Highly Efficient and Stable Binary Cross-Linkable/ Self-Assembled Organic Nonlinear Optical Molecular Glasses

Area of Science:

• Materials Science
• Organic Electronics
• Nonlinear Optics

Background:

• Developing electro-optic materials with high chromophore loading, ultrahigh electro-optic coefficients, and long-term alignment stability is challenging.
• Existing materials often compromise stability for performance or vice versa.

Purpose of the Study:

• To develop highly efficient, binary cross-linkable/self-assembled dendritic chromophores (FZL1-FZL4) for advanced electro-optic applications.
• To achieve high chromophore loading, superior electro-optic coefficients, and enhanced long-term alignment stability.

Main Methods:

• Utilized Anthracene-maleimide Diels-Alder (DA) reaction for covalent cross-linking.
• Employed π-π interactions (Anthracene-pentafluorobenzene, benzene-pentafluorobenzene) for non-covalent self-assembly.
• Electric field poling was applied to orient chromophores within the formed network.

Main Results:

• Achieved electro-optic coefficients up to 266 pm/V (cross-linked FZL1/FZL2) and 272-308 pm/V (self-assembled FZL1/FZL4, FZL3/FZL4) due to high chromophore density (3.09-4.02 × 10^20 molecules/cm³).
• High glass transition temperature of 178 °C in cross-linked film FZL1/FZL2.
• Exceptional long-term alignment stability: FZL1/FZL2 maintained 99.73% of r₃₃ after 500h at 85 °C; self-assembled films retained >97% after 500h at room temperature.

Conclusions:

• The developed binary cross-linkable/self-assembled dendritic chromophores demonstrate excellent electro-optic performance and stability.
• The combination of DA reaction or π-π interaction with electric field poling effectively enhances material alignment and durability.
• These materials show significant promise for practical applications in organic electro-optics.