Hybrid silicon-tellurium-dioxide DBR resonators coated in PMMA for biological sensing.

We report on silicon waveguide distributed Bragg reflector (DBR) cavities hybridized with a tellurium dioxide (TeO) cladding and coated in plasma functionalized poly (methyl methacrylate) (PMMA) for label free biological sensors. We describe the device structure and fabrication steps, including reactive sputtering of TeO and spin coating and plasma functionalization of PMMA on foundry processed Si chips, as well as the characterization of two DBR designs via thermal, water, and bovine serum albumin (BSA) protein sensing. Plasma treatment on the PMMA films was shown to decrease the water droplet contact angle from ∼70 to ∼35°, increasing hydrophilicity for liquid sensing, while adding functional groups on the surface of the sensors intended to assist with immobilization of BSA molecules.

Synthesis and Spatial Order Characterization of Controlled Silica Particle Sizes Organized as Photonic Crystals Arrays.

The natural occurrence of precious opals, consisting of highly organized silica particles, has prompted interest in the synthesis and formation of these structures. Previous research has shown that a highly organized photonic crystal (PhC) array is only possible when it is based on a low polydispersity index (PDI) sample of particles. In this study, a solvent-only variation method is used to synthesize different sizes of silica particles (SiPs) by following the traditional sol-gel Stöber approach.

Antiviral nanoparticles for sanitizing surfaces: A roadmap to self-sterilizing against COVID-19.

Nanoparticles provide new opportunities in merging therapeutics and new materials, with current research efforts just beginning to scratch the surface of their diverse benefits and potential applications. One such application, the use of inorganic nanoparticles in antiseptic coatings to prevent pathogen transmission and infection, has seen promising developments. Notably, the high reactive surface area to volume ratio and unique chemical properties of metal-based nanoparticles enables their potent inactivation of viruses.

Utility of far-field effects from tip-assisted Raman spectroscopy for the detection of a monolayer of diblock copolymer reverse micelles for nanolithography.

A modified set-up for Raman spectroscopy is proposed to utilize an AFM probe in a regime beyond the dependence on near field optics. Possible mechanisms for the observed enhancement have been explored through comparisons to spectra from other enhanced Raman techniques, including surface enhanced Raman, interference enhanced Raman and polarized Raman spectroscopies. The effects of polarization, focusing and interference are heightened when near field effects are diminished, giving rise to spectral enhancement.

Oxygen Coordination on Fe-N-C to Boost Oxygen Reduction Catalysis.

The coordination environments of iron (Fe) in Fe-N-C catalysts determine their intrinsic activities toward oxygen reduction reactions (ORR). The precise atomic-level regulation of the local coordination environments is thus of critical importance yet quite challenging to achieve. Here, atomically dispersed Fe-N-C catalyst with O-Fe-NC moieties is thoroughly studied for ORR catalysis.

Universal Transfer Printing of Micelle-Templated Nanoparticles Using Plasma-Functionalized Graphene.

Nanostructure incorporation into devices plays a key role in improving performance, yet processes for preparing two-dimensional (2D) arrays of colloidal nanoparticles tend not to be universally applicable, particularly for soft and oxygen-sensitive substrates for organic and perovskite-based electronics. Here, we show a method of transferring reverse micelle-deposited (RMD) nanoparticles (perovskite and metal oxide) on top of an organic layer, using a functionalized graphene carrier layer for transfer printing. As the technique can be applied universally to RMD nanoparticles, we used magnetic (γ-FeO) and luminescent (methylammonium lead bromide (MAPbBr)) nanoparticles to validate the transfer-printing methodology.

Mesoporous Ternary Nitrides of Earth-Abundant Metals as Oxygen Evolution Electrocatalyst.

As sustainable energy becomes a major concern for modern society, renewable and clean energy systems need highly active, stable, and low-cost catalysts for the oxygen evolution reaction (OER). Mesoporous materials offer an attractive route for generating efficient electrocatalysts with high mass transport capabilities. Herein, we report an efficient hard templating pathway to design and synthesize three-dimensional (3-D) mesoporous ternary nickel iron nitride (Ni3FeN).

Probing the multi-step crystallization dynamics of micelle templated nanoparticles: structural evolution of single crystalline γ-FeO.

Iron oxide nanoparticles synthesized with narrow size distribution were characterized using Raman spectroscopy, transmission electron microscopy and a superconducting quantum interference device magnetometer to investigate their composition, crystal structure and magnetic properties. Raman allowed us to explore the polymorphous transition of the iron oxide from the beginning of the synthesis process, as Raman can be used to monitor the precursors, the diblock-copolymer micelles and the resultant particles simultaneously under various processing steps. As different polymorphs possess distinct Raman active phonon modes, it also allows the identification of the exact phases of the resultant nanoparticles.

Improved hole injection for blue phosphorescent organic light-emitting diodes using solution deposited tin oxide nano-particles decorated ITO anodes.

