Fast and High-Performance Self-Powered Photodetector Based on the ZnO/Metal-Organic Framework Heterojunction.

Electrical conductive metal-organic frameworks (EC-MOFs) are emerging as an appealing class of highly tailorable electrically conducting materials with potential applications in optoelectronics. Here, we in situ grew nickel hexahydroxytriphenylene (Ni-CAT) on the surface of ZnO nanorods (NRs). The self-powered photodetectors (PDs) were fabricated with heterojunctions formed at the interface of ZnO NRs and Ni-CAT.

Heteronanostructural metal oxide-based gas microsensors.

The development of high-performance, portable and miniaturized gas sensors has aroused increasing interest in the fields of environmental monitoring, security, medical diagnosis, and agriculture. Among different detection tools, metal oxide semiconductor (MOS)-based chemiresistive gas sensors are the most popular choice in commercial applications and have the advantages of high stability, low cost, and high sensitivity. One of the most important ways to further enhance the sensor performance is to construct MOS-based nanoscale heterojunctions (heteronanostructural MOSs) from MOS nanomaterials.

Humidity-Insensitive NO Sensors Based on SnO/rGO Composites.

This study reported a novel humidity-insensitive nitrogen dioxide (NO) gas sensor based on tin dioxide (SnO)/reduced graphene oxide (rGO) composites through the sol-gel method. The sensor demonstrated ppb-level NO detection in p-type sensing behaviors (13.6% response to 750 ppb).

"Top-down" and "bottom-up" strategies for wafer-scaled miniaturized gas sensors design and fabrication.

Manufacture of large-scale patterned nanomaterials via top-down techniques, such as printing and slurry coating, have been used for fabrication of miniaturized gas sensors. However, the reproducibility and uniformity of the sensors in wafer-scale fabrication are still a challenge. In this work, a "top-down" and "bottom-up" combined strategy was proposed to manufacture wafer-scaled miniaturized gas sensors with high-throughput by in-situ growth of Ni(OH) nanowalls at specific locations.

In Situ Growth of NiO@SnO Hierarchical Nanostructures for High Performance HS Sensing.

Heterostructured metal oxides with large specific surface area are crucial for constructing gas sensors with high performance. However, using slurry-coating and screen-printing methods to fabricate gas sensors cannot result in high uniformity and reproducibility of the sensors. Here, NiO nanowalls decorated by SnO nanoneedles (NiO@SnO) were in situ grown on ceramic microchips via a chemical bath deposition method to detect HS instead of print-coating and slurry-coating methods.

High-Performance Self-Powered Ultraviolet Photodetector Based on Nano-Porous GaN and CoPc Vertical Heterojunction.

Gallium nitride (GaN) is a superior candidate material for fabricating ultraviolet (UV) photodetectors (PDs) by taking advantage of its attractive wide bandgap (3.4 eV) and stable chemical and physical properties. However, the performance of available GaN-based UV PDs (e.

Rhinophore bio-inspired stretchable and programmable electrochemical sensor.

Rhinophore, a bio-chemical sensory organ with soft and stretchable/retractable features in many marine molluscs species, exhibits tunable chemosensory abilities in terms of far/near-field chemical detection and molecules' source orientation. However, existing artificial bio-chemical sensors cannot provide tunable modality sensing. Inspired by the anatomical units (folded sensory epithelium) and the functions of a rhinophore, this work introduces a stretchable electrochemical sensor that offers a programmable electro-catalytic performance towards glucose based on the fold/unfold regulation of the gold nanomembrane on an elastic fiber.

Bioinspired Flexible Volatile Organic Compounds Sensor Based on Dynamic Surface Wrinkling with Dual-Signal Response.

Living systems can respond to external stimuli by dynamic interface changes. Moreover, natural wrinkle structures allow the surface to switch dynamically and reversibly from flat to rough in response to specific stimuli. Artificial wrinkle structures have been developed for applications such as optical devices, mechanical sensors, and microfluidic devices.

