Synthesis and Spectral Properties of 6'-Triazolyl-Dihydroxanthene-Hemicyanine Fused Near-Infrared Dyes

We describe the synthesis of a range of 6’-triazolyl-dihydroxanthene-hemicyanine (DHX-hemicyanine) fused dyes through an effective copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction, with the dual aim of providing molecular diversity and fine tuning spectral properties of these near-infrared (NIR)-active materials. This was implemented by reacting 16 different aliphatic and aromatic azides with a terminal alkynyl-based-DHX-hemicyanine hybrid scaffold prepared in four steps and 35% overall yield from 4-bromosalicylaldehyde. The resulting triazole derivatives have been fully characterized and their optical properties determined both in organic solvents and simulated physiological conditions (phosphate buffered saline containing 5% of bovine serum albumin protein). This systematic study is a first important step towards the development of NIR-I fluorogenic "click-on" dyes or related photoactive agents for light-based diagnostic and/or therapeutic applications.

Download Full-text

How the Optical Properties of Leaves Modify the Absorption and Scattering of Energy and Enhance Leaf Functionality

Remote Sensing of Plant Biodiversity ◽

10.1007/978-3-030-33157-3_14 ◽

2020 ◽

pp. 349-384 ◽

Cited By ~ 1

Author(s):

Susan L. Ustin ◽

Stéphane Jacquemoud

Keyword(s):

Optical Properties ◽

Infrared Spectrum ◽

Related Species ◽

Spectral Properties ◽

Near Infrared ◽

Solar Spectrum ◽

Cellular Organization ◽

Seed Plant ◽

Or Groups ◽

Shortwave Infrared

AbstractLeaves absorb, scatter, and transmit sunlight at all wavelengths across the visible, near-infrared, and shortwave-infrared spectrum. The optical properties of a leaf are determined by its biochemical and biophysical characteristics, including its 3-D cellular organization. The absorption and scattering properties of leaves together create the shape of their reflectance spectra. Terrestrial seed plant species share similar physiological and metabolic processes for fluxes of gases (CO2, O2, H2O), nutrients, and energy, while differences are primarily consequences of how these properties are distributed and their physical structures. Related species generally share biochemical and biophysical traits, and their optical properties are also similar, providing a mechanism for identification. However, it is often the minor differences in spectral properties throughout the wavelengths of the solar spectrum that define a species or groups of related species. This chapter provides a review and summary of the most common interactions between leaf properties and light and the physical processes that regulate the outcomes of these interactions.

Download Full-text

The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD

Micromachines ◽

10.3390/mi12060637 ◽

2021 ◽

Vol 12 (6) ◽

pp. 637

Author(s):

Hongliang Li ◽

Zewen Lin ◽

Yanqing Guo ◽

Jie Song ◽

Rui Huang ◽

...

Keyword(s):

Optical Properties ◽

Near Infrared ◽

Chemical Vapor ◽

Wide Bandgap ◽

Nonradiative Recombination ◽

Very High Frequency ◽

N Content ◽

High Frequency Plasma ◽

Frequency Plasma ◽

N Incorporation

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.

Download Full-text

Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽

10.1515/nanoph-2020-0314 ◽

2020 ◽

Vol 9 (14) ◽

pp. 4233-4252

Author(s):

Yael Gutiérrez ◽

Pablo García-Fernández ◽

Javier Junquera ◽

April S. Brown ◽

Fernando Moreno ◽

...

Keyword(s):

Optical Properties ◽

Room Temperature ◽

Phase Change Materials ◽

Two Dimensional ◽

Active Materials ◽

Promising Candidate ◽

Plasmonic Structures ◽

Resonance Tuning ◽

The Many ◽

Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

Download Full-text

High performing flexible optoelectronic devices using thin films of topological insulator

Scientific Reports ◽

10.1038/s41598-020-80738-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Animesh Pandey ◽

Reena Yadav ◽

Mandeep Kaur ◽

Preetam Singh ◽

Anurag Gupta ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Nonlinear Optical ◽

