Time-Resolved EPR Studies of Photogenerated Radical Ion Pairs Separated byp-Phenylene Oligomers and of Triplet States Resulting from Charge Recombination†

2006 ◽  
Vol 110 (50) ◽  
pp. 25163-25173 ◽  
Author(s):  
Zachary E. X. Dance ◽  
Qixi Mi ◽  
David W. McCamant ◽  
Michael J. Ahrens ◽  
Mark A. Ratner ◽  
...  
Keyword(s):  
Ion Pairs ◽  
Charge Recombination ◽  
Triplet States ◽  
Time Resolved

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.

Time-Resolved Resonance Raman Study of the Triplet States ofp-Hydroxyacetophenone and thep-Hydroxyphenacyl Diethyl Phosphate Phototrigger Compound

2004 ◽  
Vol 69 (20) ◽  
pp. 6641-6657 ◽  
Author(s):  
Chensheng Ma ◽  
Peng Zuo ◽  
Wai Ming Kwok ◽  
Wing Sum Chan ◽  
Jovi Tze Wai Kan ◽  
...  
Keyword(s):  
Resonance Raman ◽  
Triplet States ◽  
Time Resolved ◽  
Raman Study ◽  
Diethyl Phosphate

scholarly journals Ultrafast Charge Recombination of Photogenerated Ion Pairs to an Electronic Excited State

2002 ◽  
Vol 106 (19) ◽  
pp. 4833-4837 ◽  
Author(s):  
Ana Morandeira ◽  
Laurine Engeli ◽  
Eric Vauthey
Keyword(s):  
Excited State ◽  
Ion Pairs ◽  
Charge Recombination ◽  
Electronic Excited State
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