Exact wave packet dynamics of singlet fission in unsubstituted and substituted polyene chains within long-range interacting models

Prodhan, Suryoday and Ramasesha, S (2017) Exact wave packet dynamics of singlet fission in unsubstituted and substituted polyene chains within long-range interacting models. In: PHYSICAL REVIEW B, 96 (7).

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Abstract

Singlet fission (SF) is a potential pathway for significant enhancement of efficiency in organic solar cells (OSC). In this paper, we study singlet fission in a pair of polyene molecules in two different stacking arrangements employing exact many-body wave packet dynamics. In the noninteracting model, the SF yield is absent. The individual molecules are treated within Hubbard and Pariser-Parr-Pople (PPP) models and the interaction between them involves transfer terms, intersite electron repulsions, and site-charge-bond-charge repulsion terms. Initial wave packet is constructed from excited singlet state of one molecule and ground state of the other. Time development of this wave packet under the influence of intermolecular interactions is followed within the Schrdinger picture by an efficient predictor-corrector scheme. In unsubstituted Hubbard and PPP chains, 2(1) A excited singlet state leads to significant SF yield while the 1(1) B state gives negligible fission yield. On substitution by donor-acceptor groups of moderate strength, the lowest excited state will have sufficient 2(1) A character and hence results in significant SF yield. Because of rapid internal conversion, the nature of the lowest excited singlet will determine the SF contribution to OSC efficiency. Furthermore, we find the fission yield depends considerably on the stacking arrangement of the polyene molecules.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Additional Information:	Copy right for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	09 Sep 2017 04:48
Last Modified:	09 Sep 2017 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/57750

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