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Models for bathymetry retrieval from multispectral images have not considered the errors caused by tidal fluctuation. A rigorous bathymetric model that considers the variation in tide height time series, including the tide height calculation and instantaneous tide height correction at the epoch of satellite flight into the bathymetric retrieval model, is proposed in this paper. The model was applied on Weizhou Island, located in Guangxi Province, China, and its accuracy verificated with four check lines and seven checkpoints. A scene from the Landsat 8 satellite image was used as experimental data. The reference ("true") water depth data collected by a RESON SeaBat 7125 multibeam instrument was used for comparison analysis. When satellite-derived bathymetry is compared, it is found that maximum absolute error, mean absolute error, and RMSE have decreased 54, 45, and 30% relative to that of the traditional model in the entire test field. The accuracy of the water depths retrieved by our model increased 30 and 56% when validated using four check lines and seven checkpoints, respectively. Therefore, it can be concluded that the model proposed in this paper can effectively improve the accuracy of bathymetry retrieved from Landsat 8 images. [ABSTRACT FROM AUTHOR]

Thin-film transistors (TFTs) based on amorphous Indium-Gallium-Zinc Oxide (a-IGZO) can be used to drive the quantum-dot light-emitting diodes (QLEDs) for active-matrix (AM) displays. To reduce the fabrication complexity, Al reaction-induced conductive a-IGZO is developed as a common electrode, which simultaneously serves as a drain electrode for the TFT and as a bottom electrode for the QLED. The obtained a-IGZO electrode exhibits a low sheet resistance of 120 $\Omega $ / and a high transmittance of 92.1% at a thickness of 100 nm. With the proposed a-IGZO electrode, QLED demonstrates a high external quantum efficiency of 26%. Moreover, because both TFT and QLED share the same a-IGZO electrode, at least two patterning processes can be reduced in making a AM display. Our results suggest that Al reaction-induced conductive a-IGZO could be a promising pixel electrode for AMQLED displays. [ABSTRACT FROM AUTHOR]

Under a self-heating stress (SHS), amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) would exhibit a severe hump in the transfer characteristics. A model based on state transformation of oxygen vacancies is proposed to explain this phenomenon. The channel region of TFT is considerably self-heated if a large current flows through due to the poor thermal conductivity of a-IGZO. The temperature in the channel region can be raised with the high-power SHS so high that the oxygen vacancies there perform a state transformation from deep-donors and/or traps to shallow-donors, making the carrier concentration increase remarkably in the a-IGZO channel layer. The temperature is highest in the center of channel region and thus the state transformation takes place there first, leading to the carrier concentration increasing there first. As a result, the TFT has a lower turn-on voltage in the central channel region than in the rest, bringing finally about the hump in the transfer curves. The model is well verified by annealing the a-IGZO, which shows that the carrier concentration surely increases greatly when the annealing temperature is over 300 °C. [ABSTRACT FROM AUTHOR]

The influence of H2O and O2 on the performances of Mg-doped zinc oxide (ZnMgO) and ZnMgO-based inverted quantum-dot light-emitting diodes (QLEDs) are studied. With the involvement of H2O from ambience, ZnMgO exhibits a high conductivity, whereas the resultant QLEDs show a low efficiency. The efficiency of QLEDs can be enhanced by annealing ZnMgO in H2O-free glovebox; however, the uniformity and the current of the devices are degraded due to the presence of O2, which adsorbs on the surface of ZnMgO and captures the free electrons of ZnMgO. By exposing the devices with ultraviolet (UV) irradiation, the adsorbed O2 can be released, consequently leading to the increase of driving current. Our work discloses the influence of the annealing ambience on the conductivity of ZnMgO, and reveals the interaction of H2O/O2 and UV with the ZnMgO and its effect on the performance of the resultant inverted QLEDs, which could help the community to better understand the mechanisms of ZnMgO-based QLEDs. [ABSTRACT FROM AUTHOR]

In this paper, a 0.47 inch active‐matrix microdisplay with top‐emitting monochromatic quantum dot light‐emitting diode (QLED) array on silicon is demonstrated. A titanium nitride (TiN) is employed as the anode and the devices are fabricated by all‐solution process. The driver chip is designed especially for QLED microdisplay. The demonstrated microdisplay exhibits a maximum brightness of 267 cd/m2 and a gray level of 256. [ABSTRACT FROM AUTHOR]

