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Singlet fission is an important candidate to increase energy conversion efficiency in organic photovoltaics by providing a pathway to increase the quantum yield of excitons per photon absorbed in select materials. We investigate the…

Identifying multi-exciton states generated from singlet fission is key to understanding the carrier multiplication process, which presents a strategy for improving the efficiency of photovoltaics and bio-imaging. Broadband optically…

Mesoscale and Nanoscale Physics · Physics 2024-06-14 Yan Sun , M. Monteverde , V. Derkach , J. E. Anthony , A. D. Chepelianskii

We show from many-body quantum mechanical calculations that there occur structurally distinct triplet-pair eigenstates in the intramolecular singlet fission (iSF) compound pentacene-tetracene-pentacene. Triplet excitons occupy neigboring…

Strongly Correlated Electrons · Physics 2023-10-30 R. Chesler , P. Bhattacharyya , A. Shukla , S. Mazumdar

The mechanisms underlying coherent and thermally activated singlet exciton fission in pi-stacked acene crystals are clarified based on quantum dynamics simulations parameterized against a highly correlated description of the electronic…

Materials Science · Physics 2015-04-21 Hiroyuki Tamura , Miquel Huix-Rotllant , Irene Burghardt , Yoann Olivier , David Beljonne

Several recent electron spin resonance studies have observed a quintet multiexciton state during the singlet fission process. Here we provide a general theoretical explanation for the generation of this state by invoking a time-varying…

Materials Science · Physics 2020-01-08 Miles I. Collins , Dane R. McCamey , Murad J. Y. Tayebjee

Conversion of solar energy with high quantum efficiencies is a key challenge in energy technologies. Excitation energy transfer (EET) mechanisms, such as F\"orster resonance energy transfer (FRET), play a crucial role in facilitating…

The economic value of a photovoltaic installation depends upon both its lifetime and power conversion efficiency. Progress towards the latter includes mechanisms to circumvent the Shockley- Queisser limit, such as tandem designs and…

Photochemical upconversion is a promising way to boost the efficiency of solar cells using triplet exciton annihilation. Currently, predicting the performance of photochemical upconversion devices is challenging. We present an open source…

Materials Science · Physics 2019-08-15 David Jefferies , Timothy W. Schmidt , Laszlo Frazer

We develop a new first-principles approach to predict and understand rates of singlet fission with an ab initio Green's-function formalism based on many-body perturbation theory. Starting with singlet and triplet excitons computed from a GW…

Materials Science · Physics 2018-01-03 Sivan Refaely-Abramson , Felipe H. da Jornada , Steven G. Louie , Jeffrey B. Neaton

Singlet fission is commonly defined to involve a process by which an overall singlet state with local triplet structure spin-decoheres into two triplet states, thereby completing the fission process. This process, often defined in loose…

Chemical Physics · Physics 2020-07-29 Max Marcus , William Barford

We experimentally show that the rate of singlet fission in tetracene films has a superlinear dependence on the density of photo-excited singlet excitons with ultrafast transient absorption spectroscopy. The spectrotemporal features of…

Materials Science · Physics 2014-10-01 Bo Zhang , Chunfeng Zhang , Rui Wang , Zhanao Tan , Yunlong Liu , Wei Guo , Xiaoling Zhai , Xiaoyong Wang , Min Xiao

For the theoretical screening of Singlet Fission (SF) rates in molecular aggregates, commonly dimer model systems are employed. However, there is experimental evidence, that the SF process proceeds from the $^{1}$(TT) state via an…

Chemical Physics · Physics 2023-12-22 Anurag Singh , Merle I. S. Röhr

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…

Materials Science · Physics 2015-06-23 Bo Zhang , Chunfeng Zhang , Yanqing Xu , Rui Wang , Bin He , Yunlong Liu , Shimeng Zhang , Xiaoyong Wang , Min Xiao

Inclusion of heavy metal atoms in a polymer backbone allows transitions between the singlet and triplet manifolds. Interfacial dissociation of triplet excitons constitutes a viable mechanism for enhancing photovoltaic (PV) efficiencies in…

Materials Science · Physics 2009-08-10 K. Yang , U. Scherf , S. Guha

Carrier multiplication by singlet exciton fission enhances photovoltaic conversion efficiencies in organic solids. This decay of one singlet exciton into two triplet states promises to overcome the Shockley-Queisser limit as up to two…

Materials Science · Physics 2016-12-16 K. Kolata , S. Marquardt , N. W. Rosemann , A. Mager , A. Hansmann , U. Höfer , R. Berger , T. Breuer , G. Witte , S. Chatterjee

Organic light-emitting diodes (OLEDs) must be engineered to circumvent the efficiency limit imposed by the 3:1 ratio of triplet to singlet exciton formation following electron-hole capture. Here we show the spin nature of luminescent…

Singlet fission, a process that splits a singlet exciton into a biexciton, has promise in quantum information. We report time-resolved electron paramagnetic resonance measurements on a molecule, TIPS-BP1$'$, designed to exhibit strongly…

Chemical Physics · Physics 2022-02-22 Ryan D. Dill , Kori E. Smyser , Niels H. Damrauer , Joel D. Eaves

Singlet fission process has gained considerable attention because of its potential to enhance photovoltaic efficiency and break the Shockley Queisser limit. In photovoltaic devices perovskite materials have shown tremendous progress in the…

Materials Science · Physics 2022-04-07 Tejasvini Sharma , Saurav Saini , Naveen Kumar Tailor , Mahesh Kumar , Soumitra Satapathi

Organic light emitting devices and solar cells are machines that create, manipulate and destroy excited states in organic semiconductors. It is crucial to characterize these excited states, or excitons, to optimize device performance in…

Materials Science · Physics 2019-06-07 Sebastian Reineke , Marc A. Baldo

Singlet fission (SF), an exciton multiplication process occurring in organic semiconductors, offers a way to break the Shockley-Queisser limit in single-bandgap photovoltaics (PV). If the triplet excitons generated by SF can be transferred…