Molecular Design Principles for Near-Infrared Absorbing and Emitting Indolizine Dyes.

Desirable components for dye-sensitzed solar cell (DSC) sensitizers and fluorescent imaging dyes include strong donating building blocks coupled with well-balanced acceptor functionalities for absorption beyond the visible range. We have evaluated the effects of increasing acceptor strengths and incorporation of dye morphology controlling groups on molar absorptivity and absorption breadth with indolizine donor-based dyes. Indolizine-based D-A and D-π-A sensitizers incorporating bis-rhodanine, tricyanofuran (TCF), and cyanoacrylic acid functionalities were analyzed for performance in DSC devices. The TCF derivatives were also evaluated as near-infrared (NIR)-emissive materials with the AH25 emissions extending past 1000 nm.