55 research outputs found

    Room temperature vacuum-deposition of CsPbI2Br perovskite films from multiple-sources and mixed halide precursors

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    Fully inorganic cesium lead halide perovskites, such as CsPbI2Br, show enhanced thermal stability compared to hybrid ones and are being widely investigated as wide bandgap absorbers for tandem applications. Despite their simple stoichiometry, the preparation of highly crystalline and stable cesium lead halide thin films is not trivial. In general, high-efficiency solar cells based on solution-processed CsPbI2Br thin films are prepared by hightemperature annealing or the use of chemical additives. In this work, we use solvent-free synthesis to investigate the formation of CsPbI2Br in bulk or in thin films via mechanochemical synthesis and multiple-source vacuum deposition, respectively. We demonstrate the importance of fostering halide alloying in the vacuum processing of inorganic lead halide perovskites, which can be attained either by using mixed halide precursors or by increasing the number of precursors (and hence deposition sources). These strategies lead to highly oriented perovskite films even at room temperature, with improved optoelectronic properties. We obtained promising power conversion efficiencies of 8.3% for solar cells employing asdeposited perovskites (without any annealing) and 10.0% for devices based on CsPbI2Br annealed at low temperatures (150 °C). This study allowed us to highlight the most promising processes and strategies to further optimize the material deposition as well as the solar cell architecture

    Indistinguishable and efficient single photons from a quantum dot in a planar nanobeam waveguide

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    We demonstrate a high-purity source of indistinguishable single photons using a quantum dot embedded in a nanophotonic waveguide. The source features a near-unity internal coupling efficiency and the collected photons are efficiently coupled off chip by implementing a taper that adiabatically couples the photons to an optical fiber. By quasiresonant excitation of the quantum dot, we measure a single-photon purity larger than 99.4% and a photon indistinguishability of up to 94±1% by using p-shell excitation combined with spectral filtering to reduce photon jitter. A temperature-dependent study allows pinpointing the residual decoherence processes, notably the effect of phonon broadening. Strict resonant excitation is implemented as well as another means of suppressing photon jitter, and the additional complexity of suppressing the excitation laser source is addressed. The paper opens a clear pathway towards the long-standing goal of a fully deterministic source of indistinguishable photons, which is integrated on a planar photonic chip

    Evidenzbasierte Psychotherapie der Panikstörung mit und ohne Agoraphobie : ein Überblick zur S1-Leitlinie der Deutschen Gesellschaft für Psychologie

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    Alpers GW, Gerlach AL, Heinrichs N. Evidence-based psychotherapy of panic disorder with or without agoraphobia. Psychotherapeut. 2011;56(6):535-548.From the evidence reported in the recent guidelines [Heinrichs et al. (2009) Evidenzbasierte Leitlinie zur Psychotherapie der Panikstorung mit und ohne Agoraphobie. Hogrefe, Gottingen] the following conclusions can be drawn with respect to the treatment of panic disorder with or without agoraphobia, as well as for agoraphobia without panic disorder: Every psychotherapy should be preceded by suitable diagnostics and a case formulation. The effectiveness of every psychotherapy should be evaluated with well established measures. For the treatment of panic disorder without agoraphobia, cognitive behavioral treatment (CBT) and applied relaxation have been shown to be effective (evidence grade 1). For panic disorder with agoraphobia, CBT, combination treatment (CBT plus medication), as well as panic-focused psychodynamic psychotherapy in the outpatient setting have shown short-term effectiveness (evidence grade 1). Longer lasting effects have been documented for CBT (evidence grade 1). For agoraphobia without panic disorder, CBT with a focus on situational exposure can be recommended (evidence grade 1)

    Short-interval test-retest interrater reliability of the Dutch version of the structured clinical interview for DSM-IV personality disorders (SCID-II)

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    This study examined the short-interval test-retest reliability of the Structured Clinical Interview (SCID-II: First, Spitzer, Gibbon, & Williams, 1995) for DSM-IV personality disorders (PDs). The SCID-II was administered to 69 in- and outpatients on two occasions separated by 1 to 6 weeks. The interviews were conducted at three sites by ten raters. Each rater acted as first and as second rater and equal number of times. The test-retest interrater reliability for the presence or absence of any PD was fair to good (kappa = .63) and was higher than values found in previous short-interval test-retest studies with the SCID-II for DSM-III-R. Test-retest reliability coefficients for trait and sumscores were sufficient, except for dependent PD. Values for single criteria were variable, ranging from poor to good agreement. Further large-scale test-retest research is needed to test the interrater reliability of more categorical diagnoses and single traits

    Short-interval test-retest interrater reliability of the Dutch version of the structured clinical interview for DSM-IV personality disorders (SCID-II)

    No full text
    This study examined the short-interval test-retest reliability of the Structured Clinical Interview (SCID-II: First, Spitzer, Gibbon, & Williams, 1995) for DSM-IV personality disorders (PDs). The SCID-II was administered to 69 in- and outpatients on two occasions separated by 1 to 6 weeks. The interviews were conducted at three sites by ten raters. Each rater acted as first and as second rater and equal number of times. The test-retest interrater reliability for the presence or absence of any PD was fair to good (kappa = .63) and was higher than values found in previous short-interval test-retest studies with the SCID-II for DSM-III-R. Test-retest reliability coefficients for trait and sumscores were sufficient, except for dependent PD. Values for single criteria were variable, ranging from poor to good agreement. Further large-scale test-retest research is needed to test the interrater reliability of more categorical diagnoses and single traits
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