Short-branched alkyl sulfobetaine-passivated CsPbBr nanocrystals for efficient green light emitting diodes.

Inorganic cesium lead bromide nanocrystals (CsPbBr NCs) hold promising prospects for high performance green light-emitting diodes (LEDs) due to their exceptional color purity and high luminescence efficiency. However, the common ligands employed for passivating these indispensable NCs, such as long-chain organic ligands like oleic acid and oleylamine (OA/OAm), display highly dynamic binding and electronic insulating issues, thereby resulting in a low efficiency of the as-fabricated LEDs. Herein, we report a new zwitterionic short-branched alkyl sulfobetaine ligand, namely trioctyl(propyl-3-sulfonate) ammonium betaine (TOAB), to passivate CsPbBr NCs a feasible one-step solution synthesis, enabling efficiency improvement of CsPbBr NC-based LEDs.

Mitigating halide ion migration by resurfacing lead halide perovskite nanocrystals for stable light-emitting diodes.

Lead halide perovskite nanocrystals are promising for next-generation high-definition displays, especially in light of their tunable bandgaps, high color purities, and high carrier mobility. Within the past few years, the external quantum efficiency of perovskite nanocrystal-based light-emitting diodes has progressed rapidly, reaching the standard for commercial applications. However, the low operational stability of these perovskite nanocrystal-based light-emitting diodes remains a crucial issue for their industrial development.

Pseudohalogen Resurfaced CsPbBr Nanocrystals for Bright, Efficient, and Stable Green-Light-Emitting Diodes.

Lead halide perovskite nanocrystals (LHP NCs) are regarded as promising emitters for next-generation ultrahigh-definition displays due to their high color purity and wide color gamut. Recently, the external quantum efficiency (EQE) of LHP NC based light-emitting diodes (PNC LEDs) has been rapidly improved to a level required by practical applications. However, the poor operational stability of the device, caused by halide ion migration at the grain boundary of LHP NC thin films, remains a great challenge.

A LaCl-based lithium superionic conductor compatible with lithium metal.

Inorganic superionic conductors possess high ionic conductivity and excellent thermal stability but their poor interfacial compatibility with lithium metal electrodes precludes application in all-solid-state lithium metal batteries. Here we report a LaCl-based lithium superionic conductor possessing excellent interfacial compatibility with lithium metal electrodes. In contrast to a LiMCl (M = Y, In, Sc and Ho) electrolyte lattice, the UCl-type LaCl lattice has large, one-dimensional channels for rapid Li conduction, interconnected by La vacancies via Ta doping and resulting in a three-dimensional Li migration network.

Planar defect-free pure red perovskite light-emitting diodes via metastable phase crystallization.

Solution-processable all-inorganic CsPbIBr perovskite holds great potential for pure red light-emitting diodes. However, the widely existing defects in this mixed halide perovskite markedly limit the efficiency and stability of present light-emitting diode devices. We here identify that intragrain Ruddlesden-Popper planar defects are primary forms of such defects in the CsPbIBr thin film owing to the lattice strain caused by inhomogeneous halogen ion distribution.

Thermochromic Phosphors Based on One-Dimensional Ionic Copper-Iodine Chains Showing Solid-State Photoluminescence Efficiency Exceeding 99 .

Thermochromic phosphors are intriguing materials for realizing thermochromic behaviors of light-emitting diodes. Here a highly luminescent and stable thermochromic phosphor based on one-dimensional Cu I (4-dimethylamino-1-ethylpyridinium) is reported. This unique ionic copper-iodine chain-based hybrid exhibits near-unity photoluminescence efficiency owing to the through-space charge-transfer character of relevant electronic transitions.

α-BaF Nanoparticle Substrate-Enabled γ-CsPbI Heteroepitaxial Growth for Efficient and Bright Deep-Red Light-Emitting Diodes.

All-inorganic CsPbI perovskite is attractive for deep-red light-emitting diodes (LEDs) because of its excellent carrier mobility, high color purity, and solution processability. However, the high phase transition energy barrier of optically active CsPbI black phase hinders the fabrication of efficient and bright LEDs. Here, we report a novel α-BaF nanoparticle substrate-promoted solution-processable heteroepitaxial growth to overcome this hindrance and obtain high-quality optically active γ-CsPbI thin films, achieving efficient and bright deep-red LEDs.

