The dependence of singlet exciton relaxation on excitation density and temperature in polycrystalline tetracene thin films: Kinetic evidence for a dark intermediate state and implications for singlet fission

2011 ◽  
Vol 135 (21) ◽  
pp. 214508 ◽  
Author(s):  
Jonathan J. Burdett ◽  
David Gosztola ◽  
Christopher J. Bardeen
Keyword(s):  
Thin Films ◽  
Intermediate State ◽  
Excitation Density ◽  
Singlet Fission ◽  
Singlet Exciton

Efficient Singlet Fission in Loose Packing Benzodipyrrolidone Thin Films

2021 ◽  
Author(s):  
Long Wang ◽  
Changfu Feng ◽  
Chuang Wu ◽  
Shaohua Xie ◽  
Yishi Wu ◽  
...  
Keyword(s):  
Thin Films ◽  
Singlet Fission ◽  
Loose Packing

scholarly journals Singlet fission in thin films of metallo-supramolecular polymers with ditopic thiophene-bridged terpyridine ligands

2017 ◽  
Vol 5 (32) ◽  
pp. 8041-8051 ◽  
Author(s):  
David Rais ◽  
Jiří Pfleger ◽  
Miroslav Menšík ◽  
Alexander Zhigunov ◽  
Pavla Štenclová ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Supramolecular Polymers ◽  
Uv Laser ◽  
Singlet Fission ◽  
Thin Solid Films ◽  
Singlet Exciton ◽  
Solid Films ◽  
Terpyridine Ligands ◽  
Singlet Exciton Fission

Ultrafast singlet exciton fission in thin solid films after UV laser photoexcitation was observed using transient absorption spectroscopy.

Mechanism of Singlet Fission in Thin Films of 1,3-Diphenylisobenzofuran

2014 ◽  
Vol 136 (20) ◽  
pp. 7363-7373 ◽  
Author(s):  
Joel N. Schrauben ◽  
Joseph L. Ryerson ◽  
Josef Michl ◽  
Justin C. Johnson
Keyword(s):  
Thin Films ◽  
Singlet Fission

Morphology-Independent Efficient Singlet Exciton Fission in Perylene Diimide Thin Films

ChemPlusChem ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. 230-238 ◽  
Author(s):  
Yaroslav V. Aulin ◽  
Kevin M. Felter ◽  
D. Deniz Günbas ◽  
Rajeev K. Dubey ◽  
Wolter F. Jager ◽  
...  
Keyword(s):  
Thin Films ◽  
Perylene Diimide ◽  
Singlet Exciton ◽  
Singlet Exciton Fission

scholarly journals Femtosecond Transient Absorption Microscopy of Singlet Exciton Motion in Side-Chain Engineered Perylene-Diimide Thin Films

2020 ◽  
Vol 124 (13) ◽  
pp. 2721-2730 ◽  
Author(s):  
Raj Pandya ◽  
Richard Y. S. Chen ◽  
Qifei Gu ◽  
Jeffrey Gorman ◽  
Florian Auras ◽  
...  
Keyword(s):  
Thin Films ◽  
Transient Absorption ◽  
Perylene Diimide ◽  
Side Chain ◽  
Singlet Exciton ◽  
Femtosecond Transient Absorption

scholarly journals Identifying the Trade-off between Intramolecular Singlet Fission Requirements in Donor-Acceptor Copolymers

2020 ◽  
Author(s):  
Jacob Terence Blaskovits ◽  
Maria Fumanal ◽  
Sergi Vela ◽  
Raimon Fabregat ◽  
Clemence Corminboeuf
Keyword(s):  
Single Molecule ◽  
Molecular Design ◽  
Relative Energy ◽  
Frontier Molecular Orbital ◽  
Great Promise ◽  
Singlet Fission ◽  
Trade Off ◽  
Singlet Exciton ◽  
Donor Acceptor ◽  
Photoinduced Charge

Intramolecular singlet fission (iSF) has shown potential to improve the power conversion efficiency in photovoltaic devices by promoting the splitting of a photon-absorbing singlet exciton into two triplet excitons within a single molecule. Among different possibilities, the donor-acceptor modular strategy of copolymers has shown great promise in its ability to undergo iSF under certain conditions. However, the number of iSF donor-acceptor copolymers reported in the literature remains remarkably narrow and clear trends for the molecular design of better candidates have not yet been established. In this work, we identify the trade-off between the main iSF requirements of the donor-acceptor strategy and formulate design rules that allow them to be tuned simultaneously in a fragment-based approach. Based on a library of 2944 donor-acceptor copolymers, we establish simple guidelines to build promising novel materials for iSF. These consist in (1st) selecting an acceptor core with high intrinsic singlet-triplet splitting, (2nd) locating a donor with a larger monomer frontier molecular orbital (FMO) gap than that of the acceptor, and (3rd) tuning the relative energy of donor and/or acceptor FMOs through functionalization to promote photoinduced charge transfer in the resulting polymer. Remarkably, systems containing benzothiadiazole and thiophehe-1,1-dioxide acceptors, which have been shown to undergo iSF, fulfill all criteria simultaneously when paired with appropriate donors. This is due to their particular electronic features, which make them highly promising candidates in the quest for iSF materials.<br>

