Search

Objective : The aim of this study was to verify the equivalence and effectiveness of the tablet-administered Korean Repeatable Battery for the Assessment of Neuropsychological Status (K-RBANS) for the prevention and early detection of dementia.Methods : Data from 88 psychiatry and neurology patient samples were examined to evaluate the equivalence between tablet and paper administrations of the K-RBANS using a non-randomly equivalent group design. We calculated the prediction scores of the tablet-administered K-RBANS based on demographics and covariate-test scores for focal tests using norm samples and tested format effects. In addition, we compared the receiver operating characteristic curves to confirm the effectiveness of the K-RBANS for preventing and detecting dementia.Results : In the analysis of raw scores, line orientation showed a significant difference (t=-2.94, p

The introduction of an immobile passivation material leads to the suppression of the deeper defect states of Cl-mixed perovskite nanocrystals, while the inevitable halide migration is hampered, resulting in high efficiency and spectral stability of blue PeLEDs.

With a facile halide and phase modulating approach, deep-blue emissive quasi-2D perovskite films involving fewer intervening 2D phases are realized, for efficient delivery of excitons to light-emitting phases via streamlined energy transfer.

Herein, we introduced surface modification of a Cu catalyst by employing CH4 pre-annealing, which changed the uniformly rough Cu surface; this resulted in formation of high-quality and uniform Bern...

Summary The charge transferability of the electron transfer layers (ETLs) is important for achieving high performance in mesoscopic (mp) perovskite solar cells (PSCs). However, because of the low electron extraction efficiency of TiO2, lithium doping is essentially required. In this work, we compared the electrical properties of mp-TiO2 doped with Li-salts with different anions—LiTFSI, Li2CO3, LiCl, and LiF. Interestingly, we found that the anions of the Li-salt dopants affect the electrical properties of the ETLs and the solar cell performance. The Li2CO3 doping of mp-TiO2 led to conduction bands deeper than those of pristine mp-TiO2 or other doped mp-TiO2. The maximum efficiency of 25.28% and certified efficiency of 24.68% (Newport) was obtained by using Li2CO3 dopant. This optimization of the ETLs properties is expected to greatly contribute to the progress of PSCs by leading to further increases in their efficiency.

Lithium-ion batteries and pseudocapacitors are nowadays popular electrochemical energy storage for many applications, but their cathodes and anodes are still limited to accommodate rich redox ions not only for high energy density but also sluggish ion diffusivity and poor electron conductivity, hindering fast recharge. Here, we report a strategy to realize high-capacity/high-rate cathode and anode as a solution to this challenge. Multiporous conductive hollow carbon (HC) nanospheres with microporous shells for high capacity and hollow cores/mesoporous shells for rapid ion transfer are synthesized as cathode materials using quinoid:benzenoid (Q:B) unit resins of coiled conformation, leading to ∼5-fold higher capacities than benzenoid:benzenoid resins of linear conformation. Also, Ge-embedded Q:B HC nanospheres are derived as anode materials. The atomic configuration and energy storage mechanism elucidate the existence of mononuclear GeO

All-inorganic perovskite nanocrystals (PeNCs), CsPbX3 (X = Cl, Br, or I), have been considered as one of the prospective emissive materials for display applications, which showed superior photolumi...

Inorganic lead halide perovskite nanocrystals (PeNCs) have intensively drawn attention as efficient light-emitting materials for optoelectronic applications due to their fine optoelectronic properties with a high photoluminescence quantum yield and easily tunable saturated emission color. However, the poor stability of the red-emitting PeNCs has become an obstacle because of the uncontrollable iodine substitution from the PeNCs due to weak Pb-I bonding. In this work, we have demonstrated a ligand-mediated post-treatment (LMPT) method using a halide ion-pair ligand, tridodecylmethyl ammonium iodide (TrDAI), for the air stable and high-quality red-emitting PeNCs. Through the LMPT method, the optoelectronic properties of red-emitting PeNCs are dramatically improved resulting in a PLQY of 88.7% at 637 ± 2 nm emission with an increased carrier lifetime from 20.77 to 31.52 ns. We achieve highly efficient red perovskite light-emitting diodes exhibiting a maximum current efficiency of 7.69 cd A-1 and an external quantum efficiency of 6.36% at 637 ± 2 nm electroluminescence emission with a sharp full-width at half maximum of 31 nm.

