anti-proliferative activity against five tumor cells and low cytotoxicity in osteoblast. UV-vis, fluorescence, and circular dichroism (CD) spectroscopies and thermal denaturation exhibited that compounds 10 c, 5c, and 13c bearing amino side chain (except morpholinyl) on 4-phenyl had significant interactions with Ct-DNA by the intercalative mode of binding. Structure-activity relationships (SARs) analysis suggested that the amino alkyl chain would play an important role both in the compounds against tumor cells proliferation and their interactions with DNA.

Preparation and characterization of molecularly imprinted silica monolith for screening sulfamethazine.

In this work, a novel approach of preparing molecularly imprinted film-derivatized silica monolith materials was developed by a two-step procedure. The silica monolithic support was first prepared by the sol-gel method with tetramethoxysilane as the precursor. Subsequently, vinyl groups were introduced onto the surface of silica monolith by immobilization of γ-methacryloxypropyltrimethoxysilane. The prepolymerization mixtures, consisting of methacrylic acid as a functional monomer, ethylene dimethacrylate as a crosslinker, sulfamethazine as a template molecule and an ionic liquid as porogen, were injected into the silica monolith immobilized vinyl groups to form the molecularly imprinted films on the surface of the vinyl functionalized silica monolith. The monolithic materials were characterized by SEM, Fourier transform IR and solid-state reflection UV spectra. The resulted imprinted materials were evaluated under CEC and HPLC mode. The results indicated that there were enough recognition sites on the surface of the imprinted film-derivatized monolithic materials for selectively recognizing sulfamethazine from the sulfonamide mixture. Ionic liquids, which was utilized as the porogens, could improve the flow-through property and the imprinting effect of the molecularly imprinted film-functionalized silica monolithic materials.