Nanoscale Push-Push Dihydrophenanthrene Derivatives as Novel Fluorophores for Two-Photon-Excited Fluorescence

Abstract

Outperforming fluorescein by far, elongated fluorophores (e.g. 1) give rise to large two-photon absorption cross-sections σ₂ in the visible-red or NIR region and high quantum fluorescence yields Φ (see figure; GM = 10^-50 cm⁴ s photon^-1 ). This opens interesting prospects in the field of two-photon microscopy imaging of cell membranes.