Tailored polymeric, photovoltaic, and near-infrared-responsive neuroprosthesis

AbstractOrganic materials, such as conjugated polymers, are attractive building blocks for bioelectronic interfaces. In particular, organic semiconductors showed excellent performances in light-mediated excitation and silencing of neuronal cells and tissues. However, the main challenges of these organic photovoltaic interfaces compared to inorganic prostheses are the limited stability of conjugated polymers in the aqueous environment and the exploitation of materials only responsive in the visible spectrum. In this report, we show a new photovoltaic organic interface tailored for neuronal stimulation in the near-infrared spectrum. Also, we adjusted the organic materials by chemical modification in order to improve the stability in aqueous environment and to modulate the photoelectrical stimulation efficiency. As proof of principle, we tested this interface for retinal stimulation. Our results provide an efficient, reliable, and stable implant applicable for neural stimulation.

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Assessing the Stability of Surface Lights for use in Retrievals of Nocturnal Atmospheric Parameters

10.5194/amt-2019-103 ◽

2019 ◽

Author(s):

Jeremy E. Solbrig ◽

Steven D. Miller ◽

Jianglong Zhang ◽

Lewis Grasso ◽

Anton Kliewer

Keyword(s):

Near Infrared ◽

Correlation Coefficients ◽

Visible Spectrum ◽

Light Sources ◽

Infrared Observations ◽

Spatially Resolved ◽

Relative Standard ◽

Geometric Variables ◽

The Stability

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation

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Assessing the stability of surface lights for use in retrievals of nocturnal atmospheric parameters

Atmospheric Measurement Techniques ◽

10.5194/amt-13-165-2020 ◽

2020 ◽

Vol 13 (1) ◽

pp. 165-190 ◽

Cited By ~ 2

Author(s):

Jeremy E. Solbrig ◽

Steven D. Miller ◽

Jianglong Zhang ◽

Lewis Grasso ◽

Anton Kliewer

Keyword(s):

Near Infrared ◽

Correlation Coefficients ◽

Visible Spectrum ◽

Light Sources ◽

Strongly Correlated ◽

Spatially Resolved ◽

Relative Standard ◽

Geometric Variables ◽

The Stability

Abstract. The detection and characterization of aerosols are inherently limited at night because the important information provided by visible spectrum observations is not available and infrared bands have limited sensitivity to aerosols. The VIIRS Day–Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible and near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for the retrieval of atmospheric properties, including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Time series are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation <20 %). Additionally, we find that while the radiance variability of surrounding surfaces (i.e., unpopulated land and ocean) is largely dependent on lunar geometry, the anthropogenic light sources are more strongly correlated with satellite viewing geometry. Understanding the spatially resolved relationships between DNB radiance and other parameters is a necessary first step towards characterizing anthropogenic light emissions and establishes a framework for a model to describe variability in a more general sense.

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A Highly Crystalline Anthracene-Based MOF-74 Series Featuring Electrical Conductivity and Luminescence

10.26434/chemrxiv.8222492 ◽

2019 ◽

Author(s):

Patricia Scheurle ◽

Andre Mähringer ◽

Andreas Jakowetz ◽

Pouya Hosseini ◽

Alexander Richter ◽

...

Keyword(s):

Electrical Conductivity ◽

Metal Ions ◽

Light Emission ◽

Block Design ◽

High Surface ◽

Visible Spectrum ◽

Building Blocks ◽

Divalent Metal Ions ◽

Conductivity Enhancement ◽

Surface Areas

Recently, a small group of metal-organic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.

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Thienopyrrolocarbazoles: New Building Blocks for Functional Organic Materials

10.26434/chemrxiv.7777343.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Dorian Bader ◽

Johannes Fröhlich ◽

Paul Kautny

Keyword(s):

Building Block ◽

Organic Materials ◽

Building Blocks ◽

Molecular Properties ◽

The Family ◽

Facile Preparation

The facile preparation of three regioisomeric thienopyrrolocarbazoles applying a convenient C-H activation approach is presented. Derived from indolo[3,2,1-<i>jk</i>]carbazole, the incorporation of thiophene into the triarylamine framework significantly impacted the molecular properties of the parent scaffold. The developed thienopyrrolocarbazoles enrich the family of triarylamine donors and constitute a novel building block for functional organic materials.

