High-Color-Rendition White QLEDs by Balancing Red, Green and Blue Centres in Eco-Friendly ZnCuGaS:In@ZnS Quantum Dots.

White light-emitting diodes (WLEDs) are the key components in the next-generation lighting and display devices. The inherent toxicity of Cd/Pb-based quantum dots (QDs) limits the further application in WLEDs. Recently, more attention is focused on eco-friendly QDs and their WLEDs, especially the phosphor-free WLEDs based on mono-component, which profits from bias-insensitive color stability. However, the imbalanced carrier distribution between red-green-blue luminescent centers, even the absence of a certain luminescent center, hinders their balanced and stable photoluminescence/electroluminescence (PL/EL). Here, an In3+-doped strategy in Zn-Cu-Ga-S@ZnS QDs is first proposed, and the balanced carrier distribution is realized by non-equivalent substitution and In3+ doping concentration modulation. The alleviation of the green emitter by the In3+-related red emitter and the compensation of blue emitter by the Zn-related electronic states contribute to the balanced red-green-blue emitting with high PL quantum yield (PLQY) of 95.3% and long lifetime (T90) of over 1100 h in atmospheric conditions. Thus, the In3+-doped WLEDs can achieve exceedingly slight proportional variations between red-green-blue EL intensity over time (∆CIE = (0.007, 0.009)), and high champion CRI of 94.9. This study proposes a single-component QD with balanced and stable red-green-blue PL/EL spectrum, meeting the requirements of lighting and display.

Sex- and age-dependent associations of EPA and DHA with very short sleep duration in adults: a cross-sectional analysis.

OBJECTIVES: This study aimed to compare the efficacy of dietary intake of eicosapentaenoic acid (EPA; 20:5 ω-3) and docosahexaenoic acid (DHA; 22:6 ω-3) on very short sleep duration (<5 h/night) in adults. METHODS: The bootstrap method was used in the multinomial logistic regression to estimate the ORs and corresponding 95% confidence intervals (CIs) of very short sleep duration. We used rolling window method to analyze the effects of EPA and DHA dietary intakes on very short sleep durations in men and women over age. To illustrate the stability of the results for the selected window width, we built a shiny application. RESULTS: Compared to the first quartile, the mean ORs of EPA intake on very short sleep duration and the corresponding 95% CIs for the second, third and fourth quartiles of EPA intake among men under 32 years old were 1.50 (0.56, 3.44) mg, 1.55 (0.59, 3.48) mg, and 3.99 (1.15, 10.01) mg, respectively. Among women over 44 years old, the ORs for DHA intake were 1.12 (0.81, 1.52) mg, 0.94 (0.68, 1.29) mg, and 0.62 (0.38, 0.98) mg for the second, third and fourth quartiles, respectively. CONCLUSIONS: The associations of EPA and DHA with very short sleep duration are sex- and age-dependent. In males under the age of 32, a significant positive correlation exists between dietary EPA intake and very short sleep duration. For women above 44 years of age, an increase in DHA intake can notably ameliorate issues of very short sleep duration.

Eco-Friendly Zn-Ag-In-Ga-S Quantum Dots: Amorphous Indium Sulfide Passivated Silver/Sulfur Vacancies Achieving Efficient Red Light-Emitting Diodes.

I-III-VI quantum dots (QDs) and derivatives (I, III, and VI are Ag+/Cu+, Ga3+/In3+, and S2-/Se2-, respectively) are the ideal candidates to replace II-VI (e.g., CdSe) and perovskite QDs due to their nontoxicity, pure color, high photoluminescence quantum yield (PLQY), and full visible coverage. However, the chaotic cation alignment in multielement systems can easily lead to the formation of multiple surface vacancies, highlighted as VI and VVI, leading to nonradiative recombination and nonequilibrium carrier distribution, which severely limit the performance improvement of materials and devices. Here, based on Zn-Ag-In-Ga-S QDs, we construct an ultrathin indium sulfide shell that can passivate electron vacancies and convert donor/acceptor level concentrations. The optimized In-rich 2-layer indium sulfide structure not only enhances the radiative recombination rate by preventing further VS formation but also achieves the typical DAP emission enhancement, achieving a significant increase in PLQY to 86.2% at 628 nm. Moreover, the optimized structure can mitigate the lattice distortion and make the carrier distribution in the interior of the QDs more balanced. On this basis, red QD light-emitting diodes (QLEDs) with the highest external quantum efficiency (EQE; 5.32%) to date were obtained, providing a novel scheme for improving I-III-VI QD-based QLED efficiency.

