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Hybrid organic-inorganic perovskite materials have received substantial research attention due to their impressively high performance in photovoltaic devices. As one of the oldest functional materials, it is intriguing to explore the optoelectronic properties in perovskite after reducing it into a few atomic layers in which two-dimensional (2D) confinement may get involved. In this work, we report a combined solution process and vapor-phase conversion method to synthesize 2D hybrid organic-inorganic perovskite (i.e., CH3NH3PbI3) nanocrystals as thin as a single unit cell (∼1.3 nm). High-quality 2D perovskite crystals have triangle and hexagonal shapes, exhibiting tunable photoluminescence while the thickness or composition is changed. Due to the high quantum efficiency and excellent photoelectric properties in 2D perovskites, a high-performance photodetector was demonstrated, in which the current can be enhanced significantly by shining 405 and 532 nm lasers, showing photoresponsivities of 22 and 12 AW(-1) with a voltage bias of 1 V, respectively. The excellent optoelectronic properties make 2D perovskites building blocks to construct 2D heterostructures for wider optoelectronic applications.

Recently, research on graphene based photodetectors has drawn substantial attention due to ultrafast and broadband photoresponse of graphene. However, they usually have low responsivity and low photoconductive gain induced by the gapless nature of graphene, which greatly limit their applications. The synergetic integration of graphene with other two-dimensional (2D) materials to form van der Waals heterostructure is a very promising approach to overcome these shortcomings. Here we report the growth of graphene-Bi2Te3 heterostructure where Bi2Te3 is a small bandgap material from topological insulator family with a similar hexagonal symmetry to graphene. Because of the effective photocarrier generation and transfer at the interface between graphene and Bi2Te3, the device photocurrent can be effectively enhanced without sacrificing the detecting spectral width. Our results show that the graphene-Bi2Te3 photodetector has much higher photoresponsivity (35 AW(-1) at a wavelength of 532 nm) and higher sensitivity (photoconductive gain up to 83), as compared to the pure monolayer graphene-based devices. More interestingly, the detection wavelength range of our device is further expanded to near-infrared (980 nm) and telecommunication band (1550 nm), which is not observed on the devices based on heterostructures of graphene and transition metal dichalcogenides.

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The objective of this research was to characterize the anaerobic biodegradability of municipal refuse components by measuring methane yields, the extent of cellulose and hemicellulose decomposition, and leachate toxicity. Tests were conducted in quadruplicate in 2-L reactors operated to obtain maximum yields. Measured methane yields for grass, leaves, branches, food waste, coated paper, old newsprint, old corrugated containers, and office paper were 144.4, 30.6, 62.6, 300.7, 84.4, 74.3, 152.3, and 217.3 mL of CH4/dry g, respectively. Although, as a general trend, the methane yield increased as the cellulose plus hemicellulose content increased, confounding factors precluded establishing a quantitative relationship. Similarly, the degree of lignification of a particular component was not a good predictor of the extent of biodegradation. With the exception of food waste, leachate from the decomposition of refuse components was not toxic as measured by using an anaerobic toxicity assay.

Apart from conventional materials, the study of two-dimensional (2D) materials has emerged as a significant field of study for a variety of applications. Graphene-like 2D materials are important elements of potential optoelectronics applications due to their exceptional electronic and optical properties. The processing of these materials towards the realization of devices has been one of the main motivations for the recent development of photonics and optoelectronics. The recent progress in photonic devices based on graphene-like 2D materials, especially topological insulators (TIs) and transition metal dichalcogenides (TMDs) with the methodology level discussions from the viewpoint of state-of-the-art designs in device geometry and materials are detailed in this review. We have started the article with an overview of the electronic properties and continued by highlighting their linear and nonlinear optical properties. The production of TIs and TMDs by different methods is detailed. The following main applications focused towards device fabrication are elaborated: (1) photodetectors, (2) photovoltaic devices, (3) light-emitting devices, (4) flexible devices and (5) laser applications. The possibility of employing these 2D materials in different fields is also suggested based on their properties in the prospective part. This review will not only greatly complement the detailed knowledge of the device physics of these materials, but also provide contemporary perception for the researchers who wish to consider these materials for various applications by following the path of graphene.

The presence of a direct band gap and high carrier mobility in few-layer black phosphorus (BP) offers opportunities for using this material for infrared (IR) light detection. However, the poor air stability of BP and its large contact resistance with metals pose significant challenges to the fabrication of highly efficient IR photodetectors with long lifetimes. In this work, we demonstrate a graphene-BP heterostructure photodetector with ultrahigh responsivity and long-term stability at IR wavelengths. In our device architecture, the top layer of graphene functions not only as an encapsulation layer but also as a highly efficient transport layer. Under illumination, photoexcited electron-hole pairs generated in BP are separated and injected into graphene, significantly reducing the Schottky barrier between BP and the metal electrodes and leading to efficient photocurrent extraction. The graphene-BP heterostructure phototransistor exhibits a long-term photoresponse at near-infrared wavelength (1550 nm) with an ultrahigh photoresponsivity (up to 3.3 × 10 A W), a photoconductive gain (up to 1.13 × 10), and a rise time of about 4 ms. Considering the thickness-dependent band gap in BP, this material represents a powerful photodetection platform that is able to sustain high performance in the IR wavelength regime with potential applications in remote sensing, biological imaging, and environmental monitoring.

Neutrophil-mediated lung damage is an insidious feature in septic patients, although the adhesive mechanisms behind pulmonary recruitment of neutrophils in polymicrobial sepsis remain elusive. The aim of the present study was to define the role of lymphocyte function antigen-1 (LFA-1) and membrane-activated complex 1 (Mac-1) in septic lung injury. Pulmonary edema, bronchoalveolar infiltration of neutrophils, levels of myeloperoxidase, and CXC chemokines were determined after cecal ligation and puncture (CLP). Mice were treated with monoclonal antibodies directed against LFA-1 and Mac-1 before CLP induction. Cecal ligation and puncture induced clear-cut pulmonary damage characterized by edema formation, neutrophil infiltration, and increased levels of CXC chemokines in the lung. Notably, immunoneutralization of LFA-1 or Mac-1 decreased CLP-induced neutrophil recruitment in the bronchoalveolar space by more than 64%. Moreover, functional inhibition of LFA-1 and Mac-1 abolished CLP-induced lung damage and edema. However, formation of CXC chemokines in the lung was intact in mice pretreated with the anti-LFA-1 and anti-Mac-1 antibodies. Our data demonstrate that both LFA-1 and Mac-1 regulate pulmonary infiltration of neutrophils and lung edema associated with abdominal sepsis. Thus, these novel findings suggest that LFA-1 or Mac-1 may serve as targets to protect against lung injury in polymicrobial sepsis.