scholarly journals Direct evidence for singlet-triplet exciton annihilation in π-conjugated polymers

2002 ◽  
Vol 66 (23) ◽  
Author(s):  
E. J. W. List ◽  
U. Scherf ◽  
K. Müllen ◽  
W. Graupner ◽  
C.-H. Kim ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Direct Evidence ◽  
Triplet Exciton ◽  
Exciton Annihilation

Direct evidence for the singlet-triplet exciton annihilation in anthracene crystals

1978 ◽  
Vol 85 (1) ◽  
pp. 45-49 ◽  
Author(s):  
M. E. Michel-Beyerle ◽  
R. Haberkorn ◽  
J. Kinder ◽  
H. Seidlitz
Keyword(s):  
Direct Evidence ◽  
Triplet Exciton ◽  
Exciton Annihilation

Total and Radiative Triplet-Triplet Exciton-Annihilation Rate Constant in Pyrene Crystals

1973 ◽  
Vol 8 (12) ◽  
pp. 6038-6042 ◽  
Author(s):  
V. Ern ◽  
H. Bouchriha ◽  
M. Bisceglia ◽  
S. Arnold ◽  
M. Schott
Keyword(s):  
Rate Constant ◽  
Triplet Exciton ◽  
Annihilation Rate ◽  
Exciton Annihilation

Dynamic recombination of triplet exciton with trapped counterion in conjugated polymers

2020 ◽  
Vol 93 (9) ◽  
Author(s):  
Yadong Wang ◽  
Jianjun Liu ◽  
Yanxia Liu ◽  
Xiru Wang ◽  
Yan Meng
Keyword(s):  
Conjugated Polymers ◽  
Triplet Exciton

Triplet-Triplet Upconversion in Organic Light- Emitting Diodes: Implications to Injection Lasing

2020 ◽  
Author(s):  
Atul Shukla ◽  
Monirul Hasan ◽  
Gangadhar Banappanavar ◽  
Viqar Ahmad ◽  
Jan Sobus ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Threshold Current ◽  
Triplet Exciton ◽  
Positive Contribution ◽  
Solid State Lasers ◽  
Light Emitting ◽  
Organic Solid ◽  
Exciton Annihilation ◽  
Fluorescence Material ◽  
Triplet Excitons

Abstract While significant progress has been made over last few years in the field of organic solid-state lasers, achieving lasing action from organic semiconductors under electrical excitation still remains a big challenge. One of the major barriers towards electrically pumped organic lasers are optical losses due to triplet excitons. In this work, we report both experimental and theoretical results that confirm positive contribution of triplet excitons for the scope of electrically driven organic laser. We studied a model fluorescence material, 9-(9-phenylcarbazole-3-yl)-10(naphthalene-1-yl) anthracene and reveals that the threshold current densities required to achieve lasing emission under electrical injection can be significantly reduced with the aid of triplet-triplet exciton upconversion processes. Furthermore, we demonstrate that, to achieve the best performance, the singlet-triplet exciton annihilation must be minimized. These results are unprecedented and provide a pathway towards development of new class of triplet-triplet upconversion materials for injection laser.

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.

Triplet exciton annihilation in naphthalene at high triplet densities

1978 ◽  
Vol 18 (8) ◽  
pp. 4444-4453 ◽  
Author(s):  
L. Altwegg ◽  
Maria A. Davidovich ◽  
J. Fünfschilling ◽  
Iris Zschokke-Gränacher
Keyword(s):  
Triplet Exciton ◽  
Exciton Annihilation
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