Age-dependent association of high urinary iodine concentration with major depression in adults: NHANES 2007-2020.

Excessive iodine exposure can have detrimental effects on thyroid function and overall health. This study aimed to investigate the age-dependent association between high urinary iodine concentration (UIC) and major depression symptoms in adults, using data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2020. To perform stratified analysis by age, we utilized a rolling window method with a 15-year window width to examine the trend of the odds ratios (ORs) of UIC on depression symptoms with age. Full-factor and one-factor multinomial logistic regression models were employed to calculate the ORs, and violin plots were utilized to depict the ORs of UIC on major depression. The LASSO regression was applied to select variables for one-factor models. The bootstrap method was utilized to ensure the robustness of the results, and the Games-Howell test was applied to compare the differences in the bootstrapped ORs of different UIC groups. Our results indicate that, after age 46, the ORs of high UIC (≥ 300 µg/L) on major depression are significantly higher than those of normal UIC (100-199 µg/L). The bootstrapped ORs of high UIC on major depression calculated by the full-factor and one-factor multinomial logistic regression models are 1.9 (1.28, 2.82) and 1.42 (1.02, 1.93) among participants aged 46 and older, respectively. Based on these findings, we conclude that major depressive symptoms are significantly associated with high UIC among older individuals aged 46 and above.

Perovskite nanocrystal superlattices: self-assembly, collective behavior, and applications.

Metal halide perovskite nanocrystals (NCs) have been widely studied for application in photonics and optoelectronics due to their excellent photoelectric properties. Perovskite NCs with narrow luminescence linewidth and high photoluminescence quantum yield are excellent assembly modules for building large-scale NC superlattices. The coupling of optics and electricity in such excellent aggregates gives them exceptional collective photoelectric performance, such as superfluorescence, red-shifted emission, coupling-enhanced electron transport, etc. Perovskite NC superlattices are expected to become another hot research topic in optoelectronics. Here, we focus on the collective behavior of superlattices and review the recent progress of the self-assembly, collective photoelectric properties, and applications of perovskite NC superlattices. Finally, a few challenges and prospects are indicated.

Improving anion-exchange efficiency and spectrum stability of perovskite quantum dots via an Al3+ bonding-doping synergistic effect.

Anion-exchange reactions are recognized as a vital and facile post-synthesis method to precisely manipulate the emission spectra of perovskite quantum dots (QDs). However, the anion-exchange process often induces adverse structural evolution and trap-mediated mechanisms, so mixed-halide perovskite QDs suffer inefficient anion exchange and poor spectra-stability issues, which limits access to high-quality primary color perovskite QDs for display applications. Here we report an Al3+ bonding-doping synergistic strategy for manufacturing stable mixed Br/Cl deep-blue perovskite QDs. By doping Al3+ into perovskite QDs, highly-efficient Cl- anion exchange and a large-range blue shift of the PL spectrum (∼62 nm with only 0.1 mmol of Cl feed) can be easily achieved. Notably, the Al3+-mediated deep-blue emission sample exhibits superior stability against moisture and electric fields. It also shows an elevated valence band maximum level. Based on the anion-exchanged QDs, a spectrum-stable deep-blue QLED with an EQE of 1.38% at 463 nm is achieved. Our findings demonstrate a feasible and promising strategy for developing high-performance deep-blue perovskite materials and optoelectronic devices.

Hybrid mixed-dimensional WTe2/CsPbI3perovskite heterojunction for high-performance photodetectors.

