23 research outputs found

    Challenges to Implementing Partnerships in a College of Teachers’ Education and Secondary Schools in Hosanna Town, Southern Ethiopia

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    The study investigated the challenges of implementing effective partnerships in a College of Teachers’ Education and schools in Hosanna town, Southern Ethiopia, using the study used a descriptive design. The study was conducted in Hosanna town which had two public secondary schools, one private secondary school and one College of Teacher’s Education. The total number of educators was 150. The researchers sampled 37 instructors and 41 school teachers to make a total of 78 respondents.  While there are benefits of forming partnerships among Colleges of Teachers’ Education and schools, bridging the gap between theory and practices of trainees is one of the main established challenges.  Other challenges include gaps between theoretical and practical parts of teacher education programs, lack of finance in implementing partnerships between the college and schools and lack of collaboration between college instructors and teachers. The study recommends that the Ministry of Education should allocate a budget for developing effective partnerships. The regional education office should give training to develop trust among partners. Training should be given to change the pattern of the top to down work order and solve the cultural differences between the colleges and schools

    Designing Ultraflexible Perovskite X-Ray Detectors through Interface Engineering

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    X-ray detectors play a pivotal role in development and advancement of humankind, from far-reaching impact in medicine to furthering the ability to observe distant objects in outer space. While other electronics show the ability to adapt to flexible and lightweight formats, state-of-the-art X-ray detectors rely on materials requiring bulky and fragile configurations, severely limiting their applications. Lead halide perovskites is one of the most rapidly advancing novel materials with success in the field of semiconductor devices. Here, an ultraflexible, lightweight, and highly conformable passively operated thin film perovskite X-ray detector with a sensitivity as high as 9.3 ± 0.5 ÂµC Gy−1 cm−2 at 0 V and a remarkably low limit of detection of 0.58 ± 0.05 Î¼Gy s−1 is presented. Various electron and hole transporting layers accessing their individual impact on the detector performance are evaluated. Moreover, it is shown that this ultrathin form-factor allows for fabrication of devices detecting X-rays equivalently from front and back side

    Progress on lead-free metal halide perovskites for photovoltaic applications: a review

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    ABSTRACT: Metal halide perovskites have revolutionized the field of solution-processable photovoltaics. Within just a few years, the power conversion efficiencies of perovskite-based solar cells have been improved significantly to over 20%, which makes them now already comparably efficient to silicon-based photovoltaics. This breakthrough in solution-based photovoltaics, however, has the drawback that these high efficiencies can only be obtained with lead-based perovskites and this will arguably be a substantial hurdle for various applications of perovskite-based photovoltaics and their acceptance in society, even though the amounts of lead in the solar cells are low. This fact opened up a new research field on lead-free metal halide perovskites, which is currently remarkably vivid. We took this as incentive to review this emerging research field and discuss possible alternative elements to replace lead in metal halide perovskites and the properties of the corresponding perovskite materials based on recent theoretical and experimental studies. Up to now, tin-based perovskites turned out to be most promising in terms of power conversion efficiency; however, also the toxicity of these tin-based perovskites is argued. In the focus of the research community are other elements as well including germanium, copper, antimony, or bismuth, and the corresponding perovskite compounds are already showing promising properties. GRAPHICAL ABSTRACT: [Image: see text
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