Comprehensive molecular analyses revealed that papillary renal cell carcinoma (PRCC) is a heterogenous entity. Papillary renal neoplasm with reverse polarity (PRNRP) is a subset of PRCC with characteristic histomorphologies such as low-grade nuclear features, inverted nuclear location, eosinophilic cytoplasm, and indolent clinical behavior. We tried to define the molecular, clinicopathological, histologic, and immunohistochemical features of PRNRP by comparing them with type 1 PRCC (PRCC1) and type 2 PRCC (PRCC2). A cohort of 30 PRNRP, 23 PRCC1, and 26 PRCC2 cases was used. Targeted sequencing of 90 cancer-related genes including KRAS was performed in 26 PRNRP tumor samples. PNA-mediated clamping PCR of KRAS was performed using paired normal and tumor DNA from 30 PRNRP, 23 PRCC1, and 26 PRCC2 cases. Tissue microarray slides were made in three cores per tumor, which were stained with cytokeratin 7 (CK7), alpha-methylacyl-CoA racemase (AMACR), epithelial membrane antigen (EMA), E-cadherin, vimentin, and CD10. Recurrent mutations in KRAS were detected in 28 of the 30 PRNRPs. However, there were no KRAS mutations in any PRCC1 or PRCC2 cases. PRNRP exhibited distinct clinicopathological features: small tumor size, lower pathologic T stage, and no disease-specific death during the follow-up period. Histologically, peritumoral lymphoid aggregation, prominent papillary architecture (>80% of tumor), hyalinized papillae, inverted nuclear location, and lower nuclear grade were observed. PRNRP was usually positive for CK7, AMACR, EMA, and E-cadherin, and negative for CD10. The findings suggest that PRNRP is a subtype of papillary renal neoplasm that is different from PRCC1 or PRCC2 in terms of molecular, clinicopathological, histological, and immunohistochemical features.

The effect of cationic chlorides has been studied to achieve high quality perovskite films, for high performance perovskite solar cells. However, the role of cationic chloride additives which form mixed-cations on the perovskite structure is still unclear. Investigating the crystal morphology and stability of perovskite films for various sizes or concentrations of cationic chlorides is an essential part of the optoelectronic perovskite study. This paper investigates how cationic chlorides GuCl, FACl, CsCl, RbCl, and KCl, with different cationic sizes and concentrations, affected FAPbI3 perovskite. By forming mixed-cations by the addition of cationic chlorides with appropriate cation size and concentration, based on the tolerance factor, the crystallinity of the perovskite film was improved, achieving a lifetime 2.50 times longer, and a grain size 2.44 times larger. As a result, the efficiency of the perovskite solar cells is increased to 23.28%, and certified as 22.65% at Newport with optimized cationic chlorides. To understand the effect of the cation size and concentration of the cationic chlorides, theoretical analysis of the mechanism by which the cationic chlorides increased the crystallinity was performed using density functional theory calculations. The results revealed the effect of the various cationic chlorides on perovskite phase structures and matched the experimental results.

In the February 25, 2021 issue of Nature, Seo et al. reported a perovskite solar cell with a certified conversion efficiency of 25.2%. We discuss how improving the carrier management with electron transfer and the perovskite layer are key for achieving high-efficiency perovskite solar cells.

High-resolution patterning of quantum dot (QD) films is one of the preconditions for the practical use of QD-based emissive display platforms. Recently, inkjet printing and transfer printing have been actively developed; however, high-resolution patterning is still limited owing to nozzle-clogging issues and coffee ring effects during the inkjet printing and kinetic parameters such as pickup and peeling speed during the transfer process. Consequently, employing direct optical lithography would be highly beneficial owing to its well-established process in the semiconductor industry; however, exposing the photoresist (PR) on top of the QD film deteriorates the QD film underneath. This is because a majority of the solvents for PR easily dissolve the pre-existing QD films. In this study, we present a conventional optical lithography process to obtain solvent resistance by reacting the QD film surface with diethylzinc (DEZ) precursors using atomic layer deposition. It was confirmed that, by reacting the QD surface with DEZ and coating PR directly on top of the QD film, a typical photolithography process can be performed to generate a red/green/blue pixel of 3000 ppi or more. QD electroluminescence devices were fabricated with all primary colors of QDs; moreover, compared to reference QD-LED devices, the patterned QD-LED devices exhibited enhanced brightness and efficiency.

