Ternary CuInS2 quantum dots (QDs) with photoluminescence that is tunable from the visible to the near‐infrared (NIR) region are promising light‐emitters for consumer electronics due to the absence of ...toxic elements such as Pb, Cd, or As. Despite the compelling performance of visible‐light‐emitting CuInS2 QDs, reports on NIR emission remain limited, with modest efficiencies at wavelengths beyond 900 nm. In this work, the facile synthesis of NIR‐emitting CuInS2/ZnS QDs is reported. A combination of two sulfur precursors w as used in the synthesis, comprising 1‐dodecanethiol (DDT) and hexamethyldisilathiane (HMDS). The reactive HMDS facilitates faster nucleation and leads to a higher density of emissive Cu‐deficiency sites. The resulting QDs exhibit high photoluminescence quantum efficiency (PLQE) of 65% at a long emission wavelength of 920 nm. Using these QDs, NIR light‐emitting diodes (LED) are fabricated, which attain an external quantum efficiency (EQE) of 8.2%. This efficiency is comparable to the best reported PbS and InAs QD LEDs, and the emission wavelength exceeds that of lead iodide perovskites. This work thus marks one of the first reports of efficient NIR LEDs based on environmentally benign CuInS2 QDs and may open up promising new applications in consumer electronic products.
The synthesis of CuInS2/ZnS quantum dots (QDs) with a high photoluminescence quantum efficiency (PLQE) of 65% at 920 nm is reported. Notably, the synthesis employs a supplementary S precursor, hexamethyldisilathiane (HMDS), which gives rise to better size homogeneity and an improvement in PLQE. Implementation of the QDs in a light‐emitting device gives an external quantum efficiency (EQE) of 8.2%.
The preparation of highly efficient perovskite nanocrystal light‐emitting diodes is shown. A new trimethylaluminum vapor‐based crosslinking method to render the nanocrystal films insoluble is ...applied. The resulting near‐complete nanocrystal film coverage, coupled with the natural confinement of injected charges within the perovskite crystals, facilitates electron–hole capture and give rise to a remarkable electroluminescence yield of 5.7%.
The performance of perovskite light-emitting diodes (PeLEDs) has progressed rapidly in recent years, with electroluminescence efficiency now reaching 20%1–12. However, devices, so far, have featured ...small areas and usually show notable variation in device-to-device performance. Here, we show that the origin of suboptimal device performance stems from inadequate hole injection, and that the use of a hole-transporting polymer with a shallower ionization potential can improve device charge balance, efficiency and reproducibility. Using an ITO/ZnO/PEIE/FAPbI3/poly-TPD/MoO3/Al device structure, we report a 799 nm near-infrared PeLED that operates with an external quantum efficiency (EQE) of 20.2%, at a current density of 57 mA cm−2 and a radiance of 57 W sr−1 m−2. The standard deviation in the device EQE is only 1.2%, demonstrating high reproducibility. Large-area devices measuring 900 mm2 operate with a high EQE of 12.1%, and are shown to suit medical applications such as subcutaneous deep-tissue illumination and heart rate monitoring.Near-infrared LEDs as large as 30 × 30 mm2 in size are fabricated on both rigid and flexible substrates.
Metal oxide nanoparticles (MeO-NPs) are among the most consumed NPs and also have wide applications in various areas which increased their release into the environmental system. Aquatic (water and ...sediments) and terrestrial compartments are predicted to be the destination of the released MeO-NPs. In these compartments, the particles are subjected to various dynamic processes such as physical, chemical and biological processes, and undergo transformations which drive them away from their pristine state. These transformation pathways can have strong implications for the fate, transport, persistence, bioavailability and toxic-effects of the NPs. In this critical review, we provide the state-of-the-knowledge on the transformation processes and bioavailability of MeO-NPs in the environment, which is the topic of interest to researchers. We also recommend future research directions in the area which will support future risk assessments by enhancing our knowledge of the transformation and bioavailability of MeO-NPs.
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•Current state-of-the-knowledge on the transformation and bioavailability of MeO-NPs in the environment has been provided.•Effects of MeO-NPs behavior on their transformations have been reviewed.•Role of the transformation processes on bioavailability of the NPs have been discussed.•Future research directions required to fill the existing research gaps have been provided.
Transformations of MeO-NPs depend on nature of the NPs themselves and chemistry of the medium, and can significantly affect their fate, bioavailability and toxic-effects.