Near Infrared ◽

Optoelectronic Devices ◽

Nonlinear Optical Properties ◽

Metallic Surface ◽

Strong Light ◽

High Performing ◽

Decay Times

AbstractTopological insulators (TIs) possess exciting nonlinear optical properties due to presence of metallic surface states with the Dirac fermions and are predicted as a promising material for broadspectral phodotection ranging from UV (ultraviolet) to deep IR (infrared) or terahertz range. The recent experimental reports demonstrating nonlinear optical properties are mostly carried out on non-flexible substrates and there is a huge demand for the fabrication of high performing flexible optoelectronic devices using new exotic materials due to their potential applications in wearable devices, communications, sensors, imaging etc. Here first time we integrate the thin films of TIs (Bi2Te3) with the flexible PET (polyethylene terephthalate) substrate and report the strong light absorption properties in these devices. Owing to small band gap material, evolving bulk and gapless surface state conduction, we observe high responsivity and detectivity at NIR (near infrared) wavelengths (39 A/W, 6.1 × 108 Jones for 1064 nm and 58 A/W, 6.1 × 108 Jones for 1550 nm). TIs based flexible devices show that photocurrent is linearly dependent on the incident laser power and applied bias voltage. Devices also show very fast response and decay times. Thus we believe that the superior optoelectronic properties reported here pave the way for making TIs based flexible optoelectronic devices.

Download Full-text

Assessment of optical properties in cerebral ischemic rats by using near infrared spectroscopy

2014 IEEE Conference on Biomedical Engineering and Sciences (IECBES) ◽

10.1109/iecbes.2014.7047621 ◽

2014 ◽

Author(s):

Wan-Chen Shao ◽

Chun-Wei Wu ◽

Chun-Man Yuan ◽

Jia-Jin Jason Chen

Keyword(s):

Optical Properties ◽

Infrared Spectroscopy ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Cerebral Ischemic

Download Full-text

A phthalocyanine-based fluorescent sensor for Zn2+ ion

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424612501374 ◽

2013 ◽

Vol 17 (01n02) ◽

pp. 99-103 ◽

Cited By ~ 8

Author(s):

Hui He ◽

Jian-Yong Liu ◽

Dennis K.P. Ng

Keyword(s):

Metal Ions ◽

Spectral Properties ◽

Fluorescence Spectra ◽

Near Infrared ◽

Fluorescent Sensor ◽

High Sensitivity ◽

Absorption And Fluorescence Spectra

This paper describes the preparation and spectral properties of a near-infrared fluorophore in which two bis(2-picolyl)amino moieties are axially linked to a silicon(IV) phthalocyanine core. The effects of various metal ions on its absorption and fluorescence spectra have been examined. The results indicate that this compound shows a high sensitivity and moderate selectivity toward Zn2+ ion.

Download Full-text

Structure and microstructure of near infrared-absorbing Au–Au2S nanoparticles

Journal of Materials Research ◽

10.1557/jmr.2007.0314 ◽

2007 ◽

Vol 22 (9) ◽

pp. 2531-2538 ◽

Cited By ~ 5

Author(s):

Mei Chee Tan ◽

Jackie Y. Ying ◽

Gan Moog Chow

Keyword(s):

Optical Properties ◽

Surface Segregation ◽

Near Infrared ◽

Small Degree ◽

Core Shell ◽

Shell Microstructure ◽

Absorption Bands ◽

Interfacial Effects ◽

Nir Absorption ◽

Structure And Microstructure

Near infrared (NIR) absorbing nanoparticles synthesized by the reduction of HAuCl4 with Na2S exhibited absorption bands at ∼530 nm, and in the NIR region of 650–1100 nm. The NIR optical properties were not found to be related to the earlier proposed Au2S–Au core-shell microstructure in previous studies. From a detailed study of the structure and microstructure of as-synthesized particles in this work, S-containing, Au-rich, multiply-twinned nanoparticles were found to exhibit NIR absorption. They consisted of amorphous AuxS (where x = 2), mostly well mixed within crystalline Au, with a small degree of surface segregation of S. Therefore, NIR absorption was likely due to interfacial effects on particle polarization from the introduction of AuxS into Au particles, and not the dielectric confinement of plasmons associated with a core-shell microstructure.

Download Full-text