scholarly journals The entangled triplet pair state in acene and heteroacene materials

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Chaw Keong Yong ◽  
Andrew J. Musser ◽  
Sam L. Bayliss ◽  
Steven Lukman ◽  
Hiroyuki Tamura ◽  
...  
Keyword(s):  
Triplet Pair ◽  
Pair State

scholarly journals Revealing the contest between triplet-triplet exchange and triplet-triplet energy transfer coupling in correlated triplet pair states in singlet fission

2021 ◽  
Author(s):  
Vibin Abraham ◽  
Nicholas Mayhall
Keyword(s):  
Energy Transfer ◽  
Exchange Interaction ◽  
Entangled State ◽  
Separation Mechanism ◽  
Singlet Fission ◽  
Triplet Energy ◽  
Triplet Pair ◽  
Triplet Energy Transfer ◽  
State 1 ◽  
Pair State

Understanding the separation of the correlated triplet pair state 1(TT) intermediate is critical for leveraging singlet fission to improve solar cell efficiency. This separation mechanism is dominated by two key interactions: (i) the exchange interaction (K) between the triplets which leads to the spin splitting of the biexciton state into 1(TT),3(TT) and 5(TT) states, and (ii) the triplet-triplet energy transfer integral (t) which enables the formation of the spatially separated (but still spin entangled) state 1(T...T). We develop a simple ab initio technique to compute both the biexciton exchange (K) and biexciton transfer coupling. Our key findings reveal new conditions for successful correlated triplet pair state dissociation. The biexciton exchange interaction needs to be ferromagnetic or negligible to the triplet energy transfer for favourable dissociation. We also explore the effect of chromophore packing to reveal geometries where these conditions are achieved for tetracene.

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.

A Marcus-Hush Perspective on Adiabatic Singlet Fission

2019 ◽  
Author(s):  
Timothy Schmidt
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Ab Initio ◽  
Density Functional ◽  
Singlet State ◽  
Singlet Fission ◽  
Photo Induced Electron Transfer ◽  
Triplet Pair ◽  
Pair State

<div>Singlet fission is a process whereby a bichromophoric system crosses from an excitonically coupled singlet state to a singlet-coupled triplet pair state. If the electronic structure is described locally, then the process may be described by a formal exchange of electrons. As such, it lends itself to a treatment rooted in the Marcus-Hush description of electron transfer. Here we use ab initio and density functional electronic structure theories to reveal a Marcus-Hush perspective on singlet fission and propose experiments to probe singlet fission in the spirit of photo-induced electron transfer.</div>

Long-lived-correlated triplet-pair state in an imide substituted poly-thienylene vinylene-based π-conjugated polymer

2018 ◽  
Vol 8 (03) ◽  
pp. 1 ◽  
Author(s):  
Evan Lafalce ◽  
Uyen Huynh ◽  
Ella Olejnik ◽  
Tek P. Basel ◽  
Eitan Ehrenfreund ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Triplet Pair ◽  
Pair State

scholarly journals Understanding the Bound Triplet-Pair State in Singlet Fission

Chem ◽  
2019 ◽  
Vol 5 (8) ◽  
pp. 1988-2005 ◽  
Author(s):  
Samuel N. Sanders ◽  
Andrew B. Pun ◽  
Kaia R. Parenti ◽  
Elango Kumarasamy ◽  
Lauren M. Yablon ◽  
...  
Keyword(s):  
Singlet Fission ◽  
Triplet Pair ◽  
Pair State

Dynamics of the triplet-pair state reveals the likely coexistence of coherent and incoherent singlet fission in crystalline hexacene

2016 ◽  
Vol 9 (4) ◽  
pp. 341-346 ◽  
Author(s):  
Nicholas R. Monahan ◽  
Dezheng Sun ◽  
Hiroyuki Tamura ◽  
Kristopher W. Williams ◽  
Bolei Xu ◽  
...  
Keyword(s):  
Singlet Fission ◽  
Triplet Pair ◽  
Pair State

scholarly journals Excimer formation dynamics in the isolated tetracene dimer

2021 ◽  
Author(s):  
Joscha Hoche ◽  
Marco Flock ◽  
Xincheng Miao ◽  
Luca N. Philipp ◽  
Michael Wenzel ◽  
...  
Keyword(s):  
Organic Electronics ◽  
High Significance ◽  
Formation Dynamics ◽  
Triplet Pair ◽  
Excimer Formation ◽  
Pair State

The understanding of excimer formation and its interplay with the singlet-correlated triplet pair state 1(TT) is of high significance for the development of efficient organic electronics. Here, we study the...

A Marcus-Hush Perspective on Adiabatic Singlet Fission

2019 ◽  
Author(s):  
Timothy Schmidt
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Ab Initio ◽  
Density Functional ◽  
Singlet State ◽  
Singlet Fission ◽  
Photo Induced Electron Transfer ◽  
Triplet Pair ◽  
Pair State

<div>Singlet fission is a process whereby a bichromophoric system crosses from an excitonically coupled singlet state to a singlet-coupled triplet pair state. If the electronic structure is described locally, then the process may be described by a formal exchange of electrons. As such, it lends itself to a treatment rooted in the Marcus-Hush description of electron transfer. Here we use ab initio and density functional electronic structure theories to reveal a Marcus-Hush perspective on singlet fission and propose experiments to probe singlet fission in the spirit of photo-induced electron transfer.</div>

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