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Light-emitting diodes based on perovskite nanocrystals (PNCs-LEDs) have gained great interest for next-generation display and lighting technologies prized for their color purity, high brightness, and luminous efficiency which approach the intrinsic limit imposed by light extraction from the device structure. Although the time is ripe for the development of effective light outcoupling strategies to further boost the device performance, this technologically relevant aspect of PNC-LEDs is still without a definitive solution. Here, following theoretical guidelines and without the integration of complex photonic structures, we realize stable PNC-LEDs with external quantum efficiency (EQE) as high as 26.7%. Key to such performance is channeling the recombination zone in PNC emissive layers as thin as 10 nm, which we achieve by finely balancing charge transport using CsPbBr3 PNCs resurfaced with a nickel oxide layer. The ultrathin approach is general and, in principle, applicable to other perovskite nanostructures for fabricating highly efficient, color-tunable transparent LEDs.

Inverted perovskite nanocrystal light-emitting diodes with average 61% transmittance have been achieved with PFN as electron transport layer.

Halide perovskites have gained tremendous attention in the past decade owing to their excellent properties in optoelectronics. Recently, a fascinating property, ferroelectricity, has been discovered in halide perovskites and quickly attracted widespread interest. Compared with traditional perovskite oxide ferroelectrics, halide perovskites display natural advantages such as structural softness, low weight, and easy processing, which are highly desirable in applications pursuing miniaturization and flexibility. This review focuses on the current research progress in halide perovskite ferroelectrics, encompassing the emerging materials systems and their potential applications in ferroelectric photovoltaics, self-powered photodetection, and X-ray detection. We also attempt to point out the main challenges and possible solutions in the future development of halide perovskite ferroelectric materials. This article is protected by copyright. All rights reserved.

Artificial intelligence offers new opportunities for translucent displays. However, achieving translucent light-emitting diodes (LEDs) with high efficiency and high color purity remains a challenge. Here, we propose a strategy of using an alkali metal/inert metal (calcium/silver) bilayer metal electrode as a top electrode and perovskite nanocrystals as an emitter layer in the device structure, which allows us to not only fabricate excellent opaque LEDs but also manufacture highly efficient semitransparent LEDs with high color purity, total brightness (over 7000 cd m

Lead halide perovskite nanocrystals as promising ultrapure emitters are outstanding candidates for next-generation light-emitting diodes (LEDs) and display applications, but the thermal quenching behavior of light emission has severely hampered their real-world applications. Here, we report an anion passivation strategy to suppress the emission thermal quenching behavior of CsPbBr

CsPbCl3 nanocrystals are potential ultrapure emitters. But it is challenging to synthesize CsPbCl3 nanocrystals with sufficient stability, which impedes their application in light-emitting devices. In this work, we report a facile phosphoryl-chemistry-mediated synthesis approach to synthesizing stable CsPbCl3 nanocrystals, in which the phenylphosphonic dichloride (PhPOCl2) precursor is employed. In addition to the high reactivity of the P–Cl bond of PhPOCl2 for providing adequate Cl, the derived P=O with good proton affinity facilitates the formation of a distinct nanocrystal surface with the nonprotonated oleylamine (OLA) ligand. Accordingly, the L-type-ligand-capped CsPbCl3 nanocrystals exhibited not only bright luminance but also good stability that endured repeated purification up to 10 cycles. Based on the stable CsPbCl3 nanocrystals, we achieved violet LEDs with extremely narrow electroluminescence spectra (full width at half-maximum ≈ 10.6 nm).

