Nanosurface-reconstructed perovskite for highly efficient and stable active-matrix light-emitting diode display.

Perovskite quantum dots (QDs) are promising for various photonic applications due to their high colour purity, tunable optoelectronic properties and excellent solution processability. Surface features impact their optoelectronic properties, and surface defects remain a major obstacle to progress. Here we develop a strategy utilizing diisooctylphosphinic acid-mediated synthesis combined with hydriodic acid-etching-driven nanosurface reconstruction to stabilize CsPbI3 QDs. Diisooctylphosphinic acid strongly adsorbs to the QDs and increases the formation energy of halide vacancies, enabling nanosurface reconstruction. The QD film with nanosurface reconstruction shows enhanced phase stability, improved photoluminescence endurance under thermal stress and electric field conditions, and a higher activation energy for ion migration. Consequently, we demonstrate perovskite light-emitting diodes (LEDs) that feature an electroluminescence peak at 644 nm. These LEDs achieve an external quantum efficiency of 28.5% and an operational half-lifetime surpassing 30 h at an initial luminance of 100 cd m-2, marking a tenfold improvement over previously published studies. The integration of these high-performance LEDs with specifically designed thin-film transistor circuits enables the demonstration of solution-processed active-matrix perovskite displays that show a peak external quantum efficiency of 23.6% at a display brightness of 300 cd m-2. This work showcases nanosurface reconstruction as a pivotal pathway towards high-performance QD-based optoelectronic devices.

Efficient and bright broadband electroluminescence based on environment-friendly metal halide nanoclusters.

Broadband electroluminescence based on environment-friendly emitters is promising for healthy lighting yet remains an unprecedented challenge to progress. The copper halide-based emitters are competitive candidates for broadband emission, but their high-performance electroluminescence shows inadequate broad emission bandwidth of less than 90 nm. Here, we demonstrate efficient ultra-broadband electroluminescence from a copper halide (CuI) nanocluster single emitter prepared by a one-step solution synthesis-deposition process, through dedicated design of ligands and subtle selection of solvents. The CuI nanocluster exhibits high rigidity in the excitation state as well as dual-emissive modes of phosphorescence and temperature-activated delayed fluorescence, enabling the uniform cluster-composed film to show excellent stability and high photoluminescent efficiency. In consequence, ultra-broadband light-emitting diodes (LEDs) present nearly identical performance in an inert or air atmosphere without encapsulation and outstanding high-temperature operation performance, reaching an emission full width at half maximum (FWHM) of ~120 nm, a peak external quantum efficiency of 13%, a record maximum luminance of ~50,000 cd m-2, and an operating half-lifetime of 137 h at 100 cd m-2. The results highlight the potential of copper halide nanoclusters for next-generation healthy lighting.

Controlling Interfacial Amidation Reaction Rate to Regulate Crystal Growth toward High-Performance FAPbBr3-Based Inverted Light-Emitting Diodes.

Controlling interfacial reactions is critical for zinc oxide (ZnO)-based inverted perovskite light-emitting diodes (PeLEDs), boosting the external quantum efficiency (EQE) of the near-infrared device to above 20%. However, violent interfacial reactions between the bromine-based perovskites and ZnO-based films severely limit the performance of inverted green PeLEDs, whose efficiency and stability lag far behind those of their near-infrared counterparts. Here, a controllable interfacial amidation between the bromine-based perovskites and magnesium-doped ZnO (ZnMgO) film utilizing caprylyl sulfobetaine (SFB) is realized. The SFB molecules strongly interact with formamidinium bromide, decelerating the amidation reaction between formamidinium and carboxylate groups on the ZnMgO film, thus regulating the crystallization of FAPbBr3. Combined with the passivation of benzylamine, a FAPbBr3 bulk film directly deposited on a ZnMgO substrate with single-crystal characteristics is obtained, exhibiting a high photoluminescence quantum yield of above 80%. The resultant PeLEDs demonstrate a peak EQE of exceeding 20% at a high luminance of 120,000 cd m-2 and a half lifetime of 26 min at 11,000 cd m-2, representing the state-of-the-art inverted green electroluminescence. This work resolves the crucial issues of violent interfacial reactions and provides a strategy toward inverted green PeLEDs with outstanding performance.

Self-Competitive Growth of CsPbBr3 Planar Nanowire Array.