Metal halide perovskites have demonstrated rich photophysics and remarkable potential in photovoltaic and electroluminescent devices. However, the photoactivity of perovskite semiconductors in ...chemical processes remains relatively unexplored. Here, a general approach toward the synthesis of luminescent perovskite–polymer nanocomposites is reported, whereby perovskite nanocrystals are used as photoinitiators in the polymerization of vinyl monomers. The white‐light illumination of a perovskite–monomer mixture triggers a free‐radical chain‐growth polymerization process, giving rise to high molecular weight polymers of ≈200 kDa. The in situ growth of polymer chains from the perovskite crystal surface allows the formation of individually dispersed nanocrystal cores within an encapsulating polymer matrix, and leads to a significant threefold enhancement in photoluminescence quantum yield. This photoluminescence enhancement is attributed to the spatial separation of the perovskite nanocrystals and hence the deactivation of energy transfer to dark crystals. The resulting perovskite–polymer nanocomposites exhibit excellent stability against moisture and are shown to be useful as functional downconversion phosphor films for luminescent displays and lighting.
A general synthesis of luminescent perovskite–polymer nanocomposites is reported, whereby perovskite nanocrystals are used as photoinitiators in the polymerization of vinyl monomers. The white‐light illumination of a perovskite–monomer mixture triggers free‐radical polymerization to give individually dispersed nanocrystals within an encapsulating polymer matrix. The nanocomposites exhibit enhanced photoluminescence quantum yield and excellent stability, and are useful as downconversion films for luminescent displays.
Microplastic pollution has exhibited a global distribution, including seas, lakes, rivers, and terrestrial environment in recent years. However, little attention was paid on the atmospheric ...environment, though the fact that plastic debris can escape as wind-blown debris was previously reported. Thus, characteristics of microplastics in the atmospheric fallout from Dongguan city were preliminarily studied. Microplastics of three different polymers, i.e., PE, PP, and PS, were identified. Diverse shapes of microplastics including fiber, foam, fragment, and film were found, and fiber was the dominant shape of the microplastics. SEM images illustrated that adhering particles, grooves, pits, fractures, and flakes were the common patterns of degradation. The concentrations of non-fibrous microplastics and fibers ranged from 175 to 313 particles/m
2
/day in the atmospheric fallout. Thus, dust emission and deposition between atmosphere, land surface, and aquatic environment were associated with the transportation of microplastics.
Acute kidney injury (AKI) with high incidence and mortality is the main cause of chronic kidney disease. Previous studies have indicated that quercetin, an abundant flavonoid in plants, exhibited ...renoprotective role in AKI. However, the underlying mechanism is largely unknown. In this study, we try to explore whether quercetin protects against AKI by inhibiting macrophage inflammation via regulation of Mincle/Syk/NF‐κB signaling. The results demonstrated that quercetin can significantly inhibit expression and secretion of IL‐1β, IL‐6, and TNF‐α in LPS‐induced bone marrow‐derived macrophages (BMDMs) and reduce activity of Mincle/Syk/NF‐κB signaling in vitro. We also found that quercetin can strongly reduce the concentration of serum creatinine, BUN, IL‐1β, IL‐6, and TNF‐α in cisplatin‐induced AKI model. Furthermore, quercetin down‐regulated protein levels of Mincle, phosphorylated Syk and NF‐κB in kidney macrophages of AKI, as well as inhibited M1, up‐regulated M2 macrophage activity. Notably, the down‐regulation of LPS‐induced inflammation by quercetin was reversed after adding TDB (an agonist of Mincle) in BMDMs, suggesting that quercetin suppresses macrophage inflammation may mainly through inhibiting Mincle and its downstream signaling. In summary, these findings clarified a new mechanism of quercetin improving AKI‐induced kidney inflammation and injury, which provides a new drug option for the clinical treatment of AKI.
Functional nanoscale structures consisting of a DNA molecule coupled to graphene or graphene oxide (GO) have great potential for applications in biosensors, biomedicine, nanotechnology, and materials ...science. Extensive studies using the most sophisticated experimental techniques and theoretical methods have still not clarified the dynamic process of single‐stranded DNA (ssDNA) adsorbed on GO surfaces. Based on a molecular dynamics simulation, this work shows that an ssDNA segment could be stably adsorbed on a GO surface through hydrogen bonding and π–π stacking interactions, with preferential binding to the oxidized rather than to the unoxidized region of the GO surface. The adsorption process shows a dynamic cooperation adsorption behavior; the ssDNA segment first captures the oxidized groups of the GO surface by hydrogen bonding interaction, and then the configuration relaxes to maximize the π–π stacking interactions between the aromatic rings of the nucleobases and those of the GO surface. We attributed this behavior to the faster forming hydrogen bonding interaction compared to π–π stacking; the π–π stacking interaction needs more relaxation time to regulate the configuration of the ssDNA segment to fit the aromatic rings on the GO surface.
DNA on graphene: With dynamic cooperation of hydrogen bonding and π stacking, we find that single‐stranded DNA (ssDNA) is stepwise adsorbed on graphene oxide (GO) using molecular dynamics simulations; the ssDNA segment first captures the oxidized groups of the GO surface by forming hydrogen bonds, then it forms π–π stacking interactions between the aromatic rings of the nucleobases and the GO surface. We attribute this behavior to the faster forming hydrogen bonding interaction compared to π–π stacking.
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