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Inverted top-emitting organic light-emitting devices (TEOLEDs) have great potential in flat-panel displays and lighting, yet poor electron injection is a key issue limiting its use in active-matrix OLED. Here, a high-performance green phosphorescent inverted TEOLEDs with ZnO and ZnS double electron injection layers (EILs) were demonstrated. The double EILs which provide a work function gradient can greatly enhance the electron-injection efficiency. For the green phosphorescent TEOLED device based on this double EILs, a high current efficiency of 33.1 cd A−1 is achieved with low turn-on voltage of 4.0 V. Results indicate that a novel pathway of electron transport to accelerate electron injection is created by applying this double EILs.

The development of white organic light-emitting diodes (WOLEDs) holds great promise for the production of high-color-quality lighting sources. High quantum efficiencies for the conversion of electrical energy to light have been realized. The color stability and color-rendering index (CRI) become bottleneck for the commercial application of WOLEDs. Here, we employed a metal-free dimerization of 1‑phenyl‑3,5‑diamine‑triazine (DPDT) as a single non-doped emitter in WOLEDs, that exhibits mild efficiency roll-off while maintaining CRI of 92. This high CRI is attributable to the DPDT with efficient monomer and excimer emission, which together emit a relatively wide spectrum that nearly covers the entire range of visible light. The formation of the excimer can make the emission color of single-emitter based WOLEDs tunable with the applied bias over a wide range from blue to pure white.

Summary The design of blue fluorescent materials combining both deep-blue emission (CIEy, Graphical Abstract, Highlights • Highly efficient deep-blue luminogens BBPA and DMPA are synthesized • Low-efficiency roll-off deep-blue OLEDs with CIE coordinate Y < 0.06 • Record-high external quantum efficiency of 10.27% for deep-blue fluorescent OLEDs • Host matrix of twisted structure showing steric effect reduces intermolecular aggregation, Materials Science; Polymers; Optical Materials

Botrytis cinerea is the causative agent of a common and serious disease, gray mold of tomato, which can infect the flower, fruit, leaf, and stem tissues. The occurrence of gray mold account for dramatic decrease of tomato yield, threatening the food security, with rarely effective biocontrol approach. In this study, we isolated 56 bacterial strains from tomato rhizosphere, with 7 strains among which had great control effect against B. cinerea. Among the 7 identified strains, Pantoea jilinensis D25 which had the strongest inhibitory effect, was a new strain. Further we found that P. jilinensis D25 can inhibit the mycelial growth and spore production of B. cinerea, with alterations of the mycelial morphology of B. cinerea. The highest growth inhibition (83.1%) of B. cinerea occurred upon the exposure to a concentration of 5.0×105 cfu/mL of P. jilinensis D25, at pH 6 and 25 °C. The inhibitory effect against B. cinerea by P. jilinensis D25 was further validated with inoculation assay on tomato leaf tissues and tomato seedlings. The results demonstrated that P. jilinensis D25 strain from soils of tomato growing areas is a new and effective biocontrol agent against notorious tomato gray mold disease.

International audience; Flexible 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.

Blue organic light-emitting diodes (OLEDs) play an important role in OLED display and lighting applications, but short lifetime and low efficiency are still their two key issues in the commercialization. Here, we manage to address the two issues at the same time by simply inserting an ultrathin aluminum (Al) interlayer between the indium tin oxide (ITO) cathode and the electron injection layer of an inverted pure blue OLED. Current efficiency (CE) and external quantum efficiency were improved by optimizing the thickness of the Al interlayer. It has been approved from current-voltage characteristics, impedance spectra and an ultraviolet photoelectron spectrum that 1 nm thick Al interlayer is an effective work function modifier for the ITO cathode and can help to enhance electron injection from the ITO cathode to the electron transporting layer. The Al interlayer contributed also to extend dramatically the lifetime of the inverted pure blue OLED. A long operation lifetime (T80 > 83 h) with the maximum CE of 7.9 cd A−1 was achieved after adding 1 nm Al interlayer.

The electron extraction layer (EEL) plays a pivotal role in realizing high performance organic photovoltaics (OPVs). In this work, we report the effort to develop high-efficiency inverted OPVs with solution-processed ZnO/MoS2 quantum dots (QDs) EEL. The employ of MoS2 QDs helps to suppress the exciton quenching by passivating the ZnO surface defects. It is shown that ZnO/MoS2 EEL enables promoted electron extraction and suppressed charge recombination properties. A blend of poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) was applied as the active layer. The ZnO/MoS2-based OPVs demonstrate superior photovoltaic performance with a champion power conversion efficiency (PCE) of 3.83%, which is >17.5% higher than that of the pristine ZnO-based device (~3.26%). It is shown that the use of a blend ZnO/MoS2 QDs EEL offers an effective approach to obtain high performance optoelectronic devices.

Nano-silica was introduced to enhance the mechanical strength of polymer hydrogels obtained via the crosslinking of polyacrylamide (PAM) and chromium acetate. Rheological properties, compression strength and compressive stress–strain of both nanocomposite and normal hydrogels without nano-silica were investigated by HAKKE rheometer, compression strength test device and electronic universal material testing machine. Moreover, environmental scanning electronic microscopic (ESEM) was adopted to observe the three-dimension network structure of nanocomposite and normal hydrogel, as well as the distribution of nano-silica. The results demonstrated that elastic moduli (G′) and viscous moduli (G″) of nanocomposite hydrogel were both improved with increasing nano-silica concentration. Especially when silica content reached 10 wt%, G′ and G″ of nanocomposite hydrogel increased over one hundred times higher than those of normal hydrogel. The original compression strength of hydrogel was 70.8 kPa m−1, while the resulting strength of nanocomposite was enhanced to be 196.64 kPa m−1. When the hydrogel were sheared, the normal hydrogel was fractured under low strain, whereas nanocomposite hydrogel was not broken under high strain, and it quickly recovered its original shape after the release of load. In addition, the ESEM images indicated that a large quantity of silica particles aggregated and attached around the polymer chains, and others aggregated to fill into the three-dimension network of hydrogel, which induced the compaction of the space between the network layers and reduced the flowing of free water wrapped in the network, therefore the mechanical strength of hydrogel was enhanced.

Urchin-shaped Nb 2 O 5 microspheres have been synthesized through the facile hydrothermal method. Nb 2 O 5 microspheres, wrapped tightly by filaments about 10 nm in diameter and 1.5 μm in length, are about 0.8 μm in diameter. The initial discharge and charge capacities for Nb 2 O 5 microspheres are 480.43 mA h g −1 and 406.80 mA h g −1 at 50 mA g −1 , meanwhile it exhibits the capacity retention of 390.0 mA h g −1 after 200 cycles. The urchin-shaped Nb 2 O 5 microspheres are a potential anode material for lithium ion batteries.

We consider a risk sharing problem in which agents pool their random costs together and seek an allocation rule to redistribute the risk back to each agent. The problem is put into a cooperative game framework and we focus on two salient properties of an allocation rule: stability and monotonicity employing concepts of core and population monotonicity from cooperative game theory. When the risks of the agents are measured by coherent risk measures, we construct a risk allocation rule based on duality theory and establish its stability. When restricting the risk measures to the class of distortion risk measures, the duality-based risk allocation rule is population monotonic if the random costs are independent and log-concave. For the case with dependent normally distributed random costs, a simple condition on the dependence structure is identified to ensure the monotonicity property.