title: Large two-photon absorption of terpyridine-based quadrupolar derivatives: towards their applications in optical limiting and biological imaging.
abstract: Developing organic chromophores with large two-photon absorption (TPA) in both organic solvents and aqueous media is crucial owing to their applications in solid-state photonic devices and biological imaging. Herein, a series of novel terpyridine-based quadrupolar derivatives have been synthesized. The influences of electron-donating group, type of conjugated bridge, as well as solvent polarity on the molecular TPA properties have been investigated in detail. In contrast to the case in organic solvents, bis(thienyl)-benzothiadiazole as a rigid conjugated bridge will completely quench molecular two-photon emission in aqueous media. However, the combination of alkylcarbazole as the donor and bis(styryl)benzene as a conjugation bridge can enlarge molecular TPA cross-sections in both organic solvent and aqueous media. The reasonable two-photon emission brightness for the organic nanoparticles of chromophores 3-5 in the aqueous media, prepared by the reprecipitation method, enables them to be used as probes for in vivo biological imaging.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Tingchao
authors.initials: T
authors.lastname: He
authors.forename: Zheng Bang
authors.initials: ZB
authors.lastname: Lim
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.forename: Hairong
authors.initials: H
authors.lastname: Li
authors.forename: Deepa
authors.initials: D
authors.lastname: Rajwar
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Ying
authors.forename: Ziyun
authors.initials: Z
authors.lastname: Di
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Grimsdale
authors.forename: Handong
authors.initials: H
authors.lastname: Sun
mesh_terms: D015394:Molecular Structure; D053758:Nanoparticles; D017785:Photons; D011725:Pyridines / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011725:Pyridines