Blue phosphorescent organic light-emitting diodes (PHOLEDs) were fabricated with tin oxide (SnO) nano-particles (NPs) deposited at the ITO anode to improve their electrical and optical performances. SnO NPs helped ITO to increase the work function enhancing hole injection capability. Charge balance of the device was achieved using p- and n-type mixed host materials in emissive layer and the devices' luminance and maximum external quantum efficiency (EQE) increased about nearly 30%.

A 3D-printed Chamber for Organic Optoelectronic Device Degradation Testing.

In this manuscript, we outline the manufacture of a small, portable, easy-to-use atmospheric chamber for organic and perovskite optoelectronic devices, using 3D-printing. As these types of devices are sensitive to moisture and oxygen, such a chamber can aid researchers in characterizing the electronic and stability properties. The chamber is intended to be used as a temporary, reusable, and stable environment with controlled properties (including humidity, gas introduction, and temperature).

Author Correction: disLocate: tools to rapidly quantify local intermolecular structure to assess two-dimensional order in self-assembled systems.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

disLocate: tools to rapidly quantify local intermolecular structure to assess two-dimensional order in self-assembled systems.

Order classification is particularly important in photonics, optoelectronics, nanotechnology, biology, and biomedicine, as self-assembled and living systems tend to be ordered well but not perfectly. Engineering sets of experimental protocols that can accurately reproduce specific desired patterns can be a challenge when (dis)ordered outcomes look visually similar. Robust comparisons between similar samples, especially with limited data sets, need a finely tuned ensemble of accurate analysis tools.

Statistical Paradigm for Organic Optoelectronic Devices: Normal Force Testing for Adhesion of Organic Photovoltaics and Organic Light-Emitting Diodes.

In this study, we assess the utility of a normal force (pull-test) approach to measuring adhesion in organic solar cells and organic light-emitting diodes. This approach is a simple and practical method of monitoring the impact of systematic changes in materials, processing conditions, or environmental exposure on interfacial strength and electrode delamination. The ease of measurement enables a statistical description with numerous samples, variant geometry, and minimal preparation.

Controlled Fabrication of Polypyrrole Surfaces with Overhang Structures by Colloidal Templating.

Here we present the fabrication of polypyrrole (PPy) surfaces with a controlled overhang structure. Regularly structured PPy films were produced using interfacial polymerization around a sacrificial crystalline colloidal monolayer at the air/water interface. The morphology of the final inverse colloidal PPy film is controlled by the amount of monomer, the monomer: oxidant ratio and polymerization time.

Steric self-assembly of laterally confined organic semiconductor molecule analogues.

Self-assembly of planar molecules can be a critical route to control morphology in organic optoelectronic systems. In this study, Monte Carlo simulations were performed with polygonal disc analogues to planar semiconducting molecules under confinement. By examining statistically the molecular density and configurations of such analogues, we have observed that the symmetry of the confining medium can have a greater impact on the final densified particle configurations than the intramolecular interactions.

Solution-processed LiF for work function tuning in electrode bilayers.

Although ambient processing is the key to low-cost organic solar cell production, high-vacuum thermal evaporation of LiF is often a limiting step, motivating the exploration of solution processing of LiF as an alternative electrode interlayer. Submonolayer films are realized with the assistance of polymeric micelle reactors that enable LiF particle deposition with controlled nanoscale surface coverage. Scanning Kelvin probe reveals a work function tunable with nanoparticle coverage with higher values than that of bare indium tin oxide (ITO).

Strain-effect for controlled growth mode and well-ordered structure of quaterrylene thin films.

We investigated the evolution of quaterrylene thin films on SiO(2) and on an octadecyltrichlorosilane self-assembled monolayer (OTS-SAM) to examine the impact of film strains on the growth processes and evolving structure. Surface modification by SAMs allowed tailoring of the growth process from a Stranski-Krastanov (SK) mode (layer-plus-island) on the SiO(2) surface to a Frank-van der Merwe mode (layer-by-layer) on the OTS surface. Detailed structural analysis by x-ray diffraction techniques confirmed that the SK mode was driven by lattice strain in the initial wetting layers on the SiO(2) surface.

Transition metal-catalyzed dissociation of phosphine-gallane adducts: isolation of mechanistic model complexes and heterogeneous catalyst poisoning studies.

Attempts to induce the catalytic dehydrocoupling of the phosphine-gallane adduct Cy2PH.GaH3 (Cy=cyclohexyl) (1) by treatment with ca. 5 mol% of either the Rh(I) complex [{Rh(mu-Cl)(1,5-cod)}2] (cod=cyclooctadiene) or the Rh(0) species Rh/Al2O3 and [Oct4N]Cl-stabilized colloidal Rh led to catalytic P-Ga bond cleavage to generate the phosphine, H2, and Ga metal.

Poisoning of heterogeneous, late transition metal dehydrocoupling catalysts by boranes and other group 13 hydrides.

Borane reagents are widely used as reductants for the generation of colloidal metals. When treated with a variety of heterogeneous catalysts such as colloidal Rh, Rh/Al2O3, and Rh(0) black, BH3.THF (THF = tetrahydrofuran) was found to generate H2 gas with the concomitant formation of a passivating boron layer on the surface of the Rh metal, thereby acting as a poison and rendering the catalyst inactive toward the dehydrocoupling of Me2NH.