is produced in multiple unrelated organ isms, [3] ranging from ants to spiders, with one of the most prevalent examples being the silkworm Bombyx mori (B. mori). The B. mori silkworm spins fibers from a precursor solution of liquid silk pro tein, stored in the animal's silk gland, and uses them to form a nonwoven composite cocoon protecting the animal during its further metamorphosis. [4] The silk fiber formation process exerts shear and elon gation stresses on a concentrated solu tion containing fibroin (up to 30% wt/vol) in the gland, causing soluble fibroin to denature and aggregate. [5] Many studies have been conducted on different types of silk, including the characterization of the structural nature of fibroin, [6,7] the aggre gation and fiber formation pathway, [8] as well as the mechanical and rheological properties of silk solutions and fibers. [9][10][11] These studies have shown that the mole cular architecture of fibrous silk assemblies and the associated irreversible aggregation processes are similar to those found for highly ordered amyloid fibrils. [12][13][14] As functional materials, silk fibroin (SF) fibers are of particular interest because of their Native Silk Fibrils Native silk fibroin (NSF) is a unique biomaterial with extraordinary mechanical and biochemical properties. These key characteristics are directly associated with the physical transformation of unstructured, soluble NSF into highly organized nano-and microscale fibrils rich in β-sheet content. Here, it is shown that this NSF fibrillation process is accompanied by the development of intrinsic fluorescence in the visible range, upon near-UV excitation, a phenomenon that has not been investigated in detail to date. Here, the optical and fluorescence characteristics of NSF fibrils are probed and a route for potential applications in the field of self-assembled optically active biomaterials and systems is explored.In particular, it is demonstrated that NSF can be structured into autofluorescent microcapsules with a controllable level of β-sheet content and fluorescence properties. Furthermore, a facile and efficient fabrication route that permits arbitrary patterns of NSF microcapsules to be deposited on substrates under ambient conditions is shown. The resulting fluorescent NSF patterns display a high level of photostability. These results demonstrate the potential of using native silk as a new class of biocompatible photonic material.

Here we present a comprehensive investigation of TiO2-Cu2O hetero-junction solar cells with different back contacts (Au, ITO, Cu or Ag). Combinatorial hetero-junction libraries consisting of a linear TiO2 thickness gradient produced by spray pyrolysis and a bell shaped Cu2O profile synthesized by pulsed laser deposition were chosen to investigate the impact of the two metal oxide layer thicknesses. The back contacts were deposited as round patches onto a grid of 13 × 13 points, 169 contacts for each contact material, forming a library containing 4 × 13 × 13 = 676 back contacts. Each back contact represented a solar cell with an individual TiO2 and Cu2O thickness. I-V measurements show that all four materials provide an ohmic contact and that the open circuit voltage of ∼300 mV is rather independent of both layer thicknesses and contact material. The size of the Cu2O crystals drastically decreases with distance from the center of deposition, which leads to a drastic increase of series resistance when the crystal size is <50 nm.

The evolution of nanotechnology based sensors has enabled detection of ultra-low-level concentrations of target species owing to their high aspect ratio. However, these sensors have a limited dynamic range at room temperature characterized by saturation in the sensor response following certain concentration exposure. In this work, we show that the dynamic range towards a target gas can be significantly enhanced using the electrostatically formed nanowire sensor. The size and shape of the nanowire conducting channel are defined and tuned by controlling the bias applied to the surrounding gates. The nanowires thus formed vary in their response, detection limit, and dynamic range for a given target gas exposure depending on its size and shape. By electrostatically tuning to the appropriate nanowire, we can not only enhance the sensor response in the low concentration regime, but also broaden the overall dynamic range capacity using a single sensor. It is demonstrated that the sensor is capable of detecting ∼26–2030 ppm ethanol and ∼40–2800 ppm of acetone efficiently with reasonably high response (≥20%) throughout the whole range. The broad dynamic range concept is also demonstrated using scanning gate microscopy measurements of the device. This represents the first nanotechnology-inspired work towards tunable dynamic range of a sensor using a single electronic device.

Pulsed laser deposition (PLD) is widely used in combinatorial material science, as it enables rapid fabrication of different composite materials. Nevertheless, this method was usually limited to small substrates, since PLD deposition on large substrate areas results in severe lateral inhomogeneity. A few technical solutions for this problem have been suggested, including the use of different designs of masks, which were meant to prevent inhomogeneity in the thickness, density, and oxidation state of a layer, while only the composition is allowed to be changed. In this study, a possible way to take advantage of the large scale deposition inhomogeneity is demonstrated, choosing an iron oxide PLD-deposited library with continuous compositional spread (CCS) as a model system. An Fe₂O₃-Nb₂O₅ library was fabricated using PLD, without any mask between the targets and the substrate. The library was measured using high-throughput scanners for electrical, structural, and optical properties. A decrease in electrical resistivity that is several orders of magnitude lower than pure α-Fe₂O₃ was achieved at ∼20% Nb-O (measured at 47 and 267 °C) but only at points that are distanced from the center of the PLD plasma plume. Using hierarchical clustering analysis, we show that the PLD inhomogeneity can be used as an additional degree of freedom, helping, in this case, to achieve iron oxide with much lower resistivity.