High Color Purity and Efficient Green Light-Emitting Diode Using Perovskite Nanocrystals with the Size Overly Exceeding Bohr Exciton Diameter.

Lead halide perovskite nanocrystals (PNCs) are emerging as promising light emitters to be actively explored for high color purity and efficient light-emitting diodes. However, the most reported lead halide perovskite nanocrystal light-emitting diodes (PNCLEDs) encountered issues of emission line width broadening and operation voltage elevating caused by the quantum confinement effect. Here, we report a new type of PNCLED using large-size CsPbBr PNCs overly exceeding the Bohr exciton diameter, achieving ultranarrow emission line width and rapid brightness rise around the turn-on voltage.

Spectrally Stable and Efficient Pure Red CsPbI Quantum Dot Light-Emitting Diodes Enabled by Sequential Ligand Post-Treatment Strategy.

Metal halide perovskites are promising semiconductors for next-generation light-emitting diodes (LEDs) due to their high luminance, excellent color purity, and handily tunable band gap. However, it remains a great challenge to develop perovskite LEDs (PeLEDs) with pure red emission at the wavelength of 630 nm. Herein, we report a spectrally stable and efficient pure red PeLED by employing sequential ligand post-treated CsPbI quantum dots (QDs).

Chiral Phosphine-Copper Iodide Hybrid Cluster Assemblies for Circularly Polarized Luminescence.

Chiral chromophores and their ordered assemblies are intriguing for yielding circularly polarized luminescence (CPL) and exploring intrinsic structure-light emission relationships. With the extensively studied chiral organic molecules and inorganic nanoparticle assemblies for the amplified CPL, the assemblies of copper halide hybrid clusters have attracted intensive attention due to their potential efficient CPL. Here, we report robust chiral phosphine-copper iodide hybrid clusters and their layered assemblies in crystalline states for amplified CPL.

Bright and Near-Unity Polarized Light Emission Enabled by Highly Luminescent CuI-Dimer Cluster-Based Hybrid Materials.

As one fundamental property of light, polarization has a huge impact in quantum optics and optoelectronics through light-matter interactions. However, the bright and near-unity polarized light emissions in the visible range by solid crystalline materials are scantly realized. Here, we report well-defined quasi two-dimensional (2D) hybrid crystals based on the linear alignment of CuI-dimer/bidentate ligand hybrid clusters for achieving bright and near-unity linearly polarized light emissions.

Modulation of Metal Halide Structural Units for Light Emission.

ConspectusWith the development of solid-state lighting technology, efficient light sources that combine high brightness, wide range, and good stability are in high demand for next-generation lighting and displays. Metal halides are emerging as promising luminescent materials due to their versatility for desirable light emission manipulations. This is because the optical activity of the metal halide material depends on the metal halide structural unit and the organic ions or coordinated organic ligands.

Suppressing Auger Recombination in Cesium Lead Bromide Perovskite Nanocrystal Film for Bright Light-Emitting Diodes.

All-inorganic cesium lead halide perovskite colloidal nanocrystals are attractive for next-generation light-emitting diodes because of their high color purity, but the nonradiative Auger recombination in perovskite nanocrystal film limits the efficiency and brightness of the fabricated devices. Here, we introduce a surface-engineering process to exchange the original long-chain oleic acid/oleylamine ligands by the cerium-tributylphosphine oxide hybrid ligands to suppress nonradiative Auger recombination in CsPbBr NC film for bright and low-efficiency roll-off light-emitting diodes. Using ultrafast transient absorption and time-resolved photoluminescence spectroscopy, we demonstrate that the hybrid ligand passivation can efficiently remove surface trap states to enhance radiative recombination and homogenize the exciton concentration to suppress nonradiative Auger recombination in the CsPbBr nanocrystal thin film.

Highly Luminescent Copper Iodide Cluster Based Inks with Photoluminescence Quantum Efficiency Exceeding 98.

