Center for Excellence in Education

About: Center for Excellence in Education is a education organization based out in McLean, Virginia, United States. It is known for research contribution in the topics: Plateau & Organic solar cell. The organization has 7010 authors who have published 8489 publications receiving 187172 citations.

Organic and solution-processed tandem solar cells with 17.3% efficiency

Abstract: Although organic photovoltaic (OPV) cells have many advantages, their performance still lags far behind that of other photovoltaic platforms. A fundamental reason for their low performance is the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption. In this work, guided by a semi-empirical model analysis and using the tandem cell strategy to overcome such issues, and taking advantage of the high diversity and easily tunable band structure of organic materials, a record and certified 17.29% power conversion efficiency for a two-terminal monolithic solution-processed tandem OPV is achieved.

The healing myocardium sequentially mobilizes two monocyte subsets with divergent and complementary functions

Abstract: Healing of myocardial infarction (MI) requires monocytes/macrophages These mononuclear phagocytes likely degrade released macromolecules and aid in scavenging of dead cardiomyocytes, while mediating aspects of granulation tissue formation and remodeling The mechanisms that orchestrate such divergent functions remain unknown In view of the heightened appreciation of the heterogeneity of circulating monocytes, we investigated whether distinct monocyte subsets contribute in specific ways to myocardial ischemic injury in mouse MI We identify two distinct phases of monocyte participation after MI and propose a model that reconciles the divergent properties of these cells in healing Infarcted hearts modulate their chemokine expression profile over time, and they sequentially and actively recruit Ly-6Chi and -6Clo monocytes via CCR2 and CX3CR1, respectively Ly-6Chi monocytes dominate early (phase I) and exhibit phagocytic, proteolytic, and inflammatory functions Ly-6Clo monocytes dominate later (phase II), have attenuated inflammatory properties, and express vascular–endothelial growth factor Consequently, Ly-6Chi monocytes digest damaged tissue, whereas Ly-6Clo monocytes promote healing via myofibroblast accumulation, angiogenesis, and deposition of collagen MI in atherosclerotic mice with chronic Ly-6Chi monocytosis results in impaired healing, underscoring the need for a balanced and coordinated response These observations provide novel mechanistic insights into the cellular and molecular events that regulate the response to ischemic injury and identify new therapeutic targets that can influence healing and ventricular remodeling after MI

Ultrathin metal–organic framework nanosheets for electrocatalytic oxygen evolution

Abstract: The design and synthesis of efficient electrocatalysts are important for electrochemical conversion technologies. The oxygen evolution reaction (OER) is a key process in such conversions, having applications in water splitting and metal–air batteries. Here, we report ultrathin metal–organic frameworks (MOFs) as promising electrocatalysts for the OER in alkaline conditions. Our as-prepared ultrathin NiCo bimetal–organic framework nanosheets on glassy-carbon electrodes require an overpotential of 250 mV to achieve a current density of 10 mA cm−2. When the MOF nanosheets are loaded on copper foam, this decreases to 189 mV. We propose that the surface atoms in the ultrathin MOF sheets are coordinatively unsaturated—that is, they have open sites for adsorption—as evidenced by a suite of measurements, including X-ray spectroscopy and density-functional theory calculations. The findings suggest that the coordinatively unsaturated metal atoms are the dominating active centres and the coupling effect between Ni and Co metals is crucial for tuning the electrocatalytic activity. Efficient electrocatalysts for the oxygen–evolution reaction are desired due to their importance in applications such as water splitting and metal–air batteries. Here, the authors engineer ultrathin metal–organic frameworks that require low overpotential to generate oxygen from alkaline media.