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Thienopyrrolocarbazoles: New Building Blocks for Functional Organic Materials

10.26434/chemrxiv.7777343 ◽

2019 ◽

Author(s):

Dorian Bader ◽

Johannes Fröhlich ◽

Paul Kautny

Keyword(s):

Building Block ◽

Organic Materials ◽

Building Blocks ◽

Molecular Properties ◽

The Family ◽

Facile Preparation

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Dibenzochrysene Enables Tightly Controlled Docking and Stabilizes Photoexcited States in Dual-Pore Covalent Organic Frameworks

10.26434/chemrxiv.9638633.v1 ◽

2019 ◽

Author(s):

Torben Sick ◽

Niklas Keller ◽

Nicolai Bach ◽

Andreas Koszalkowski ◽

Julian Rotter ◽

...

Keyword(s):

Molecular Docking ◽

Photophysical Properties ◽

Visible Spectrum ◽

Large Family ◽

Building Blocks ◽

Band Gaps ◽

Docking Site ◽

Covalent Organic Frameworks ◽

Connected Node ◽

Optoelectronic Applications

Covalent organic frameworks (COFs), consisting of covalently connected organic building units, combine attractive features such as crystallinity, open porosity and widely tunable physical properties. For optoelectronic applications, the incorporation of heteroatoms into a 2D COF has the potential to yield desired photophysical properties such as lower band gaps, but can also cause lateral offsets of adjacent layers. Here, we introduce dibenzo[g,p]chrysene (DBC) as a novel building block for the synthesis of highly crystalline and porous 2D dual-pore COFs showing interesting properties for optoelectronic applications. The newly synthesized terephthalaldehyde (TA), biphenyl (Biph), and thienothiophene (TT) DBC-COFs combine conjugation in the a,b-plane with a tight packing of adjacent layers guided through the molecular DBC node serving a specific docking site for successive layers. The resulting DBC-COFs exhibit a hexagonal dual-pore kagome geometry, which is comparable to COFs containing another molecular docking site, namely 4,4′,4″,4‴-(ethylene-1,1,2,2-tetrayl)-tetraaniline (ETTA). In this context, the respective interlayer distances decrease from about 4.60 Å in ETTA-COFs to about 3.6 Å in DBC-COFs, leading to well-defined hexagonally faceted single crystals sized about 50-100 nm. The TT DBC-COFs feature broad light absorption covering large parts of the visible spectrum, while Biph DBC-COF shows extraordinary excited state lifetimes exceeding 10 ns. In combination with the large number of recently developed linear conjugated building blocks, the new DBC tetra-connected node is expected to enable the synthesis of a large family of strongly p-stacked, highly ordered 2D COFs with promising optoelectronic properties.

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An Infrared Microscope for Use on a Focused Ion Beam for Circuit Edit and Backside Edit Applications

ISTFA 2015: Conference Proceedings from the 41st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2015p0097 ◽

2015 ◽

Author(s):

Alexander Richards ◽

Matthew Weschler ◽

Michael Durller

Keyword(s):

Focused Ion Beam ◽

Near Infrared ◽

Ion Beam ◽

Visible Spectrum ◽

Camera System ◽

Buried Structures ◽

Ir Camera ◽

Area Of Interest ◽

Near Ultraviolet ◽

Infrared Microscope

Abstract To help solve the navigational problem, i.e., being able to successfully locate a circuit for probing or editing without destroying chip functionality, a near-infrared (NIR), near-ultraviolet (NUV), and visible spectrum camera system was developed that attaches to most focused ion beam (FIB) or scanning electron microscope vacuum chambers. This paper reviews the details of the design and implementation of the NIR/NUV camera system, as instantiated upon the FEI FIB 200, with a particular focus on its use for the visualization of buried structures, and also for non-destructive real time area of interest location and end point detection. It specifically considers the use of the micro-optical camera system for its benefit in assisting with frontside and backside circuit edit, as well as other typical FIB milling activities. The quality of the image obtained by the IR camera rivals or exceeds traditional optical based imaging microscopy techniques.

