King Abdullah University of Science and Technology

About: King Abdullah University of Science and Technology is a education organization based out in Jeddah, Saudi Arabia. It is known for research contribution in the topics: Membrane & Catalysis. The organization has 6221 authors who have published 22019 publications receiving 625706 citations. The organization is also known as: KAUST.

MOFs for the Sensitive Detection of Ammonia: Deployment of fcu-MOF Thin Films as Effective Chemical Capacitive Sensors

Abstract: This work reports on the fabrication and deployment of a select metal–organic framework (MOF) thin film as an advanced chemical capacitive sensor for the sensing/detection of ammonia (NH3) at room temperature. Namely, the MOF thin film sensing layer consists of a rare-earth (RE) MOF (RE-fcu-MOF) deposited on a capacitive interdigitated electrode (IDE). Purposely, the chemically stable naphthalene-based RE-fcu-MOF (NDC-Y-fcu-MOF) was elected and prepared/arranged as a thin film on a prefunctionalized capacitive IDE via the solvothermal growth method. Unlike earlier realizations, the fabricated MOF-based sensor showed a notable detection sensitivity for NH3 at concentrations down to 1 ppm, with a detection limit appraised to be around 100 ppb (at room temperature) even in the presence of humidity and/or CO2. Distinctly, the NDC-Y-fcu-MOF based sensor exhibited the required stability to NH3, in contrast to other reported MOFs, and a remarkable detection selectivity toward NH3 vs CH4, NO2, H2, and C7H8. The N...

High performance ambient-air-stable FAPbI3 perovskite solar cells with molecule-passivated Ruddlesden–Popper/3D heterostructured film

Abstract: Ambient stability remains a critical hurdle for commercialization of perovskite solar cells. Two-dimensional Ruddlesden–Popper (RP) perovskite solar cells exhibit excellent stability but suffer from low photovoltaic performance so far. Herein, a RP/3D heterostructure passivated by semiconducting molecules is reported, which systematically addresses both charge dynamics and degradation mechanisms in concert for cesium-free FAPbI3 solar cells, delivering a power-conversion efficiency as high as 20.62% and remarkable long-term ambient stability with a t80 lifetime exceeding 2880 hours without encapsulation. In situ characterizations were carried out to gain insight into structural evolution and crystal growth mechanisms during spin coating. Comprehensive film and device characterizations were performed to understand the influences of the RP perovskite and molecule passivation on the film quality, photovoltaic performance and degradation mechanisms. This enables fabrication of a superior quality film with significantly improved optoelectronic properties, which lead to higher charge collection efficiency. The underlying mitigated degradation mechanisms of the passivated RP/3D devices were further elucidated. The understanding of the necessity of addressing both the charge dynamics and degradation mechanisms of solar cells will guide the future design and fabrication of chemically stable, high-efficiency photovoltaic devices.

Mesoscale eddies are oases for higher trophic marine life.

Abstract: Mesoscale eddies stimulate biological production in the ocean, but knowledge of energy transfers to higher trophic levels within eddies remains fragmented and not quantified. Increasing the knowledge base is constrained by the inability of traditional sampling methods to adequately sample biological processes at the spatio-temporal scales at which they occur. By combining satellite and acoustic observations over spatial scales of 10 s of km horizontally and 100 s of m vertically, supported by hydrographical and biological sampling we show that anticyclonic eddies shape distribution and density of marine life from the surface to bathyal depths. Fish feed along density structures of eddies, demonstrating that eddies catalyze energy transfer across trophic levels. Eddies create attractive pelagic habitats, analogous to oases in the desert, for higher trophic level aquatic organisms through enhanced 3-D motion that accumulates and redistributes biomass, contributing to overall bioproduction in the ocean. Integrating multidisciplinary observation methodologies promoted a new understanding of biophysical interaction in mesoscale eddies. Our findings emphasize the impact of eddies on the patchiness of biomass in the sea and demonstrate that they provide rich feeding habitat for higher trophic marine life.