Structures and nonlinear optical properties of new symmetrical two-photon photopolymerization initiators

Abstract

Four new symmetrical, two-photon photopolymerization initiators, 9-(4-{(1E,11E)-4-[(E)-4-(9H-carbazol-9-yl)styryl]-2,5-dimethoxystyryl}phenyl)-9H-carbazole (1), N-(4-{(1E,8E)-4-[(E)-4-(diphenylamino)styryl]-2,5-dimethoxystyryl}phenyl)-N-phenylbenzeneamine (2), 1,4-bis{2-[4-(2-pyridin-4-ylvinyl)phenyl]vinyl}-2,5-bisdimethoxybenzene (3) and 1,4-bis{2-[4-(2-pyridin-4-ylvinyl)phenyl]vinyl}-2,5-bisdodecyloxybenzene (4), have been synthesized and characterized. One-photon fluorescence, one-photon fluorescence quantum yields, one-photon fluorescence lifetimes, and two-photon fluorescence have been investigated. The results show that they are all good two-photon absorbing chromophores and effective two-photon photopolymerization initiators. The two-photon absorption cross-sections of these molecules have been evaluated by theoretical calculations. Microfabrication via two-photon-initiated polymerization has been studied and the possible photopolymerization mechanism is discussed.