scholarly journals Ultrafast Triplet Pair Separation and Triplet Trapping following Singlet Fission in Amorphous Pentacene Films

2020 ◽  
Vol 124 (43) ◽  
pp. 23567-23578
Author(s):  
Kyle T. Munson ◽  
Jianing Gan ◽  
Christopher Grieco ◽  
Grayson S. Doucette ◽  
John E. Anthony ◽  
...  
Keyword(s):  
Singlet Fission ◽  
Pair Separation ◽  
Triplet Pair

Efficient triplet pair separation from intramolecular singlet fission in dibenzopentalene derivatives

2019 ◽  
Vol 62 (8) ◽  
pp. 1037-1043 ◽  
Author(s):  
Yanping Liu ◽  
Yishi Wu ◽  
Long Wang ◽  
Lanfen Wang ◽  
Jiannian Yao ◽  
...  
Keyword(s):  
Singlet Fission ◽  
Pair Separation ◽  
Triplet Pair

scholarly journals Triplet Transfer Mediates Triplet Pair Separation during Singlet Fission in 6,13-Bis(triisopropylsilylethynyl)-Pentacene

2017 ◽  
Vol 27 (46) ◽  
pp. 1703929 ◽  
Author(s):  
Christopher Grieco ◽  
Grayson S. Doucette ◽  
Jason M. Munro ◽  
Eric R. Kennehan ◽  
Youngmin Lee ◽  
...  
Keyword(s):  
Singlet Fission ◽  
Pair Separation ◽  
Triplet Pair

Two temperature regimes of triplet transfer in the dissociation of the correlated triplet pair after singlet fission

2019 ◽  
Vol 97 (6) ◽  
pp. 465-473 ◽  
Author(s):  
Tia S. Lee ◽  
YunHui L. Lin ◽  
Hwon Kim ◽  
Barry P. Rand ◽  
Gregory D. Scholes
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Temperature Regime ◽  
Transient Absorption Spectroscopy ◽  
Type Model ◽  
Singlet Fission ◽  
Temperature Dependent ◽  
Thermally Activated ◽  
Pair Separation ◽  
Triplet Pair

The ability to undergo spin-allowed exciton multiplication makes singlet fission materials promising for photovoltaic applications. Here, we examine the separation of correlated triplet pairs, 1(T…T), in polycrystalline pentacene films via temperature-dependent transient absorption spectroscopy. Single wavelength analysis reveals a profound delay in 1(T…T) dynamics. Moreover, the dynamics of 1(T…T) exhibit temperature dependence, whereas other features show no discernable temperature dependence. Previous literatures have suggested that correlated triplet separation is mediated by a thermally activated hopping process. Surprisingly, we found that the time constants governing triplet pair separation display two distinct temperature-dependent regimes of triplet transport. The high temperature regime follows a thermally activated hopping mechanism. The experimentally derived reorganization energy and electronic coupling is verified by density matrix renormalization group quantum chemical calculations. In addition, we evaluated the low temperature regime and show that the trend can be modelled by a Miller–Abrahams-type model that incorporates the effects of energetic disorder. We conclude that the correlated triplet pair separation is mediated by thermally activated hopping or a disorder driven Miller–Abrahams-type mechanism at high and low temperature, respectively. We observe that crossover between two regimes occurs ∼226 K. We find the time constant for triplet–triplet energy transfer to be 1.8 ps at ambient temperature and 21 ps at 77 K.

scholarly journals Uncovering dark multichromophoric states in Peridinin–Chlorophyll–Protein

2020 ◽  
Vol 17 (164) ◽  
pp. 20190736
Author(s):  
Elliot J. Taffet ◽  
Francesca Fassioli ◽  
Zi S. D. Toa ◽  
David Beljonne ◽  
Gregory D. Scholes
Keyword(s):  
Crystal Structure ◽  
Excited States ◽  
Quantum Chemical ◽  
Light Harvesting ◽  
Singlet Fission ◽  
Chlorophyll Protein ◽  
Triplet Pair ◽  
A Charge ◽  
Hole Generation ◽  
Chemical Evidence

It has long been recognized that visible light harvesting in Peridinin–Chlorophyll–Protein is driven by the interplay between the bright (S 2 ) and dark (S 1 ) states of peridinin (carotenoid), along with the lowest-lying bright (Q y ) and dark (Q x ) states of chlorophyll- a . Here, we analyse a chromophore cluster in the crystal structure of Peridinin–Chlorophyll–Protein, in particular, a peridinin–peridinin and a peridinin–chlorophyll- a dimer, and present quantum chemical evidence for excited states that exist beyond the confines of single peridinin and chlorophyll chromophores. These dark multichromophoric states, emanating from the intermolecular packing native to Peridinin–Chlorophyll–Protein, include a correlated triplet pair comprising neighbouring peridinin excitations and a charge-transfer interaction between peridinin and the adjacent chlorophyll- a . We surmise that such dark multichromophoric states may explain two spectral mysteries in light-harvesting pigments: the sub-200-fs singlet fission observed in carotenoid aggregates, and the sub-200-fs chlorophyll- a hole generation in Peridinin–Chlorophyll–Protein.

scholarly journals Elucidation of Excitation Energy Dependent Correlated Triplet Pair Formation Pathways in an Endothermic Singlet Fission System

2017 ◽  
Vol 140 (13) ◽  
pp. 4613-4622 ◽  
Author(s):  
Arya Thampi ◽  
Hannah L. Stern ◽  
Alexandre Cheminal ◽  
Murad J. Y. Tayebjee ◽  
Anthony J. Petty ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Pair Formation ◽  
Singlet Fission ◽  
Triplet Pair ◽  
Energy Dependent

scholarly journals Porous Shape-Persistent Rylene Imine Cages with Tunable Optoelectronic Properties and Delayed Fluorescence

2020 ◽  
Author(s):  
Hsin-Hua Huang ◽  
Kyung Seob Song ◽  
Alessandro Prescimone ◽  
Rajesh Mannancherry ◽  
Ali Coskun ◽  
...  
Keyword(s):  
Excited State ◽  
Electronic Properties ◽  
Green Light ◽  
Delayed Fluorescence ◽  
Optoelectronic Properties ◽  
Covalent Organic Frameworks ◽  
Singlet Fission ◽  
Triplet Pair ◽  
Material Porosity

A simultaneous combination of porosity and tunable optoelectronic properties, common in covalent organic frameworks, are rare in shape-persistent organic cages. Yet, organic cages offer important molecular advantages, the solubility and modularity. Herein, we report the synthesis of a series of chiral imine organic cages with three built-in rylene units by means of dynamic imine chemistry and we investigate their textural and optoelectronic properties. Thereby we demonstrate that the synthesized rylene cages are porous, can be reversibly reduced at accessible potentials, and can absorb from UV up to green light. We also show that they preferentially adsorb CO2 over N2 and CH4 with a good selectivity. In addition, we discovered that the cage incorporating three perylene-3,4:9,10-bis(dicarboximide) units displays a delayed fluorescence, likely as a consequence of formation of a correlated triplet pair, the multiexciton state in singlet fission. Rylene cages thus represent a unique platform to investigate the effect of electronic properties on material porosity and, at the same time, to probe excited-state phenomena in the limit of vanishing interchromophore coupling. <br>

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.

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