scholarly journals Hole-transfer induced energy transfer in perylene diimide dyads with a donor–spacer–acceptor motif

2015 ◽  
Vol 17 (38) ◽  
pp. 25061-25072 ◽  
Author(s):  
Patrick Kölle ◽  
Igor Pugliesi ◽  
Heinz Langhals ◽  
Roland Wilcken ◽  
Andreas J. Esterbauer ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Perylene Diimide ◽  
Energy Transfer Mechanism ◽  
Time Resolved Fluorescence ◽  
Efficient Energy Transfer ◽  
Time Resolved ◽  
Pump Probe ◽  
Efficient Energy ◽  
Probe Spectroscopy ◽  
Transfer State

Pump–probe spectroscopy, time resolved fluorescence, chemical variation and quantum chemical calculations reveal an efficient energy transfer mechanism enabled by a bright charge transfer state located on the spacer.

scholarly journals Ultrafast Electron/Energy Transfer and Intersystem Crossing Mechanisms in BODIPY-Porphyrin Compounds

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 312
Author(s):  
Yusuf Tutel ◽  
Gökhan Sevinç ◽  
Betül Küçüköz ◽  
Elif Akhuseyin Yildiz ◽  
Ahmet Karatay ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Spectra ◽  
Visible Region ◽  
Energy Transfer Mechanism ◽  
Free Base ◽  
Pump Probe ◽  
Harvesting Efficiency ◽  
Probe Spectroscopy ◽  
Absorption Features ◽  
Transfer Mechanisms

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.

Sensitizing effect of Yb3+ on near-infrared fluorescence emission of Cr4+-doped calcium aluminate glasses

2000 ◽  
Vol 15 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Yong Gyu Choi ◽  
Kyong Hon Kim ◽  
Yong Seop Han ◽  
Jong Heo
Keyword(s):  
Energy Transfer ◽  
Calcium Aluminate ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Dipole Interaction ◽  
Energy Transfer Mechanism ◽  
Efficient Energy Transfer ◽  
Efficient Energy ◽  
Sensitizing Effect ◽  
Decay Behavior

We have demonstrated that an efficient energy transfer takes place from Yb3+ to Cr4+ in calcium aluminate glasses. Yb3+ improves excitation efficiency at around 980 nm, enhancing emission intensity of Cr4+ fluorescence at 1.2–1.6 μm. Nonradiative energy transfer via electric dipole–dipole interaction between ytterbium and chromium ions was found to be dominant over radiative Yb3+ → Cr4+ energy transfer. A diffusionlimited energy transfer mechanism well explains the decay behavior of Yb3+/Cr4+- codoped glasses. This codoping scheme may be applicable to other Cr4+-containing crystals and glasses.

scholarly journals Investigation of Energy Transfer in Star-Shaped White Polymer Light-Emitting Devices via the Time-Resolved Photoluminescence

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1719 ◽  
Author(s):  
Hui He ◽  
Xiaoqing Liao ◽  
Jiang Cheng ◽  
Ying Li ◽  
Junsheng Yu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Current Efficiency ◽  
Intermolecular Interactions ◽  
Efficient Energy Transfer ◽  
Time Resolved ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Efficient Energy ◽  
Polymer Light Emitting Devices ◽  
Time Resolved Photoluminescence

A series of white polymer light-emitting devices (WPLEDs) were fabricated by utilizing star-shaped white-emission copolymers containing tri[1-phenylisoquinolinato-C2,N]iridium (Ir(piq)3), fluorenone (FO) and poly(9,9-dioctylfluorene) (PFO) as red-, green- and blue-emitting (RGB) components, respectively. In these WPLEDs, a maximum current efficiency of 6.4 cd·A−1 at 20 mA·cm−2 and Commission Internationale d’Eclairage (CIE) coordinates of (0.33, 0.32) were achieved, and the current efficiency was still kept to 4.2 cd·A−1 at the current density of 200 mA·cm−2. To investigate energy transfer processes among the three different chromophores of the star-shaped copolymers in these WPLEDs, the time-resolved photoluminescence (PL) spectra were recorded. By comparing the fluorescence decay lifetimes of PFO chromophores in the four star-like white-emitting copolymers, the efficient energy transfer from PFO units to Ir(piq)3 and FO chromophores was confirmed. From time-resolved PL and the analysis of energy transfer process, the results as follows were proved. Owing to the star-like molecular structure and steric hindrance effect, intermolecular interactions and concentrations quenching in the electroluminescence (EL) process could also be sufficiently suppressed. The efficient energy transfer also reduced intermolecular interactions’ contribution to the enhanced device performances compared to the linear single-polymer white-light systems. Moreover, saturated stable white emission results from the joint of energy transfer and trap-assisted recombination. This improved performance is expected to provide the star-like white-emitting copolymers with promising applications for WPLEDs.