Summary One of the most effective methods to achieve high-performance perovskite solar cells has been to include additives that serve as dopants, crystallization agents, or passivate defect sites. Cl-based additives are among the most prevalent in literature, yet their exact role is still uncertain. In this work, we systematically study the function of methylammonium chloride (MACl) additive in formamidinium lead iodide (FAPbI3)-based perovskite. Using density functional theory, we provide a theoretical framework for understanding the interaction of MACl with a perovskite. We show that MACl successfully induces an intermediate to the pure FAPbI3 α-phase without annealing. The formation energy is related to the amount of incorporated MACl. By tuning the incorporation of MACl, the perovskite film quality can be significantly improved, exhibiting a 6× increase in grain size, a 3× increase in phase crystallinity, and a 4.3× increase in photoluminescence lifetime. The optimized solar cells achieved a certified efficiency of 23.48%.

Device performance and in particular device stability for blue perovskite light-emitting diodes (PeLEDs) remain considerable challenges for the whole community. In this manuscript, we conceive an approach by tuning the ‘A-site’ cation composition of perovskites to develop blue-emitters. We herein report a Rubidium-Cesium alloyed, quasi-two-dimensional perovskite and demonstrate its great potential for pure-blue PeLED applications. Composition engineering and in-situ passivation are conducted to further improve the material’s emission property and stabilities. Consequently, we get a prominent film photoluminescence quantum yield of around 82% under low excitation density. Encouraged by these findings, we finally achieve a spectra-stable blue PeLED with the peak external quantum efficiency of 1.35% and a half-lifetime of 14.5 min, representing the most efficient and stable pure-blue PeLEDs reported so far. The strategy is also demonstrated to be able to generate efficient perovskite blue emitters and PeLEDs in the whole blue spectral region (from 454 to 492 nm)., Besides device operational stability, the color stability is also an important challenge for the perovskite light-emitting diodes, especially the blue ones. Here Jiang et al. report the most efficient and color stable pure-blue perovskite LEDs so far, with a half-lifetime of 14.5 minutes.

The high quality perovskite film construction is the most crucial factor for the high performance perovskite solar cells. Solvent vaopr annelaing (SVA) is one of the best method to achieve the high quality perovkite film. We have fully compared the various high boiling point aprotic solvents N,N-dimethylformamide (DMF), Dimethyl sulfoxide (DMSO) and 1-Methyl-2-pyrrolidone (NMP) for SVA effect for perovskite solar cells. By optimizing temperature and time of SVA, vertically growthed high quality perovskite film via intermediate phase of PbI2-NMP structure was achieved which induces high performance of device. PbI2-NMP intermediate phase of perovskite film can be attributed to pinhole-free, longer carrier lifetime, and oxygen state free. The optimized device with NMP SVA treatment achieved 15.71% of PCE compared to without SVA treatment 7.85% of PCE.

The all-inorganic perovskite CsPbI3 has emerged as an alternative photovoltaic material to organic–inorganic hybrid perovskites due to its non-volatile composition and comparable photovoltaic performance. However, its spontaneous deformation from the light-active black phase to a light-inactive yellow phase under ambient conditions, poor air stability, low thermal stability as well as high-temperature processing are challenging issues in the fabrication of CsPbI3-based solar cells. Herein, we introduce a new surface passivation strategy using camphor sulfonic acid (CSA) to improve the surface morphology and air stability of Ba-stabilized α-CsPbI3 perovskites at low temperature. The surface passivated, Ba-doped α-CsPbI3 was thermally stable upon annealing and highly photo-stable over a year, and it also exhibited a band gap of ∼1.72 eV, which is suitable for optoelectronic applications. The all-inorganic solar cell based on the Ba-doped α-CsPbI3 retained 98% of its initial PCE value even after 700 h, and red light-emitting diodes (LED) exhibited light emission at 700 nm with a bandwidth of 39 nm. To date, this is the first study on surface passivated, Ba-stabilized α-CsPbI3, which provides opportunities for the development of highly efficient tandem solar cells and other optoelectronic devices.

