scholarly journals Making triplets from photo-generated charges: observations, mechanisms and theory

2020 ◽  
Vol 19 (2) ◽  
pp. 136-158 ◽  
Author(s):  
Dáire J. Gibbons ◽  
Aram Farawar ◽  
Paul Mazzella ◽  
Stéphanie Leroy-Lhez ◽  
René M. Williams
Keyword(s):  
Excited State ◽  
Electron Donor ◽  
Charge Recombination ◽  
Triplet Excited State ◽  
Spin Flip ◽  
Donor Acceptor ◽  
A Charge

Photo-excitation of electron donor–acceptor systems can lead to the generation of a charge separated state (CT). Sometimes the charge recombination occurs mainly to the local triplet excited state (T1). How does the spin flip?

Long-lived charge-separated states of simple electron donor-acceptor dyads using porphyrins and phthalocyanines

2008 ◽  
Vol 12 (09) ◽  
pp. 993-1004 ◽  
Author(s):  
Kei Ohkubo ◽  
Shunichi Fukuzumi
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Electron Donor ◽  
Driving Force ◽  
Reorganization Energy ◽  
Charge Recombination ◽  
Zinc Phthalocyanine ◽  
Intramolecular Electron Transfer ◽  
Triplet Excited State ◽  
Donor Acceptor

Control of electron-transfer processes is described for a number of electron donor-acceptor dyads containing porphyrins or phthalocyanines as models for the photosynthetic reaction center. The rates for intramolecular electron transfer in the dyads are controlled by the driving force and reorganization energy of electron transfer. The small reorganization energy of electron transfer reactions and large driving force of charge recombination are required to form long-lived charge-separated states. A directly linked zinc chlorin-fullerene dyad, especially, has the longest lifetime of charge-separated state at 120 s at -150 °C, which is a much longer lifetime and higher energy than those of natural photosynthetic reaction centers. On the other hand, the charge-separated states of the phthalocyanine-based donor-acceptor dyads (silicon phthalocyanine-fullerene, and zinc phthalocyanine-perylenebisimide) are short-lived since charge recombination forms the low-lying triplet excited state of the chromophore. The energy of the charge-separated state of a zinc phthalocyanine-perylenebisimide dyad is decreased by binding of metal ions to the radical anion moiety in order to be lower than the triplet excited state. This results in formation of a long-lived charge-separated state. The mechanistic viability of formation of long-lived charge-separated states is demonstrated by a variety of examples based on the Marcus theory of electron transfer.

Spin–orbit charge transfer intersystem crossing in perylenemonoimide–phenothiazine compact electron donor–acceptor dyads

2018 ◽  
Vol 54 (87) ◽  
pp. 12329-12332 ◽  
Author(s):  
Yingjie Zhao ◽  
Ruomeng Duan ◽  
Jianzhang Zhao ◽  
Chen Li
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Electron Donor ◽  
Intersystem Crossing ◽  
Spin Orbit ◽  
Triplet Excited State ◽  
Donor Acceptor ◽  
State Production

Efficient triplet excited state production (57%) was observed for perylenemonoimide–phenothiazine compact electron donor–acceptor dyads based on spin–orbit charge transfer ISC.

scholarly journals Charge separation in the excited state electron donor—acceptor compounds containing the piperazine moiety

1991 ◽  
Vol 180 (6) ◽  
pp. 556-562 ◽  
Author(s):  
A.M. Brouwer ◽  
R.D. Mout ◽  
P.H.Maassen van den Brink ◽  
H.J. van Ramesdonk ◽  
J.W. Verhoeven ◽  
...  
Keyword(s):  
Excited State ◽  
Electron Donor ◽  
Charge Separation ◽  
State Electron ◽  
Donor Acceptor

Light harvesting vesicular donor–acceptor scaffold limits the rate of charge recombination in the presence of an electron donor

2014 ◽  
Vol 7 (5) ◽  
pp. 1661-1669 ◽  
Author(s):  
Rijo T. Cheriya ◽  
Ajith R. Mallia ◽  
Mahesh Hariharan
Keyword(s):  
Charge Transfer ◽  
Survival Time ◽  
Electron Donor ◽  
Self Assembly ◽  
Light Harvesting ◽  
Charge Recombination ◽  
Donor Acceptor

This work highlights the utility of π–π stacked self-assembly for enhanced survival time of charge transfer intermediates upon photoexcitation of donor–acceptor systems.

Bending-Type Electron Donor–Donor–Acceptor Triad: Dual Excited-State Charge-Transfer Coupled Structural Relaxation

2019 ◽  
Vol 31 (15) ◽  
pp. 5981-5992 ◽  
Author(s):  
Jia-An Lin ◽  
Shu-Wei Li ◽  
Zong-Ying Liu ◽  
Deng-Gao Chen ◽  
Chun-Ying Huang ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Electron Donor ◽  
Structural Relaxation ◽  
Donor Acceptor ◽  
State Charge
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