Semiconductor planar nanowire arrays (PNAs) are essential for achieving large-scale device integration. Direct heteroepitaxy of PNAs on a flat substrate is constrained by the mismatch in crystalline symmetry and lattice parameters between the substrate and epitaxial nanowires. This study presents a novel approach termed "self-competitive growth" for heteroepitaxy of CsPbBr3 PNAs on mica. The key to inducing the self-competitive growth of CsPbBr3 PNAs on mica involves restricting the nucleation of CsPbBr3 nanowires in a high-adsorption region, which is accomplished by overlaying graphite sheets on the mica surface. Theoretical calculations and experimental results demonstrate that CsPbBr3 nanowires oriented perpendicular to the boundary of the high-adsorption area exhibit greater competitiveness in intercepting the growth of nanowires in the other two directions, resulting in PNAs with a consistent orientation. Moreover, these PNAs exhibit low-threshold and stable amplified spontaneous emission under one-, two-, and three-photon excitation, indicating their potential for an integrated laser array.

Nucleophilic Reaction-Enabled Chloride Modification on CsPbI3 Quantum Dots for Pure Red Light-Emitting Diodes with Efficiency Exceeding 26 .

High-performance pure red perovskite light-emitting diodes (PeLEDs) with an emission wavelength shorter than 650 nm are ideal for wide-color-gamut displays, yet remain an unprecedented challenge to progress. Mixed-halide CsPb(Br/I)3 emitter-based PeLEDs suffer spectral stability induced by halide phase segregation and CsPbI3 quantum dots (QDs) suffer from a compromise between emission wavelength and electroluminescence efficiency. Here, we demonstrate efficient pure red PeLEDs with an emission centered at 638 nm based on PbClx -modified CsPbI3 QDs. A nucleophilic reaction that releases chloride ions and manipulates the ligand equilibrium of the colloidal system is developed to synthesize the pure red emission QDs. The comprehensive structural and spectroscopic characterizations evidence the formation of PbClx outside the CsPbI3 QDs, which regulates exciton recombination and prevents the exciton from dissociation induced by surface defects. In consequence, PeLEDs based on PbClx -modified CsPbI3 QDs with superior optoelectronic properties demonstrate stable electroluminescence spectra at high driving voltages, a record external quantum efficiency of 26.1 %, optimal efficiency roll-off of 16.0 % at 1000 cd m-2 , and a half lifetime of 7.5 hours at 100 cd m-2 , representing the state-of-the-art pure red PeLEDs. This work provides new insight into constructing the carrier-confined structure on perovskite QDs for high-performance PeLEDs.

Unraveling Mechanisms of Highly Efficient Yet Stable Electrochemiluminescence from Quantum Dots.

With CdSe/CdS/ZnS core/shell/shell quantum dots (QDs) as the model system, time- and potential-resolved spectroelectrochemical measurements are successfully applied for studying the general mechanisms and kinetics of electrochemiluminescence (ECL) generation. The rate constant of electron injection from the cathode into a QD to form a negatively charged QD (QD-) increases monotonically from -0.88 V to -1.2 V (vs Ag/AgCl). Mainly due to the deep LUMO of the QDs, the resulting QD- as the key intermediate for ECL generation is structurally stable and possesses very slow spontaneous deionization channels. The latter (the main non-ECL channels) are usually 3-4 orders of magnitude slower than the rate constant of the successive hole injection from an active co-reactant into a QD-. The kinetic studies quantify the internal ECL quantum yield of ideal QD ECL emitters to be nearly identical to that of photoluminescence, which is near unity for the current system. Identification of the key intermediate, discovery of the related elementary steps, and determination of all rate constants not only establish a general framework for understanding ECL generation but also offer basic design rules for ECL emitters.

Robust Hand Gesture Recognition Using a Deformable Dual-Stream Fusion Network Based on CNN-TCN for FMCW Radar.

Hand Gesture Recognition (HGR) using Frequency Modulated Continuous Wave (FMCW) radars is difficult because of the inherent variability and ambiguity caused by individual habits and environmental differences. This paper proposes a deformable dual-stream fusion network based on CNN-TCN (DDF-CT) to solve this problem. First, we extract range, Doppler, and angle information from radar signals with the Fast Fourier Transform to produce range-time (RT) and range-angle (RA) maps. Then, we reduce the noise of the feature map. Subsequently, the RAM sequence (RAMS) is generated by temporally organizing the RAMs, which captures a target's range and velocity characteristics at each time point while preserving the temporal feature information. To improve the accuracy and consistency of gesture recognition, DDF-CT incorporates deformable convolution and inter-frame attention mechanisms, which enhance the extraction of spatial features and the learning of temporal relationships. The experimental results show that our method achieves an accuracy of 98.61%, and even when tested in a novel environment, it still achieves an accuracy of 97.22%. Due to its robust performance, our method is significantly superior to other existing HGR approaches.

