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Metal halide perovskites have shown promising optoelectronic properties suitable for light-emitting applications. The development of perovskite light-emitting diodes (PeLEDs) has progressed rapidly over the past several years, reaching high external quantum efficiencies of over 20%. In this Review, we focus on the key requirements for high-performance PeLEDs, highlight recent advances on materials and devices, and emphasize the importance of reliable characterization of PeLEDs. We discuss possible approaches to improve the performance of blue and red PeLEDs, increase the long-term operational stability and reduce toxicity hazards. We also provide an overview of the application space made possible by recent developments in high-efficiency PeLEDs. The development of perovskite emitters, their use in light-emitting devices, and the challenges in enhancing the efficiency and stability, as well as reducing the potential toxicity of this technology are discussed in this Review.

Although perovskite light-emitting diodes (PeLEDs) have recently experienced significant progress, there are only scattered reports of PeLEDs with both high efficiency and long operational stability, calling for additional strategies to address this challenge. Here, we develop perovskite-molecule composite thin films for efficient and stable PeLEDs. The perovskite-molecule composite thin films consist of in-situ formed high-quality perovskite nanocrystals embedded in the electron-transport molecular matrix, which controls nucleation process of perovskites, leading to PeLEDs with a peak external quantum efficiency of 17.3% and half-lifetime of approximately 100 h. In addition, we find that the device degradation mechanism at high driving voltages is different from that at low driving voltages. This work provides an effective strategy and deep understanding for achieving efficient and stable PeLEDs from both material and device perspectives. The field of perovskite light-emitting diodes witnesses rapid development in both device processing strategies and performances. Here Wang et al . develop high-quality perovskite-molecule composite thin films and achieve high quantum efficiency of 17.3% and half-lifetime of 100 h.

Black phase CsPbI 3 is attractive for optoelectronic devices, while usually it has a high formation energy and requires an annealing temperature of above 300 °C. The formation energy can be significantly reduced by adding HI in the precursor. However, the resulting films are not suitable for light-emitting applications due to the high trap densities and low photoluminescence quantum efficiencies, and the low temperature formation mechanism is not well understood yet. Here, we demonstrate a general approach for deposition of γ- CsPbI 3 films at 100 °C with high photoluminescence quantum efficiencies by adding organic ammonium cations, and the resulting light-emitting diode exhibits an external quantum efficiency of 10.4% with suppressed efficiency roll-off. We reveal that the low-temperature crystallization process is due to the formation of low-dimensional intermediate states, and followed by interionic exchange. This work provides perspectives to tune phase transition pathway at low temperature for CsPbI 3 device applications. Exploiting low-temperature formed black phase CsPbI 3 for light-emitting applications remains a challenge. Here, the authors propose a method to enable the deposition of γ-CsPbI 3 films at 100C and demonstrate a light-emitting diode with an external quantum efficiency of 10.4% with suppressed efficiency roll-off.

To date, the pathogenesis of the serofast state is unclear and it is hard to predict serofast occurrence. [...]we evaluated factors related to the serofast state. A lower baseline RPR titer may indicate that the immune system is suppressed or dysfunctional. [...]the immune system is unable to mount an efficient inflammatory and immune response, which may be owing to the failure of rapid and thorough spirochete removal. [15] However, in these studies, the sample size was small and performed only in China. [...]the link between serofast status and T. pallidum repeat gene subtypes requires further study. Rolfs et al[17] performed a randomized trial in 541 early-stage patients treated with penicillin G benzathine (2.4 million units); they observed that despite enhancement with a 10-day amoxicillin-probenecid regimen, no improvement in serofast rates after 1 year of treatment was observed, regardless of HIV status.

The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor–acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor–acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.

A 24 year old man with two years of progressively worsening, mildly pruritic skin lesions presented after failed treatment for presumed dermatitis, folliculitis, and subacute cutaneous lupus erythematosus (figs 1 and 2).

Metabolic-sensing ATP-sensitive K+ channels (KATP channels) adjust membrane excitability to match cellular energetic demand. In the heart, KATP channel activity has been linked to homeostatic shortening of the action potential under stress, yet the requirement of channel function in securing cardiac electrical stability is only partially understood. Here, upon catecholamine challenge, disruption of KATP channels, by genetic deletion of the pore-forming Kir6.2 subunit, produced defective cardiac action potential shortening, predisposing the myocardium to early afterdepolarizations. This deficit in repolarization reserve, demonstrated in Kir6.2-knockout hearts, translated into a high risk for induction of triggered activity and ventricular dysrhythmia. Thus, intact KATP channel function is mandatory for adequate repolarization under sympathetic stress providing electrical tolerance against triggered arrhythmia.

In this month's Case Study, Cha and colleagues present a 51-year-old male patient referred for consideration for heart transplantation because of recently diagnosed congestive heart failure refractory to medical therapy. He was diagnosed with cardiomyopathy resulting from pulmonary vein tachycardia, which was treated with catheter-based radiofrequency ablation of pulmonary vein tachycardia focus. Background A 51-year-old male was referred for consideration for heart transplantation because of recently diagnosed congestive heart failure refractory to medical therapy. Previous echocardiography demonstrated a left ventricular ejection fraction of approximately 15% with global hypokinesia. Coronary angiography did not reveal any clinically significant obstructive coronary artery disease and an electrocardiogram documented atrial fibrillation with a rapid ventricular rate of 130 beats/min. Other laboratory tests including thyroid function test were unremarkable. The patient's main complaints were dyspnea on exertion, and orthopnea with minimal palpitations. Investigations Physical examination, laboratory testing, electrocardiography, Holter monitoring, chest radiography, transthoracic echocardiography, transesophageal echocardiography, coronary angiogram, and electrophysiologic study with catheter ablation. Diagnosis Cardiomyopathy resulting from pulmonary vein tachycardia. Management Catheter-based radiofrequency ablation of the focus of pulmonary vein tachycardia.