Perovskites have showed significant potential for the application in photodetectors due to their outstanding electrical and optical properties. Integrating two-dimensional (2D) materials with perovskites can make full use of the high carrier mobility of 2D materials and strong light absorption of perovskite to realize excellent optoelectrical properties. Here, we demonstrate a photodetector based on the WTe2/CsPbI3heterostructure. The quenching and the shortened lifetime of photoluminescence (PL) for CsPbI3perovskite confirms the efficient charge transfer at the WTe2/CsPbI3heterojunction. After coupled with WTe2, the photoresponsivity of the CsPbI3photodetector is improved by almost two orders of magnitude due to the high-gain photogating effect. The WTe2/CsPbI3heterojunction photodetector reveals a large responsivity of 1157 A W-1and a high detectivity of 2.1 × 1013Jones. The results pave the way for the development of high-performance optoelectronic devices based on 2D materials/perovskite heterojunctions.

A Demulsification-Crystallization Model for High-Quality Perovskite Nanocrystals.

A room-temperature technique with all-nonpolar-solvent, which circumvents the sensitivity of ionic perovskite to polar solvent, has become attractive for the synthesis of metal halide perovskite nanocrystals (PNCs). However, the lack of understanding of the inner mechanism, especially for the state of the precursor and the crystallization process of the PNCs, hinders further development of this technique. Here, through systematic study of the Pb precursor and in situ characterization of the PNCs, it is revealed that the reverse micelle nature of the Pb precursor exactly creates a novel demulsification-crystallization (D-C) model, namely, a two-stage nucleation is divided by a demulsification process for the PNCs. On this basis, a top efficiency for green light-emitting diodes based on PNCs is obtained with a maximum external quantum efficiency of 22.5% through tailoring the D-C model using a multiple-acid-anion synergistic assisted strategy to obtain high-quality PNCs. Beyond the high efficiency, the work paves the way for diverse ideas in PNC synthesis.

Associations of α-linolenic acid dietary intake with very short sleep duration in adults.

Objectives: This study aimed to investigate the association of α-linolenic acid (ALA; 18:3 ω-3) dietary intake with very short sleep duration (<5 h) in adults based on the CDC's National Health and Nutrition Examination Survey data. Methods: Multinomial logistic regression was used to explore the association of ALA intake with very short sleep. To make the estimation more robust, bootstrap methods of 1,000 replications were performed. Rolling window method was used to investigate the trend of the odds ratios of very short sleep with age. A Kruskal-Wallis test was applied to estimate the differences in the ORs of very short sleep between genders and different age groups. Results: Compared with the first tertile, the ORs of very short sleep and the corresponding 95% CIs for the second and the third tertile of dietary ALA intake in males were 0.618 (0.612, 0.624) and 0.544 (0.538, 0.551), respectively, and in females were 0.575 (0.612, 0.624) and 0.432 (0.427, 0.437). In most cases, the differences between different ages were more significant than those between different sexes. Men's very short sleep odds ratios for the second tertile of ALA intake increased linearly with age before 60. Conclusions: The risk of a very short sleep duration was negatively related to the dietary intake of ALA. The effect of ALA on very short sleep is significantly different among groups of different genders and ages.

Trend analysis of the association of urinary metals and obesity in children and adolescents.

Based on data from the United States National Health and Nutrition Examination Survey (NHANES), this study investigated whether the association between urinary trace metals and obesity changes with age. A multinomial logistic regression was used to explore the association between metals and obesity. We built models based on rolling window data with a seven-year time interval to investigate the trend of odd ratios (ORs) in metals. Finally, an application was built to show the trend of the ORs of metals with age. We found that obesity was positively associated with barium but negatively associated with cobalt, cadmium, and lead among children and adolescents. The trend analysis shows that different metals have different trends. Both barium and cobalt showed an age-related trend, and the younger the age, the greater the effect; the former and the latter were positively and negatively correlated with obesity, respectively. Lead showed no trend. The length of the confidence interval of barium's ORs decreased with age, whereas the confidence interval lengths for cobalt's OR values did not show significant changes across age groups. Our results indicate that: 1. The body mass index (BMI) of younger children is more susceptible to certain metals. 2. Barium's effect on young children is highly volatile. 3. The effects of cobalt on children of different ages are less volatile.

