Efficient Organic Light Emitting Diodes Using Solution-Processed Alkali Metal Carbonate Doped ZnO as Electron Injection Layer

In this study, we demonstrate highly efficient, inverted organic light-emitting diodes (IOLEDs) using solution-processed alkali metal carbonate doped ZnO as an electron injection layer (EIL) and tris-(8-hydroxyquinoline) aluminum (Alq3) as an emitter layer. In order to enhance the electron injection efficiency of the IOLEDs, the ZnO EIL layers were modified by doping various alkali metal carbonate materials, including Li2CO3, Na2CO3, K2CO3, and Cs2CO3, using the low-temperature wet-chemical method. Compared to the control neat ZnO EIL-based IOLEDs, the alkali metal carbonate doped ZnO EIL-based IOLEDs possess obviously improved device performance. An optimal current efficiency of 6.04 cd A−1 were realized from the K2CO3 doped ZnO EIL based IOLED, which is 54% improved compared to that of the neat ZnO EIL based device. The enhancement is ascribed to the increased electron mobility and reduced barrier height for more efficient electron injection. Our results indicate that alkali metal carbonate doped ZnO has promising potential for application in highly efficient solution-processed OLEDs

Bottom-up Solution Synthesis of Graphene Nanoribbons with Precisely Engineered Nanopores

The incorporation of nanopores into graphene nanostructures has been demonstrated as an efficient tool in tuning their band gaps and electronic structures. However, precisely embedding the uniform nanopores into graphene nanoribbons (GNRs) at the atomic level remains underdeveloped especially for in-solution synthesis due to the lack of efficient synthetic strategies. Herein we report the first case of solution-synthesized porous GNR (pGNR) with a fully conjugated backbone via the efficient Scholl reaction of tailor-made polyphenylene precursor (P1) bearing pre-installed hexagonal nanopores. The resultant pGNR features periodic subnanometer pores with a uniform diameter of 0.6 nm and an adjacent-pores-distance of 1.7 nm. To solidify our design strategy, two porous model compounds (1 a, 1 b) containing the same pore size as the shortcuts of pGNR, are successfully synthesized. The chemical structure and photophysical properties of pGNR are investigated by various spectroscopic analyses. Notably, the embedded periodic nanopores largely reduce the π-conjugation degree and alleviate the inter-ribbon π–π interactions, compared to the nonporous GNRs with similar widths, affording pGNR with a notably enlarged band gap and enhanced liquid-phase processability

Image-based onsite object recognition for automatic crane lifting tasks

The construction industry is suffering from aging workers and frequent accidents, as well as low productivity. Automation and robotics is regarded as a promising approach for enhancing the development of the industry, and the automatic operation of cranes, as an important aspect of construction, is attracting increasing attention. However, due to the complexity and dynamics of construction sites, it is difficult for cranes to automatically recognize and locate lifting objects (e.g., precast facades and partitions) on site. To solve this problem, an image-based automated onsite object recognition approach for the automatic operation of cranes is developed in this study. This is a fusion of Faster-R-CNN (Region-based Convolutional Neural Network), Canny, Hough Transformation, Endpoint clustering analysis and Vertex-based Determining Model, to uniquely locate a lifting object with exact pose and extract its features (e.g., centroid coordinates, size, and color). Based on the extracted features, the lifting object can be retrieved in the database with the IFC (Industry Foundation Classes) format of BIM (Building Information Modeling) to obtain more features for the automatic operation of a crane. It is shown from a field experiment that the developed approach is workable and has the potential to support the automatic operation of cranes. This contributes a basic approach to the automatic operation of cranes and promotes the rapid development of construction automation and robotics.</p

High-Performance White Organic Light-Emitting Diodes Using Distributed Bragg Reflector by Atomic Layer Deposition

White organic light-emitting diodes (WOLEDs) with higher performance, which have enjoyed application in high-quality lighting sources, are here demonstrated with improved optical and electrical properties. The integration of a novel transparent distributed Bragg reflector (DBR), which consists of periodically alternating layers of atomic layer deposition-fabricated ZrO2/Zircone films and sputtered tin-doped indium oxide into OLEDs microcavities were studied to obtain four-peak electroluminescence (EL) spectra. Three types of OLEDs with two-peak, three-peak, and four-peak EL spectra have been developed. The results of the two-peak spectra show that the DBR structures have an outstanding effect on carrier capture; as a result, the device exhibits a stronger stability in color at various applied voltages. The Commission Internationale de L&#8217;Eclairage (CIE) coordinates of the two-peak device at 5&#8211;13 V shows few displacements and a negligible slight variation of (&#177;0.01, &#177;0.01). In addition, the four-peak WOLED also yields a high color purity white emission as the luminance changes from 100 cd m&#8722;2 to 10,000 cd m&#8722;2

