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Ferroelectric Phase Content in 7 nm Hf (1- x ) Zr x O 2 Thin Films Determined by X-Ray-Based Methods
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Brillouin-Mandelstam spectroscopy of stress-modulated spatially confined spin waves in Ni thin films on piezoelectric substrates
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Magneto-Impedance measurements in thin films of the Spin-Glass Cu100-Mn Au13.5 (x = 6.75 and 13.5) alloys
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Nanostructured Pr-doped Ceria (PCO) thin films as sensing electrodes in solid-electrolyte type gas sensors with enhanced toluene sensitivity
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In-situ study of the crystallization of amorphous CuInSe2 thin films and the effect of InCl3 treatment
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Reveal of Magnetic Domains and Tunable Supercell Structures in Two-dimensional Layered Oxide Thin Film via Differential Phase Contrast Imaging and Atomic-resolution STEM
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Reduced recombination via tunable surface fields in perovskite thin films
Here, the ability to reduce energy loss at semiconductor surfaces through passivation or surface field engineering is an essential step in the manufacturing of efficient photovoltaic (PV) and optoelectronic devices. Similarly, surface modification of emerging halide perovskites with quasi-two-dimensional (2D) heterostructures is now ubiquitous to achieve PV power conversion efficiencies (PCEs) >25%, yet a fundamental understanding to how these treatments function is still generally lacking. Here we use a unique combination of depth-sensitive nanoscale characterization techniques to uncover a tunable passivation strategy and mechanism found in perovskite PV devices that were the first to reach the >25% PCE milestone. Namely, treatment with hexylammonium bromide leads to the simultaneous formation of an iodide-rich 2D layer along with a Br halide gradient that extends from defective surfaces and grain boundaries into the bulk three-dimensional (3D) layer. This interface can be optimized to extend the charge carrier lifetime to record values >30 μs and to reduce interfacial recombination velocities to values as low as <7 cm s −1 .
Role of the electronically-active amorphous state in low-temperature processed In2O3 thin-film transistors
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Vacuum ultraviolet thin films. I - Optical constants of BaF2, CaF2, LaF3, MgF2, Al2O3, HfO2, and SiO2 thin films. II - Vacuum ultraviolet all-dielectric narrowband filters
An iteration process matching calculated and measured reflectance and transmittance values in the 120-230 nm VUV region is presently used to ascertain the optical constants of bulk MgF2, as well as films of BaF2, CaF2, LaF3, MgF2, Al2O3, HfO2, and SiO2 deposited on MgF2 substrates. In the second part of this work, a design concept is demonstrated for two filters, employing rapidly changing extinction coefficients, centered at 135 nm for BaF2 and 141 nm for SiO2. These filters are shown to yield excellent narrowband spectral performance in combination with narrowband reflection filters.
Results from Laboratory and Field Study of Thin Triple Pane Windows
Heat transfer through windows accounts for a significant percentage of a building’s energy use and adds substantially to the peak cooling load of a home. In recent years, improvements in glass manufacturing have enabled the use of a very thin central pane of glass similar to a cell phone screen to produce a thin triple-pane window, for finished insulated glass units (IGUs) with an overall thickness similar to standard double-pane windows. Because this highly insulating “thin triple” glass product can be incorporated into almost any existing window frame and can be fabricated at a modest added cost, the U.S. Department of Energy sponsored laboratory and field demonstration testing of thin triple-pane windows to validate thermal performance and installation requirements in real-life field settings. Thin triple pane windows were evaluated at the PNNL Lab Homes, a matched pair of manufactured houses located on PNNL’s campus in Richland, Washington and also at 16 different field study sites around the country. The experimental results include a comparison of heating, ventilation, and air-conditioning (HVAC) energy usage, condensation potential, occupant comfort, sound infiltration, and thermal performance. Field study data will be gathered through June of 2022; preliminary results are being shared in this paper. The lab houses are identical except that the reference house had standard double pane windows with assembly U-0.66 and the test house had thin triple pane windows with assembly U-0.19. Across the experimental test days, the daily HVAC savings ranged from 0.2 to 18.7 kWh (3%–18%) for the heating season and from 2.5 to 8.0 kWh (23%–41%) for the cooling season. The higher thermal performance of the thin triple-pane windows also reduced the condensation potential on the interior surface during winter months and provided more even distribution of temperatures throughout the home in comparison to the baseline. In addition to the added thermal performance, the thin triple-pane windows demonstrated significant acoustic benefits, reducing sound infiltration by 8 dB to 10 dB. For the field test portion of the project thin triple pane insulated glass units were produced by two different manufacturers, and then installed without modification into the ½” IGU pockets of the standard double pane frames of four other manufacturers. Field tests performed on existing homes in Washington, Montana, Colorado, and New York compared thin triple pane retrofits to original window conditions (before and after). Field tests at new construction sites in Minnesota, Michigan, and New York compared thin triple pane windows to commercially available solutions such as double pane or traditional triple pane (with a standard-thickness center pane). Field test work is ongoing, but preliminary results appear to follow the sound, surface temperature, and energy improvement results from the Lab Homes comparison. Additionally, reports from builders and installers indicate that thin triples require almost no added time or effort to install and look nearly identical to other windows, indicating the possibility of offering next-level performance with a product that requires very little modification to current production or installation practices, long considered a major barrier to technology uptake in the construction market.