A Universal Ternary-Solvent-Ink Strategy toward Efficient Inkjet-Printed Perovskite Quantum Dot Light-Emitting Diodes.

Toward next-generation electroluminescent quantum dot (QD) displays, inkjet printing technique has been convinced as one of the most promising low-cost and large-scale manufacturing of patterned quantum dot light-emitting diodes (QLEDs). The development of high-quality and stable QD inks is a key step to push this technology toward practical applications. Herein, a universal ternary-solvent-ink strategy is proposed for the cesium lead halides (CsPbX3 ) perovskite QDs and their corresponding inkjet-printed QLEDs. With this tailor-made ternary halogen-free solvent (naphthene, n-tridecane, and n-nonane) recipe, a highly dispersive and stable CsPbX3 QD ink is obtained, which exhibits much better printability and film-forming ability than that of the binary solvent (naphthene and n-tridecane) system, leading to a much better qualitied perovskite QD thin film. Consequently, a record peak external quantum efficiency (EQE) of 8.54% and maximum luminance of 43 883.39 cd m-2 is achieved in inkjet-printed green perovskite QLEDs, which is much higher than that of the binary-solvent-system-based devices (EQE = 2.26%). Moreover, the ternary-solvent-system exhibits a universal applicability in the inkjet-printed red and blue perovskite QLEDs as well as cadmium (Cd)-based QLEDs. This work demonstrates a new strategy for tailor-making a general ternary-solvent-QD-ink system for efficient inkjet-printed QLEDs as well as the other solution-processed electronic devices in the future.

Perovskite White Light Emitting Diodes: Progress, Challenges, and Opportunities.

As global warming, energy shortages, and environment pollution have intensified, low-carbon and energy-saving lighting technology has attracted great attention worldwide. Light emitting diodes (LEDs) have been around for decades and are considered to be the most ideal lighting technology currently due to their high luminescence efficiency (LE) and long lifespan. Besides, along with the development of modern technology, lighting technologies with higher performance and more functions are desired. Perovskite based LEDs (PeLEDs) have recently emerged as ideal candidates for lighting technology owing to the extraordinary photoelectric properties of perovskite, such as high photoluminescence quantum yields (PLQYs), easy wavelength tuning, and low-cost synthesis. Herein, we open this review by introducing the background of white LEDs (WLEDs), including their light-emitting mechanism, typical characteristics, and key indicators in applications. Then, four main approaches to fabricate WLEDs are discussed and compared. After that, in accordance with the four categories, we focus on the recent progress of white PeLEDs (Pe-WLEDs), followed by the challenges and opportunities for Pe-WLEDs in practical application. Meanwhile, some pertinent countermeasures to their challenges are put forward. Finally, the development promise of Pe-WLEDs is explored.

Perovskite light-emitting/detecting bifunctional fibres for wearable LiFi communication.

Light fidelity (LiFi), which is emerging as a compelling technology paradigm shifting the common means of high-capacity wireless communication technologies, requires wearable and full-duplex compact design because of its great significance in smart wearables as well as the 'Internet of Things'. However, the construction of the key component of wearable full-duplex LiFi, light-emitting/detecting bifunctional fibres, is still challenging because of the conflicting process between carrier separation and recombination, as well as the highly dynamic film-forming process. Here, we demonstrate light-emitting/detecting bifunctional fibres enabled by perovskite QDs with hybrid components. The hybrid perovskite inks endow fibres with super-smooth QD films. This, combined with the small exciton binding energy and high carrier mobility of perovskite QDs, enables successful integration of electroluminescence and photodetection into monofilaments. The bifunctional fibres possess the narrowest electroluminescence full width at half maximum of ~19 nm and, more importantly, the capability for simultaneously transmitting and receiving information. The successful fabrication of narrow emission full-duplex LiFi fibres paves the way for the fabrication and integration of low crosstalk interoperable smart wearables.

