Photochemical synthesis and photophysical properties of coumarins bearing extended polyaromatic rings studied by emission and transient absorption measurements

2017 ◽  
Vol 16 (4) ◽  
pp. 555-563 ◽  
Author(s):  
Minoru Yamaji ◽  
Yuma Hakoda ◽  
Hideki Okamoto ◽  
Fumito Tani
Keyword(s):  
Transient Absorption ◽  
Photophysical Properties ◽  
Photochemical Synthesis ◽  
Electron Systems ◽  
Absorption Measurements

Coumarins having expanded π-electron systems were prepared via a photocondensation process and the photophysical features in solution were investigated based on emission and transient absorption measurements.

Photochemical synthesis and photophysical features of ethynylphenanthrenes studied by emission and transient absorption measurements

2016 ◽  
Vol 15 (12) ◽  
pp. 1586-1593 ◽  
Author(s):  
Yuma Hakoda ◽  
Masatoshi Aoyagi ◽  
Ken-ichi Irisawa ◽  
Shin-ichiro Kato ◽  
Yosuke Nakamura ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Photochemical Synthesis ◽  
Triple Bonds ◽  
Absorption Measurements

Phenanthrenes substituted with C–C triple bonds were photochemically prepared, and the photophysical features in solution were investigated based on emission and transient absorption measurements.

scholarly journals 1,2,3-Tri(9-anthryl)benzene. Photophysical Properties and Solid State Intermolecular Interactions of Radially Arranged, Congested Aromatic π-Planes

2021 ◽  
Author(s):  
Tomohiko Nishiuchi ◽  
Hikaru Sotome ◽  
Kazuto Shimizu ◽  
Hiroshi Miyasaka ◽  
Takashi Kubo
Keyword(s):  
Quantum Chemical ◽  
Crystalline State ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Benzene Derivatives ◽  
Aromatic Rings ◽  
Negishi Coupling ◽  
Exciton Localization ◽  
Packing Structure ◽  
Absorption Measurements

We report the Negishi coupling based synthesis of 1,2,3-tri(9-anthryl)benzene derivatives, containing three radially arranged anthracenes in a π-cluster. In the crystalline state of the unsubstituted derivative, intermolecular π-π and CH-π interactions between the anthracene units drive the formation of a two-dimensional packing structure. Owing to though-space π-conjugation between anthracene units, the substances have unique electronic properties. The excited state dynamic behavior occurring between the three radially arranged anthracene moieties, such as exciton localization/delocalization, was elucidated by means of transient absorption measurements and quantum chemical calculations. Interestingly, even though the three anthracenes are closely oriented with a ca. 3.0 Å distances between their C-9 positions, exciton localization on two anthracene units is energetically favorable because of the flexible nature of the radially arranged aromatic rings.

Preparation and photophysical properties of fluorescent difluoroboronated β-diketones having phenanthrene moieties studied by emission and transient absorption measurements

2016 ◽  
Vol 15 (2) ◽  
pp. 278-286 ◽  
Author(s):  
Michitaka Mamiya ◽  
Yurie Suwa ◽  
Hideki Okamoto ◽  
Minoru Yamaji
Keyword(s):  
Transient Absorption ◽  
Photophysical Properties ◽  
Absorption Measurements

Six difluoroboronated β-diketones having the phenanthrene skeleton (Phe@Ar) are prepared, and the photophysical features are studied.

Photophysical properties of a carbazolyl mesogen of 8PCzC as revealed by absorption, fluorescence, and transient absorption measurements

2005 ◽  
Vol 4 (1) ◽  
pp. 128 ◽  
Author(s):  
Kentaro Irie ◽  
Shinjiro Machida ◽  
Tohru Ikegami ◽  
Nobuo Tanaka ◽  
Hiroshi Miyasaka ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Photophysical Properties ◽  
Absorption Measurements

Photoinduced electron transfer processes in three component rotaxanes with porphyrins, [60]fullerene and triphenylamine

2006 ◽  
Vol 10 (12) ◽  
pp. 1346-1359 ◽  
Author(s):  
Hisahiro Sasabe ◽  
Yoshio Furusho ◽  
Atula S.D. Sandanayaka ◽  
Yasuyuki Araki ◽  
Nobuhiro Kihara ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Time Resolved ◽  
Transfer Processes ◽  
Back Electron Transfer ◽  
Electron Transfer Processes ◽  
Absorption Measurements

