Search results

Filter

Filetype

Your search for "*" yielded 530146 hits

TOI-1268b : The youngest hot Saturn-mass transiting exoplanet

We report the discovery of TOI-1268b, a transiting Saturn-mass planet from the TESS space mission. With an age of less than 1 Gyr, derived from various age indicators, TOI-1268b is the youngest Saturn-mass planet known to date; it contributes to the small sample of well-characterised young planets. It has an orbital period of P = 8.1577080 ± 0.0000044 days, and transits an early K-dwarf star with

Regionövergripande samverkan : - utvärdering av "Samarbete för bättre vård" (SFBV) i Södra sjukvårdsregionen

Samverkan har sedan lång tid tillbaka varit viktigt inom både regionala ochkommunala verksamheter och det finns mycket som talar för attsamverkansbehoven kommer att öka än mer. Inom hälso- och sjukvården finns en kontinuerlig utveckling mot ny och mera specialiserad kunskap som även fårorganisatoriska konsekvenser. Teamarbete i vården har blivit allt viktigare, liksom nivåstrukturering och koncentCooperation has long been important within both regional andmunicipal activities and there is much to suggest thatcollaboration needs will increase even more. Within health care there is onecontinuous development towards new and more specialized knowledge that also gains organizational consequences. Teamwork in healthcare has become increasingly important, as well level structuring and concentrati

Augmented reality face recognition for musical interaction

This paper reports on early work in a project devoted to the exploration of music, musical quality, interaction design and sensory stimulation for persons with multiple and/or severe impairments. The text focuses on the explorative work done on using face tracking and face recognition for musical interaction. The current design and the design process so far is described. Further developments are o

The Highs and the Lows: Bank failures in Sweden through inflation and deflation, 1914-1926

This paper revisits the Swedish banking crisis (1919-26) that materialized as post war deflation replaced wartime inflation (1914-18). Inspired by Fisher’s ‘debt deflation theory’, we employ survival analysis to ‘predict’ which banks would fail, given certain ex-ante bank characteristics. Our tests support the theory; maturity structures mattered most in a regime of falling prices, with vulnerable

Collective Diffraction Effects in Perovskite Nanocrystal Superlattices

ConspectusFor almost a decade now, lead halide perovskite nanocrystals have been the subject of a steadily growing number of publications, most of them regarding CsPbBr3 nanocubes. Many of these works report X-ray diffraction patterns where the first Bragg peak has an unusual shape, as if it was composed of two or more overlapping peaks. However, these peaks are too narrow to stem from a nanoparti

Highly Emitting Perovskite Nanocrystals with 2-Year Stability in Water through an Automated Polymer Encapsulation for Bioimaging

Lead-based halide perovskite nanocrystals are highly luminescent materials, but their sensitivity to humid environments and their biotoxicity are still important challenges to solve. Here, we develop a stepwise approach to encapsulate representative CsPbBr3nanocrystals into water-soluble polymer capsules. We show that our protocol can be extended to nanocrystals coated with different ligands, enab

Generation of Free Carriers in MoSe2 Monolayers Via Energy Transfer from CsPbBr3 Nanocrystals

Transition metal dichalcogenide (TMDCs) monolayers make an excellent component in optoelectronic devices such as photodetectors and phototransistors. Selenide-based TMDCs, specifically molybdenum diselenide (MoSe2) monolayers with low defect densities, show much faster photoresponses compared to their sulfide counterpart. However, the typically low absorption of the atomically thin MoSe2 monolayer

Red-emissive nanocrystals of Cs4Mnx Cd1-xSb2Cl12 layered perovskites

Layered double perovskites are currently being investigated as emerging halide-based materials for optoelectronic applications. Herein, we present the synthesis of Cs4MnxCd1−xSb2Cl12 (0 ≤ x ≤ 1) nanocrystals (NCs). X-ray powder diffraction evidences the retention of the same crystal structure for all the inspected compositions; transmission electron microscopy revealed monodisperse particles

Exploiting the Transformative Features of Metal Halides for the Synthesis of CsPbBr3@SiO2 Core-Shell Nanocrystals

The encapsulation of colloidal lead halide perovskite nanocrystals within silica (SiO2) is one of the strategies to protect them from polar solvents and other external factors. Here, we demonstrate the overcoating of CsPbBr3 perovskite nanocrystals with silica by exploiting the anhydride-induced transformation of Cs4PbBr6 nanocrystals. CsPbBr3@SiO2 core–shell nanocrystals are obtained after (i) a

Structure and Surface Passivation of Ultrathin Cesium Lead Halide Nanoplatelets Revealed by Multilayer Diffraction