Hydrochromic materials characterized by noticeable color change upon water exposure have attracted pervasive attention for their frontier applications in sensing and information technologies. However, existing hydrochromic materials typically suffer from a slow hydrochromic response as well as limited stability and color tunability. This work describes a novel hydrochromic perovskite crystal composed of zero-dimensional Cs

Sn-based perovskites are the most promising alternative materials for Pb-based perovskites to address the toxicity problem of lead. However, the development of Sn

The thermal quenching of light emission is a critical bottleneck that hampers the real-world application of lead halide perovskite nanocrystals in both electroluminescent and down-conversion light-emitting diodes. Here, we report CsPbBr3 perovskite nanocrystals with a temperature-independent emission efficiency of near unity and constant decay kinetics up to a temperature of 373 K. This unprecedented regime is obtained by a fluoride post-synthesis treatment that produces fluorine-rich surfaces with a wider energy gap than the inner nanocrystal core, yielding suppressed carrier trapping, improved thermal stability and efficient charge injection. Light-emitting diodes incorporating these fluoride-treated perovskite nanocrystals show a low turn-on voltage and spectrally pure green electroluminescence with an external quantum efficiency as high as 19.3% at 350 cd m−2. Importantly, nearly 80% of the room-temperature external quantum efficiency is preserved at 343 K, in contrast to the dramatic drop commonly observed for standard CsPbBr3 perovskite nanocrystal light-emitting diodes. These results provide a promising pathway for high-performance, practical light-emitting diodes based on perovskite nanostructures. Fluoride-treated CsPbBr3 nanocrystals emit light with near unity efficiency at temperatures of up to 373 K.

Perovskite nanocrystals (NCs) have gained great interest for next-generation light-emitting diodes (LEDs) prized for their spectrally tunable, narrow luminescence and their defect-tolerant electron...

Insulating alumina (Al2O3) prevents charge transport, which is often considered to be profitless for the performance of a photoelectric device. However, in this study, we report a strategy to impro...

The thermal quenching behavior (temperature-dependent luminescence) has severely hindered the practical applications of CsPbX3 nanocrystals. Here, we find that a simple surface treatment using ammo...

CsPbBr3 nanocrystals (NCs) are successfully prepared by using SrBr2 salt as a growth medium in a melt crystallization process. The obtained CsPbBr3 NCs exhibit a photoluminescence peak of 524 nm with a narrow emission linewidth of 25 nm, which can offer a wide color gamut display. This study can be extended to other alkali metal and alkali earth metal halides and may become a general method for the synthesis of perovskite NCs.

Nickel oxides exhibit a great potential as hole transport layers for the fabrication of efficient perovskite light-emitting diodes (LEDs) due to their high carrier mobility and good energy band matching with perovskite nanocrystals. In this work, nickel oxides were directly decorated on the CsPbBr3 nanocrystal surface through adsorption and a sequential oxidation treatment. The resulting sample shows a high photoluminescence quantum-yield of 82%. The LED using CsPbBr3 nanocrystals with nickel oxides achieves a high external quantum efficiency (EQE) of up to 16.8% with a low turn-on voltage of 2.8 V, which is much superior to that of the counterpart LED based on pristine CsPbBr3 nanocrystals (EQE = 0.7%, turn-on voltage = 5.6 V). The excellent performance of the nickel oxide decorated CsPbBr3 nanocrystal device could be attributed to the better energy level matching between the decorated nanocrystals and the transport layers of the device and more balanced charge carrier injection. Furthermore, the operational lifetime of the nickel oxide decorated CsPbBr3 nanocrystal device is 40 times longer than that of the pristine CsPbBr3 nanocrystal device.

Achieving good stability while maintaining excellent properties is one of the main challenges for enhancing the competitiveness of luminescent perovskite CsPbX3 (X=Cl, Br, I) nanocrystals (NCs). Here, we propose a facile strategy to synthesize ceramic-like stable and highly luminescent CsPbBr3 NCs by encapsulating them into silica derived from molecular sieve templates at high temperature (600–900 oC). The obtained CsPbBr3-SiO2 powders not only show high photoluminescence quantum yield (~71%), but also show an exceptional stability comparable to the ceramic Sr2SiO4:Eu2+ green phosphor. They can maintain 100% of their photoluminescence value under illumination on blue light-emitting diodes (LEDs) chips (20 mA, 2.7 V) for 1000 h, and can also survive in a harsh hydrochloric acid aqueous solution (1 M) for 50 days. We believe that the above robust stabilities will significantly enhance the potential of perovskite CsPbX3 NCs to be practically applied in LEDs and backlight displays. Synthesizing lead halide perovskite nanocrystals with good stability and excellent luminescent properties is a challenge. Here, the authors prepare ceramic-like stable perovskite nanocrystals by encapsulating them in silica derived from molecular sieve templates at high temperature.