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Complexes of Copper and Iron with Pyridoxamine, Ascorbic Acid, and a Model Amadori Compound: Exploring Pyridoxamine’s Secondary Antioxidant Activity

Antioxidants ◽

10.3390/antiox10020208 ◽

2021 ◽

Vol 10 (2) ◽

pp. 208

Author(s):

Guillermo García-Díez ◽

Roger Monreal-Corona ◽

Nelaine Mora-Diez

Keyword(s):

Antioxidant Activity ◽

Ascorbic Acid ◽

Rate Constant ◽

Stable Complex ◽

Aqueous Environment ◽

Oh Radicals ◽

Bidentate Ligands ◽

Superoxide Radical Anion ◽

Amadori Compound ◽

The Stability

The thermodynamic stability of 11 complexes of Cu(II) and 26 complexes of Fe(III) is studied, comprising the ligands pyridoxamine (PM), ascorbic acid (ASC), and a model Amadori compound (AMD). In addition, the secondary antioxidant activity of PM is analyzed when chelating both Cu(II) and Fe(III), relative to the rate constant of the first step of the Haber-Weiss cycle, in the presence of the superoxide radical anion (O2•−) or ascorbate (ASC−). Calculations are performed at the M05(SMD)/6-311+G(d,p) level of theory. The aqueous environment is modeled by making use of the SMD solvation method in all calculations. This level of theory accurately reproduces the experimental data available. When put in perspective with the stability of various complexes of aminoguanidine (AG) (which we have previously studied), the following stability trends can be found for the Cu(II) and Fe(III) complexes, respectively: ASC < AG < AMD < PM and AG < ASC < AMD < PM. The most stable complex of Cu(II) with PM (with two bidentate ligands) presents a ΔGf0 value of −35.8 kcal/mol, whereas the Fe(III) complex with the highest stability (with three bidentate ligands) possesses a ΔGf0 of −58.9 kcal/mol. These complexes can significantly reduce the rate constant of the first step of the Haber-Weiss cycle with both O2•− and ASC−. In the case of the copper-containing reaction, the rates are reduced up to 9.70 × 103 and 4.09 × 1013 times, respectively. With iron, the rates become 1.78 × 103 and 4.45 × 1015 times smaller, respectively. Thus, PM presents significant secondary antioxidant activity since it is able to inhibit the production of ·OH radicals. This work concludes a series of studies on secondary antioxidant activity and allows potentially new glycation inhibitors to be investigated and compared relative to both PM and AG.

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Integrated Optical Phased Arrays for Beam Forming and Steering

Applied Sciences ◽

10.3390/app11094017 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4017

Author(s):

Yongjun Guo ◽

Yuhao Guo ◽

Chunshu Li ◽

Hao Zhang ◽

Xiaoyan Zhou ◽

...

Keyword(s):

Near Infrared ◽

Phased Arrays ◽

Mechanical Stability ◽

Building Blocks ◽

High Yield ◽

Beam Forming ◽

Integrated Optical ◽

Optical Phased Arrays ◽

Infrared Spectral ◽

Spectral Ranges

Integrated optical phased arrays can be used for beam shaping and steering with a small footprint, lightweight, high mechanical stability, low price, and high-yield, benefiting from the mature CMOS-compatible fabrication. This paper reviews the development of integrated optical phased arrays in recent years. The principles, building blocks, and configurations of integrated optical phased arrays for beam forming and steering are presented. Various material platforms can be used to build integrated optical phased arrays, e.g., silicon photonics platforms, III/V platforms, and III–V/silicon hybrid platforms. Integrated optical phased arrays can be implemented in the visible, near-infrared, and mid-infrared spectral ranges. The main performance parameters, such as field of view, beamwidth, sidelobe suppression, modulation speed, power consumption, scalability, and so on, are discussed in detail. Some of the typical applications of integrated optical phased arrays, such as free-space communication, light detection and ranging, imaging, and biological sensing, are shown, with future perspectives provided at the end.

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