To date, the light emitting diode (LED) based halide perovskite was rapidly developed due to the outstanding property of perovskite materials. However, the blue perovskite LEDs based on the bulk halide perovskites have been rarely researched and showed low efficiencies. The bulk blue perovskite LEDs suffered from insufficient coverage on the substrate due to the low solubility of the inorganic Cl sources or damaged by the structural instability with participation of organic cations. Here, we show the new method of fabricating stable inorganic bulk blue perovskite LEDs with the anion exchange approach to avoid use of insoluble Cl precursors. The devices showed nice operational spectral stability at the desired blue emission peak. The bulk perovskite blue LEDs showed a maximum luminance of 1468 and 494 cd m-2 for the 490 and 470 nm emission peaks, respectively.

Purpose The incidence of depression and anxiety is higher in patients with breast cancer than in the general population. We evaluated the degree of depression and anxiety and investigated the changes in patients with breast cancer during the treatment period and short-term follow-up period. Methods Overall, 137 patients with breast cancer were evaluated using the Patient Health Questionnaire 9-item depression scale (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7). The scales were developed as a web-based electronic patient-reported outcome measure, and serial results were assessed before the operation, after the operation, in the post-treatment period, and in the 6-month follow-up period after surgery. Results The degree of depression and anxiety increased during treatment and decreased at 6-month follow-up, even if there were no statistical differences among the four periods (PHQ-9: p = 0.128; GAD-7: p = 0.786). However, daily fatigue (PHQ-9 Q4) and insomnia (PHQ-9 Q3) were the most serious problems encountered during treatment and at 6-month follow-up, respectively. In the GAD-7, worrying too much (Q3) consistently showed the highest scores during the treatment and follow-up periods. Of the patients, 7 (5.11%) and 11 (8.03%) patients had a worsened state of depression and anxiety, respectively, after treatment compared with before treatment. Conclusion Most factors associated with depression and anxiety improved after treatment. However, factors such as insomnia and worrying too much still disturbed patients with breast cancer, even at 6-month follow-up. Therefore, serial assessment of depression and anxiety is necessary for such patients.

Nan et al. reported an interesting point of view on the phase stabilization mechanism of formamidinium lead halide (FAPbX3) perovskites in the September 2021 issue of Chem. A critical intermediate phase bearing the structure characteristics from the 2H phase to the 3C phase is successfully explained using a molecular-level description of the phase transition process and mechanism. In this study, we investigate how the intermediate stabilization with cationic or anionic additives affects the representative efficiency enhancement of perovskite solar cells.

Though halide perovskite nanocrystal (PeNC) based blue light emitting devices have been improved in the last few years, and the reasons for the improvements have been successfully explained, the origin of the narrow emission spectra of PeNCs have not been studied much. Here, the factors that affect the width of the emission spectra of PeNCs are analyzed with controlled synthesis and surface passivation treatment. The overall spectra are governed by the size of PeNCs; however, the width could be narrowed by surface passivation treatment. The anion passivation effect of the surface passivation improved most of optoelectronic properties, but had less effect on the emission spectra width. The narrower emission spectra of PeNCs are obtained by ligand passivation effect of the surface passivation. Light emitting devices with enhanced optoelectronic properties are successfully fabricated and narrow (0.094 eV, 16.72 nm) blue electroluminescence emission spectra (∼470 nm) are obtained.

Additive-assisted organic–inorganic perovskite materials have attracted substantial attention as photovoltaic light absorbers which lead to outstanding power conversion efficiency. Here we report an easy and effective fabrication of cubic-phase perovskite with an inorganic molecule additive like hydrazinium chloride (N2H5Cl, to be denoted as HZCl). We predict that this inorganic cation of N2H5+, which can substitute for the organic A-site in the perovskite structure, can tune Frohlich polaron properties by controlling the interaction strength and the number of proton coordinations to halide. This prediction is experimentally demonstrated with an optimized perovskite device with 2% N2H5Cl additive, which exhibits an unprecedented 85% fill factor (FF) with the highest value close to the Shockley–Queisser limit. An extra power conversion efficiency (PCE) of 2.3% and a fill factor (FF) efficiency of 14% are boosted. These optimized performances by additive effects lead to a new approach based on the theoretic...

