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No full textOver 18.2%-Efficiency Organic Solar Cells with Exceptional Device Stability Enabled by Bay-Area Benzamide-Functionalized Perylene Diimide Interlayer
No full textA simultaneous further increase in the power conversion efficiency (PCE) and device stability of organic solar cells (OSCs) over the current levels needs to be overcome for their commercial viability. Herein, a bay-area benzamide-functionalized perylene diimide-based electron transport layer, namely H75 is developed, to obtain the aforementioned characteristics. The advantages of H75-employed OSCs include a notable PCE up to 18.26% and outstanding device stabilities under conditions of varying severity (>95% PCE retention after 1500 h upon long-term aging and exceptional T80 lifetimes (the time required to reach 80% of initial performance) of over 1000 h in light-soaking, 500 h in thermal stress at 85 degrees C, 72 h in 85% high relative humidity, and 100 h in atmospheric-air conditions without encapsulation in conventional architecture). The excellent performance of H75-employed OSC can be attributed to its various beneficial features derived from the bay-area benzamide functionalities (e.g., excellent film-forming ability, suitable energy level, reduced aggregation, and intrinsic high structural stability). The findings of this work provide further insights into the molecular design of electron transport layers for realizing more efficient and stable OSCs
Enhanced electrochemical performance of WO3 thin films prepared from polyvinyl alcohol-modified nanoparticle ink
No full textTungsten oxide (WO3) is a potential material in catalysis, sensors, electrochromic devices, etc. In this research work, porous WO3 thin films are prepared on FTO-glass employing spin coating of WO3 nanoparticle's ink modified with polyvinyl alcohol (PVA) in the concentration range of 0 to 25.0 wt%. This study explored the change in structure and morphology of WO3 thin films with varying PVA concentration in ink composition and their effect on the ability to intercalate and de-intercalate Li+ ions as a function of applied bias. The wettability of ink on FTO-glass improved by raising its PVA content. All WO3 thin films exhibited a monoclinic structure. Scanning electron microscopy images indicated that the porosity of WO3 thin films gradually increased with increasing PVA concentration up to 25 wt% but the thin film became highly nonuniform at a very high con-centration of additive. WO3 thin film prepared with ink having 10 wt% of PVA had optimum porosity and uniformity, therefore, yielded better electrochemical performance compared with all other samples. The addition of an optimum amount of PVA to ink is found to be an effective approach to modulating ink's characteristics and inducing porosity in thin films which eventually improves their redox reaction characteristics
Novel Gene Polymorphisms for Stable Warfarin Dose in a Korean Population: Genome-Wide Association Study
No full textWarfarin has a narrow therapeutic window and high intra- and inter-individual variability. Considering that many published papers on genotype-guided dosing are derived from European populations, the aim of this study was to investigate novel genetic variants associated with the variability of stable warfarin dose in the Korean population with cardiac valve replacement, using the GWAS approach. This retrospective cohort study was performed from January 1982 to December 2020 at the Severance Cardiovascular Hospital of Yonsei University College of Medicine. GWAS was performed to identify associations between genotypes and the warfarin maintenance dose, by comparing the allele frequency of genetic variants between individuals. Then, the extent of genetic and non-genetic factors on the dose variability was determined by multivariable regression analysis. The study enrolled 214 participants, and the most robust signal cluster was detected on chromosome 16 around VKORC1. Followed by VKORC1, three novel variants (NKX2-6 rs310279, FRAS1 rs4386623, and FAM201A rs1890109) showed an association with stable warfarin dose requirement in univariate analysis. The algorithm was constructed by using multivariable analysis that includes genetic and non-genetic factors, and it could explain 58.5% of the variations in stable warfarin doses. In this variability, VKORC1 rs9934438 and FRAS1 rs4386623 accounted for 33.0% and 9.9%, respectively. This GWAS analysis identified the fact that three novel variants (NKX2-6 rs310279, FRAS1 rs4386623, and FAM201A rs1890109) were associated with stable warfarin doses. Additional research is necessary to validate the results and establish personalized treatment strategies for the Korean population
Progress in the development of flexible metal-organic frameworks for hydrogen storage and selective separation of its isotopes
No full textBetween 2018 and 2050, global energy usage is expected to increase by approximately 50% because of rapid technological advancements, high population growth rates, and urbanization. Various alternative energy sources have been proposed in response to the energy crisis, among which hydrogen is the most promising owing to its high gravimetric energy density and environmental benignity. Although deuterium is exceptionally useful in various applications such as nuclear-power production, H-1 nuclear magnetic resonance spectroscopy, isotope tracing, and neutron-scattering experiments, its natural occurrence is only similar to 0.0156%. However, hydrogen isotope mixtures are extremely challenging to separate because of their similar sizes and chemical properties. Metal-organic frameworks (MOFs) have been envisioned as cutting-edge materials for gas storage and isotope separation because of their tunable pore aperture, which is one of the most important criteria for high capacity and selectivity. Especially, flexible MOFs have reversible structural transformation and pore-shifting capabilities that provide better control in gate opening phenomena. Herein, flexible MOFs are reviewed according to design and types, for the storage and separation of energy-efficient H-2 from mixtures. Because hydrogen isotopes are difficult to separate, the fundamental concepts of hydrogen isotope separation are given careful consideration in the development of efficient materials. Flexible MOFs with gate-opening behavior exhibit excellent hydrogen isotope separation efficiency owing to dynamic pore shifting, which is one of the key requirements for isotope separation. We believe that this review will provide insights into the current trends and future aspects of flexible MOFs with respect to hydrogen storage and its isotope separation