Neuritin affects the activity of neuralized-like 1 by promoting degradation and weakening its affinity for substrate.

Neuritin plays a key role in neural development and regeneration by promoting neurite outgrowth and synapse maturation. Our previous research revealed the mechanism by which neuritin inhibits Notch signaling through interaction with neuralized-like 1 (Neurl1) to promote neurite growth. However, how neuritin regulates Notch signaling through Neurl1 has not been elucidated. Here, we first confirm that neuritin is an upstream regulator of Neurl1 and inhibits Notch signaling through Neurl1. Neurl1 is an E3 ubiquitin ligase that can promote ubiquitination and endocytosis of the Notch1 ligand Jagged1. Therefore, we observe the effect of neuritin on the ligase activity of Neurl1. The results indicate that neuritin inhibits Neurl1 activity by reducing the ubiquitination level and endocytosis of the target protein Jagged1. Moreover, we find that decreased activity of Neurl1 results in reduced expression of Notch receptor Notch intracellular domain (NICD) and downstream target gene hairy and enhancer of split-1 ( HES1). Furthermore, we investigate how neuritin affects Neurl1 enzyme activity. The results show that neuritin not only weakens the affinity between Neurl1 and Jagged1 but also promotes the degradation of Neurl1 by the 26S proteasome pathway. Taken together, our results suggest that neuritin negatively regulates Notch signaling by inhibiting the activity of Neurl1, promoting the degradation of Neurl1 and weakening the affinity of Neurl1 for Jagged1. Our study clarifies the molecular mechanisms of neuritin in regulating the Notch signaling pathway and provides new clues about how neuritin mediates neural regeneration and plasticity.

Impact of wechat-based "hospital-home" integrated health education on exercise minded patients with chronic heart failure

Objective: to explore the impact of integrated health education based on WeChat "hospital-family" on exercise-minded patients with chronic heart failure. Methods: One hundred and forty patients with CHF who were hospitalized in the Department of Cardiovascular Medicine from December 2019 to May 2020 were randomly divided into a control group (n=64) and an intervention group (n=65) according to the random number table method. The control group used the traditional preaching model, and the intervention group implemented the integrated hospital-family health education model based on WeChat. After 3 months of intervention, the self-efficacy, self-management ability, quality of life and exercise tolerance of the two groups were compared. Results: Exercise-minded Patients in the intervention group had significantly higher dry strength, quality of life and exercise tolerance (P< 0.05). Conclusion: WeChat-based integrated hospital-family health education can improve self-efficacy and self-management ability of CHF exercise-minded patients, thus improving quality of life cardiac function. (AU)

Visual outcomes and subjective experience with three intraocular lenses based presbyopia correcting strategies in cataract patients.

To compare the visual outcomes and subjective experience of three intraocular lenses (IOL) implant strategies. Retrospective comparative study. This study comprised patients who underwent phacoemulsification and bilateral implantation of extended depth of focus (EDOF) IOL (ZXR00; EDOF group), blended implantation of EDOF and bifocal IOL (ZXR00/ZLB00; blended group), and bilateral implantation of trifocal IOL (AT LISA tri 839MP; trifocal group). The outcomes included visual acuity (VA), visual defocus curve, contrast sensitivity, visual quality, quality of life, spectacle independence, and patient satisfaction. Follow-up was performed 3 months after the surgery. This study included 114 eyes of 57 patients (20 in EDOF group; 16 in blended group; 21 in trifocal group). Patients in the three groups had high quality of life, patient satisfaction, and good contrast sensitivity. The EDOF group had the worst near VA, but the visual quality was the best. The blended group had good VA and slight photic disturbance. The trifocal group obtained the best whole range of VA, but the photic disturbance was significantly severe than the EDOF group. Both the blended and trifocal groups achieved high spectacle independence, but some patients in the EDOF group need spectacle when dealing with close-range tasks.

