Beyond the Threshold: A Study of Chalcogenophene-Based Two-Photon Initiators

Area of Science:

• Materials Science
• Photochemistry
• Polymer Chemistry

Background:

• Two-photon absorption (2PA) initiators are crucial for advanced polymerization techniques.
• Developing efficient and versatile photoinitiators is an ongoing research area.

Purpose of the Study:

• To design and synthesize novel chalcogenophene-based compounds as potential 2PA photoinitiators.
• To evaluate the photophysical properties and performance of these new materials.

Main Methods:

• Synthesis of nine soluble, symmetric chalcogenophenes with triphenylamine, indolocarbazole, or phenylcarbazole moieties.
• Detailed photophysical analysis including 2PA cross-section measurements.
• Structuring and threshold tests in acrylate resin formulations.

Main Results:

• The synthesized compounds exhibited good 2PA properties, with selenium significantly enhancing 2PA cross sections.
• Two selenium-containing compounds (TPA-S and TPA-BBS) demonstrated high efficiency and broad spectral versatility.
• These novel initiators outperformed commercial standards (Irg369, BAPO, ITX) in reactivity and required dose.
• Reduced polymerization thresholds were achieved by increasing the concentration of TPA-BBS.

Conclusions:

• Selenium-based chalcogenophenes are highly promising 2PA photoinitiators.
• The developed materials offer significant advantages over traditional photoinitiators for two-photon polymerization.
• These compounds hold great potential for low-power 2PP systems.