High Sensitivity Nanosecond Mid-Infrared Transient Absorption Spectrometer Enabling Low Excitation Density Measurements of Electronic Materials

2016 ◽  
Vol 70 (10) ◽  
pp. 1726-1732 ◽  
Author(s):  
Adam Rimshaw ◽  
Christopher Grieco ◽  
John B. Asbury
Keyword(s):  
Thin Films ◽  
Transient Absorption ◽  
Electronic Materials ◽  
State Of The Art ◽  
High Sensitivity ◽  
Excitation Density ◽  
Time Resolved ◽  
Mid Infrared ◽  
Lock In ◽  
Vibrational Features

A dispersive nanosecond transient absorption instrument was developed to enable rapid time-resolved and steady-state measurements in the mid-infrared (mid-IR) region for thin films without the need for gated integrators or lock-in amplifiers. Two detectors are used depending on the experimental needs (100 MHz and 16 MHz) with time resolution from nano-millisecond and spectral coverage from 1000–5000 cm−1 (2000–10 000 nm). The instrument utilizes flexible digitization resolution (8 bit to 14 bit) to enable high sensitivity (10−5) measurements on thin films under low excitation (<50 µJ/cm2). We highlight the instrument’s improvement over prior state-of-the-art time-resolved capabilities by measuring transient species (e.g., polarons) under extremely low energy densities (<5 µJ/cm2) in less than 10 minutes to achieve high fidelity signals. Additionally, to highlight the spectral capabilities we study two optoelectronic materials for which we resolve vibrational features as small as 10 µOD.

scholarly journals Singlet exciton fission via an intermolecular charge transfer state in coevaporated pentacene-perfluoropentacene thin films

2019 ◽  
Vol 151 (16) ◽  
pp. 164706 ◽  
Author(s):  
Vincent O. Kim ◽  
Katharina Broch ◽  
Valentina Belova ◽  
Y. S. Chen ◽  
Alexander Gerlach ◽  
...  
Keyword(s):  
Thin Films ◽  
Charge Transfer ◽  
Charge Transfer State ◽  
Singlet Exciton ◽  
Intermolecular Charge Transfer ◽  
Singlet Exciton Fission ◽  
Transfer State

scholarly journals Singlet fission of hot excitons in π -conjugated polymers

2015 ◽  
Vol 373 (2044) ◽  
pp. 20140327 ◽  
Author(s):  
Yaxin Zhai ◽  
Chuanxiang Sheng ◽  
Z. Valy Vardeny
Keyword(s):  
Conjugated Polymers ◽  
Threshold Energy ◽  
High Energy ◽  
Triplet Exciton ◽  
Singlet Fission ◽  
General Process ◽  
Singlet Exciton ◽  
Triplet Pair ◽  
Luminescent Polymer ◽  
Pair State

We used steady-state photoinduced absorption (PA), excitation dependence (EXPA( ω )) spectrum of the triplet exciton PA band, and its magneto-PA (MPA( B )) response to investigate singlet fission (SF) of hot excitons into two separated triplet excitons, in two luminescent and non-luminescent π -conjugated polymers. From the high energy step in the triplet EXPA( ω ) spectrum of the luminescent polymer poly(dioctyloxy)phenylenevinylene (DOO-PPV) films, we identified a hot-exciton SF (HE-SF) process having threshold energy at E ≈2 E T (=2.8 eV, where E T is the energy of the lowest lying triplet exciton), which is about 0.8 eV above the lowest singlet exciton energy. The HE-SF process was confirmed by the triplet MPA( B ) response for excitation at E >2 E T , which shows typical SF response. This process is missing in DOO-PPV solution, showing that it is predominantly interchain in nature. By contrast, the triplet EXPA( ω ) spectrum in the non-luminescent polymer polydiacetylene (PDA) is flat with an onset at E = E g (≈2.25 eV). From this, we infer that intrachain SF that involves a triplet–triplet pair state, also known as the ‘dark’ 2A g exciton, dominates the triplet photogeneration in PDA polymer as E g >2 E T . The intrachain SF process was also identified from the MPA( B ) response of the triplet PA band in PDA. Our work shows that the SF process in π -conjugated polymers is a much more general process than thought previously.

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