Intrinsically stretchable organic light‐emitting diodes (ISOLEDs) are becoming essential components of wearable electronics. However, the efficiencies of ISOLEDs have been highly inferior compared ...with their rigid counterparts, which is due to the lack of ideal stretchable electrode materials that can overcome the poor charge injection at 1D metallic nanowire/organic interfaces. Herein, highly efficient ISOLEDs that use graphene‐based 2D‐contact stretchable electrodes (TCSEs) that incorporate a graphene layer on top of embedded metallic nanowires are demonstrated. The graphene layer modifies the work function, promotes charge spreading, and impedes inward diffusion of oxygen and moisture. The work function (WF) of 3.57 eV is achieved by forming a strong interfacial dipole after deposition of a newly designed conjugated polyelectrolyte with crown ether and anionic sulfonate groups on TCSE; this is the lowest value ever reported among ISOLEDs, which overcomes the existing problem of very poor electron injection in ISOLEDs. Subsequent pressure‐controlled lamination yields a highly efficient fluorescent ISOLED with an unprecedently high current efficiency of 20.3 cd A−1, which even exceeds that of an otherwise‐identical rigid counterpart. Lastly, a 3 inch five‐by‐five passive matrix ISOLED is demonstrated using convex stretching. This work can provide a rational protocol for designing intrinsically stretchable high‐efficiency optoelectronic devices with favorable interfacial electronic structures.
A protocol to fabricate highly efficient organic light‐emitting diodes that use an intrinsically stretchable 2D‐contact electrode topped with graphene is reported. As a benefit of the fast carrier mobility with complete 2D contact with the organic material and the tunable work function of the 2D‐contact stretchable electro (TCSE), the limited charge injection of the widely used silver‐nanowire‐based stretchable electrode is solved.
Cost-effective, high-throughput industrial applications of metal halide perovskites in large-area displays are hampered by the fundamental difficulty of controlling the process of polycrystalline ...film formation from precursors, which results in the random growth of crystals, leading to non-uniform large grains and thus low electroluminescence efficiency in large-area perovskite light-emitting diodes (PeLEDs). Here we report that highly efficient large-area PeLEDs with high uniformity can be realized through the use of colloidal perovskite nanocrystals (PNCs), decoupling the crystallization of perovskites from film formation. PNCs were precrystallized and surrounded by organic ligands, and thus they were not affected by the film formation process, in which a simple modified bar-coating method facilitated the evaporation of residual solvent to provide uniform large-area films. PeLEDs incorporating the uniform bar-coated PNC films achieved an external quantum efficiency (EQE) of 23.26% for a pixel size of 4 mm
and an EQE of 22.5% for a large pixel area of 102 mm
with high reproducibility. This method provides a promising approach towards the development of large-scale industrial displays and solid-state lighting using perovskite emitters.
Fisetin, a well-known plant flavonol from the natural flavonoid group, is found in traditional medicines, plants, vegetables, and fruits. Fisetin also has anti-oxidant, anti-inflammatory, and ...anti-tumor effects. This study investigated the anti-inflammatory effects of fisetin in LPS-induced Raw264.7 cells and found that fisetin reduced the LPS-induced production of pro-inflammation markers, such as TNF-α, IL-1β, and IL-6, demonstrating the anti-inflammatory effects of fisetin. Furthermore, this study investigated the anti-cancer effects of fisetin and found that fisetin induced apoptotic cell death and ER stress through intracellular calcium (Ca
) release, the PERK-ATF4-CHOP signaling pathway, and induction of GRP78 exosomes. However, the suppression of PERK and CHOP inhibited the fisetin-induced cell death and ER stress. Interestingly, fisetin induced apoptotic cell death and ER stress and inhibited the epithelial-mesenchymal transition phenomenon under radiation in radiation-resistant liver cancer cells. These findings indicate that the fisetin-induced ER stress can overcome radioresistance and induce cell death in liver cancer cells following radiation. Therefore, the anti-inflammatory agent fisetin, in combination with radiation, may be a powerful immunotherapy strategy to overcome resistance in an inflammatory tumor microenvironment.
