Wavelength-optimized Two-Photon Polymerization Using Initiators Based on Multipolar Aminostyryl-1,3,5-triazines

Area of Science:

• Materials Science
• Optics and Photonics
• Chemical Engineering

Background:

• Two-photon induced polymerization (2PP) is a key microfabrication technology.
• Two-photon initiators (2PIs) are crucial for 2PP resin photosensitivity.
• Developing efficient 2PIs with enhanced two-photon absorption (2PA) is vital for advancing 3D printing.

Purpose of the Study:

• To synthesize and characterize novel 1,3,5-triazine-based multipolar two-photon initiators (2PIs).
• To investigate the cooperative enhancement of two-photon absorption cross-sections (σ2PA) in these new 2PIs.
• To evaluate the performance of these 2PIs in 2PP-based 3D printing applications.

Main Methods:

• Synthesis and characterization of triazine derivatives with varying aminostyryl-donor arms (dipolar, quadrupolar, octupolar).
• Measurement of σ2PA using z-scan and spectrally resolved two-photon excited fluorescence.
• Comparison of experimental σ2PA data with high-level ab initio computations.
• 2PP structuring tests using tunable femtosecond lasers.

Main Results:

• Successfully synthesized and characterized novel multipolar 2PIs based on 1,3,5-triazine.
• Experimental and computational results showed enhanced σ2PA in the designed push-pull systems.
• Octupolar triazine derivatives demonstrated superior performance in 2PP compared to a reference quadrupolar 2PI.
• Achieved lower fabrication thresholds and higher writing speeds (up to 200 mm/s) with broader processing windows.

Conclusions:

• The designed octupolar triazine derivatives represent highly efficient 2PIs for 2PP.
• These novel initiators offer significant advantages for high-resolution and high-speed 3D microfabrication.
• The findings pave the way for developing next-generation photosensitive materials for advanced additive manufacturing.