Summary Organometallic perovskite devices have been intensively studied in recent years; however, a comprehensive understanding of their many unique material properties remains to be unveiled. In this work, we demonstrate for the first time a simple, reversible, and non-destructive post-treatment method of anion exchange between CsPbX3 perovskite nanocrystals (CsPbCl3 ⇌ CsPbBr3 ⇌ CsPbI3) with halogenated solvents, which is mediated by nucleophilic phosphine ligands. Anion exchange between CsPbX3 perovskite nanocrystals and haloalkane solvents (CHCl3, CHBr3, CH3CH2I) proceeded readily upon addition of nucleophilic trialkyl phosphines and could be controlled via nucleophile concentration and reaction time, allowing precise tuning of the anion composition and band gap. With our simple method, we obtained luminescence covering the entire visible spectrum from 400 to 700 nm. Furthermore, saturated and vivid RGB LED devices were successfully fabricated using the anion-exchanged nanocrystals.

We have deeply studied vaporized anti-solvents effects on the perovskite solar cell performance. Various non polar anti-solvents were tested to achieve the high quality perovskite film. Depending on the boiling point of the anti-solvent, the surface morphology is dramatically changed. In case of high boiling point anti-solvent, 1,2-dichlorobenzene (180.5 °C) remains on the perovskite surface even after thermal annealing at 100 °C for 10 min. However, the low boiling point chloroform (61.2 °C) anti-solvent makes smooth surface morphology of the perovskite film which leads the high performance of perovskite solar cells. This report introduces the vaporization of the anti-solvent affect the surface morphology that needs careful optimization for high performance perovskite solar cells.

Processing for obtaining compact and uniform perovskite photoactive layers has been intensively studied over the last few years to achieve high power conversion efficiencies (PCEs) in solar cells. Particularly, high quality crystal growth of perovskite layers is critical to enhance device performance. We demonstrate an easy and effective new process for high efficiency p–i–n planar heterojunction structures of perovskite solar cells (PeSCs) by using a compact seed perovskite layer (CSPL). The CSPL assists vertical growth of perovskite crystals and obtains the highly crystalline perovskite photoactive layer, which leads to the reduction in the charge transfer resistance and a longer photoluminescence lifetime. The PeSC device with a CSPL shows a remarkably improved PCE, from 15.07% to 19.25%, with a record open circuit voltage (VOC) of 1.16 V in the p–i–n structure with pure crystal perovskite and negligible current density–voltage hysteresis. Additionally, a PCE of 20.37% was achieved in CSPL assisted n–i–p structure PeSCs.

We herein demonstrate n-i-p-type planar heterojunction perovskite solar cells employing spin-coated ZnO nanoparticles modified with various alkali metal carbonates including Li2CO3, Na2CO3, K2CO3 and Cs2CO3, which can tune the energy band structure of ZnO ETLs. Since these metal carbonates doped on ZnO ETLs lead to deeper conduction bands in the ZnO ETLs, electrons are easily transported from the perovskite active layer to the cathode electrode. The power conversion efficiency of about 27% is improved due to the incorporation of alkali carbonates in ETLs. As alternatives to TiO2 and n-type metal oxides, electron transport materials consisting of doped ZnO nanoparticles are viable ETLs for efficient n-i-p planar heterojunction solar cells, and they can be used on flexible substrates via roll-to-roll processing.