Saikosaponin A is a triterpene saponin and a potentially bioactive compound derived from
L. However, the molecular mechanisms and effects of saikosaponin A in gastric cancer remain unknown. In the ...present study, I evaluated the effects of saikosaponin A on cell death and endoplasmic reticulum stress via calcium and reactive oxygen species release. Targeting reactive oxygen species with diphenyleneiodonium and N-acetylcysteine inhibited cell death and protein kinase RNA-like ER kinase signaling pathway by down-regulating Nox4 and inducing glucose-regulated protein 78 exosomes. Furthermore, saikosaponin A caused a synergistic inhibitory effect of the epithelial mesenchymal transition phenomenon, indicating the reversible phenotype modulation by epithelial cells under radiation exposure in radiation-resistant gastric cancer cells. These results suggest that saikosaponin A-mediated calcium and reactive oxygen species-induced endoplasmic reticulum stress overcome radio-resistance and induce cell death under radiation in gastric cancer cells. Therefore, saikosaponin A in combination with radiation may be a potential strategy for gastric cancer therapy.
Solution‐processed small‐molecule organic light‐emitting diodes (OLEDs) are regarded as next‐generation flat‐panel displays and solid‐state lighting sources due to low material loss and a simple ...device fabrication process. However, they still suffer from low device efficiency and severe efficiency roll‐off. Here, molecular‐scale strategies are proposed to achieve highly efficient solution‐processed small‐molecule OLEDs with reduced efficiency roll‐off. By combining experiments with ab initio and molecular dynamics simulations, it is shown that an acetylacetonate group in a phosphorescent dopants lowers the dipole moment and molecular interaction energy of dopants, reducing dopant aggregation and increasing charge carrier transport. Furthermore, a charge‐balance assistant molecule is incorporated in the mixed‐host emitting layer to increase the balance of charge carrier transport and to broaden the exciton recombination zone in the center of the emitting layer. The resulting OLEDs have a current efficiency (CE) of 103.7 cd A−1, which is the highest yet reported in solution‐processed OLEDs, and low efficiency roll‐off (CE = 99.68 cd A−1 at a luminance LEL = 100 cd m−2, and CE = 75.00 cd A−1 at LEL = 1000 cd m−2) even with the simplified device architecture. It is expected that this strategy will advance the feasibility of commercialization of low‐cost high‐efficiency OLEDs.
Highly efficient solution‐processed organic light‐emitting diodes with low efficiency roll‐off are realized by using an aggregation‐free phosphorescent dopant and a charge‐balance assistant molecule. As a result, current efficiency of 103.7 cd A−1 is achieved, which is the highest yet reported in this type of device.
Introduction The decision to extract teeth for orthodontic treatment is important and difficult because it tends to be based on the practitioner's experiences. The purposes of this study were to ...construct an artificial intelligence expert system for the diagnosis of extractions using neural network machine learning and to evaluate the performance of this model. Methods The subjects included 156 patients. Input data consisted of 12 cephalometric variables and an additional 6 indexes. Output data consisted of 3 bits to divide the extraction patterns. Four neural network machine learning models for the diagnosis of extractions were constructed using a back-propagation algorithm and were evaluated. Results The success rates of the models were 93% for the diagnosis of extraction vs nonextraction and 84% for the detailed diagnosis of the extraction patterns. Conclusions This study suggests that artificial intelligence expert systems with neural network machine learning could be useful in orthodontics. Improved performance was achieved by components such as proper selection of the input data, appropriate organization of the modeling, and preferable generalization.
Graphene-based flexible electronic devices Han, Tae-Hee; Kim, Hobeom; Kwon, Sung-Joo ...
