The electronic structure of C60/ZnPc interface for organic photovoltaic device with blended layer architecture

The interfacial electronic structures of fullerene (C-60)/zinc-phthalocyanine (ZnPc) and C-60/ZnPc:C-60 (50 wt %) containing a blended layer were investigated by in situ ultraviolet photoelectron spectroscopy (UPS), in an attempt to understand the role of the blended layer in improving the performance of organic photovoltaic devices that contain such layers. From the UPS spectra, the band bending found to be 0.30 eV in the ZnPc layer and 0.43 eV in the C-60 layer at the C-60/ZnPc interface. On the other hand, the band bending was 0.25 eV in both of the organic layers at the ZnPc:C-60/ZnPc interface and no significant band bending in the C-60 layer at the C-60/ZnPc:C-60 interface was found. The observed interface dipole was 0.06 eV at the C-60/ZnPc interface and 0.26 eV at the ZnPc:C-60/ZnPc interface. The offset between the highest unoccupied molecular orbital of ZnPc and the lowest occupied molecular orbital of C-60 was 0.75 eV at C-60/ZnPc and was 1.04 eV at the ZnPc:C-60/ZnPc interface. The increased offset can be attributed to an increase in the interface dipole, caused by the blending donor and acceptor material. The blending facilitates charge transfer between the donor and acceptor, resulting in an increase in the interface dipole, resulting in a larger offset.1146sciescopu

The effect of ZnO surface conditions on the electronic structure of the ZnO/CuPc interface

The interfacial electronic structures of zinc oxide (ZnO)/copper-phthalocyanine (CuPc) were investigated by in situ x-ray and ultraviolet photoelectron spectroscopy (UPS) to determine the effects of air contamination on the ZnO substrate. UPS spectra showed that the 0.2 eV of the interface dipole is generated at the interface of the air exposed ZnO/CuPc while the interface of the annealed ZnO/CuPc generated 0.2 eV. In both cases, no band bending was observed. On the other hand, band bending at 0.3 eV and an interface dipole of 0.2 eV were observed at the interface of the sputter cleaned ZnO/CuPc. The energy offset between the conduction band maximum of ZnO and the highest occupied molecular orbital of CuPc was determined to be 0.6-0.7 eV for the contaminated ZnO interface while the offset was 1.0 eV for the cleaned ZnO interface. Contaminating moisture has little effect on the offset while the charge transfer was blocked and the offset was decreased in the presence of hydrocarbons. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3555440]1118sciescopu

Modeling angle-resolved photoemission of graphene and black phosphorus nano structures

Angle-resolved photoemission spectroscopy (ARPES) data on electronic structure are difficult to interpret, because various factors such as atomic structure and experimental setup influence the quantum mechanical effects during the measurement. Therefore, we simulated ARPES of nano-sized molecules to corroborate the interpretation of experimental results. Applying the independent atomic-center approximation, we used density functional theory calculations and custom-made simulation code to compute photoelectron intensity in given experimental setups for every atomic orbital in poly-aromatic hydrocarbons of various size, and in a molecule of black phosphorus. The simulation results were validated by comparing them to experimental ARPES for highly-oriented pyrolytic graphite. This database provides the calculation method and every file used during the work flow.11Ysciescopu

Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by $U$ and $g$, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between $U$ and $g$. As $U$ ($g$) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter

An Empirical Analysis of Consumption Patterns for Mobile Apps and Web: A Multiple Discrete-Continuous Extreme Value Approach

Using a unique panel data set detailing individual-level mobile app consumption, this study develops a utility theory-based structural model for multiple discrete/continuous choices in app use. We identify the dynamics and inter-dependencies between mobile apps and jointly quantify consumers’ app choice and satiation simultaneously. The results suggest that mobile users’ baseline utility is the highest for communication apps, while the lowest for personal financing apps. In addition, users’ satiation level is the highest for the personal financing apps and the lowest for the game apps. However, a substantial heterogeneity in baseline utility and satiation is observed across diverse users. Furthermore, both positive and negative correlations exist in the baseline utility and satiation levels of mobile web and app categories. Consequently, the proposed frameworks could open new perspectives for handling large-scale, micro-level data, serving as important resources for big data analytics in general and mobile app analytics in particular

Time to Progress: the Impact of Temporal Ownership on Time Perception

Time is often linguistically portrayed either in a narrative or possessive framing. Building on this tendency, the authors demonstrate that communicating time in possession framing increases perceived ownership and feelings of responsibility towards making use of time. The heightened responsibility leads consumers to minimize time loss, but maximize time investment

