1,721,223 research outputs found
High-Efficiency Deflection of High-Energy Protons through Axial Channeling in a Bent Crystal
No full textThe Renaissance of Luminescent Solar Concentrators: The Role of Inorganic Nanomaterials
No full textWhile luminescent solar concentrators (LSCs) have a simple architecture—a transparent matrix embedding a luminescent fluorophore coupled with solar cells at the lateral side of the LSC slab—multiple paths for possible light losses exist. These are inherently interconnected, and in the past, limited the interest in this device, due to the gap between the theoretical possibilities and experimental achievements. This gap was a result, primarily, of the optical features of the luminescent dyes, since conventional organic luminophores are affected by limited performance in LSC devices. The rise of a wide portfolio of optically active inorganic nanomaterials in the last decade provides an alternative to organic dyes and has lead to a renaissance in the role of LSCs among the unconventional solar energy conversion devices. This paper reviews the latest results in the development of LSCs based on different classes of nanomaterials, focusing on the specific features and critically analyzing the pros and cons of the proposed structures. Particular attention is devoted to the role of the luminescence properties, e.g., the Stokes shift and the photoluminescence quantum yield, with respect to the performance of the LSC device. Future challenges to the successful employment of these devices for building integrated photovoltaics are also discussed
Observation of Multiple Volume Reflection of ultrarelativistic protons by a sequence of several bent silicon crystals
No full textUltrasensitive, Biocompatible, Self-Calibrating, Multiparametric Temperature Sensors
No full textCore-shell quantum dots serve as self-calibrating, ultrasensitive, multiparametric, near-infrared, and biocompatible temperature sensors. They allow temperature measurement with nanometer accuracy in the range 150-373 K, the broadest ever recorded for a nanothermometer, with sensitivities among the highest ever reported, which makes them essentially unique in the panorama of biocompatible nanothermometers with potential for in vivo biological thermal imaging and/or thermoablative therapy
Tailoring the Heterostructure of Colloidal Quantum Dots for Ratiometric Optical Nanothermometry
No full textColloidal quantum dots (QDs) are a fascinating class of semiconducting nanocrystals, thanks to their optical properties tunable through size and composition, and simple synthesis methods. Recently, colloidal double-emission QDs have been successfully applied as competitive optical temperature sensors, since they exhibit structure-tunable double emission, temperature-dependent photoluminescence, high quantum yield, and excellent photostability. Until now, QDs have been used as nanothermometers for in vivo biological thermal imaging, and thermal mapping in complex environments at the sub-microscale to nanoscale range. In this Review, recent progress for QD-based nanothermometers is highlighted and perspectives for future work are described
Multiple volume reflections of high-energy protons in a sequence of bent silicon crystals assisted by volume capture
No full textConfined Catalysis: Progress and Prospects in Energy Conversion
Full text linkSpace confined catalysis has emerged as viable strategy for achieving potent and efficient catalysts in various important reactions. It offers a means of creating unique nanoscale chemical environments partitioned from the surrounding bulk space. This gives rise to the phenomena of nanoconfinement, where the energetics and kinetics of catalytic reactions can be modulated upon confining the catalysts in a particular site. Various scaffolds have been reported so far for confinement. Among these, void spaces under the cover of 2D materials, van der Waals (vdW) gaps of layered 2D materials, nanotubes, and porous surfaces have recently won copious attention. In this review, the concept of space confinement with respect to its effect on the electronic and structural properties of a catalyst is discussed. Emphasis is devoted to the catalysis of water splitting and CO2 reduction reactions. The progress in the design and applications of space confined catalysts is then traced. Finally, a discussion of emerging issues yet to be explored for this strategy to achieve a high efficiency, and future directions with the potential to become a new hotspots are presented
Structural and functional characterization of W-Si-N sputtered thin films for copper metallizations
No full textMetal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells
No full textThis Review provides a brief summary of the most recent research developments in the synthesis and application of nanostructured metal oxide semiconductors for dye sensitized and quantum dot sensitized solar cells. In these devices, the wide bandgap semiconducting oxide acts as the photoanode, which provides the scaffold for light harvesters (either dye molecules
or quantum dots) and electron collection. For this reason,
proper tailoring of the optical and electronic properties of the photoanode can significantly boost the functionalities of the operating device. Optimization of the functional properties relies with modulation of the shape and structure of the photoanode, as well as on application of different materials (TiO2, ZnO, SnO2) and/or composite systems, which allow fine tuning of electronic band structure. This aspect is critical because it determines exciton and charge dynamics in the photoelectrochemical system and is strictly connected to the photoconversion efficiency of the solar cell. The different strategies for increasing light harvesting and charge collection, inhibiting charge losses due to recombination phenomena, are reviewed thoroughly, highlighting the benefits
of proper photoanode preparation, and its crucial role in the development of high efficiency dye sensitized and quantum dot sensitized solar cells
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