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排序方式: 共有128条查询结果,搜索用时 31 毫秒
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Ivona Kafedjiska Igal Levine Artem Musiienko Natalia Maticiuc Tobias Bertram Amran Al-Ashouri Christian A. Kaufmann Steve Albrecht Rutger Schlatmann Iver Lauermann 《Advanced functional materials》2023,33(34):2302924
The performance of five hole-transporting layers (HTLs) is investigated in both single-junction perovskite and Cu(In, Ga)Se2 (CIGSe)-perovskite tandem solar cells: nickel oxide (NiOx,), copper-doped nickel oxide (NiOx:Cu), NiOx+SAM, NiOx:Cu+SAM, and SAM, where SAM is the [2-(3,-6Dimethoxy-9H-carbazol-9yl)ethyl]phosphonic acid (MeO-2PACz) self-assembled monolayer. The performance of the devices is correlated to the charge-carrier dynamics at the HTL/perovskite interface and the limiting factors of these HTLs are analyzed by performing time-resolved and absolute photoluminescence ((Tr)PL), transient surface photovoltage (tr-SPV), and X-ray/UV photoemission spectroscopy (XPS/UPS) measurements on indium tin oxide (ITO)/HTL/perovskite and CIGSe/HTL/perovskite stacks. A high quasi-Fermi level splitting to open-circuit (QFLS-Voc) deficit is detected for the NiOx-based devices, attributed to electron trapping and poor hole extraction at the NiOx-perovskite interface and a low carrier effective lifetime in the bulk of the perovskite. Simultaneously, doping the NiOx with 2% Cu and passivating its surface with MeO-2PACz suppresses the electron trapping, enhances the holes extraction, reduces the non-radiative interfacial recombination, and improves the band alignment. Due to this superior interfacial charge-carrier dynamics, NiOx:Cu+SAM is found to be the most suitable HTL for the monolithic CIGSe-perovskite tandem devices, enabling a power-conversion efficiency (PCE) of 23.4%, Voc of 1.72V, and a fill factor (FF) of 71%, while the remaining four HTLs suffer from prominent Voc and FF losses. 相似文献
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Maxine M. Denniston Nancy D. Brener Laura Kann Danice K. Eaton Timothy McManus Tonja M. Kyle Alice M. Roberts Katherine H. Flint James G. Ross 《Computers in human behavior》2010
The Youth Risk Behavior Surveillance System (YRBSS) monitors priority health-risk behaviors among US high school students. To better understand the ramifications of changing the YRBSS from paper-and-pencil to Web administration, in 2008 the Centers for Disease Control and Prevention conducted a study comparing these two modes of administration. Eighty-five schools in 15 states agreed to participate in the study. Within each participating school, four classrooms of students in grades 9 or 10 were randomly assigned to complete the Youth Risk Behavior Survey questionnaire in one of four conditions (in-class paper-and-pencil, in-class Web without programmed skip patterns, in-class Web with programmed skip patterns, and “on your own” Web without programmed skip patterns). Findings included less missing data for the paper-and-pencil condition (1.5% vs. 5.3%, 4.4%, 6.4%; p < .001), less perceived privacy and anonymity among respondents for the in-class Web conditions, and a lower response rate for the “on your own” Web condition than for in-class administration by either mode (28.0% vs. 91.2%, 90.1%, 91.4%; p < .001). Although Web administration might be useful for some surveys, these findings do not favor the use of a Web survey for the YRBSS. 相似文献
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Chuan Pu Sangtae Park Chu P.B. Shi-Sheng Lee Ming Tsai Peale D. Bonadeo N.H. Brener I. 《IEEE journal of selected topics in quantum electronics》2004,10(3):472-477
We propose and demonstrate electrostatic sidewall-electrodes actuation of three-dimensional (3-D) microelectromechanical systems (MEMS) gimbal mirrors. The linearity of the mirror angle dependence on actuation voltage is improved with the sidewall-electrodes actuation. In addition, the undesired spring-softening effect commonly found in electrostatic actuation, where the mirror resonance frequency decreases with increased tilt angle, is significantly reduced. Sidewall actuation enables superior performance of 3-D MEMS mirrors including large pull-in angles, reduced actuation voltages, improved device reliability, and fast switching times. 相似文献
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Design and nonlinear servo control of MEMS mirrors and their performance in a large port-count optical switch 总被引:2,自引:0,他引:2
Chu P.B. Brener I. Chuan Pu Shi-Sheng Lee Dadap J.I. Sangtae Park Bergman K. Bonadeo N.H. Chau T. Ming Chou Doran R.A. Gibson R. Harel R. Johnson J.J. Lee C.D. Peale D.R. Bo Tang Tong D.T.K. Ming-Ju Tsai Qi Wu Zhong W. Goldstein E.L. Lin L.Y. Walker J.A. 《Journal of microelectromechanical systems》2005,14(2):261-273
In this paper, we demonstrate full closed-loop control of electrostatically actuated double-gimbaled MEMS mirrors and use them in an optical cross-connect. We show switching times of less than 10 ms and optical power stability of better than 0.2 dB. The mirrors, made from 10-/spl mu/m-thick single-crystal silicon and with a radius of 400-450 /spl mu/m, are able to tilt to 8/spl deg/ corresponding to 80% of touchdown angle. This is achieved using a nonlinear closed-loop control algorithm, which also results in a maximum actuation voltage of 85 V, and a pointing accuracy of less than 150 /spl mu/rad. This paper will describe the MEMS mirror and actuator design, modeling, servo design, and measurement results. 相似文献
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Igal M. Shohet 《Canadian Metallurgical Quarterly》2006,132(4):345-352
The salient phases in a facility’s service life that are most decisive for the effectiveness of its facilities management (FM) are the preliminary design, construction, and maintenance. The effectiveness of facilities is vastly affected by decisions pertaining to the strategy of the organization that owns or uses the facilities. The goal of this study was to develop key performance indicators (KPIs) for strategic FM that will provide a conclusive approach towards the facility’s service life conditions. Parameters were developed by means of field surveys and statistical analyses, and were validated by means of case studies. The research resulted in a series of 11 KPIs for strategic healthcare FM, which can be classified into four categories: development, organization and management, performance, and maintenance efficiency parameters. The study proposes age and occupancy coefficients as essential parameters for the assessment of large healthcare facilities needs, as an effective measure for long term facility maintenance planning, and for measuring FM effectiveness. The paper stresses that strategic healthcare facilities management must integrate quantitative performance, manpower, and maintenance indicators. 相似文献
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X.G. Peralta I. Brener W.J. Padilla E.W. Young A.J. Hoffman M.J. Cich R.D. Averitt M.C. Wanke J.B. Wright H.-T. Chen J.F. O’Hara A.J. Taylor J. Waldman W.D. Goodhue J. Li J. Reno 《Metamaterials》2010,4(2-3):83-88
We have designed, fabricated and measured electrically-driven active metamaterials which operate as external modulators for TeraHertz Quantum Cascade Lasers. The modulation is achieved by applying a voltage to the metamaterial layer which actively displaces carriers from the n-doped layer causing changes in damping and frequency location of the lowest metamaterial response. We demonstrate their operation at 2.4 and 2.8 TeraHertz and obtain a maximum modulation depth of ~60% with a large degree of modulation linearity. 相似文献