scholarly journals MOLECULAR MODELING, REACTIVITY PARAMETERS AND SPECTROCHEMIC STUDIES OF ε-CAPROLACTAM AND o-PHENANTROLINE

2022 ◽  
Author(s):  
Francisco José Santos Lima ◽  
Keyword(s):  
Near Infrared ◽  
Visible Region ◽  
Transition Dipole Moment ◽  
Molar Absorptivity ◽  
Molecular Spectra ◽  
Transition Dipole ◽  
Light Emitting ◽  
Molecular Systems ◽  
Uv Visible ◽  
Molecular Compounds

In this work, molecular models were obtained, and the reactivity parameters of ε-caprolactam and ophenanthroline were calculated to evaluate the interaction in the formation of complex molecular compounds. It was observed that the main electron donor atoms, in the formation of the metal-ligand bond, are centered mainly on the oxygen and nitrogen atoms, respectively, which are sterically more favorable in these species. Conductance measurements in an aqueous solution were obtained to observe the electrolytic behavior of these compounds. Infrared spectra were also recorded to characterize vibrational transitions in identifying these species when present in complex systems. Molecular spectra of absorption in the UV-visible region were recorded to evaluate the spectrochemical properties of these individual ligands and further verify their influence on the formation of complex molecular systems. The parameters evaluated include the molar absorptivity ε, integrated absorption coefficient, oscillator force, and transition dipole moment. It was observed that the ε parameter indicates molecular transitions in the 190 – 300 nm region and the near-infrared, and the oscillator strength is typical of molecules used as dyes and sensitizers for optical light-emitting systems or light-to-electricity converters.

Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of <i> 2-dimensional aggregates</i> whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an <i>intermediate </i>“I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

Geometrically isomeric [Ir(iqbt)(ppy)(hpa)] complexes with differential molecule orientations for efficient near-infrared (NIR) polymer light-emitting diodes (PLEDs)

2021 ◽  
Vol 9 (36) ◽  
pp. 12068-12072
Author(s):  
Wentao Li ◽  
Jiaxiang Liu ◽  
Baowen Wang ◽  
Siyu Hou ◽  
Xingqiang Lü ◽  
...  
Keyword(s):  
Near Infrared ◽  
Light Emitting Diodes ◽  
Dipole Transition ◽  
Transition Dipole ◽  
Light Emitting ◽  
Horizontal Orientation ◽  
Polymer Light Emitting Diodes

Based on geometrical isomerisation of [Ir(C^N1)(C^N2)((N^O))]-tris-heteroleptic Ir(iii)-complexes, the augmented transition dipole transition (TMD) with a preferential horizontal orientation, which is beneficial for their NIR-phosphorescence, is reported.

scholarly journals Calculating transition dipole moments of phosphorescent emitters for efficient organic light-emitting diodes

2019 ◽  
Vol 21 (19) ◽  
pp. 9740-9746
Author(s):  
Mohammad Babazadeh ◽  
Paul L. Burn ◽  
David M. Huang
Keyword(s):  
Dipole Moment ◽  
Quantum Chemical ◽  
Dipole Moments ◽  
Molecular Geometry ◽  
Transition Dipole Moment ◽  
Organic Light Emitting Diodes ◽  
Transition Dipole ◽  
Light Emitting ◽  
Organic Light ◽  
Transition Dipole Moments

Quantum-chemical calculations show that the direction of the transition dipole moment of organometallic phosphorescent emitters is sensitive to molecular geometry.

scholarly journals Near-infrared and Visible Opacities of S-type Stars: The B1Π—X1Σ+ Band System of ZrO

2021 ◽  
Vol 923 (2) ◽  
pp. 234
Author(s):  
Jason J. Sorensen ◽  
Peter F. Bernath
Keyword(s):  
Ab Initio Calculation ◽  
Optical Spectrum ◽  
Near Infrared ◽  
Spectroscopic Analysis ◽  
Band System ◽  
Transition Dipole Moment ◽  
Solar Observatory ◽  
Spectroscopic Constants ◽  
Transition Dipole ◽  
National Solar Observatory

Abstract The ZrO B1Π—X1Σ+ transition is an important opacity source in the near-infrared and optical spectrum of S-type stars. The 0–0, 0–1, 0–2, 1–0, 1–2, 1–3, 2–0, 2–1, 2–3, 2–4, 3–1, 3–4, and 4–2 bands of the 90Zr16O B1Π—X1Σ+ transition are reanalyzed using a high-temperature (2390 K) high-resolution (0.04 cm−1) emission spectrum collected at the National Solar Observatory (Kitt Peak). A modern spectroscopic analysis was performed using the PGOPHER program to provide updated spectroscopic constants and to produce a high-precision line list with line strengths based on an ab initio calculation of the transition dipole moment.

scholarly journals Design Principles for 2-Dimensional Molecular Aggregates using Kasha’s Model: Tunable Photophysics in Near and Shortwave Infrared

