Sample characteristics by condition.

<p>Doctors included consultant and staff grade psychiatrists.</p

The Distribution of Confidence Ratings by Profession and Gender.

<p>The Distribution of Confidence Ratings by Profession and Gender.</p

‘Suicide’ and ‘Non-suicide’ responses by condition.

<p>‘Suicide’ and ‘Non-suicide’ responses by condition.</p

Confidence ratings by condition and by response.

<p>Confidence ratings by condition and by response.</p

‘Suicide’ responses for male and female participants by professional group.

<p>‘Suicide’ responses for male and female participants by professional group.</p

Quantitative Phase-Change Thermodynamics and Metastability of Perovskite-Phase Cesium Lead Iodide

The perovskite phase of cesium lead iodide (α-CsPbI₃ or “black” phase) possesses favorable optoelectronic properties for photovoltaic applications. However, the stable phase at room temperature is a nonfunctional “yellow” phase (δ-CsPbI₃). Black-phase polycrystalline thin films are synthesized above 330 °C and rapidly quenched to room temperature, retaining their phase in a metastable state. Using differential scanning calorimetry, it is shown herein that the metastable state is maintained in the absence of moisture, up to a temperature of 100 °C, and a reversible phase-change enthalpy of 14.2 (±0.5) kJ/mol is observed. The presence of atmospheric moisture hastens the black-to-yellow conversion kinetics without significantly changing the enthalpy of the transition, indicating a catalytic effect, rather than a change in equilibrium due to water adduct formation. These results delineate the conditions for trapping the desired phase and highlight the significant magnitude of the entropic stabilization of this phase

Surface Chemically Switchable Ultraviolet Luminescence from Interfacial Two-Dimensional Electron Gas

We report intense, narrow line-width, surface chemisorption-activated and reversible ultraviolet (UV) photoluminescence from radiative recombination of the two-dimensional electron gas (2DEG) with photoexcited holes at LaAlO₃/SrTiO₃. The switchable luminescence arises from an electron transfer-driven modification of the electronic structure via H-chemisorption onto the AlO₂-terminated surface of LaAlO₃, at least 2 nm away from the interface. The control of the onset of emission and its intensity are functionalities that go beyond the luminescence of compound semiconductor quantum wells. Connections between reversible chemisorption, fast electron transfer, and quantum-well luminescence suggest a new model for surface chemically reconfigurable solid-state UV optoelectronics and molecular sensing

BaTiO₃ Thin Films from Atomic Layer Deposition: A Superlattice Approach

A superlattice approach for the atomic layer deposition of polycrystalline BaTiO₃ thin films is presented as an example for an effective route to produce high-quality complex oxide films with excellent thickness and compositional control. This method effectively mitigates any undesirable reactions between the different precursors and allows an individual optimization of the reaction conditions for the Ba–O and the Ti–O subcycles. By growth of nanometer thick alternating Ba­(OH)₂ and TiO₂ layers, the advantages of binary oxide atomic layer deposition are transferred into the synthesis of ternary compounds, permitting extremely high control of the cation ratio and superior uniformity. Whereas the Ba­(OH)₂ layers are partially crystalline after the deposition, the TiO₂ layers remain mostly amorphous. The layers react to polycrystalline, polymorph BaTiO₃ above 500 °C, releasing H₂O. This solid-state reaction is accompanied by an abrupt decrease in film thickness. Transmission electron microscopy and Raman spectroscopy reveal the presence of hexagonal BaTiO₃ in addition to the perovskite phase in the annealed films. The microstructure with relatively small grains of ∼70 Å and different phases is a direct consequence of the abrupt formation reaction. The electrical properties transition from the initially highly insulating dielectric semiamorphous superlattice into a polycrystalline BaTiO₃ thin film with a dielectric constant of 117 and a dielectric loss of 0.001 at 1 MHz after annealing at 600 °C in air, which, together with the suppression of ferroelectricity at room temperature, are very appealing properties for voltage tunable devices