The research on two-dimensional colloidal semiconductors has received a boost from the emergence of ultrathin lead halide perovskite nanoplatelets. While the optical properties of these materials have been widely investigated, their accurate structural and compositional characterization is still challenging. Here, we exploited the natural tendency of the platelets to stack into highly ordered film

Fast Intrinsic Emission Quenching in Cs4PbBr6 Nanocrystals

Cs4PbBr6 (0D) nanocrystals at room temperature have both been reported as nonemissive and green-emissive systems in conflicting reports, with no consensus regarding both the origin of the green emission and the emission quenching mechanism. Here, via ab initio molecular dynamics (AIMD) simulations and temperature-dependent photoluminescence (PL) spectroscopy, we show that the PL in these 0D m

News in Nanocrystals Seminar : Self-Assembly of Early Career Researchers toward Globally Accessible Nanoscience

In 2020, many in-person scientific events were canceled due to the COVID-19 pandemic, creating a vacuum in networking and knowledge exchange between scientists. To fill this void in scientific communication, a group of early career nanocrystal enthusiasts launched the virtual seminar series, News in Nanocrystals, in the summer of 2020. By the end of the year, the series had attracted over 850 part

Relations between absorption, emission, and excited state chemical potentials from nanocrystal 2D spectra

For quantum-confined nanomaterials, size dispersion causes a static broadening of spectra that has been difficult to measure and invalidates all-optical methods for determining the maximum photovoltage that an excited state can generate. Using femtosecond two-dimensional (2D) spectroscopy to separate size dispersion broadening of absorption and emission spectra allows a test of single-molecule gen

Detection of Pb2+traces in dispersion of Cs4PbBr6 nanocrystals by in situ liquid cell transmission electron microscopy

The Cs4PbBr6 nanocrystals are often used as a starting material for the preparation of green-emitting CsPbBr3 perovskite nanocrystals by means of chemical and physical transformations. Herein, we probe the Cs4PbBr6 nanocrystals dispersed in a solvent by liquid cell transmission electron microscopy (LCTEM). The nanocrystal dispersion in toluene is placed between two electron-transparent membranes s

Multilayer Diffraction Reveals That Colloidal Superlattices Approach the Structural Perfection of Single Crystals

Colloidal superlattices are fascinating materials made of ordered nanocrystals, yet they are rarely called “atomically precise”. That is unsurprising, given how challenging it is to quantify the degree of structural order in these materials. However, once that order crosses a certain threshold, the constructive interference of X-rays diffracted by the nanocrystals dominates the diffraction pat

Metamorphoses of Cesium Lead Halide Nanocrystals

Following the impressive development of bulk lead-based perovskite photovoltaics, the “perovskite fever” did not spare nanochemistry. In just a few years, colloidal cesium lead halide perovskite nanocrystals have conquered researchers worldwide with their easy synthesis and color-pure photoluminescence. These nanomaterials promise cheap solution-processed lasers, scintillators, and light-emitti

Aging of Self-Assembled Lead Halide Perovskite Nanocrystal Superlattices : Effects on Photoluminescence and Energy Transfer

Excitonic coupling, electronic coupling, and cooperative interactions in self-assembled lead halide perovskite nanocrystals were reported to give rise to a red-shifted collective emission peak with accelerated dynamics. Here we report that similar spectroscopic features could appear as a result of the nanocrystal reactivity within the self-assembled superlattices. This is demonstrated by study

Superlattices are greener on the other side : How light transforms self-assembled mixed halide perovskite nanocrystals

Perovskite nanocrystal superlattices (NC SLs) are the nearest real-world approximations to monodisperse NC ensembles. NC SLs thus represent ideal model systems for evaluating the optical and structural stability of CsPb(I1−xBrx)3 NCs at a macroscopic level. Here, photoinduced changes to CsPb(I1−xBrx)3 NC SLs (0 < x < 1.0) are probed via in situ photoluminescence, X-ray diffraction, and electron mi

Transforming colloidal Cs4PbBr6 nanocrystals with poly(maleic anhydride-alt-1-octadecene) into stable CsPbBr3 perovskite emitters through intermediate heterostructures

The preparation of strongly emissive CsPbBr3 perovskite nanocrystals with robust surface passivation is a challenge in the field of lead halide perovskite nanomaterials. We report an approach to prepare polymer-capped CsPbBr3 perovskite nanocrystals by reacting oleylammonium/oleate-capped Cs4PbBr6 nanocrystals with poly(maleic anhydride-alt-1-octadecene) (PMAO). PMAO contains succinic anhydride un