Continuous fiber reinforcements are widely used to enhance mechanical properties of composite materials, but the impregnation of continuous fiber reinforcements with thermoplastics is a challenge due to high melt viscosity of the thermoplastic matrix. One of promising routes to improve the impregnation is to prepare commingled yarns with continuous matrix filaments and reinforcement fibers. In this study, we investigate mechanical properties of commingled yarns comprising different ratios of continuous glass fibers and polypropylene filaments, and of the composite plates made up of fabrics woven by the commingled yarns with a different polypropylene content. We found that undistributed or bunched glass fibers occur at high PP contents (>50 wt%), inducing an inhomogeneous mixing of the continuous reinforcement fibers and polypropylene filaments, which resultantly leads to abrupt changes in mechanical properties of both commingled yarns and resulting composites. Notably, the inhomogeneous distribution of continuous glass fibers in the commingled yarn at high PP contents gives rise to unexpected viscoelastic characteristics of resulting composites although impregnation of continuous glass fibers with polypropylene matrix is enhanced as the absolute amount of the polymer matrix increases.

CsPbX3 (X = I, Br, Cl) perovskite nanocrystals (NCs) have recently emerged as emitting materials for optoelectronic and display applications owing to their easily tunable emissions, high photolumin...

In this study, a novel ultrafast facile green microwave-assisted method was developed for the synthesis of high-entropy oxide (HEO) (Mg, Cu, Ni, Co, Zn)O nanoparticles for the first time. The results indicated that all the five metallic elements were uniformly distributed in the single-phase rocksalt structure of the HEO nanoparticles. The particle-size distribution was within the range of 20–70 nm, with the average size of 44 nm. When used as anode materials for Li-ion batteries, the HEO nanoparticles exhibited remarkable lithium storage properties with the impressive stability as was demonstrated during 1000 cycles at 1 A/g. The exceptional advantages of the proposed method in this work, including ultrafast speed (few minutes), low temperature, nanoscale and high-purity products, and low cost, make it an excellent synthesis technique for application in newly developed high-entropy ceramics, particularly for Li-ion batteries.

Multimetallic electrocatalysts have shown great potential to improve electrocatalytic performance, but their deteriorations in activity and durability are yet to be overcome. Here, metal‐organic fragments with adhesive excipient to realize high activity with good durability in oxygen evolution reaction (OER) are developed. First, a leaf‐like zeolitic–imidazolate framework (ZIF‐L) is synthesized. Then, ionized species in hydrogen plasma attack preferentially the organic linkers of ZIF‐L to derive cobalt–imidazole fragments (CIFs) as adhesive excipient, while they are designed to retain the coordinated cobalt nodes. Moreover, the vacant coordination sites at cobalt nodes and the unbound nitrogen at organic linkers induce high porosity and conductivity. The CIFs serve to stably impregnate trimetallic FeNiMo electrocatalysts (CIF:FeNiMo), and CIF:FeNiMo containing Fe contents of 22% and hexavalent Mo contents show to enable high activity with low overpotentials (203 mV at 10 mA cm−2 and 238 mV at 100 mA cm−2) in OER. The near O K‐edge extended X‐ray absorption fine structure proves further that high activity for OER originates from the partially filled eg orbitals. Additionally, CIF:FeNiMo exhibit good durability, as demonstrated by high activity retention during at least 45 days in OER., A strategy is developed to produce metal‐organic fragments allowing to stabilize multimetallic electrocatalysts in which a leaf‐like zeolitic–imidazolate framework is transformed into Co–imidazole fragments (CIFs) with unsaturated orbitals and dangling bonds as adhesive excipient. Fe, Ni, and Mo elements impregnated within CIFs, referred as CIF:FeNiMo catalysts, demonstrate high activity with low overpotentials (203 mV at 10 mA cm−2 and 238 mV at 100 mA cm−2) and robust durability with high activity retention (during at least 45 days) in oxygen evolution reaction.

Aim of the paper is to find how the acoustic and vibration responses of rectangular carbon-fiber-reinforced plastic (CFRP) plates is changed by the various orientation of fiber in a CFRP plate. First, the vibration and acoustic response of the CFRP plate excited by a concentrated harmonic force along with the natural vibration were evaluated theoretically. The theoretical solutions were verified by comparing with numerical simulations, which were conducted using commercial software. Second in order to confirm the numerical solutions, the experimental works were performed with three CFRP plates having different fiber orientation of 0°, 45°, and 90°. Finally the influence of fiber orientation on vibration and acoustics was investigated in CFRP plates.