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. It is therefore necessary to develop materials that absorb light efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~800 nm to 1000 nm and 1050 nm respectively with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). We use Frenkel exciton theory to extend Kasha’s model for J and H aggregation and describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. I-aggregates hold potential for applications as charge injection moieties for semiconductors and donors for energy transfer in NIR and SWIR. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

Effect of Coupling Indium Tin Oxide with the TiO2–NaYF4:(Gd, Si) Composite for Photocatalytic Properties

2020 ◽  
Vol 20 (12) ◽  
pp. 7629-7635
Author(s):  
Shielah Mavengere ◽  
Sang-Chul Jung ◽  
Jung-Sik Kim
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
Visible Region ◽  
Impregnation Method ◽  
Solar Simulator ◽  
Visible Spectra ◽  
Multi Wavelength ◽  
Uv Visible ◽  
Ito Nanoparticles

Indium tin oxide (ITO) nanoparticles were coupled with NaYF4:(Gd, Si) using a TiO2-solution impregnation method. Scanning electron microscopy confirmed that TiO2 and ITO nanoparticles were loaded on the surface of the NaYF4:(Gd, Si) upconversion phosphor. The ultraviolet/visible spectra of the 20 wt.% ITO-NaYF4:(Gd, Si)/TiO2 composites were extended at the absorption edges towards the UV-visible region. The 20 wt.% ITO-coupled NaYF4:(Gd, Si)/TiO2 composites exhibited superior photocatalytic efficiency compared to only NaYF4:(Gd, Si)/TiO2 under near-infrared (NIR) irradiation. Multi-wavelength NIR photons of γ > 760 nm from a Xe solar simulator source induced photo-activation through the NaYF4:(Gd, Si) activator centers. The three-cycle photocatalytic reusability performance of the 20 wt.% ITO-impregnated NaYF4:(Gd, Si)/TiO2 composite was positively enhanced by up to 20% more than that of NaYF4:(Gd, Si)/TiO2.

Spectroscopy with a Light Optical Microscope

2012 ◽  
Vol 21 (1) ◽  
pp. 22-26
Author(s):  
Paul Martin
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Infrared Region ◽  
Optical Microscope ◽  
Infrared Range ◽  
Molecular Spectra ◽  
Light Optical Microscope ◽  
Deep Ultraviolet ◽  
Uv Visible ◽  
Near Infrared Range

The microspectrophotometer can be described as a type of hyphenated instrument: it is a hybrid that combines the magnifying power of a light microscope with a UV-visible-NIR (ultraviolet–visible–near infrared) range spectrophotometer. These instruments are used to measure the molecular spectra from microscopic samples, from the deep ultraviolet to the near infrared region. Microspectrophotometers can be configured in many different ways and used to measure absorbance, reflectance, and even emission spectra, such as fluorescence, of sub-micron-sized sample areas. With the addition of specialized algorithms, the microspectrophotometer can also be used to measure the thickness of thin films or to act as a colorimeter for microscopic samples.

scholarly journals Two-Dimensional Nanoplatelet Superlattices Overcoming Light Outcoupling Efficiency Limit in Perovskite Quantum Dot Light-Emitting Diodes

2021 ◽  
Author(s):  
Sudhir Kumar ◽  
Tommaso Marcato ◽  
Frank Krumeich ◽  
Yen-Ting Li ◽  
Yu-Cheng Chiu ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Power Efficiency ◽  
Light Emitting Diodes ◽  
Transition Dipole Moment ◽  
Two Dimensional ◽  
Transition Dipole ◽  
Light Emitting ◽  
Planar Arrays ◽  
Out Of Plane

Abstract Quantum dot (QD) light-emitting diodes (LEDs) are emerging as one of the most promising candidates for next-generation displays. However, their intrinsic light outcoupling efficiency remains considerably lower than the organic counterpart, because it is not yet possible to control the transition-dipole-moment (TDM) orientation in QD solids at device level. Here, using the colloidal lead halide perovskite nanoplatelets (NPLs) as a model system, we report a directed self-assembly approach to form the two-dimensional superlattices (2DSLs) with the out-of-plane vector perpendicular to the substrate plane. The ligand and substrate engineering yields close-packed planar arrays with the side faces linked to each other. Emission polarization in individual NPLs rescales the radiation from horizontal and vertical transition dipoles, effectively resulting in preferentially horizontal TDM orientation. Based on the emissive thin films comprised of stacks of 2D superlattices, we demonstrate an enhanced ratio of horizontal dipole as revealed by 2D k-space spectroscopy. Our optimized single-junction QD LEDs showed peak external quantum efficiency of up to 24% and power efficiency exceeding 110 lm W-1, comparable to state-of-the-art organic LEDs.

Design Principles for 2-Dimensional Molecular Aggregates using Kasha’s Model: Tunable Photophysics in Near and Shortwave Infrared

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. It is therefore necessary to develop materials that absorb light efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~800 nm to 1000 nm and 1050 nm respectively with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). We use Frenkel exciton theory to extend Kasha’s model for J and H aggregation and describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. I-aggregates hold potential for applications as charge injection moieties for semiconductors and donors for energy transfer in NIR and SWIR. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

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