Highly luminescent inks are desirable for various applications such as decorative coating, art painting, and anticounterfeiting, to name a few. However, present inks display low photoluminescent efficiency requiring a strong excitation light to make them glow. Here, we report a highly luminescent ink based on the copper-iodide/1-Propyl-1,4-diazabicyclo[2.

Potassium Bromide Surface Passivation on CsPbIBr Nanocrystals for Efficient and Stable Pure Red Perovskite Light-Emitting Diodes.

All-inorganic lead halide perovskite nanocrystals (NCs) are potential candidates for fabricating high-performance light-emitting diodes (LEDs) owing to their precisely tunable bandgaps, high photoluminescence (PL) efficiency, and excellent color purities. However, the performance of pure red (630-640 nm) all-inorganic perovskite LEDs is still limited by the halide segregation-induced instability of the electroluminescence (EL) of mixed halide CsPbIBr NCs. Herein, we report an effective approach to improving the EL stability of pure red all-inorganic CsPbIBr NC-based LEDs via the passivation of potassium bromide on NCs.

Metal Halide Perovskite Supercrystals: Gold-Bromide Complex Triggered Assembly of CsPbBr Nanocubes.

Using nanocrystals as "artificial atoms" to construct supercrystals is an interesting process to explore the stacking style of nanoscale building blocks and corresponding collective properties. Various types of semiconducting supercrystals have been constructed via the assembly of nanocrystals driven by the entropic, electrostatic, or van der Waals interactions. We report a new type of metal halide perovskite supercrystals via the gold-bromide complex triggered assembly of newly emerged attractive CsPbBr nanocubes.

Attitudes Toward Advance Directives Among Patients and Their Family Members in China.

Objectives: Chinese people are generally unfamiliar with the concept of advance care planning or advance directives (ACP/ADs), which raises dilemmas in life-support choice and can even affect clinical decision making. To understand and address the issues involved better, we investigated the awareness of ACP/ADs in China, as well as people's attitudes toward medical autonomy and end-of-life care.

Design: A multicenter cross-sectional survey, conducted from August 1 to December 31, 2016.

Free-Standing Copper Nanowire Network Current Collector for Improving Lithium Anode Performance.

Lithium metal is one of the most attractive anode materials for next-generation lithium batteries due to its high specific capacity and low electrochemical potential. However, the poor cycling performance and serious safety hazards, caused by the growth of dendritic and mossy lithium, has long hindered the application of lithium metal based batteries. Herein, we reported a rational design of free-standing Cu nanowire (CuNW) network to suppress the growth of dendritic lithium via accommodating the lithium metal in three-dimensional (3D) nanostructures.

[The clinical application of bi-level positive airway pressure noninvasive ventilator for home mechanical ventilation via tracheostomy in patients with amyotrophic lateral sclerosis].

Objective: To study the feasibility of the bi-level positive airway pressure (BiPAP) non-invasive ventilator used in home mechanical ventilation for long-term tracheostomy-mechanical ventilation (TMV) in patients with amyotrophic lateral sclerosis (ALS).

Methods: Sixteen patients (12 men and 4 women, mean age 59 years) with ALS were selected for this study at Respiratory Department of the Shougang Hospital, Peking University from January 2002 to March 2008. After the disease had been controlled by anti-infective therapy and comprehensive treatment, the patients received TMV, through the improved ("Xiang's" connection) non-invasive BiPAP ventilator connected with tracheotomy tube, and on-going home mechanical ventilation (HMV).

[The efficacy and safety of long term home noninvasive positive pressure ventilation in patients with stable severe chronic obstructive pulmonary disease].

Objective: To evaluate the long term efficacy and safety of long term home noninvasive positive pressure ventilation (HNPPV) in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD).

Methods: Forty patients with stable severe COPD [arterial PaCO2>or=55 mm Hg (1 mm Hg=0.133 kPa)] after hospital discharge were divided into 2 groups: the HNPPV group (n=20) with conventional therapy and HNPPV, and the control group (n=20) with conventional therapy only.