1,982 research outputs found

    Evidence for ion irradiation induced dissociation and reconstruction of Si-H bonds in hydrogen-implanted silicon

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    We observe that H-related chemical bonds formed in H-implanted Si will evolve under subsequent ion irradiation. During ion irradiation hydrogen is inclined to dissociate from simple H-related defect complexes (i.e., VHx and IHx), diffuse, and attach to vacancy-type defects resulting in new platelet formation, which facilitate surface blistering after annealing, a process completely inhibited in the absence of ion irradiation. The understanding of our results provides insight into the structure and stability of hydrogen-related defects in silicon. © 2008 American Institute of Physics

    Irradiation-induced molecular dipole reorientation in inverted polymer solar cell using small molecular electron collection layer

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    Inverted polymer solar cell is developed using small molecular tris(8-hydroxyquinolinato) aluminum (Alq3) as an electron collection layer between the active layer and indium-tin-oxide bottom cathode. Upon post-processing light irradiation by simulated solar illumination, the open-circuit voltage of the inverted device increases from 0.52 V to 0.60 V, resulting in the enhancement of the power conversion efficiency from 2.54 to 3.33 with negligible change in the short-circuit current. The performance improvement is attributed to the removal of surface potential due to irradiation-induced molecular dipole reorientation in the Alq3 layer, which reduces the charge transport barrier and improves the charge collection efficiency. © 2011 American Institute of Physics

    Efficient inverted polymer solar cells with thermal-evaporated and solution-processed small molecular electron extraction layer

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    Efficient inverted polymer solar cell is reported upon by integrating with a small molecular 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL) at low processing temperature with thermal-evaporation and solution-process, resulting in the power conversion efficiencies of 3.70 and 3.47, respectively. The potential of TPBi as an efficient EEL is associated with its suitable electronic energy level for electron extraction and hole blocking from the active layer to the indium tin oxide cathode. © 2013 American Institute of Physics

    The effect of an NgR1 antagonist on the neuroprotection of cortical axons after cortical infarction in rats

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    Enhanced performance in polymer photovoltaic cells with chloroform treated indium tin oxide anode modification

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    Enhanced performance of a poly(3-hexylthiophene):(6,6)-phenyl C61 butyric acid methyl ester bulk heterojunction polymer photovoltaic cell is reported by modifying the indium tin oxide (ITO) anode with chloroform solution. Instead of the traditional UV-ozone treatment, the optimized chloroform modification on ITO anode can result in an enhancement in the power conversion efficiency of an identical device, originating from an increase in the photocurrent with negligible change in the open-circuit voltage. The performance enhancement is attributed to the work function modification of the ITO substrate through the surface incorporation of the chlorine, and thus improved charge collection efficiency. © 2011 American Institute of Physics

    Impact of BRCA1/2 cascade testing on anxiety, depression, and cancer worry levels among unaffected relatives in a multiethnic Asian cohort

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    Cascade testing for families with BRCA pathogenic variants is important to identify relatives who are carriers. These relatives can benefit from appropriate risk management and preventative strategies arising from an inherited increased risk of breast, ovarian, prostate, melanoma, and pancreatic cancers. Cascade testing has the potential to enable cost-effective cancer control even in low- and middle-income settings, but few studies have hitherto evaluated the psychosocial impact of cascade testing in an Asian population, where the cultural and religious beliefs around inheritance and destiny have previously been shown to influence perception and attitudes toward screening. In this study, we evaluated the short- and long-term psychosocial impact of genetic testing among unaffected relatives of probands identified through the Malaysian Breast Cancer Genetics Study and the Malaysian Ovarian Cancer Study, using validated questionnaires (Hospital Anxiety and Depression Scale and Cancer Worry Scale) administered at baseline, and 1-month and 2-year post-disclosure of results. Of the 305 unaffected relatives from 98 independent families who were offered cascade testing, 256 (84%) completed predictive testing and family history of cancers was the only factor significantly associated with uptake of predictive testing. We found that the levels of anxiety, depression, and cancer worry among unaffected relatives decreased significantly after result disclosure and remained low 2-year post-result disclosure. Younger relatives and relatives of Malay descent had higher cancer worry at both baseline and after result disclosure compared to those of Chinese and Indian descent, whereas relatives of Indian descent and those with family history of cancers had higher anxiety and depression levels post-result disclosure. Taken together, the results from this Asian cohort highlight the differences in psychosocial needs in different communities and inform the development of culture-specific genetic counseling strategies

    Surface plasmon-enhanced electroluminescence in organic light-emitting diodes incorporating Au nanoparticles

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    Surface plasmon-enhanced electroluminescence (EL) in an organic light-emitting diode is demonstrated by incorporating the synthesized Au nanoparticles (NPs) in the hole injection layer of poly(3,4-ethylene dioxythiophene):polystyrene sulfonic acid. An increase of ∼25% in the EL intensity and efficiency are achieved for devices with Au NPs, whereas the spectral and electrical properties remain almost identical to the control device. Time-resolved photoluminescence spectroscopy reveals that the EL enhancement is ascribed to the increase in spontaneous emission rate due to the plasmonic near-field effect induced by Au NPs. © 2012 American Institute of Physics

    Effect of substrate growth temperatures on H diffusion in hydrogenated Si/Si homoepitaxial structures grown by molecular beam epitaxy

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    We have investigated hydrogen diffusion in hydrogenated 〈100〉 Si/Si homoepitaxial structures, which were grown by molecular beam epitaxy at various temperatures. The substrate growth temperature can significantly affect the H diffusion behavior, with higher growth temperatures resulting in deeper H diffusion. For the Si/Si structure grown at the highest temperature of 800°C, H trapping occurs at the epitaxial Si/Si substrate interface, which results in the formation of (100) oriented microcracks at the interface. The mechanism of H trapping and the potential application of these findings for the development of a method of transferring ultrathin Si layers are discussed. © 2006 American Institute of Physics
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