Micro- and nanoplastics: Contamination routes of food products and critical interpretation of detection strategies.

Micro-and nanoplastics (M/NPs) are emerging pollutants released into the food, beverages, and environment from plastic products by weathering, oxidative damage, and mechanical stress. Detection of M/NPs in food and beverages is a vital factor in preventing the deleterious effects of these materials on human health and other ecosystems. Analytical strategies for M/NPs demonstrate numerous drawbacks, including detection sensitivity limitation, matrix digestion, and sample pretreatment. Moreover, the content of M/NPs in food and beverages varies with food production, storage, and transport, making it hard to precisely detect them. The contamination route is a key factor affecting the level of M/NPs in food and beverages. Strict control over the contamination route could be beneficial in preventing M/NP pollution. This review highlighted routes of food and beverage contamination by M/NPs, various pros and cons of detection strategies, and critical interpretation of reported techniques, including microscopy, spectroscopy, light scattering, and thermal methods. Besides, the bottlenecks of detection and quantification approaches for M/NPs and recent advancements have also been highlighted. Much is still unknown concerning the fate, activities, and properties of M/NPs present in various matrices. This review aims to assist the investigators to tackle the drawbacks and pave the way for upcoming research, minimizing the health complications by regulating the control over M/NPs pollution.

Liquid Phase Edge Epitaxy of Transition-Metal Dichalcogenide Monolayers.

Precise monolayer epitaxy is important for two-dimensional (2D) semiconductors toward future electronics. Here, we report a new self-limited epitaxy approach, liquid phase edge epitaxy (LPEE), for precise-monolayer epitaxy of transition-metal dichalcogenides. In this method, the liquid solution contacts 2D grains only at the edges, which confines the epitaxy only at the grain edges and then precise monolayer epitaxy can be achieved. High-temperature in situ imaging of the epitaxy progress directly supports this edge-contact epitaxy mechanism. Typical transition-metal dichalcogenide monolayers (MX2, M = Mo, W, and Re; X = S or Se) have been obtained by LPEE with a proper choice of molten alkali halide solvents (AL, A = Li, Na, K, and Cs; L = Cl, Br, or I). Furthermore, alloying and magnetic-element doping have also been realized by taking advantage of the liquid phase epitaxy approach. This LPEE method provides a precise and highly versatile approach for 2D monolayer epitaxy and can revolutionize the growth of 2D materials toward electronic applications.

Ultralow-Transition-Energy Organic Complex on Graphene for High-Performance Shortwave Infrared Photodetection.

Room-temperature, high-sensitivity, and broadband photodetection up to the shortwave infrared (SWIR) region is extremely significant for a wide variety of optoelectronic applications, including contamination identification, thermal imaging, night vision, agricultural inspection, and atmospheric remote sensing. Small-bandgap semiconductor-based SWIR photodetectors generally require deep cooling to suppress thermally generated charge carriers to achieve increased sensitivity. Meanwhile, the photogating effect can provide an alternative way to achieve superior photosensitivity without the need for cooling. The optical photogating effect originates from charge trapping of photoinduced carriers at defects or interfaces, resulting in an extremely high photogain (106 or higher). Here, a highly sensitive SWIR hybrid photodetector, fabricated by integrating an organic charge transfer complex on a graphene transistor, is reported. The organic charge transfer complex (tetrathiafulvalene-chloranil) has an exceptional low-energy intermolecular electronic transition down to 0.5 eV, with the aim of achieving efficient SWIR absorption for wavelengths greater than 2 µm. The photogating effect at the organic complex and graphene interface enables an extremely high photogain and a high detectivity of ≈1013 Jones, along with a response time of 8 ms, at room temperature for a wavelength of 2 µm.