Stereopsis and visual acuity: Bilateral trifocal versus blended extended depth of focus and diffractive bifocal intraocular lenses.

Purpose: To compare stereopsis and visual acuity (VA) between bilateral implantation of trifocal intraocular lenses (IOL) and blended implantation of an extended depth of focus (EDOF) IOL with a bifocal IOL. Methods: This is a non-randomized, prospective comparative study included 74 eyes of 37 patients who underwent phacoemulsification and bilateral implantation of AT LISA tri 839MP IOL (bilateral group; 21 patients) or blended implantation of Tecnis Symfony ZXR00 and Tecnis ZLB00 IOL (blended group; 16 patients). The primary outcomes were stereoacuity and binocular VA. The secondary outcomes were visual defocus curve, quality of life, and patient satisfaction. Follow-up was performed 3 months after the surgery. Results: The mean near stereoacuity was 49.76 ± 22.67 and 120.63 ± 90.94 seconds of arc (arcsec) in the bilateral and blended groups, respectively (P < 0.001). Near stereoacuity was positively correlated with VA difference of two eyes (r = 0.896, P < 0.001). The mean binocular uncorrected visual acuity at 40 cm, 80 cm, 5 m, and corrected distance visual acuity at 5 m of the bilateral and blended groups was not statistically significant different. The bilateral group had better VA at a vergence from -2.5 to -4.0 D. Both groups obtained high quality of life and patient satisfaction scores. Conclusion: The bilateral and blended groups achieved good binocular VA, quality of life, and high patient satisfaction. However, the near stereoacuity of the blended group was worse.

Anomalous Emission Shift of CdSe/CdS/ZnS Quantum Dots at Cryogenic Temperatures.

The band-gap energy of most bulk semiconductors tends to increase as the temperature decreases. However, non-monotonic temperature dependence of the emission energy has been observed in semiconductor quantum dots (QDs) at cryogenic temperatures. Here, using stable and highly efficient CdSe/CdS/ZnS QDs as the model system, we quantitatively reveal the origins of the anomalous emission red-shift (∼8 meV) below 40 K by correlating ensemble and single QD spectroscopy measurements. About one-quarter of the anomalous red-shift (∼2.2 meV) is caused by the temperature-dependent population of the band-edge exciton fine levels. The enhancement of electron-optical phonon coupling caused by the increasing population of dark excitons with temperature decreases contributes an ∼3.4 meV red-shift. The remaining ∼2.4 meV red-shift is attributed to temperature-dependent electron-acoustic phonon coupling.

Phonon-assisted up-conversion photoluminescence of quantum dots.

Phonon-assisted up-conversion photoluminescence can boost energy of an emission photon to be higher than that of the excitation photon by absorbing vibration energy (or phonons) of the emitter. Here, up-conversion photoluminescence power-conversion efficiency (power ratio between the emission and excitation photons) for CdSe/CdS core/shell quantum dots is observed to be beyond unity. Instead of commonly known defect-assisted up-conversion photoluminescence for colloidal quantum dots, temperature-dependent measurements and single-dot spectroscopy reveal the up-conversion photoluminescence and conventional down-conversion photoluminescence share the same electron-phonon coupled electronic states. Ultrafast spectroscopy results imply the thermalized excitons for up-conversion photoluminescence form within 200 fs, which is 100,000 times faster than the radiative recombination rate of the exciton. Results suggest that colloidal quantum dots can be exploited as efficient, stable, and cost-effective emitters for up-conversion photoluminescence in various applications.

Delocalized Surface Electronic States on Polar Facets of Semiconductor Nanocrystals.

Wurtzite CdSe@CdS dot@platelet nanocrystals with (001) and (00-1) polar facets as the basal planes and (100) family of nonpolar facets as the side planes are applied for studying surface defects on semiconductor nanocrystals. When they are terminated with cadmium ions coordinated with carboxylate ligands, a single set of absorption features and band-edge photoluminescence (PL) with near unity PL quantum yield and monoexponential PL decay dynamics (lifetime ∼28 ns) are observed. In addition to these spectral signatures, when the surface is converted to sulfur-terminated, a second set of sharp absorption features with decent extinction coefficients and a secondary band-edge PL with low PL quantum yield and long-lifetime (>78 ns) PL decay dynamics are reproducibly recorded. Photochemical analysis confirms that the secondary UV-vis and PL spectral features are quantitatively correlated with each other. Chemical analysis and X-ray photoelectron spectroscopy measurements confirm that such secondary spectral features are well correlated with the sulfide (such as -SH) and disulfide (such as -S-S-) surface sites of a basal plane, which likely form surface hole electronic states delocalized on the entire basal plane. Results suggest that, for studying surface defects on semiconductor nanocrystals, it is essential to prepare a nearly monodisperse surface structure in terms of facets and surface chemical bonding.

