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Polymorphic chiral squaraine crystallites in textured thin films.

Chirality (2020-03-11)
Jennifer Zablocki, Oriol Arteaga, Frank Balzer, Dirk Hertel, Julian J Holstein, Guido Clever, Jana Anhäuser, Rakesh Puttreddy, Kari Rissanen, Klaus Meerholz, Arne Lützen, Manuela Schiek
ABSTRACT

An enantiomerically pure (R)-2-methylpyrrolidine-based anilino squaraine crystallizes in two chiral polymorphs adopting a monoclinic C2 and an orthorhombic P21 21 21 structure, respectively. By various thin-film preparation techniques, a control of the polymorph formation is targeted. The local texture of the resulting textured thin films is connected to the corresponding optical properties. Special attention is paid to an unusual Davydov splitting, the anisotropic chiroptical response arising from preferred out-of-plane orientation of the crystallites, and the impact of the polymorph specific excitonic coupling.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
2-Methylpyrrolidine, 96%