Efficient two-photon absorbing photosensitizers based on diazafluorene moiety for 3-D TPP fabrication

Abstract

Efficient diazaflourene-based two-photon absorbing dyes for two-photon induced photopolymerization (TPP) have been synthesized. Their linear optical properties display a slight bathochromic shift with increasing branches. The chromophores give rise to a blue emission which is useful for two-photon lithographic microfabrication. Their TPA cross-section (sigma(2)) values evaluated by 100 femtosecond pulsed laser are found to be increased with the number of branches; 570 GM (760 nm) for dibranched diazafluorene (1) and 820 GM (760 nm) for tribranched diazafluorene (2). By using the resulting TPA chromophores we have succeeded to fabricate three-dimensional pattern with lattice structure.