Self-Powered UV-Near Infrared Photodetector Based on Reduced Graphene Oxide/n-Si Vertical Heterojunction.

A novel self-powered photodetector based on reduced graphene oxide (rGO)/n-Si p-n vertical heterojunction with high sensitivity and fast response time is presented. The photodetector contains a p-n vertical heterojunction between a drop-casted rGO thin film and n-Si. Contacts between the semiconductor layer (rGO, n-Si) and source-drain Ti/Au electrodes allow efficient transfer of photogenerated charge carriers.

Wash-off potential of urban use insecticides on concrete surfaces.

Contamination of surface aquatic systems by insecticides is an emerging concern in urban watersheds, but sources of contamination are poorly understood, hindering development of regulatory or mitigation strategies. Hardscapes such as concrete surfaces are considered an important facilitator for pesticide runoff following applications around homes. However, pesticide behavior on concrete has seldom been studied, and standardized evaluation methods are nonexistent.

Epimerization of cypermethrin stereoisomers in alcohols.

Isomerization induced by light, heat, and organic solvents has been shown to occur for some pyrethroid insecticides. Alcohols are popular solvents that are used in sample extraction, storage, and analysis. Thus, alcohol-induced epimerization may contribute to the incorrect interpretation of results from enantioselective chemical analysis and bioassay of pyrethroids like cypermethrin.

Abiotic enantiomerization of permethrin and cypermethrin: effects of organic solvents.

All synthetic pyrethroids are chiral compounds, and isomerization has been frequently observed from exposure to certain solvents. However, so far, pyrethroid isomerization caused by solvents has not been characterized at the enantiomer level. In this study, we evaluated the occurrence of enantiomerization of two commonly used pyrethroids, permethrin and cypermethrin, in various organic solvents and solvent-water systems.

Enantiomeric differences in permethrin degradation pathways in soil and sediment.

Chirality occurs widely in synthetic pyrethroids. Studies have shown significant differences in both aquatic toxicity and degradation rates between enantiomers from the same diastereomer of selected pyrethroids. To better understand chiral selectivity in biodegradation of pyrethroids, 14C-labeled permethrin was used to characterize enantiomeric differences in the formation of transformation intermediates in two soils and a sediment.

Enantioselective degradation and chiral stability of pyrethroids in soil and sediment.

Synthetic pyrethroids contain two or three chiral centers, making them a family of chiral pesticides with a large number of stereoisomers. Recent studies showed significant differences in aquatic toxicity between enantiomers from the same diastereomers of pyrethroids. To better understand the ecotoxicological effect and fate of pyrethroid insecticides, chirality in biodegradation must also be considered.

Chiral stability of synthetic pyrethroid insecticides.

Synthetic pyrethroids are chiral compounds consisting of multiple stereoisomers. Evaluation of enantioselectivity in environmental fate and ecotoxicity requires analytical methods that preserve stereoisomer integrity during analysis. In this study, we characterized the stability of stereoisomers from four commonly used pyrethroids, cis-bifenthrin (cis-BF), permethrin (PM), cypermethrin (CP), and cyfluthrin (CF), during gas chromatography (GC) analysis and sample preparation.

Separation and aquatic toxicity of enantiomers of synthetic pyrethroid insecticides.

Synthetic pyrethroid insecticides are chiral compounds with multiple asymmetric positions. In this study, isomers of four commonly used pyrethroids were separated at the enantiomeric level by enantioselective high-performance liquid chromatography (HPLC), and differences between enantiomers in aquatic toxicity were characterized using individual isomers. Isomers of cis-bifenthrin and permethrin were completely resolved on a Sumichiral OA-2500-I column.

Degradation and adsorption of fosthiazate in soil.

Adsorption and degradation behavior of a pesticide in soil has a strong effect on its environmental fate as well as efficacy for pest control. Fosthiazate is an organophosphate compound that is currently under development as a nonfumigant nematicide. In this study, we evaluated adsorption and degradation kinetics of fosthiazate in three U.