Organic-Inorganic Hybrid Passivation Enables Perovskite QLEDs with an EQE of 16.48.

Perovskite quantum dots (QDs) with high photoluminescence quantum yields (PLQYs) and narrow emission peak hold promise for next-generation flexible and high-definition displays. However, perovskite QD films often suffer from low PLQYs due to the dynamic characteristics between the QD's surface and organic ligands and inefficient electrical transportation resulting from long hydrocarbon organic ligands as highly insulating barrier, which impair the ensuing device performance. Here, a general organic-inorganic hybrid ligand (OIHL) strategy is reported on to passivate perovskite QDs for highly efficient electroluminescent devices. Films based on QDs through OIHLs exhibit enhanced radiative recombination and effective electrical transportation properties compared to the primal QDs. After the OIHL passivation, QD-based light-emitting diodes (QLEDs) exhibit a maximum peak external quantum efficiency (EQE) of 16.48%, which is the most efficient electroluminescent device in the field of perovskite-based LEDs up to date. The proposed OIHL passivation strategy positions perovskite QDs as an extremely promising prospect in future applications of high-definition displays, high-quality lightings, as well as solar cells.

Room-Temperature Triple-Ligand Surface Engineering Synergistically Boosts Ink Stability, Recombination Dynamics, and Charge Injection toward EQE-11.6% Perovskite QLEDs.

Developing low-cost and high-quality quantum dots (QDs) or nanocrystals (NCs) and their corresponding efficient light-emitting diodes (LEDs) is crucial for the next-generation ultra-high-definition flexible displays. Here, there is a report on a room-temperature triple-ligand surface engineering strategy to play the synergistic role of short ligands of tetraoctylammonium bromide (TOAB), didodecyldimethylammonium bromide (DDAB), and octanoic acid (OTAc) toward "ideal" perovskite QDs with a high photoluminescence quantum yield (PLQY) of >90%, unity radiative decay in its intrinsic channel, stable ink characteristics, and effective charge injection and transportation in QD films, resulting in the highly efficient QD-based LEDs (QLEDs). Furthermore, the QD films with less nonradiative recombination centers exhibit improved PL properties with a PLQY of 61% through dopant engineering in A-site. The robustness of such properties is demonstrated by the fabrication of green electroluminescent LEDs based on CsPbBr3 QDs with the peak external quantum efficiency (EQE) of 11.6%, and the corresponding peak internal quantum efficiency (IQE) and power efficiency are 52.2% and 44.65 lm W-1 , respectively, which are the most-efficient perovskite QLEDs with colloidal CsPbBr3 QDs as emitters up to now. These results demonstrate that the as-obtained QD inks have a wide range application in future high-definition QD displays and high-quality lightings.

Nanowire network-based photodetectors with imaging performance for omnidirectional photodetecting through a wire-shaped structure.

Wearable photodetectors (PDs) have attracted extensive attention from both scientific and industrial areas due to intrinsic detection abilities as well as promising applications in flexible, intelligent, and portable fields. However, most of the existing PDs have rigid planar or bulky structures which cannot fully meet the demands of these unique occasions. Here, we present a highly flexible, omnidirectional PD based on ZnO nanowire (NW) networks. ZnO NW network-based PDs exhibit the imageable level performance with an on/off ratio of about 104. Importantly, a ZnO NW network can be assembled onto wire-shaped substrates to construct omnidirectional PDs. As a result, the wire-shaped PDs have excellent flexibility, a large light on/off ratio larger than 103, and 360° no blind angle detecting. Besides, they exhibit extraordinary stability against bending and irradiation. These results demonstrate a novel strategy for building wire-shaped optoelectronic devices through a NW network structure, which is highly promising for future smart and wearable applications.

High Performance Metal Halide Perovskite Light-Emitting Diode: From Material Design to Device Optimization.