Background In China, chronic obstructive pulmonary disease (COPD) was accounted for a quarter of the global COPD population and has become a large economic burden. However, the comprehensive picture of the COPD burden, which could inform health policy, is not readily available for all of the provinces of China. Here, we aimed to describe the burden of COPD in China, providing an up-to-date and comprehensive analysis at the national and provincial levels, and time trends from 1990 to 2019.Methods Following the methodology framework and general analytical strategies used in the GBD 2019, we analyzed the incidence, prevalence, mortality, and disability-adjusted life years (DALYs) attributable to COPD across China and the corresponding time trends from 1990 to 2019, stratified by age and province. We also presented the contribution of risk factors (e.g., smoking, ambient particulate matter, and occupational risks) to COPD-related mortality and DALYs. The association between COPD burden and socio-demographic index (SDI) were also evaluated. Results From 1990 to 2019, the incidence and prevalence of COPD increased by 61.2% and 67.8%, respectively, whereas the number of deaths and DALYs owing to COPD decreased. The age-standardized rates (ASRs) of COPD burden continuously decreased from 1990 to 2019. The crude rates of COPD burden dramatically increased with age and reached a peak in the older than 95 years age group. In 2019, the leading risk factor for COPD mortality and DALYs was tobacco use in the whole population, but ambient particulate matter pollution was the most significant risk factor in females. At the provincial level, the ASRs of COPD burden was significantly associated with the SDIs, with the highest ASRs in the western provinces with low SDIs. ConclusionsAlthough the ASRs of COPD burden in China substantially decreased at the national and provincial levels from 1990 to 2019, absolute numbers of COPD incidence and prevalence are still rising, indicating that COPD remains an important public health problem in China. Geographically targeted considerations should be developed to enhance COPD health and reduce the COPD burden throughout China and in specific provinces.

Perovskite nanocrystals (NCs) as promising narrow green emitters are widely studied, and many colloidal synthetic methods have been developed. However, large amounts of expensive and toxic organic ...

Background We have reported that heparin-binding epidermal growth factor (HB-EGF) is increased in patients with chronic obstructive pulmonary disease (COPD) and associated with collagen deposition, but the mechanisms remain unclear. In the present study, we aimed to investigated the inflammatory cytokines secreted by bronchial epithelial cells following exposure to HB-EGF that promoted proliferation and migration of human lung fibroblast. Methods HB-EGF–induced inflammatory cytokines were assayed in two airway epithelial cells (primary human bronchial epithelial cells [HBECs] and BEAS-2B cells). Moreover, the culture supernatants derived from HB-EGF-treated HBECs and BEAS-2B cells were added to human primary lung fibroblasts. The effect of culture supernatants on proliferation and migration of fibroblasts was assessed. Results IL-8 expression was significantly increased in bronchial epithelial cells treated with HB-EGF, which was at least partially dependent on NF-kB pathways activation. HB-EGF–induced IL-8 was found to further promote lung fibroblasts proliferation and migration, and the effects were attenuated after neutralizing IL-8. Conclusions These findings suggest that HB-EGF may be involved in the pathology of airway fibrosis by induction of IL-8 from airway epithelium, subsequently causing lung fibroblasts proliferation and migration. Thus, inhibition of HBEGF and/or IL-8 production could prevent the development of airway fibrosis by modulating fibroblast activation.

Recently, two-dimensional colloidal perovskite nanoplatelets (NPLs) have attracted great attention as one of the most promising candidate blue emitters due to their large exciton binding energy and...

