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2D and 3D unsteady flow past a rigid prism of a squarecross-section with one side facing the oncoming flow is numerically simulated for Reynolds numbers between 200 to 500. An incompressible code is used employing an implicit fractional step method finite-volume with second-order accuracy in space and time. For 2D flow, it is found that, for Re >300, the time-mean flow patterns are not perfectly s
Ruddlesden-Popper perovskites (RPPs) have been demonstrated as a very promising approach for tuning the emission color of perovskite light-emitting diodes (PeLEDs). However, achieving high-performance red PeLEDs with recommendation 2020 color coordinates is still challenging due to the lack of reasonable control over the properties of RPP films. Here, we demonstrate that the judicious selection of
Defect management strategies are vital for enhancing the performance of perovskite-based optoelectronic devices, such as perovskite-based light-emitting diodes (PeLEDs). As additives can fucntion both as acrystallization modifier and/or defect passivator, a thorough study on the roles of additives is essential, especially for blue emissive Pe-LEDs, where the emission is strictly controlled by the
Harvesting the excess energy from absorbed above bandgap photons is a promising approach to overcome the detailed balance limit for higher solar cell efficiencies. However, this remains very challenging for 2D layered halide perovskites as the fast excess energy loss competes effectively with charge extraction. Herein, the authors engineer the energy cascade manifold of quantum well (QW) states in
Perovskite light-emitting diodes (PeLEDs) have recently shown significant progress with external quantum efficiencies (EQEs) exceeding 20%. However, PeLEDs with pure-red (620−660 nm) light emission, an essential part for full-color displays, remain a great challenge. Herein, a general approach of spacer cation alloying is employed in Ruddlesden–Popper perovskites (RPPs) for efficient red PeLEDs wi
Excitonic effects underpin the fascinating optoelectronic properties of 2D perovskites that are highly favorable for photovoltaics and light-emitting devices. Analogous to switching in transistors, manipulating these excitonic properties in 2D perovskites using coherent phonons could unlock new applications. Presently, a detailed understanding of this underlying mechanism remains modest. Herein, t
Two-dimensional (2D) lead halide Ruddlesden-Popper perovskites (RPP) have recently emerged as a prospective material system for optoelectronic applications. Their self-assembled multi quantum-well structure gives rise to the novel interwell energy funnelling phenomenon, which is of broad interests for photovoltaics, light-emission applications, and emerging technologies (e.g., spintronics). Herein
The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion properties. As the perovskite material dimensionality is reduced to exploit the quantum confinement effects, the disruption to the perovskite lattice, often with insulating organic ligands, raises new questions on the charge diffusion properties. Herein, we report direct imaging of >1
Amongst the many spectacular properties of hybrid lead halide perovskites, their defect tolerance is regarded as the key enabler for a spectrum of high-performance optoelectronic devices that propel perovskites to prominence. However, the plateauing efficiency enhancement of perovskite devices calls into question the extent of this defect tolerance in perovskite systems; an opportunity for perovsk
In recent years, two-dimensional (2D) Ruddlesden-Popper perovskites have emerged as promising candidates for environmentally stable solar cells, highly efficient light-emitting diodes, and resistive memory devices. The remarkable existence of self-assembled quantum well (QW) structures in solution-processed 2D perovskites offers a diverse range of optoelectronic properties, which remain largely un
Of a series of new 2D lead-bromide perovskites, templated by closely related dications 1-5, a corrugated (110)-oriented structure was attained only in one, 1[PbBr4]. The others display (100) structures. Upon excitation by UV-light, 1[PbBr4] exhibits intrinsic white-light emission that is "colder" than previously reported for this class of compounds.
Long term stability of lutetium rhodite (LuRhO3) as an electrode for photoelectrochemical decomposition of water is investigated. The thermodynamic properties of LuRhO3are determined in the temperature range from 875 to 1300 K using an electrochemical cell incorporating calcia–stabilized zirconia as the solid electrolyte. The standard Gibbs energy of formation of LuRhO3from its constituent binary
Background: Sepsis is common in the intensive care unit (ICU). Two of the ICU’s most widely used mortality prediction models are the Simplified Acute Physiology Score 3 (SAPS-3) and the Sequential Organ Failure Assessment (SOFA) score. We aimed to assess the mortality prediction performance of SAPS-3 and SOFA upon ICU admission for sepsis and find a simpler mortality prediction model for these pat
There is no standard formula for estimating the starting daily dose (SDD) of basal-bolus insulin therapy (BBT). We aimed to develop a formula for estimating SDD and evaluate its efficacy and safety in patients with type 2 diabetes hospitalized for BBT. In the first study (n = 104), we retrospectively analyzed the relationship between peak daily dose (PDD) during hospitalization and clinical parame
Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible and infrared wavelengths have been challenging to reconcile with a planetary reflection and emission model. In this study, we analyse a set of 41 occultations obtained over a two-year timespan with the CHEOPS satellite. We report the detection of 55 Cnc e's occultation with an average d
Low rank recovery problems have been a subject of intense study in recent years. While the rank function is useful for regularization it is difficult to optimize due to its nonconvexity and discontinuity. The standard remedy for this is to exchange the rank function for the convex nuclear norm, which is known to favor low rank solutions under certain conditions. On the downside the nuclear norm ex
Objective: Follicle-stimulating hormone (FSH) receptor expression has been reported in many extra-gonadal tissues, raising the question of non-reproductive effects of FSH. Because of increasing usage of FSH in treatment of male infertility, deeper knowledge of possible harmful off-target effects of FSH is warranted. Methods: In total, 33 healthy young men (mean age 30 years) were included in the s
