Push–Pull Acylo-Phosphine Oxides for Two-Photon-Induced Polymerization

The two-step method for the synthesis of acyl–phosphine oxides from aromatic aldehydes was optimized giving the products in 52–97% overall yield. Linear and nonlinear optical properties of series of acyl–phosphine oxides possessing substituents with different electron-donating ability were investigated. Two-photon absorption cross sections (σ₂) of push–pull acyl–phosphine oxide was determined as 9GM via z-scan measurements with femtosecond laser pulses. Using acyl–phosphine oxides possessing dipolar structure as initiators, 3D nanopatterns were successfully fabricated by two-photon initiated polymerization. These compounds also initiate classical photopolymerization when excited with UV radiation.