Synthesis of unsymmetrical porphyrin triad containing three different porphyrin subunits assembled by covalent and non-covalent interactions

2008 ◽  
Vol 12 (09) ◽  
pp. 1030-1040 ◽  
Author(s):  
Sokkalingam Punidha ◽  
Smita Rai ◽  
Mangalampalli Ravikanth
Keyword(s):  
Building Block ◽  
Functional Group ◽  
Photophysical Properties ◽  
Time Resolved Fluorescence ◽  
Efficient Energy Transfer ◽  
Time Resolved ◽  
Fluorescence Studies ◽  
Efficient Energy ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Cis-21,23-dithiaporphyrin building block containing one iodophenyl and one pyridyl functional group at meso positions was synthesized by condensing unsymmetrical thiophene diol and symmetrical 16-thiatripyrrin under refluxing propionic acid conditions. The 21,23-dithiaporphyrin building block was coupled with mono-functionalized 21-thiaporphyrin building block containing meso-phenylethyne functional group under mild Pd (0) coupling conditions. The steady-state and time-resolved fluorescence studies support an efficient energy transfer in the singlet excited state from N 3 S porphyrin subunit to N 2 S 2 porphyrin subunit in the dyad. The N 3 S - N 2 S 2 porphyrin dyad was then treated with RuTPP ( CO )( EtOH ) in toluene at refluxing temperature and purified by column chromatography to afford a porphyrin triad containing N 3 S , N 2 S 2 and RuN 4 porphyrin subunits assembled using both covalent and non-covalent interactions. The photophysical properties showed the fluorescence quenching of N 3 S and N 2 S 2 porphyrin subunits in triad due to heavy ruthenium ion which was coordinated to meso-pyridyl ' N ' of N 2 S 2 porphyrin subunit of porphyrin triad.

scholarly journals Key interactions with deazariboflavin cofactor for light-driven energy transfer in Xenopus (6–4) photolyase

2021 ◽  
Author(s):  
Ayaka Morimoto ◽  
Yuhei Hosokawa ◽  
Hiromu Miyamoto ◽  
Rajiv Kumar Verma ◽  
Shigenori Iwai ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Light Harvesting ◽  
Spectroscopic Studies ◽  
Efficient Energy Transfer ◽  
Time Resolved ◽  
Catalytic Center ◽  
Efficient Energy ◽  
Coulombic Interactions ◽  
Hydrophobic Amino Acid Residue

AbstractPhotolyases are flavoenzymes responsible for light-driven repair of carcinogenic crosslinks formed in DNA by UV exposure. They possess two non-covalently bound chromophores: flavin adenine dinucleotide (FAD) as a catalytic center and an auxiliary antenna chromophore that harvests photons and transfers solar energy to the catalytic center. Although the energy transfer reaction has been characterized by time-resolved spectroscopy, it is strikingly important to understand how well natural biological systems organize the chromophores for the efficient energy transfer. Here, we comprehensively characterized the binding of 8-hydroxy-7,8-didemethyl-5-deazariboflavin (8-HDF) to Xenopus (6–4) photolyase. In silico simulations indicated that a hydrophobic amino acid residue located at the entrance of the binding site dominates translocation of a loop upon binding of 8-HDF, and a mutation of this residue caused dysfunction of the efficient energy transfer in the DNA repair reaction. Mutational analyses of the protein combined with modification of the chromophore suggested that Coulombic interactions between positively charged residues in the protein and the phenoxide moiety in 8-HDF play a key role in accommodation of 8-HDF in the proper direction. This study provides a clear evidence that Xenopus (6–4) photolyase can utilize 8-HDF as the light-harvesting chromophore. The obtained new insights into binding of the natural antenna molecule will be helpful for the development of artificial light-harvesting chromophores and future characterization of the energy transfer in (6–4) photolyase by spectroscopic studies.

Efficient artificial light-harvesting systems based on aggregation-induced emission constructed in supramolecular gels

Soft Matter ◽  
2021 ◽  
Author(s):  
Xinxian Ma ◽  
bo qiao ◽  
Jinlong Yue ◽  
JingJing Yu ◽  
yutao geng ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Light Harvesting ◽  
Artificial Light ◽  
Efficient Energy Transfer ◽  
Aggregation Induced Emission ◽  
Efficient Energy ◽  
Harvesting Systems ◽  
Acyl Hydrazone

Based on a new designed acyl hydrazone gelator (G2), we developed an efficient energy transfer supramolecular organogel in glycol with two different hydrophobic fluorescent dyes rhodamine B (RhB) and acridine...

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