A Simple Dyad Exhibiting Microsecond Charge-Separation in Non-Polar Solvents

2006 ◽  
Vol 59 (3) ◽  
pp. 179 ◽  
Author(s):  
Kenneth P. Ghiggino ◽  
James A. Hutchison ◽  
Steven J. Langford ◽  
Melissa J. Latter ◽  
Marcia A.-P. Lee ◽  
...  
Keyword(s):  
Electron Spin ◽  
Charge Separation ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved Fluorescence ◽  
Polar Solvents ◽  
Separation Processes ◽  
Time Resolved ◽  
A Charge

A simple photovoltaic device in which two chromophoric components are assembled by Zn–N coordination yields a charge-separated state with microsecond lifetime upon photoexcitation in non-polar solvents. Characterization of the electron transfer dynamics using time-resolved fluorescence and transient absorption spectroscopy suggests that the unusual longevity is due to charge recombination occurring between states with different electron spin character. Control of electron spin may provide a novel paradigm for optimizing light-induced charge-separation processes.

Electron-transfer dyads suitable for novel self-assembled light-harvesting antenna/electron-transfer devices

2001 ◽  
Vol 73 (3) ◽  
pp. 469-474 ◽  
Author(s):  
Alfred R. Holzwarth ◽  
Martin Katterle ◽  
Marc G. Müller ◽  
Ying-Zong Ma ◽  
Valentin Prokhorenko
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Fullerene C60 ◽  
Transient Absorption Spectroscopy ◽  
Time Range ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Light Harvesting Antenna

The synthesis and photophysical and photochemical characterization of four novel bacterio-chlorin-fullerene dyads with fullerene C60 coupled at various positions and by various bridges to the chlorin ring are described. All dyads undergo rapid charge separation in the sub-picosecond to picosecond time range as characterized by time-resolved fluorescence and transient absorption spectroscopy.

scholarly journals The role of spin in the degradation of organic photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ivan Ramirez ◽  
Alberto Privitera ◽  
Safakath Karuthedath ◽  
Anna Jungbluth ◽  
Johannes Benduhn ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Bulk Heterojunction ◽  
Critical Factor ◽  
Model Systems ◽  
Transient Absorption Spectroscopy ◽  
Triplet States ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
A Charge

AbstractStability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C60 via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C60 excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.

Charge carrier kinetics of carbon nitride colloid: a femtosecond transient absorption spectroscopy study

2016 ◽  
Vol 18 (22) ◽  
pp. 14904-14910 ◽  
Author(s):  
Huiyu Zhang ◽  
Yaping Chen ◽  
Rong Lu ◽  
Ruiyu Li ◽  
Anchi Yu
Keyword(s):  
Charge Carrier ◽  
Carbon Nitride ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Spectroscopy Study ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Kinetics Of

The charge carrier kinetics of carbon nitride colloid was investigated using a combination of femtosecond transient absorption and picosecond time-resolved fluorescence spectroscopy.

Intramolecular electron transfer reactions in meso-(4-nitrophenyl)-substituted subporphyrins

2016 ◽  
Vol 52 (7) ◽  
pp. 1424-1427 ◽  
Author(s):  
Graeme Copley ◽  
Juwon Oh ◽  
Kota Yoshida ◽  
Daiki Shimizu ◽  
Dongho Kim ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Absorption Spectroscopy ◽  
Charge Separation ◽  
Transient Absorption ◽  
Charge Recombination ◽  
Transient Absorption Spectroscopy ◽  
Transfer Reactions ◽  
Intramolecular Electron Transfer ◽  
Time Resolved ◽  
Electron Transfer Reactions

A2B-type meso-(4-nitrophenyl)-substituted subporphyrins have been synthesized and shown to undergo very fast photoinduced intramolecular charge separation (CS) and charge recombination (CR) between the subporphyrin core and the meso-4-nitrophenyl group in CH2Cl2 as probed by femtosecond time-resolved transient absorption spectroscopy.

Photophysics of bis(p-N,N-dimethylamino)benzylidene acetone: Does photoinduced electron transfer occur from a twisted excited state?

1989 ◽  
Vol 67 (10) ◽  
pp. 1565-1575 ◽  
Author(s):  
R. J. DeVoe ◽  
M. R. V. Sahyun ◽  
E. Schmidt ◽  
Mahin Sadrai ◽  
N. Serpone ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Transient Absorption ◽  
Polar Solvent ◽  
Transient Absorption Spectroscopy ◽  
Triplet States ◽  
Polar Solvents ◽  
Excited Species ◽  
A Charge ◽  
Franck Condon ◽  
Sequential Formation

Photoexcitation of the title compound (DMBA) in polar solvents leads to sequential formation of at least three excited species as detected by laser transient absorption spectroscopy: the lowest Franck–Condon singlet, a twisted singlet (P-state), and the lowest triplet states. Only the initially formed, localized singlet is emissive under our conditions. Interystem crossing to triplet occurs primarily from the twisted P-state in acetonitrile and in methanol. Photo-CIDNP and quantum yield measurements indicate that electron transfer occurs exclusively from the triplet in acetonitrile or methanol to sensitize decomposition of diphenyliodonium cation and to bleach DMBA. Analysis of the photochemistry is complicated by formation of a charge transfer complex of enhanced photolability. Using tris(trichloromethyl)-sym-triazine as the electron acceptor in hydrocarbon solvent, bleaching of DMBA again occurs, somewhat more efficiently than with the 'onium salt in polar solvent. We infer that under these conditions electron transfer occurs from the P-state. Keywords: photochemistry, fluorescence, electron transfer, TICT, chalcone.

Catching metallic nitride endohedral fullerenes in organic and aqueous media

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1025-1033 ◽  
Author(s):  
Volker Strauss ◽  
Shankara Gayathri Radhakrishnan ◽  
Jenny Malig ◽  
Norbert Jux ◽  
Dirk M. Guldi
Keyword(s):  
Steady State ◽  
Absorption Spectroscopy ◽  
Charge Separation ◽  
Transient Absorption ◽  
Aqueous Media ◽  
Transient Absorption Spectroscopy ◽  
Time Resolved ◽  
Endohedral Fullerenes ◽  
Multi Wavelength ◽  
Metallic Nitride

Two bis-tetraphenylporphyrin tweezers-like conjugates bearing different linkers have been characterized by means of electrochemical and photophysical methods. The thrust of this work was the complexation of these bis-porphyrins with C[Formula: see text] and metallic nitride endohedral fullerenes (MNEF) like Sc3N@C[Formula: see text] in organic and in aqueus media — studied by a combination of steady-state and time-resolved spectroscopies. In the context of charge separation evidence for the formation of the 1a[Formula: see text]-Sc3N@C[Formula: see text] and 1c[Formula: see text]-Sc3N@C[Formula: see text] charge separated states in organic and aqueous media, respectively, came from transient absorption spectroscopy. Multi-wavelength analyses afforded charge separated state lifetimes of around 400 ps.

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