Record Details

Theory of Singlet Fission in Polyenes, Acene Crystals, and Covalently Linked Acene Dimers

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title Theory of Singlet Fission in Polyenes, Acene Crystals, and Covalently Linked Acene Dimers
 
Creator ARYANPOUR, K
SHUKLA, A
MAZUMDAR, S
 
Subject PUMP-PROBE SPECTROSCOPY
PENTACENE THIN-FILMS
EXCITON-FISSION
LINEAR POLYENES
ELECTRONIC EXCITATIONS
ULTRAFAST DYNAMICS
CHARGE SEPARATION
SOLAR-CELLS
STATES
TETRACENE
 
Description We report quadruple configuration interaction calculations within the extended Pariser-Parr-Pople Hamiltonian on the excited states of aggregates of polyenes, crystalline acenes, and covalently linked dimers of acene molecules. We determine the precise energy orderings and analyze the cluster wave functions in order to arrive at a comprehensive physical understanding of singlet fission in these diverse families of materials. Our computational approach allows us to retain a very large number of basis states and thereby obtain the correct relative energy orderings of one electron-one hole Frenkel and charge-transfer excitons versus intra- and intermolecular two electron-two hole triple-ttriplet excited states. We show that from the energy orderings it is possible to understand the occurrence of singlet fission in polyene and acene crystals, as well as its near total absence in the covalently linked acene dimers. As in the acene crystals, singlet fission in the polyenes is a multichromophoric phenomenon, with the well-known 2(1)Ag playing no direct role. Intermolecular charge transfer is essential for singlet fission in both acenes and polyenes, but because of subtle differences in the natures and orderings of the aggregate excited states, the mechanisms of singlet fission are slightly different in the two classes. We are thus able to give qualitative physical reasoning for the slower singlet fission in the polyenes, relative to that in crystalline pentacene. Our work also gives new insight into the complex exciton dynamics in tetracene crystals, which has been difficult to understand theoretically. Our large-scale many-body calculations provide us with the ability to understand the qualitative differences in the singlet fission yields and rates between different classes of p-conjugated materials.
 
Publisher AMER CHEMICAL SOC
 
Date 2016-01-15T06:30:40Z
2016-01-15T06:30:40Z
2015
 
Type Article
 
Identifier JOURNAL OF PHYSICAL CHEMISTRY C, 119(13)6966-6979
1932-7447
http://dx.doi.org/10.1021/jp5124019
http://dspace.library.iitb.ac.in/jspui/handle/100/17937
 
Language en