Enhanced Performance of Flexible Organic Photovoltaics Based on MoS₂ Micro-Nano Array

In this work, we investigated the influence of MoS2 functioning as an electron transport layer (ETL) on the inverted flexible organic photovoltaics (FOPVs). Three ETLs, including MoS2, lithium quinolate (Liq), and a MoS2/Liq bilayer, were evaporated onto ITO-integrated polyethylene terephthalate substrates (PET-ITO), and the properties of transmittance, water contact angle, and reflectivity of the films were analyzed. The results revealed that MoS2 was helpful to improve the lipophilicity of the surface of the ETL, which was conducive to the deposition of the active layer. In addition, the reflectivity of MoS2 to the light ranging from 400 to 600 nm was the largest among the pristine PET-ITO substrate and the PET-ITO coated with three ETLs, which promoted the efficient use of the light. The efficiency of the FOPV with MoS2/Liq ETL was 73% higher than that of the pristine device. This was attributed to the nearly two-fold amplification of the MoS2 array to the light field, which promoted the FOPV to absorb more light. Moreover, the efficiency of the FOPV with MoS2 was maintained under different illumination angles and bending angles. The results demonstrate the promising applications of MoS2 in the fabrication of FOPVs

Atractylodin alleviates nonalcoholic fatty liver disease by regulating Nrf2-mediated ferroptosis

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Oxidative stress is one of the main inducers of NAFLD. Atractylodin (ART), a major active ingredient of Atractylodes lancea, possesses potential antioxidant and anti-inflammatory activity in many types of disease. In the current study, the underlying mechanism by which ART alleviates the progression of NAFLD was explored. The function of ART in facilitating NAFLD was investigated in vitro and in vivo. Functionally, ART attenuated high-fat diet (HFD)-induced NAFLD in mice and palmitic acid (PA)-induced oxidative stress in HepG2 cells. Furthermore, our data verified that ART attenuated HFD-induced NAFLD by inhibiting ferroptosis of hepatocyte cells, as evidenced by decreased Fe2+ concentration, reactive oxygen species (ROS) level, malondialdehyde (MDA) content, and increased glutathione (GSH) content. The protective effect of ART on the cell viability of hepatocytes was blocked by a specific ferroptosis inhibitor (ferrostatin-1). Mechanistically, ART treatment promoted the translocation of nuclear factor erythroid 2-related Factor 2 (NFE2L2/NRF2) and thus increased glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), and solute carrier family 7 member 11 (SLC7A11) expression. Taken together, ART alleviates NAFLD by regulating Nrf2-mediated ferroptosis

Mechanically and thermally stable, transparent electrodes with silver nanowires encapsulated by atomic layer deposited aluminium oxide for organic optoelectronic devices

International audienceFlexible conductive electrodes are essential components for organic optoelectronic devices (OODs). One of the main challenges in the development of flexible OODs is to achieve an optimal combination of photoelectrical properties, enhanced flexibility and stability in transparent conductive electrodes (TCEs). In this work, high-performance flexible nonfullerene organic solar cells (OSCs) and polymer light-emitting diodes (PLEDs) based on TCEs of silver nanowires (AgNWs) encapsulated with an ultra-thin atomic layer deposited aluminum oxide (Al 2 O 3) have been demonstrated. The hybrid AgNWs/Al 2 O 3 composite electrodes with enhanced thermal, ambient and mechanical stabilities enable an efficient flexible transparent electrode with high transmittance and conductivity, which can synergistically optimize the device performance of nonfullerene OSCs and PLEDs. The maximum power conversion efficiency value of 7.03%, as well as a current efficiency of 7.26 cd A À 1 for flexible OSCs and PLEDs are achieved, respectively. Notably, excellent flexibility, long-term atmospheric and thermal stabilities have been systematically investigated and demonstrated. These results provide a new design platform for the fabrication of high-performance, flexible transparent electrodes, which can be further explored in a wide range of organic optoelectronics field