After nanocrystals synthesis, the purification process with anti-solvents is an essential step to get clean nanocrystals, which could get rid of the by-products of the synthesis. It is generally recognized that this process could bring a positive effect for the afterward optoelectronic applications. Unfortunately, we found that the optical properties and photostability of perovskite CsPbBr3 nanocrystals were unavoidably deteriorated after they were washed with anti-solvents, and this deterioration is strongly related to the decreasing of surface ligands density. Therefore, in this paper, we tried to purposely not wash the CsPbBr3 nanocrystals solution after adding didodecyl dimethylammonium bromide (DDAB), and found the existing of DDAB in solution could result in a dramatically enhanced photostability. Inspired by these results, we proposed a new strategy to stabilize perovskite nanocrystals from the view of packaging process: adding protective ligands into the perovskite nanocrystals resin directly, then encapsulating them on blue light-emitting diodes (LED) chips. Surprisingly, stable LED devices (20 mA, 2.7V) were achieved by this way, which can keep 80% of the initial photoluminescence (PL) intensity for more than 50 h, while the devices with CsPbBr3 nanocrystals without adding protective ligands into resin dropped to 50% of their initial PL intensity within 6 h. This approach offers a new thought to stabilize perovskite nanocrystals as down-conversion phosphor in quantum dots liquid crystal display.

A new hybrid RANS/LES approach with scale-adaptive capabilities is developed. The blending function in the SST model is adopted to prevent the invasion of the von Karman length scale to the RANS re...

BackgroundEndometriosis causes severe chronic pelvic pain and infertility. Chinese medicine plays an active role in the treatment of endometriosis. ELeng Capsule(ELC) is a Chinese medicine formula used for the treatment of endometriosis for several years. The previous studies have shown that ELC inhibits endometriosis. However, the mechanisms of action of ELC have not been characterized. In this study, network pharmacology and mRNA transcriptome analysis were used to study various therapeutic targets in ELC.Methods Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry analysis(UPLC-Q-TOF/MS) was used to identify the compounds in ELC.And network pharmacology was used to analyze the network of targets and identified compounds of ELC. Apoptosis was assessed using the terminal deoxynucleotidyl transferase (TdT) deoxyuridine 5'-triphosphate (dUTP) nick-end labeling (TUNEL) assay.The protein expression of VEGFA,VEGFB,VEGFC and α-SMA in the ectopic endometrium were identified by immunohistochemistry(IHC).The level of VEGFA,VEGFB and IL1-β in serum were used by ELISA. Further, RNA-sequencing was used to identify differentially expressed genes (DEGs) in ELC. Biological functions and pathways were determined through the Gene Ontology(GO) and Kyoto encyclopedia of genes and genomes pathway(KEGG) analyses. In addition, Gene Set Enrichment Analysis (GSEA) analysis was used to further analyze the genetic network and modular genetics. ResultsWe had identified 26 new bioactive compounds in ELeng Capsule by UPLC-Q-TOF/MS analysis. The KEGG pathways of ELC associtaed targets related to neuroactive ligand-receptor interaction, the toll-like receptor signaling pathway, and the vascular endothelial growth factor signaling pathway by network pharmacology analysis.Further, ELC could induce cell apoptosis, inhibit angiogenesis through reduce the expression of VEGFA and VEGFC, and inhibit the fibrosis through reduce the expression of α-SMA in ectopic lesions(P＜0.05). In addition, the development of endometriosis in the rat model may be related to mechanisms of inflammation,epithelial-mesenchymal transition(EMT) by RNA-sequencing. And the targets in the treatment of ELC were predominantly associated with actin and cytoskeleton,EMT,focal adhesion,and inflammatory immunity based on the DEGs analysis. In additon, the GSEA analysis showed that the treatment of ELC was associated with the Notch signaling pathway, Hippo signaling pathway, etc.ConclusionELeng Capsules exerted beneficial effects against endometriosis, potentially by induce apoptosis,modulating the angiogenesis,cytoskeleton, epithelial-mesenchymal transition(EMT), and cell junction-associated pathways,etc. These findings could provide evidence for an innovative treatment strategy and novel therapeutic targets for endometriosis.