Electron transfer processes occurring through-space and through-bond were studied for novel mechanically linked triad [2]rotaxanes, which contain a porphyrin (MP) unit as a pendant and [60]fullerene ( C 60) and triphenylamine ( TPA ) moieties as stopper groups at the axle ends (abbreviated as ( MP ; C 60- TPA ) rot+ with MP = H 2 P or ZnP . The photophysical properties were investigated by means of time-resolved fluorescence and transient absorption measurements with changing solvent polarity. The charge separation took place mainly via(1 MP *; C 60- TPA ) rot+ and ( MP ;1 C 60*- TPA ) rot + in polar solvents. Within the charge-separated states of triads ( MP ; C 60- TPA ) rot +, hole-shift and/or back electron transfer took place competitively. The lifetime of the charge separation state of ( ZnP ; C 60- TPA ) rot+ was similar to that of dyad ( C 60- TPA ) rot+ (140 ns in dimethylformamide), whereas that of ( H 2 P ; C 60- TPA ) rot + was as long as 230 ns, suggesting two final charge separation states such as ( MP ; C 60•-- TPA •+) rot + and ( MP •+; C 60•-- TPA ) rot+ depending on the kind of porphyrin.

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

scholarly journals Photoinduced electron transfer processes of single-wall carbon nanotube (SWCNT)–based hybrids

Nanophotonics ◽  
2020 ◽  
Vol 9 (16) ◽  
pp. 4689-4701
Author(s):  
Lili Du ◽  
Wenjuan Xiong ◽  
Wai Kin Chan ◽  
David Lee Phillips
Keyword(s):  
Electron Transfer ◽  
Transient Absorption ◽  
Electronic Materials ◽  
Photophysical Properties ◽  
Functional Materials ◽  
Single Wall Carbon Nanotubes ◽  
Spectroscopic Techniques ◽  
Time Resolved ◽  
Single Wall Carbon ◽  
Electron Transfer Processes

AbstractIn this review, noncovalent functionalization of single-wall carbon nanotubes (SWCNTs) is briefly reviewed. The functional materials summarized here include metalloporphyrin derivatives, biomolecules and conjugated polymers. Notably, time-resolved spectroscopic techniques such as time-resolved fluorescence and transient absorption were employed to directly investigate the electron transfer and recombination processes between the functionalities and the SWCNTs. In addition, Raman spectroscopy is also useful to identify the interaction and the electron transfer direction between both the functionalities and the SWCNTs. An improved understanding of the mechanisms of these SWCNT-based nanohybrids in terms of their structural and photophysical properties can provide more insights into the design of new electronic materials.

Contactless Spatially Resolved Measurement of Bulk Free-Carrier Lifetime in Silicon Ingots

1986 ◽  
Vol 69 ◽  
Author(s):  
S. M. Johnson ◽  
L. G. Johnson ◽  
R. Hemphill
Keyword(s):  
Spatial Dependence ◽  
Polycrystalline Silicon ◽  
Carrier Lifetime ◽  
Transient Absorption ◽  
Free Carrier ◽  
Large Area ◽  
Spatially Resolved ◽  
Probe Transmission ◽  
Transmission Measurements ◽  
Absorption Measurements

AbstractA contactless spatially resolved measurement of bulk free-carrier lifetime in polycrystalline silicon ingots was accomplished using optically modulated free-carrier infrared absorption. Using a CW Nd:YAG laser (λ = 1.319 μm) for a probe and novel pulsed, tunable, infrared dye laser (λ = 1.10 to 1.13 μm) with photon energies near the Si bandgap, for a pump, the free-carrier lifetime was determined from transient absorption measurements to a maximum depth of 3.0 cm from the surface of an ingot. The spatial dependence of the free-carrier lifetime and the distribution of precipitates (determined from infrared probe transmission measurements) measured along the growth axis of an ingot were found to be strongly related to the spatial dependence of the I–V characteristics of large area solar cells fabricated from the subsequently wafered ingot.

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