Making Thin Sections from National Treasures: A Little Moon Rock Goes a Long Way
NASA’s Johnson Space Center curates the Apollo sample collection through their facilities in Houston, TX. It is a dual-purpose facility, intended both to store and preserve the precious samples, as well as to make them available for ongoing scientific study and public examination. The facilities consist of multiple vaults and lab spaces, including the Apollo Thin Section Lab. Although it is a part of the Curation facilities, this lab is intended to process specific lunar rock and dust samples into what are called “thin sections”. A thin section is a microscope slide with a very thin, highly polished slice of rock material mounted on it. These are used not only for microscope viewing, but also for a range of other sophisticated scientific instruments to map and measure fine details of the rock’s physical and chemical composition and structure. The process of making a thin section requires great care and patience and is an art in itself; each one is unique, and each sample can behave very differently while going through the same basic procedures. In general, it begins by taking a small chip of rock from a much larger sample. The rock fragment is placed within a small mold and liquid epoxy is poured over it and allowed to harden, producing what is called a “potted butt” (Figure 1). This is to stabilize the rock so that it won’t fragment or crumble during polishing, and to fill any cracks or voids within the rock. Once hardened, the epoxy on the bottom is carefully ground away to expose the rock surface within, which is then polished to a 1-micron finish. A thin new layer of fresh epoxy is then applied to the polished surface and used to mount it to a silica slide. Once the mounting epoxy has hardened, the potted butt is cut off less than one millimeter above the slide using a low-speed circular saw. This thin layer of sample material attached to the slide undergoes further grinding and polishing, typically bringing the sample thickness down to about 35 microns – roughly one third of the thickness of a human hair. The remaining potted butt is saved for future scientific investigations and can be re-polished and used again until all the rock material within it is used up. A single thin section can be reused countless times by numerous different researchers. In addition, thin sections are often exquisitely beautiful (Figure 2) and in some cases, lunar thin sections are used as public display samples, such as at the Smithsonian Air and Space Museum in Washington, DC. The production of thin sections allows an immense variety of research to be conducted on a tiny amount of rock or mineral material, allowing the bulk of the Apollo collection to stay pristine and unaltered, and thus, remain available for next generation of lunar scientists to further our insight into the Moon’s geological diversity, and to bring valuable new insights to our understanding of the origin of the Earth-Moon system.
Facile microwave synthesis of zirconium metal-organic framework thin films on gold and silicon and application to sensor functionalization
Zirconium-based metal-organic frameworks, including UiO-66 and related frameworks, have become the focus of considerable research in the area of chemical warfare agent (CWA) decontamination. However, little work has been reported exploring these metal-organic frameworks (MOFs) for CWA sensing applications. For many sensing approaches, the growth of high-quality thin films of the active material is required, and thin film growth methods must be compatible with complex device architectures. Several approaches to synthesize thin films of UiO-66 have been described but many of these existing methods are complex or time consuming. In this work, we describe the development of a simple and rapid microwave assisted synthesis of oriented UiO-66 thin films on unmodified silicon (Si) and gold (Au) substrates. Thin films of UiO-66 and UiO-66-NH 2 can be grown in as little as 2 min on gold substrates and 30 min on Si substrates. The film morphology and orientation are characterized and the effects of reaction time and temperature on thin film growth on Au are investigated. Both reaction time and temperature impact the overgrowth of protruding discrete crystallites in the thin film layer but, surprisingly, no strong correlation is observed between film thickness and reaction time or temperature. We also briefly describe the synthesis of Zr/Ce solid solution thin films of UiO-66 on Au and report the first synthesis of a solid solution thin film MOF. Finally, we demonstrate the utility of the microwave method for the facile functionalization of two sensor architectures, plasmonic nanohole arrays and microresonators, with UiO-66 thin films.