An efficient method for visualization and growth of fluorescent Xanthomonas oryzae pv. oryzae in planta

<p>Abstract</p> <p>Background</p> <p><it>Xanthomonas oryzae </it>pv. <it>oryzae</it>, the causal agent of bacterial blight disease, is a serious pathogen of rice. Here we describe a fluorescent marker system to study virulence and pathogenicity of <it>X. oryzae </it>pv. <it>oryzae</it>.</p> <p>Results</p> <p>A fluorescent <it>X. oryzae </it>pv. <it>oryzae </it>Philippine race 6 strain expressing green fluorescent protein (GFP) (PXO99_GFP) was generated using the <it>gfp </it>gene under the control of the neomycin promoter in the vector, pP<it>neo</it>-<it>gfp</it>. The PXO99_GFPstrain displayed identical virulence and avirulence properties as the wild type control strain, PXO99. Using fluorescent microscopy, bacterial multiplication and colonization were directly observed in rice xylem vessels. Accurate and rapid determination of bacterial growth was assessed using fluoremetry and an Enzyme-Linked ImmunoSorbant Assay (ELISA).</p> <p>Conclusion</p> <p>Our results indicate that the fluorescent marker system is useful for assessing bacterial infection and monitoring bacterial multiplication <it>in planta</it>.</p

Epitaxially strained ultrathin LaNiO3_3/LaAlO3_3 and LaNiO3_3/SrTiO3_3 superlattices: a density functional theory + UU study

By employing first-principles electronic structure calculations we investigate nickelate superlattices [LaNiO$_3$]$_1$/[LaAlO$_3$]$_1$ and [LaNiO$_3$]$_1$/[SrTiO$_3$]$_1$ with (001) orientation under epitaxial tensile strain. Within density functional theory augmented by mean-field treatement of on-site electronic correlations, the ground states show remarkable dependence on the correlation strength and the strain. In the weakly and intermediately correlated regimes with small epitaxial strain, the charge-disproportionated insulating states with antiferromagneitc order is favored over the other orbital and spin ordered phases. On the other hand, in the strongly correlated regime or under the large tensile strain, ferromagnetic spin states with Jahn-Teller orbital order become most stable. The effect from polar interfaces in LaNiO$_3$]$_1$/[SrTiO$_3$]$_1$ is found to be noticeable in our single-layered geometry. Detailed discussion is presented in comparison with previous experimental and theoretical studies.Comment: 9 pages, 8 figure

Fabrication of pyramidal probes with various periodic patterns and a single nanopore

The nanometer-scale patterned pyramidal probe with an electron beam-induced nanopore on the pyramid apex is an excellent candidate for an optical biosensor. The nanoapertures surrounded with various periodic groove patterns on the pyramid sides were fabricated using a focused ion beam technique, where the optical characteristics of the fabricated apertures with rectangular, circular, and elliptical groove patterns were investigated. The elliptical groove patterns on the pyramid were designed to maintain an identical distance between the grooves and the apex for the surface waves and, among the three patterns, the authors observed the highest optical transmission from the elliptically patterned pyramidal probe. A 103-fold increase of the transmitted optical intensity was observed after patterning with elliptical grooves, even without an aperture on the pyramid apex. The nanopore on the apex of the pyramid was fabricated using electron beam irradiation and was optically characterized

Clinical Approach to the Standardization of Oriental Medical Diagnostic Pattern Identification in Stroke Patients

In Korea, many stroke patients receive oriental medical care, in which pattern-identification plays a major role. Pattern-identification is Oriental Medicine's unique diagnostic system. This study attempted to standardize oriental medical pattern-identification for stroke patients. This was a community-based multicenter study that enrolled stroke patients within 30 days after their ictus. We assessed the patients' general characteristics and symptoms related to pattern-identification. Each patient's pattern was determined when two doctors had the same opinion. To determine which variables affect the pattern-identification, binary logistic regression analysis was used with the backward method. A total of 806 stroke patients were enrolled. Among 480 patients who were identified as having a certain pattern, 100 patients exhibited the Fire Heat Pattern, 210 patients the Phlegm Dampness Pattern, nine patients the Blood Stasis Pattern, 110 patients the Qi Deficiency Pattern, and 51 patients the Yin Deficiency Pattern. After the regression analysis, the predictive logistic equations for the Fire Heat, Phlegm Dampness, Qi Deficiency, and Yin Deficiency patterns were determined. The Blood Stasis Pattern was omitted because the sample size was too small. Predictive logistic equations were suggested for four of the patterns. These criteria would be useful in determining each stroke patient's pattern in clinics. However, further studies with large samples are necessary to validate and confirm these criteria