Abstract: The performance of the blue quantum dot light‐emitting diodes (QLEDs) is largely affected by the hole transport layers (HTLs). As a consequence of the deep valance band level of blue quantum dots (QDs), hole injection is relatively difficult in blue QLEDs. To favor the hole injection, HTLs with high hole mobility and deep‐lying highest occupied molecular orbital level are desired. In this work, various HTLs and their influence on the performance of blue QLEDs are demonstrated. Devices with poly(N‐vinylcarbazole) (PVK) HTL exhibit the highest external quantum efficiency while devices with poly[9,9‐dioctylfluorene‐co‐N‐(4‐(3‐methylpropyl))‐diphenylamine] (TFB) exhibit the lowest driving voltage. By combining the advantages of PVK and TFB, the blue QLEDs with TFB/PVK bilayered HTL simultaneously exhibit a low driving voltage of 2.6 V and a high external quantum efficiency of 5.9%. Moreover, the exciplex emission at the interface of HTL/QDs is also observed, and the emission intensity can be tuned by modulating the hole injection. By utilizing PVK doped with 25% poly(3‐hexylthiophene) (P3HT) as HTL, exciplex emission is significantly enhanced at low driving voltage while QD emission is dominant at high driving voltage. By combining the exciplex emission and the QD emission, the emission color can be effectively tuned from red to blue as the driving voltage changing from 2 to 10 V. [ABSTRACT FROM AUTHOR]

Flexible quantum dotlight‐emitting diodes (QLEDs) are demonstrated by using hot‐pressing AgNWs as the transparent conductive electrode and EGaIn as the back electrode. Both AgNWs and EGaIn are printable, and thus the whole device can be fabricated via vacuum‐free processes. The hot‐pressing AgNWs electrode exhibits excellent physical characteristics such as high transparency of 96.7% in the visible spectral region, and low sheet resistance of 28 Ω/sq. With the AgNWs and EGaIn, vacuum‐free‐fabricated QLEDs are successfully achieved with efficiency 13.2cd/A. Because of the elimination of the costly vacuum processes, the proposed fabrication processes are low cost and allow rapid fabrication of flexible QLEDs with high performance. [ABSTRACT FROM AUTHOR]

Liquid metals based on eutectic gallium–indium (EGaIn) alloys are promising printable electrode materials for various printed devices such as light-emitting diodes or solar cells. To achieve a controllable and fine patterning of the EGaIn electrodes, herein, a facile bottom-up, additive technique has been developed by manipulating wetting/dewetting of the substrate. The substrate is first dewetted by coating a hydrophobic layer; then, to selectively dewet the substrate, the coated hydrophobic layer is patterned by laser ablation. EGaIn, which is painted onto the substrate, can only adhere to the wetting regions and thus can perfectly copy the patterns of the wetting regions. Via this method, high-resolution EGaIn patterns with a line width smaller than 100 μm can be obtained. Using the patterned EGaIn electrodes, all-printed quantum dot light-emitting diodes were successfully demonstrated. The proposed method offers a feasible route for fast patterning of EGaIn and thus allows for inexpensive, rapid fabrication of various devices without the need of costly vacuum processing. [ABSTRACT FROM AUTHOR]

We demonstrate a rechargeable zinc-ion battery with high energy density and cyclability using MnO2 and reduced graphene oxide (MnO2/rGO) electrode. The flexible and binder free electrode, with high MnO2 mass ratio (80 wt% of MnO2), is fabricated using vacuum filtration without any additional additives other than rGO. Compared to batteries with conventional MnO2 electrodes, the Zn–MnO2/rGO battery shows a significant enhanced capacity (332.2 mAh g-1 at 0.3 A g-1), improved rate capability (172.3 mAh g-1 at 6 A g-1) and cyclability. The capacity retention remains 96% after 500 charge/discharge cycles at 6 A g-1. The high MnO2 mass ratio makes MnO2/rGO electrode advantageous when the capacity is normalized to the whole electrode, particularly at high rates. The calculated gravimetric energy density of Zn–MnO2/rGO battery is 33.17 W h kg-1, which is comparable to the existing commercial lead-acid batteries (30–40 W h kg-1). Furthermore, the discharge profile and capacity of our Zn–MnO2/rGO battery shows no deterioration during bending test, indicating good flexibility. As a result, zinc-ion battery is believed to be a promising technology for powering next generation flexible electronics. Zinc-ion batteries: a carbon based promoter Simple carbon materials are shown to modify the MnO2 electrodes and greatly enhance the capacity and cyclability for zinc-ion batteries. An international team led by Prof Hang Zhou from Peking University Shenzhen Graduate School, China developed high performance flexible zinc-ion batteries with MnO2 and reduced graphene-oxide composites as the electrodes. The electrodes are prepared by vacuum filtering the suspension of the mixture of reduced graphene oxide and hydrothermal synthesized MnO2 nanosheets. The incorporation of reduced graphene oxide not only enhances the battery capacity by improving the conductivity and increasing the specific surface area, but also reduces the production cost by saving the trouble to use other binders or additives. Due to above advantages, this approach is competitive for wearable energy storage devices. [ABSTRACT FROM AUTHOR]

Five deep blue carbene-based iridium(III) phosphors were synthesized and characterized. Interestingly, one of them can be fabricated into deep blue, sky blue and white organic light-emitting diodes (OLEDs) through changing the host materials and exciton blocking layers. These deep and sky blue devices exhibit Commission Internationale de l'Éclairage (CIE) coordinates of (0.145, 0.186) and (0.152, 0.277) with external quantum efficiency (EQE) of 15.2% and 9.6%, respectively. The EQE of the deep blue device can be further improved up to 19.0% by choosing a host with suitable energy level of its lowest unoccupied molecular orbital (LUMO).