Metal halide perovskites have drawn significant interest in the past decade. Superior optoelectronic properties, such as a narrow bandwidth, precise and facile tunable luminance over the entire visible spectrum, and high photoluminescence quantum yield of up to ≈100%, render metal halide perovskites suitable for next-generation high-definition displays and healthy lighting systems. The external quantum efficiency of perovskite light-emitting diodes (LEDs) increases from 0.1 to 11.7% in three years; however, the energy conversion efficiency and the long-term stability of perovskite LEDs are inadequate for practical application. Strategies to optimize the emitting layer and the device structure, with respect to material design, synthesis, surface passivation, and device optimization, are reviewed and highlighted. The long-term stability of perovskite LEDs is evaluated as well. Meanwhile, several challenges and prospects for future development of perovskite materials and LEDs are identified.

Double-Protected All-Inorganic Perovskite Nanocrystals by Crystalline Matrix and Silica for Triple-Modal Anti-Counterfeiting Codes.

Novel fluorescence with highly covert and reliable features is quite desirable to combat the sophisticated counterfeiters. Herein, we report a simultaneously triple-modal fluorescent characteristic of CsPbBr3@Cs4PbBr6/SiO2 by the excitation of thermal, ultraviolet (UV) and infrared (IR) light for the first time, which can be applied for the multiple modal anti-counterfeiting codes. The diphasic structure CsPbBr3@Cs4PbBr6 nanocrystals (NCs) was synthesized via the typical reprecipitation method followed by uniformly encapsulation into silica microspheres. Cubic CsPbBr3 is responsible for the functions of anti-counterfeiting, while Cs4PbBr6 crystalline and SiO2 are mainly to protect unstable CsPbBr3 NCs from being destroyed by ambient conditions. The as-prepared CsPbBr3@Cs4PbBr6/SiO2 NCs possess improved stability and are capable of forming printable ink with organic binders for patterns. Interestingly, the fluorescence of diphasic CsPbBr3@Cs4PbBr6/SiO2 capsule patterns can be reversibly switched by the heating, UV, and IR light irradiation, which has been applied as triple-modal fluorescent anti-counterfeiting codes. The results demonstrate that the perovskite@silica capsules are highly promising for myriad applications in areas such as fluorescent anti-counterfeiting, optoelectronic devices, medical diagnosis, and biological imaging.

An all-inkjet-printed flexible UV photodetector.

In this work, a novel concept of the all-inkjet-printed flexible photodetectors based on ZnO nanocrystals with high performance was proposed and demonstrated with emphasis on the influence of different post-treatments including UV light irradiation and high temperature annealing. The photodetectors based on UV-treated ZnO nanocrystal films exhibit a responsivity and an on/off ratio as high as 0.14 A W-1 and >103, respectively, which are better than the thermally treated devices. The high performance of ZnO nanocrystal-based photodetectors originates from unique band-edge modulation among the nanoparticles, where the existence of Schottky barriers leads to a low dark current and gives rise to a fast photoelectric response. The photodetector is capable of 500 bending cycles, and almost no degradation is observed. The as-obtained all-printable devices open up the possibility of fabricating a low-cost, solution processed, flexible, and large-area integrated optoelectronic sensor circuitry for future practical applications.

Constructing Mie-Scattering Porous Interface-Fused Perovskite Films to Synergistically Boost Light Harvesting and Carrier Transport.

Light harvesting (LH) and carrier transport abilities of a photoactive layer, which are both crucial for optoelectronic devices such as solar cells and photodetectors (PDs), are typically hard to be synergistically improved. Taking perovskite as an example, a freeze-drying recrystallization method is used to construct porous films with improvements of both LH and carrier transport ability. During the freeze-drying casting process, the rapid solvent evaporation produces massive pores, the sizes of which can be adjusted to exploit the Mie scattering for enhancement of the LH ability. Meanwhile, owing to the strong iconicity, the interface between perovskite nanocrystals fused during recrystallization, which favors carrier transport. Subsequently, PDs based on these Mie porous and interface-fused films show a high on/off ratio of more than 104 and an external quantum efficiency value of 658 % under 9 V bias and 520 nm light irradiation.