Effect of bulky substituents on thiopyrylium polymethine aggregation in the solid state: A theoretical evaluation of the implications for all-optical switching applications
KAUST DepartmentKAUST Solar Center (KSC)
Laboratory for Computational and Theoretical Chemistry of Advanced Materials
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Online Publication Date2014-11-06
Print Publication Date2014-11-25
Permanent link to this recordhttp://hdl.handle.net/10754/563869
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AbstractPolymethine dyes in dilute solutions display many of the optical properties required for all-optical switching applications. However, in thin films, aggregation and polymethine-counterion interactions can substantially modify their properties and limit their utility. Here, we examine the impact of a series of bulky substituents on the solid-state molecular packing of thiopyrylium polymethines by using a theoretical approach combining molecular-dynamics simulations and quantum-chemical calculations. Importantly, it is found that the positions of the substituents near the center and/or ends of the dye determine the extent to which aggregation is reduced; in particular, substituents near the polymethine center primarily modify the type of aggregation that is observed, while substituents near the polymethine ends reduce aggregation and aid in maintaining solution-like properties in the solid state. Our theoretical study elucidates relationships between molecular structure and bulk optical properties and provides design guidelines for all-optical switching materials.
SponsorsThis work was supported by the AFOSR MURI program (FA9550-10-1-0558) within the Center for Organic Materials for All-Optical Switching (COMAS). We gratefully acknowledge stimulating discussions with Drs. S. Barlow, J.M. Hales, and J.W. Perry.
PublisherAmerican Chemical Society (ACS)
JournalChemistry of Materials