Solution-Processable Graphene Oxide as an Efficient Hole Injection Layer for High Luminance Organic Light-Emitting Diodes

The application of solution-processable graphene oxide (GO) as hole injection layer in organic light-emitting diodes (OLEDs) is demonstrated. High luminance of over 53,000 cd m-2 is obtained at only 10 V. The results will unlock a route of applying GO in flexible OLEDs and other electrode applications.Comment: 14 pages, 3 figures, 1 tabl

Geotechnical properties of sewage sludge solidified with Sulphoaluminate cement

The geotechnical properties of sewage sludge solidified with sulphoaluminate cement are presented. The sludge has a high water content and organic matter which is not easy to disposal. After Solidification/Stabilization (S/S), landfill disposal of sewage sludge is widely adopted in China. However, there is little research focused on the geotechnical properties of sewage sludge after S/S treatment and the impact on the landfill site is also difficult to be evaluated. To solve this problem, this paper is aimed to evaluate the basic mechanics properties of solidified materials by means of Atterberg limit, triaxial test, consolidation test and permeability test. The result showed that the strength and the hydraulic conductivity of the modified sludge was close to that of the high organic soil. By adding suitable additives, modified sludge could not only satisfy the requirement of being landfilled but also be utilized as a construction material

The influence of nutrient management on soil organic carbon storage, crop production, and yield stability varies under different climates

Acknowledgements Present study was conducted with the support of German-Chinese cooperation on agriculture and climate change (CHN-19-02) and Coordination of International Research Cooperation on Soil Carbon Sequestration in Agriculture (CIRCASA 774378).Peer reviewedPostprin

Observation of integer and fractional quantum anomalous Hall states in twisted bilayer MoTe2

The interplay between strong correlations and topology can lead to the emergence of intriguing quantum states of matter. One well-known example is the fractional quantum Hall effect, where exotic electron fluids with fractionally charged excitations form in partially filled Landau levels. The emergence of topological moir\'e flat bands provides exciting opportunities to realize the lattice analogs of both the integer and fractional quantum Hall states without the need for an external magnetic field. These states are known as the integer and fractional quantum anomalous Hall (IQAH and FQAH) states. Here, we present direct transport evidence of the existence of both IQAH and FQAH states in twisted bilayer MoTe2 (AA stacked). At zero magnetic field, we observe well-quantized Hall resistance of h/e2 around moir\'e filling factor {\nu} = -1 (corresponding to one hole per moir\'e unit cell), and nearly-quantized Hall resistance of 3h/2e2 around {\nu} = -2/3, respectively. Concomitantly, the longitudinal resistance exhibits distinct minima around {\nu} = -1 and -2/3. The application of an electric field induces topological quantum phase transition from the IQAH state to a charge transfer insulator at {\nu} = -1, and from the FQAH state to a generalized Wigner crystal state, further transitioning to a metallic state at {\nu} = -2/3. Our study paves the way for the investigation of fractionally charged excitations and anyonic statistics at zero magnetic field based on semiconductor moir\'e materials

Characterization of deep sub-wavelength nanowells by imaging the photon state scattering spectra

Optical-matter interactions and photon scattering in a sub-wavelength space are of great interest in many applications, such as nanopore-based gene sequencing and molecule characterization. Previous studies show that spatial distribution features of the scattering photon states are highly sensitive to the dielectric and structural properties of the nanopore array and matter contained on or within them, as a result of the complex optical-matter interaction in a confined system. In this paper, we report a method for shape characterization of subwavelength nanowells using photon state spatial distribution spectra in the scattering near field. Far-field parametric images of the near-field optical scattering from sub-wavelength nanowell arrays on a SiN substrate were obtained experimentally. Finite-difference time-domain simulations were used to interpret the experimental results. The rich features of the parametric images originating from the interaction of the photons and the nanowells were analyzed to recover the size of the nanowells. Experiments on nanoholes modified with Shp2 proteins were also performed. Results show that the scattering distribution of modified nanoholes exhibits significant differences compared to empty nanoholes. This work highlights the potential of utilizing the photon status scattering of nanowells for molecular characterization or other virus detection applications

Energy level alignment and interactive spin polarization at organic/ferromagnetic metal interfaces for organic spintronics

Energy level alignment and spin polarization at tetracyanoquinodimethane/Fe and acridine orange base/Fe interfaces are investigated by means of photoelectron spectroscopy and X-ray magnetic circular dichroism (XMCD), respectively, to explore their potential application in organic spintronics. Interface dipoles are observed at both hybrid interfaces, and the work function of Fe is increased by 0.7 eV for the tetracyanoquinodimethane (TCNQ) case, while it is decreased by 1.2 eV for the acridine orange base (AOB) case. According to XMCD results, TCNQ molecule has little influence on the spin polarization of Fe surface. In contrast, AOB molecule reduces the interfacial spin polarization of Fe significantly. Induced spin polarization of the two organic molecules at the interfaces is not observed. The results reveal the necessity of investigating the magnetic property changes of both the OSC and the FM during the process of energy level alignment engineering.EU-project NMP3-SL-2011-263104-HINTSSwedish Research Council (VR) Grant 2011-730

A simplified method for optimal design of solar water heating systems based on life-cycle energy analysis

Significant energy mismatch exists in solar water heating systems as the time and amount of solar energy supply are usually different from that of hot water demand. Using a hot water storage tank can reduce or eliminate such mismatch in short term while it is difficult to avoid this mismatch in long term. In many optimal design and life-cycle analysis methods, the energy mismatch is ignored which causes the system performance to be overestimated and also misleads the optimal design of the system. This paper presents a simplified method for optimizing the key parameters of solar water heating systems based on life-cycle energy analysis. This optimal method considering the energy mismatch phenomenon can be implemented through two steps. In the first step, a simplified energy model based hourly energy matching different components of the system, is developed for determining the operating performance of system with different solar collector areas and water storage volumes. In the second step, the law of diminishing marginal utility is employed to determine the optimum size of the system. The optimum size is identified when the maximal life-cycle net energy saving is achieved. A case study on the application of the proposed method in a building is presented as well