scholarly journals Synthesis and Photobehavior of a NewDehydrobenzoannulene-Based HOF with Fluorine Atoms: From Solution to Single Crystals Observation

2021 ◽  
Vol 22 (9) ◽  
pp. 4803
Author(s):  
Eduardo Gomez ◽  
Ichiro Hisaki ◽  
Abderrazzak Douhal
Keyword(s):  
Charge Transfer ◽  
Single Crystals ◽  
Parent Compound ◽  
Time Resolved ◽  
Strong Basis ◽  
Triplet Structure ◽  
Carboxylic Groups ◽  
Potential Applications ◽  
A Charge ◽  
Further Development

Hydrogen-bonded organic frameworks (HOFs) are the focus of intense scientific research due their potential applications in science and technology. Here, we report on the synthesis, characterization, and photobehavior of a new HOF (T12F-1(124TCB)) based on a dehydrobenzoannulene derivative containing fluorine atoms (T12F-COOH). This HOF exhibits a 2D porous sheet, which is hexagonally networked via H-bonds between the carboxylic groups, and has an interlayers distance (4.3 Å) that is longer than that of a typical π–π interaction. The presence of the fluorine atoms in the DBA molecular units largely increases the emission quantum yield in DMF (0.33, T12F-COOH) when compared to the parent compound (0.02, T12-COOH). The time-resolved dynamics of T12F-COOH in DMF is governed by the emission from a locally excited state (S1, ~ 0.4 ns), a charge-transfer state (S1(CT), ~ 2 ns), and a room temperature emissive triplet state (T1, ~ 20 ns), in addition to a non-emissive triplet structure with a charge-transfer character (T1(CT), τ = 0.75 µs). We also report on the results using T12F-ester. Interestingly, FLIM experiments on single crystals unravel that the emission lifetimes of the crystalline HOF are almost twice those of the amorphous ones or the solid T12F-ester sample. This shows the relevance of the H-bonds in the photodynamics of the HOF and provides a strong basis for further development and study of HOFs based on DBAs for potential applications in photonics.

scholarly journals Water-Soluble Visible Light Sensitive Photoinitiating System Based on Charge Transfer Complexes for the 3D Printing of Hydrogels

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3195
Author(s):  
Hong Chen ◽  
Mehdi Vahdati ◽  
Pu Xiao ◽  
Frédéric Dumur ◽  
Jacques Lalevée
Keyword(s):  
Charge Transfer ◽  
3D Printing ◽  
Visible Light ◽  
Water Solubility ◽  
Charge Transfer Complex ◽  
Water Soluble ◽  
Charge Transfer Complexes ◽  
Free Radical Photopolymerization ◽  
Potential Applications ◽  
A Charge

The development of visible-light 3D printing technology by using water-soluble initiating systems has attracted widespread attention due to their potential applications in the manufacture of hydrogels. Besides, at present, the preparation of water-soluble photoinitiators suitable for visible light irradiation (such as LEDs) still remains a challenge. Therefore, this work is devoted to developing water-soluble photoinitiators (PI)/photoinitiating systems (PIS) upon irradiation with a LED @ 405 nm. In detail, a new water-slightly-soluble chalcone derivative dye [(E)-3-(4-(dimethylamino) phenyl)-1-(4-(2-(2-(2-methoxyethoxy) ethoxy) ethoxy) phenyl) prop-2-en-1-one] was synthesized here and used as a PI with a water-soluble coinitiator, i.e., triethanolamine (TEA) which was also used as an electron donor. When combined together, a charge transfer complex (CTC) formed immediately which exhibited excellent initiating ability for the free radical photopolymerization of poly(ethyleneglycol)diacrylate (PEG-DA). In light of the powerful CTC effect, the [dye-TEA] CTC could not only exhibit enhanced water solubility and mechanical properties but could also be effectively applied for 3D printing. This CTC system is environmentally friendly and cost-saving which demonstrates a great potential to prepare hydrogels via photopolymerization.

scholarly journals Charge transfer state emission dynamics in blue-emitting functionalized silicon nanocrystals

2015 ◽  
Vol 17 (44) ◽  
pp. 30125-30133 ◽  
Author(s):  
Glenda B. De los Reyes ◽  
Mita Dasog ◽  
MengXing Na ◽  
Lyubov V. Titova ◽  
Jonathan G. C. Veinot ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Silicon Nanocrystals ◽  
Blue Emission ◽  
Photoluminescence Spectroscopy ◽  
Charge Transfer State ◽  
Time Resolved ◽  
A Charge ◽  
Time Resolved Photoluminescence ◽  
Transfer State

Time-resolved photoluminescence spectroscopy reveals a charge transfer state dynamics responsible for the size-independent blue emission observed from dodecylamine and ammonia functionalized silicon nanocrystals.

Time-resolved photoelectron spectroscopy of IR-driven electron dynamics in a charge transfer model system

2017 ◽  
Vol 19 (30) ◽  
pp. 19683-19690 ◽  
Author(s):  
Mirjam Falge ◽  
Friedrich Georg Fröbel ◽  
Volker Engel ◽  
Stefanie Gräfe
Keyword(s):  
Charge Transfer ◽  
Photoelectron Spectroscopy ◽  
Model System ◽  
Photoelectron Spectra ◽  
Transfer Model ◽  
Electron Dynamics ◽  
Time Resolved ◽  
System P ◽  
A Charge ◽  
Charge Transfer Model

IR and XUV pulse interaction result in modulated asymmetries of photoelectron spectra.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

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