Nickel oxides exhibit a great potential as hole transport layers for the fabrication of efficient perovskite light-emitting diodes (LEDs) due to their high carrier mobility and good energy band matching with perovskite nanocrystals. In this work, nickel oxides were directly decorated on the CsPbBr3 nanocrystal surface through adsorption and a sequential oxidation treatment. The resulting sample shows a high photoluminescence quantum-yield of 82%. The LED using CsPbBr3 nanocrystals with nickel oxides achieves a high external quantum efficiency (EQE) of up to 16.8% with a low turn-on voltage of 2.8 V, which is much superior to that of the counterpart LED based on pristine CsPbBr3 nanocrystals (EQE = 0.7%, turn-on voltage = 5.6 V). The excellent performance of the nickel oxide decorated CsPbBr3 nanocrystal device could be attributed to the better energy level matching between the decorated nanocrystals and the transport layers of the device and more balanced charge carrier injection. Furthermore, the operational lifetime of the nickel oxide decorated CsPbBr3 nanocrystal device is 40 times longer than that of the pristine CsPbBr3 nanocrystal device.

The thermal quenching behavior (temperature-dependent luminescence) has severely hindered the practical applications of CsPbX

Surgery is the primary curative treatment for patients with nonmetastasized colorectal cancer (CRC). Rate of complications, morbidity, mortality, and overall survival of patients with CRC are factors associated with speed of recovery following surgery. Wuda granule (WD) is a traditional Chinese medicine (TCM) prescription used to promote rapid recovery after surgery. However, the specific mechanism of action of WD has not been characterized. Our study included 60 patients with clear histopathological evidence of colon or rectal cancer who underwent CRC laparoscopic surgery and 30 healthy individuals. Serum biochemistry and clinical evaluation of gastrointestinal function showed that WD could improve the nutritional status and gastrointestinal function and reduce the level of inflammation of patients with CRC following laparoscopic surgery. In addition, we used UPLC/Q-TOF-MS/MS-based metabolomics analysis to determine the mechanism of WD-related rapid recovery following laparoscopic surgery in patients with CRC. Twenty metabolites associated with arachidonic acid, alanine, aspartate and glutamate, α-linolenic acid, pyruvate, histidine, and glycerophospholipids were identified. The results suggested that the therapeutic mechanism of laparoscopic surgery combined with WD may be related to regulation of nutritional status, inflammation, immune function, energy, and gastrointestinal function in patients with CRC. This study also highlighted the ability of TCM compounds to interact with multiple targets to induce synergistic effects. This study may result in further studies of WD as a therapeutic agent to promote recovery following surgical resection of CRC tumors.

Background. In the past several years, there has been an increasing concern on miscarriage caused by endometriosis or adenomyosis. However, the results reported by different studies remain controversial. The present study is aimed at assessing the impact of endometriosis and adenomyosis on miscarriage. Materials and Methods. Searches were carried out in PubMed, Embase, and the Cochrane library for studies published from inception until February 29, 2020. The investigators included studies that evaluated miscarriage risk in pregnant women with endometriosis or adenomyosis by assisted reproductive technology (ART), or with spontaneous conception (SC). Miscarriage ( I 2 = 96 % ) compared with those without endometriosis, while women with endometriosis who underwent ART had a similar miscarriage risk, when compared to those with tubal infertility (OR: 1.03, 95% CI: 0.92-1.14, I 2 = 0 % ). Compared with those without adenomyosis, women with adenomyosis had an augmented miscarriage risk in ART (OR: 2.81, 95% CI: 1.44-5.47, I 2 = 64 % ). Compared with those without endometriosis, women with endometriosis had higher odds of APH, PPH, preterm birth, stillbirth, and placenta praevia. No difference was observed in the incidence of ectopic pregnancy, placental abruption, pre-eclampsia, gestational diabetes, low birthweight, and IUGR. Conclusion. Women with endometriosis had an augmented miscarriage risk in SC and a similar miscarriage risk during ART. Adenomyosis was associated with miscarriage in pregnant women using ART.