Direct Evidence of Significantly Different Chemical Behavior and Excited-State Dynamics of 1,7- and 1,6-Regioisomers of Pyrrolidinyl-Substituted Perylene Diimide

2013 ◽  
Vol 19 (21) ◽  
pp. 6791-6806 ◽  
Author(s):  
Rajeev K. Dubey ◽  
Marja Niemi ◽  
Kimmo Kaunisto ◽  
Alexander Efimov ◽  
Nikolai V. Tkachenko ◽  
...  
Keyword(s):  
Excited State ◽  
Direct Evidence ◽  
Perylene Diimide ◽  
Chemical Behavior ◽  
Excited State Dynamics

scholarly journals Impact of Side-Chain Substituents on the Excited State Dynamics of Perylene Diimide Amorphous Films

2020 ◽  
Author(s):  
Qiu-Shi Ma ◽  
Cheng-Wei Ju ◽  
Ruihua Pu ◽  
Wenjie Zhang ◽  
Xian Lin ◽  
...  
Keyword(s):  
Excited State ◽  
Triplet State ◽  
Transient Absorption ◽  
Excited State Absorption ◽  
Perylene Diimide ◽  
Side Chain ◽  
Significant Feature ◽  
Singlet Fission ◽  
Amorphous Films ◽  
Excited State Dynamics

<p>Side-chain substitutions have important influence on the aggregation of perylene diimide (PDI), which show a great impact on their excited-state dynamics as well. Herein, by employing photoluminescence (PL), time-resolved photoluminescence (TRPL) and transient absorption (TA) spectroscopy, we investigated excited-state dynamics of two perylene diimide (PDI) derivative amorphous films, i.e. undecane-substituted PDI (PDI-1) and diisopropylphenyl-substituted PDI (PDI-2), fabricated with spin coating method. Femtosecond transient absorption spectra reveal that both films show pronounced ground state bleach (GSB) with lifetime longer than 10 ns while the relaxation of excited state absorption (ESA) has typical lifetime less than 1 ns. The significant feature of excited state decay in PDI-2 is dominated by transforming the singlet excited state into two triplet states via singlet fission, which is evidenced by the appearance of triplet state absorption. By contrast, the absence of triplet state absorption and the appearance of long-lived emission species in PDI-1 suggest that the decay of excited-like state could be dominated by the formation of excimer. Our present study reveals for the first time that the singlet fission does occur in amorphous PDI film, the study also demonstrates that side-chain substitutions have great impact on the excited-state dynamics of PDI. </p>

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

Modulation of Excited State Dynamics in Lead Halide Perovskite Films with Electrical Bias

2019 ◽  
Author(s):  
Gergely Samu ◽  
R.A. Scheidt ◽  
A. Balog ◽  
C. Janáky ◽  
P.V. Kamat
Keyword(s):  
Excited State ◽  
Excited State Dynamics ◽  
Halide Perovskite ◽  
Electrical Bias ◽  
Lead Halide

Femtosecond Spectroscopic Studies of the One- and Two-Photon Excited-State Dynamics of 2,2,17,17-Tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne:  A Trimeric Oligodiacetylene

2006 ◽  
Vol 110 (40) ◽  
pp. 11435-11439 ◽  
Author(s):  
Grzegorz M. Balkowski ◽  
Michiel Groeneveld ◽  
Hong Zhang ◽  
Cindy C. J. Hendrikx ◽  
Michael Polhuis ◽  
...  
Keyword(s):  
Excited State ◽  
Spectroscopic Studies ◽  
Excited State Dynamics ◽  
Two Photon ◽  
The One

scholarly journals Ultrafast excited-state dynamics of SnSe2–SnSe composite thin film

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025040
Author(s):  
Manoj Kumar ◽  
Prince Sharma ◽  
Sanju Rani ◽  
Mahesh Kumar ◽  
V. N. Singh
Keyword(s):  
Thin Film ◽  
Excited State ◽  
Composite Thin Film ◽  
Excited State Dynamics
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