The exciton dynamics in tetracene thin films

Tayebjee, Murad J. Y.; Clady, R.; Schmidt, Timothy W.

doi:10.1039/c3cp52609g

Cited by 118 publications

(181 citation statements)

References 71 publications

(92 reference statements)

Supporting

Mentioning

161

Contrasting

Order By: Relevance

“…We can compare the results here with studies from films of tetracene, where the first step of highly efficient endothermic singlet fission is temperature independent (22,23) and has been proposed to involve barrier-free formation of an intermediate state (32,33) or tunnelling into a bound triplet pair (22). We find that our model is in qualitative agreement with these other studies; our endothermic system reveals rapid formation of a bound intermediate with triplet character that goes on to produce two free triplet excitons over a longer timescale.…”

Section: Resultsmentioning

confidence: 89%

Identification of a triplet pair intermediate in singlet exciton fission in solution

Stern

Musser

Gélinas

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

190

260

View full text Add to dashboard Cite

Singlet exciton fission is the spin-conserving transformation of one spin-singlet exciton into two spin-triplet excitons. This exciton multiplication mechanism offers an attractive route to solar cells that circumvent the single-junction Shockley-Queisser limit. Most theoretical descriptions of singlet fission invoke an intermediate state of a pair of spin-triplet excitons coupled into an overall spinsinglet configuration, but such a state has never been optically observed. In solution, we show that the dynamics of fission are diffusion limited and enable the isolation of an intermediate species. In concentrated solutions of bis(triisopropylsilylethynyl)[TIPS]-tetracene we find rapid (<100 ps) formation of excimers and a slower (∼10 ns) break up of the excimer to two triplet exciton-bearing free molecules. These excimers are spectroscopically distinct from singlet and triplet excitons, yet possess both singlet and triplet characteristics, enabling identification as a triplet pair state. We find that this triplet pair state is significantly stabilized relative to free triplet excitons, and that it plays a critical role in the efficient endothermic singlet fission process.T he fission of photogenerated spin-singlet excitons into pairs of spin-triplet excitons is an effective way to generate triplet excitons in organic materials (1, 2). Because the triplets produced are coupled into an overall singlet state, spin is conserved and triplet formation can proceed on sub-100-fs timescales (1, 3-5) with yields of up to 200% (1, 6, 7). Current interest in singlet fission is driven by its potential to improve the efficiency of solar cells by circumventing the Shockley-Queisser limit for single-junction devices (8-10). Incorporating singlet fission material within a lowband-gap solar cell should make it possible to capture the energy normally lost to thermalization following the absorption of highenergy photons (11,12). An external quantum efficiency of 129% (13) and an internal quantum efficiency of >180% (14) have been reported using pentacene as the singlet fission material and fullerene (C 60 ) as electron acceptor. Despite such significant advances, many questions remain about the underlying mechanism of triplet formation, such as the role of intermediate electronic states and the ability of systems to undergo endothermic fission.The basis of most kinetic descriptions of singlet fission is the triplet pair state 1 (TT), which is entangled into an overall singlet and is an essential intermediate for the formation of two free triplet excitons (1, 15). Whether this intermediate state is present only transiently, as expected in exothermic systems such as pentacene, or whether it can be sufficiently long lived to also play a central role in the fission process in slower systems is unclear. Transient absorption measurements of the canonical systems pentacene and tetracene in the solid state allow clear identification of only the singlet and triplet states (3,6,16,17), meaning the character of any intermediate has not been ob...

show abstract

Section: Resultsmentioning

confidence: 89%

Identification of a triplet pair intermediate in singlet exciton fission in solution

Stern

Musser

Gélinas

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

190

260

View full text Add to dashboard Cite

show abstract

“…Roughly speaking, the late-stage signal (~ 3 ns, Fig. 2 Moreover, it is noticeable that the signal at 2.45 eV shows the feature of triplet exciton dynamics as reported in literatures, 14,22,40 which is likely to be associated to the feature of T → observed in tetracene solution. 14,40 We can now get a better understanding of the SF process in tetracene concerning the polarization dependences of different processes.…”

Section: Decomposition Of the Dynamics For Singlet And Triplet Excmentioning

confidence: 96%

“…17,18,21 These results have been inspiring for modeling the nature of SF. 9-11, 17, 21, 39 Nonetheless, some of the key issues are still under debates, such as the effect of coherent coupling, 9,14,17 the role of thermal activation for the endothermicity, 12,17,23 and the discrepancy on the results recorded from polycrystalline films and single crystals. 23,40 Crystalline tetracene has a triclinic structure with herringbone alignment of molecules in ab-plane ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…4 In parallel to the impressive development in device engineering, efforts have been made to unravel the physical mechanisms behind such interesting phenomena. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] Most of the experimental and theoretical works have focused on the material family of polyacenes.…”

Section: Introductionmentioning

confidence: 99%

“…9,10,12,14,17,18,22,29,30,[38][39][40][41][42][43][44][45] In crystalline tetracene, SF is very efficient although it is a slightly endothermic process. In the latest studies on tetracene with transient optical spectroscopy, the fission rate has been characterized 9,12,14,17,23 and an intermediate multiexciton state has been identified to mediate the SF process. 17,18,21 These results have been inspiring for modeling the nature of SF.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Polarization-dependent exciton dynamics in tetracene single crystals

Zhang

et al. 2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

Abstract:We conduct polarization-dependent ultrafast spectroscopy to study the dynamics of singlet fission in tetracene single crystals. The spectrotemporal species for singlet and triplet excitons in transient absorption spectra are found to be strongly dependent on probe polarization. By carefully analyzing the polarization dependence, the signals contributed by different transitions related to singlet excitons have been disentangled, which is further applied to construct the correlation between dynamics of singlet and triplet excitons. The anisotropy of exciton dynamics provides an alternative approach to tackle the long-standing challenge in understanding the mechanism of singlet fission in organic semiconductors.

show abstract

Singlet Fission for Solar Cells

Schmidt,

Tayebjee

2024

Photovoltaic Solar Energy

View full text Add to dashboard Cite

The exciton dynamics in tetracene thin films

Cited by 118 publications

References 71 publications

Identification of a triplet pair intermediate in singlet exciton fission in solution

Identification of a triplet pair intermediate in singlet exciton fission in solution

Polarization-dependent exciton dynamics in tetracene single crystals

Singlet Fission for Solar Cells

Contact Info

Product

Resources

About