1 research outputs found
Heteroatom/Heterocycle-Substituted Ketone Dyes as Efficient Photoinitiators in Visible Light-Emitting Diode/Near Infrared Light Photopolymerization with Enhanced Two-Photon Lithography Capability
Photopolymerization is a burgeoning technology with a
wide range
of applications from coatings and inks to nanotechnology. The development
of photosensitized systems that can work at long wavelengths with
safety and environmental friendliness, such as visible light-emitting
diodes and near infrared light, is essential. In this study, a series
of ketone dyes containing heteroatom/heterocyclic substituents were
designed on the basis of the carbazole–coumarin backbone to
compare with aryl ring-substituted ones. The photophysical and photochemical
properties of the dyes were studied by UV–vis spectroscopy,
time-dependent density functional theory calculations, fluorescence
spectroscopy, and steady-state photolysis. The potential application
of dyes in one/two-photon polymerization was investigated. Results
showed that the introduction of heterocycles/heteroatoms has a considerable
influence on the absorption and polymerization properties of dyes.
CCK–Th, which contains a thiophene substitute, exhibits the
most excellent light absorption properties as well as the fastest
reaction efficiency with amine additives. Notably, when comparing
the two-photon lithography capability, the photoresist containing
0.1 wt % CCK–Th, which can achieve a writing speed of 46 mm
s–1, exhibits high two-photon sensitivity, about
two times that of the benzene ring-substituted CCK–Ben. In
addition, CCK–Th shows outstanding ability to construct complex
three-dimensional patterns. These modified CCKs show great application
potential in nanotechnology, additive manufacturing, and optoelectronics
and provide design concepts for the development of photoinitiators