Zinc Finger CCCH-Type Antiviral Protein 1 Restricts the Viral Replication by Positively Regulating Type I Interferon Response.

Zinc finger CCCH-type antiviral protein 1 (ZC3HAV1) is a host antiviral factor that can repress translation and promote degradation of specific viral mRNAs. In this study, we found that expression of ZC3HAV1 was significantly induced by infection with influenza A virus (IAV) and Sendai virus (Sev). It was shown that deficiency of IFNAR resulted in a dramatic decrease in the virus-induced expression of ZC3HAV1. Furthermore, transfection with poly(I:C) and treatment with interferon ß (IFN-ß) induced the ZC3HAV1 expression. Interference with the endogenous expression of ZC3HAV1 enhanced the replication of influenza virus by impairing the production of IFN-ß and MxA, following the infection of influenza virus. In contrast, ectopic expression of ZC3HAV1 significantly restricted the replication of influenza virus by increasing the IFN-ß expression. In addition, ZC3HAV1 also promoted the induction of tumor necrosis factor and interleukin 6. These results suggest that ZC3HAV1 is induced by IFN-ß/IFNAR signaling during IAV and Sev infection and involved in positive regulation of IFN-dependent innate antiviral response.

Electrochemically-stable ligands bridge the photoluminescence-electroluminescence gap of quantum dots.

Colloidal quantum dots are promising emitters for quantum-dot-based light-emitting-diodes. Though quantum dots have been synthesized with efficient, stable, and high colour-purity photoluminescence, inheriting their superior luminescent properties in light-emitting-diodes remains challenging. This is commonly attributed to unbalanced charge injection and/or interfacial exciton quenching in the devices. Here, a general but previously overlooked degradation channel in light-emitting-diodes, i.e., operando electrochemical reactions of surface ligands with injected charge carriers, is identified. We develop a strategy of applying electrochemically-inert ligands to quantum dots with excellent luminescent properties to bridge their photoluminescence-electroluminescence gap. This material-design principle is general for boosting electroluminescence efficiency and lifetime of the light-emitting-diodes, resulting in record-long operational lifetimes for both red-emitting light-emitting-diodes (T95 > 3800 h at 1000 cd m-2) and blue-emitting light-emitting-diodes (T50 > 10,000 h at 100 cd m-2). Our study provides a critical guideline for the quantum dots to be used in optoelectronic and electronic devices.

Ideal CdSe/CdS Core/Shell Nanocrystals Enabled by Entropic Ligands and Their Core Size-, Shell Thickness-, and Ligand-Dependent Photoluminescence Properties.

This work explored possibilities to obtain colloidal quantum dots (QDs) with ideal photoluminescence (PL) properties, i.e., monoexponential PL decay dynamics, unity PL quantum yield, ensemble PL spectrum identical to that at the single-dot level, single-dot PL nonblinking, and antibleaching. Using CdSe/CdS core/shell QDs as the model system, shell-epitaxy, ligand exchange, and shape conversion of the core/shell QDs were studied systematically to establish a strategy for reproducibly synthesizing QDs with the targeted properties. The key synthetic parameter during epitaxy was application of entropic ligands, i.e., mixed carboxylate ligands with different hydrocarbon chain length and/or structure. Well-controlled epitaxial shells with certain thickness (∼3-8 monolayers of the CdS shells) were found to be necessary to reach ideal photoluminescence properties, and the size of the core QDs was found to play a critical role in determining both photophysical and photochemical properties of the core/shell QDs. Effects of shape of the core QDs were unnoticeable, and shape of the core/shell QDs only affected photophysical properties quantitatively. Surface ligands, amines versus carboxylates, were important for photochemical properties (antiblinking and antibleaching) but barely affected photophysical properties as long as entropic ligands (mixed carboxylate ligands with distinguishable hydrocarbon chain lengths) were applied during epitaxy. Chemical environment (in polymer or in air), coupled with surface ligands, determined photochemical properties of the core/shell QDs with a given core size and shell thickness.