Large area inkjet printed metal halide perovskite LEDs enabled by gas flow assisted drying and crystallization

We demonstrate the upscaling of inkjet printed metal halide perovskite light emitting diodes. To achieve this, the drying process, critical for controlling the crystallization of the perovskite layer, was optimized with an airblade like slit nozzle in a gas flow assisted vacuum drying step. This yields large, continuous perovskite layers in light emitting diodes with an active area up to 1600 mm

Gas flow assisted vacuum drying Identification of a novel process for attaining high quality perovskite films

Controlling the nucleation and crystal growth in solution processed metal halide perovskite MHP thin films is the pivotal point in fabricating homogenous and pinhole free films. Using scalable coating and printing techniques, vacuum and gas flow assisted drying processes turn out to be the most promising methods to induce nucleation and crystallization. Yet, the exact interplay and nature of these processes are unclear. In our work, we optically monitor these processes in situ. For the first time, we can show that a controlled venting of the vacuum chamber and the use of a subsequent gas flow are key to achieve homogenous nucleation. Utilizing this gas flow assisted vacuum drying process, we find that regular, optically dense and pinhole free MHP layers can be fabricated via inkjet printing, which yield solar cells with a power conversion efficiency of 16 , as compared to 4.5 for vacuum dryin

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Unraveling Reversible Quenching Processes of O2, N2, Ar, and H2O in Metal Halide Perovskites at Moderate Photon Flux Densities

Metal halide perovskites MHP , as used in photovoltaic PV applications, show a rich photophysics in inert and ambient atmosphere. The presence of atmospheric molecules leads to processes that enhance as well as reduce their photoluminescence PL emission. Various phenomena are previously described for a wide variety of gas molecules and different classes of MHP, with a particular interest on the long term stability for PV applications. However, reversible PL quenching PLQ processes, which may be regarded equally important for the performance of PV and other optoelectronic applications, are neglected in other studies. This holds true for O2 and H2O, but especially for low reactive gases such as nitrogen and argon. Using low excitation densities, it is shown that noticeable and reversible PLQ, in addition to PL enhancements, can already be observed for O2, N2, and Ar as well as for H2O at low concentrations of 1 mbar. The nature and origin of the quenching processes are further elucidated by applying the Stern Volmer analysis, also employed to determine whether static and dynamic PLQ processes happen for the different quenching gases. The strongest static PLQ is found for O2 and H2O. MHPs in N2 and Ar atmospheres display a moderate PLQ effec

The Electronic Properties of a 2D Ruddlesden Popper Perovskite and its Energy Level Alignment with a 3D Perovskite Enable Interfacial Energy Transfer

The success of using 2D Ruddlesden Popper metal halide perovskites MHPs in optoelectronic devices has ignited great interest as means for energy level tuning at the interface with 3D MHPs. Inter alia, the application of 2D phenylethylammonium lead quaternary iodide PEA2PbI4 3D MHPs interfaces has improved various optoelectronic devices, where a staggered type II energy level alignment is often assumed. However, a type II heterojunction seems to contradict the enhanced photoluminescence observed for 2D PEA2PbI4 3D MHP interfaces, which raises fundamental questions about the electronic properties of such junctions. In this study, using direct and inverse photoelectron spectroscopy, it is revealed that a straddling type I energy level alignment is present at 2D PEA2PbI4 3D methylammonium lead triiodide MAPbI3 interfaces, thus explaining that the photoluminescence enhancement of the 3D perovskite is induced by energy transfer from the 2D perovskite. These results provide a reliable fundamental understanding of the electronic properties at the investigated 2D 3D MHP interfaces and suggest careful re consideration of the electronic properties of other 2D 3D MHP heterostructure