Materials science & engineering. R, Reports : a review journal,
August 2017, 2017-08-00, 20170801, Letnik:
118
Journal Article
Recenzirano
Display omitted
Flexible electronic devices fabricated on plastic substrate are more desirable than rigid counterparts for future displays, lightings, or solar cells. For flexible electronics to ...become practical, the indium-tin-oxide (ITO) electrode should be replaced due to its brittleness, increasing cost, and chemical instability. Graphene has emerged as a promising material for flexible transparent conducting electrodes because of its unique electronic and mechanical properties with high optical transmittance. Therefore, graphene has been widely used in flexible electronic devices including light-emitting diodes (LEDs), solar cells (SCs), and field-effect transistors (FETs). However, for practical applications of graphene in flexible electronics, its limitations should also be overcome. This review describes the use of graphene in LEDs, SCs and FETs, and various strategies to overcome the deficiencies of graphene to obtain highly-efficient and stable flexible electronics. Finally, we present future prospects and suggest further directions for research on graphene-based flexible electronic devices.
A versatile metal nanowiring platform enables the fabrication of Ag nanowires (AgNW) at a desired position and orientation in an individually controlled manner. A printed, flexible AgNW has a ...diameter of 695 nm, a resistivity of 5.7 μΩ cm, and good thermal stability in air. Based on an Ag nanowiring platform, an all‐NW transistors array, as well as various optoelectronic applications, are successfully demonstrated.
Organic–inorganic hybrid perovskite nanoparticles (NPs) are a very strong candidate emitter that can meet the high luminescence efficiency and high color standard of Rec.2020. However, the ...instability of perovskite NPs is the most critical unsolved problem that limits their practical application. Here, an extremely stable crosslinked perovskite NP (CPN) is reported that maintains high photoluminescence quantum yield for 1.5 years (>600 d) in air and in harsher liquid environments (e.g., in water, acid, or base solutions, and in various polar solvents), and for more than 100 d under 85 °C and 85% relative humidity without additional encapsulation. Unsaturated hydrocarbons in both the acid and base ligands of NPs are chemically crosslinked with a methacrylate‐functionalized matrix, which prevents decomposition of the perovskite crystals. Counterintuitively, water vapor permeating through the crosslinked matrix chemically passivates surface defects in the NPs and reduces nonradiative recombination. Green‐emitting and white‐emitting flexible large‐area displays are demonstrated, which are stable for >400 d in air and in water. The high stability of the CPN in water enables biocompatible cell proliferation which is usually impossible when toxic Pb elements are present. The stable materials design strategies provide a breakthrough toward commercialization of perovskite NPs in displays and bio‐related applications.
An extraordinarily long stability, exceeding 1.5 years, for crosslinked perovskite nanoparticles (NPs) under harsh environments, by a novel materials design strategy, is reported. Surprisingly, the photoluminescence of the perovskite NPs is significantly increased under air, moisture, and chemicals, overcoming their instability in oxygen, water, and polar chemicals.
The purpose of this study was to investigate the topographic relationship between the decreased parapapillary retinal microvasculature as assessed by optical coherence tomography angiography (OCTA) ...and retinal nerve fiber layer (RNFL) defect in eyes with primary open-angle glaucoma (POAG) and a localized RNFL defect.
The peripapillary retinal circulation was evaluated using the OCTA centered on the optic nerve head in 98 POAG eyes having a localized RNFL defect and 45 healthy control eyes. A vascular impairment (VI) was identified in OCTA by the presence of a sign indicating decreased microvasculature. The frequencies of VI were compared between the POAG and control groups, and the topographic correlation between the VI and the RNFL defect identified in red-free fundus photographs was determined in the POAG group.
The VI was observed as an area of decreased density of the microvascular network of the retina in 100% of the POAG eyes. The VI exactly coincided with the RNFL defect evident in red-free fundus photographs in terms of both the location and extent (Pearson's correlation coefficient = 0.997 and 0.988, respectively, all P < 0.001). None of the control eyes exhibited VI in OCTA.
Decreased parapapillary microvasculature of the retina determined by OCTA was found at the location of RNFL defect in POAG patients. This finding suggests that the decreased retinal microvasculature is likely secondary loss or closure of capillaries at the area of glaucomatous RNFL atrophy.
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