Singlet Fission and Excimer Formation in Disordered Solids of Alkyl-Substituted 1,3-Diphenylisobenzofurans

0506384 - ÚOCHB 2020 RIV US eng J - Journal Article
Dron, P. I. - Michl, Josef - Johnson, J. C.
Singlet Fission and Excimer Formation in Disordered Solids of Alkyl-Substituted 1,3-Diphenylisobenzofurans.
Journal of Physical Chemistry A. Roč. 121, č. 45 (2017), s. 8596-8603. ISSN 1089-5639. E-ISSN 1520-5215
R&D Projects: GA ČR GA15-19143S
Institutional support: RVO:61388963
Keywords : exciton fission * charge transfer * thin films
OECD category: Physical chemistry
Impact factor: 2.836, year: 2017
Method of publishing: Limited access
https://pubs.acs.org/doi/10.1021/acs.jpca.7b07362

We describe the preparation and excited state dynamics of three alkyl derivatives of 1,3-diphenylisobenzofuran (1) in both solutions and thin films. The substitutions are intended to disrupt the slip-stacked packing observed in crystals of 1 while maintaining the favorable energies of singlet and triplet for singlet fission (SF). All substitutions result in films that are largely amorphous as judged by the absence of strong X-ray diffraction peaks. The films of 1 carrying a methyl in the para position of one phenyl ring undergo SF relatively efficiently (>= 75% triplet yield, (Phi(T)) but more slowly than thin films of 1. When the methyl is replaced with a t-butyl, kinetic competition in the excited state favors excimer formation rather than SF (Phi(T) = 55%). When t-Bu groups are placed in both meta positions of the phenyl substituent, SF is slowed further and Phi(T) = 35%.
Permanent Link: http://hdl.handle.net/11104/0297633