Synthesis and characterization of high-performance NLO molecular glasses for seamless integration in silicon photonics

This work reports the design, synthesis, and comprehensive characterization of three new high-performance nonlinear optical (NLO) molecular glasses – J-TPA, J-TPC, and B-TPA – derived from benchmark chromophores JRD1 and BAH13. By replacing tert-butyldiphenylsilyl groups with more rigid triphenylmethane-based substituents, the materials exhibit significantly improved thermal properties, including an increase of 9–18 °C in glass transition temperature (T_g) and enhanced thermal stability. The chromophores maintain excellent solubility and form high-quality amorphous thin films suitable for solution processing. Hyper-Rayleigh scattering measurements reveal strong resonance-enhanced NLO responses at telecommunication wavelengths, with J-TPA and J-TPC surpassing JRD1 at 1540 nm, and B-TPA showing up to a 50% improvement at 1300 nm. Linear optical characterization confirms low absorption in both O- and C-bands, while inkjet printing experiments demonstrate successful heterogeneous integration into photonic trench waveguides. These results highlight the potential of triphenylmethane-modified chromophores as candidates for heterogeneous integration of organic electro-optic materials in silicon photonics devices.