Two-photon absorption cross-sections of common photoinitiators
Abbreviated Journal Title
J. Photochem. Photobiol. A-Chem.
two-photon absorption; photoinitiators; photopolymerization; irgacure; darocure; FLUORENE DERIVATIVES; POLYMERIZATION; MICROFABRICATION; INITIATORS; Chemistry, Physical
Recent interests in and applications of two-photon absorption (2PA) induced photopolymerization have afforded advanced opportunities to perform three-dimensionally resolved polymerization, resulting in intricate microfabrication and imaging. Many of the reported 2PA-induced polymerizations make use of commercially available photoinitiators, and a key parameter to consider is the two-photon absorption cross-section (delta) of the initiator. To date, there has been no comprehensive investigation of two-photon absorptivity of commercial photoinitiators, though a few studies presenting novel photoinitiators for two-photon polymerization have appeared. Herein, we report the 2PA properties of common, commercially available photoinitiators typically utilized in conventional radiation curing science and technologies, and often used in 2PA-based polymerizations. Z-scan and white-light continuum (WLC) pump-probe techniques were utilized to obtain two-photon absorption cross-sections (delta). The results for most compounds were found to yield good agreement between the two methods. Most of the photoinitiators studied possess low delta, except Irgacure OXE01, indicating a need for the development of new photoinitiators with improved properties optimized for 2PA applications. A compound prepared in our laboratories exhibits high 2PA and was useful as a two-photon free-radical photoinitiator. (C) 2004 Elsevier B.V. All rights reserved.
Journal of Photochemistry and Photobiology a-Chemistry
"Two-photon absorption cross-sections of common photoinitiators" (2004). Faculty Bibliography 2000s. 4774.