Monolayer 2H-MoS2 has been widely noticed as a typical transition metal dichalcogenides (TMDC) for surface-enhanced Raman scattering (SERS). However, monolayer MoS2 is limited to a narrow range of applications due to poor detection sensitivity caused by the combination of a lower density of states (DOS) near the Fermi energy level as well as a rich fluorescence background. Here, surfaced S and Mo atomic defects are fabricated on a monolayer MoS2 with a perfect lattice. Defects exhibit metallic properties. The presence of defects enhances the interaction between MoS2 and the detection molecule, and it increases the probability of photoinduced charge transfer (PICT), resulting in a significant improvement of Raman enhancement. Defect-containing monolayer MoS2 enables the fluorescence signal of many dyes to be effectively burst, making the SERS spectrum clearer and making the limits of detection (LODs) below 10−8 M. In conclusion, metallic defect-containing monolayer MoS2 becomes a promising and versatile substrate capable of detecting a wide range of dye molecules due to its abundant DOS and effective PICT resonance. In addition, the synergistic effect of surface defects and of the MoS2 main body presents a new perspective for plasma-free SERS based on the chemical mechanism (CM), which provides promising theoretical support for other TMDC studies.

Although chemical substances are beneficial to human life, large quantities of these chemicals flow into the environment as they are used and released. The transport of chemical substances in multiple environmental media widens the damage scope of these chemicals to the ecological environment and increases the difficulty of controlling chemical pollution. Atmospheric transport is the major pathway for the transport and redistribution of chemical pollutants in the environment of land and water bodies [1-2]. Approximately 70% to 90% of chronic disease risks

Surface charge transfer doping has attracted much attention in modulating the optical and electrical behavior of 2D transition metal dichalcogenides (TMDCs), where finding controllable and efficient dopants is crucial. Here, 1,1,2,2-tetraphenylethylene (TPE) derivative molecules with aggregation-induced emission (AIE) effect were selected as adjustable dopants. By designing nitro and methoxyl functional groups and surface coating, controlled p/n-type doping can be achieved on a chemical vapor deposition (CVD) grown monolayer, MoS2. We investigated the electron transfer behavior between these two dopants and MoS2 with fluorescence, Raman, X-ray photoelectron spectra and transient absorption spectra. 1,1,2,2-Tetrakis(4-nitrophenyl)ethane (TPE-4NO2) with a negative charge aggregation can be a donor to transfer electrons to MoS2, while 1,1,2,2-Tetrakis(4-methoxyphenyl)ethane (TPE-4OCH3) is the opposite and electron-accepting. Density functional theory calculations further explain and confirm these experimental results. This work shows a new way to select suitable dopants for TMDCs, which is beneficial for a wide range of applications in optoelectronic devices.

Phthalate derivatives with low estrogenic activity, high infrared spectrum signals, high Raman characteristic vibration spectrum, high fluorescence intensity, and high ultraviolet sensitivity were selected as precursors from our previous studies, so that the changes in their toxicity and estrogenic activity during biological metabolism, ozone oxidation, photocatalytic degradation, photodegradation, and microbial degradation could be studied.The transformation pathways of these derivatives were simulated, and the reaction energy barriers were calculated. To determine the potential environmental risks of these phthalate derivatives, the pharmacophore models of biotoxicity and estrogen activity of phthalates were used to predict the biotoxicity and estrogen activity of the transformed products. The results showed an increase in the biotoxicity and estrogen activity of the biometabolites, ozonation products, photocatalytic degradation products, and microbial degradation products; the only products that did not follow this trend were the photodegradation products. Notably, the pathways that produced more potentially toxic compounds were the less favorable paths. Our results indicate that the transformation products of the designed environmentally friendly phthalate derivatives potentially pose environmental risks. To avoid such risks, the environmental transformation pathway of these derivatives should be simulated to screen for environmentally friendly phthalate molecules. Environ Toxicol Chem 2020;39:1138–1148. © 2020 SETAC

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Mesoporous silica nanoparticles (MSNs) functionalized with benzimidazole‐derived fluorescent molecules (DHBM) are fabricated via a feasible interfacial superassembly strategy for the highly sensitive and selective detection of Cu2+. DHBM‐MSN exhibits an obvious quenching effect on Cu2+ in aqueous solutions, and the detection limit can be as low as 7.69×10−8 M. The DHBM‐MSN solid‐state sensor has good recyclability, and the silica framework can simultaneously improve the photostability of DHBM. Two mesoporous silica nanoparticles with different morphologies were specially designed to verify that nanocarriers with different morphologies do not affect the specific detectionability. The detection mechanism of the fluorescent probe was systematically elucidated by combining experimental results and density function theory calculations. Moreover, the detection system was successfully applied to detect Cu2+ in bovine serum, juice, and live cells. These results indicate that the DHBM‐MSN fluorescent sensor holds great potential in practical and biomedical applications.

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