Preparation and Third-Order Nonlinear Optical Properties of Novel Axial Fullerenol-Substituted Phthalocyanines

This research presents the optical limiting properties of a novel axially linked D-A type compound, LaPc-C60(OH)n, where lanthanide phthalocyanine serves as the donor and fullerenol as the acceptor. The incorporation of fullerenol expands the pi-conjugated system, decreases the aggregation of the phthalocyanine, and significantly increases the solubility of the compound. The establishment of this D-A system promotes intramolecular electron transfer, effectively improving both the non-linear optical (NLO) response and optical limiting properties. In addition, homogeneous poly(methyl methacrylate) (PMMA) composite films (LaPc-C60(OH)n/PMMA) are prepared using a simple solution casting method. Compared to fullerenol or lanthanum phthalocyanine individually, LaPc-C60(OH)n exhibited a superior NLO response both in solution and in the solid composite film. In particular, LaPc-C60(OH)n/PMMA demonstrated an increase in the non-linear absorption coefficient (2050 cm GW-1) and a larger third-order magnetization (1.84 x 10-8 esu). In addition to exhibiting an excellent NLO response at 532 nm, LaPc-C60(OH)n also shows significant NLO enhancement at 1064 nm, extending the limiting range into the near-infrared region. This behavior is attributed to different nonlinear absorption mechanisms and the synergistic effect that arise from the photo-induced electron transfer process between the fullerenol and LaPc. The study explores LaPc-C60(OH)n, a D-A compound combining lanthanide phthalocyanine and fullerenol for enhanced optical limiting. The nonlinear optical response in its solution and in PMMA films is enhanced due to efficient intramolecular electron transfer. It shows strong nonlinear optical responses at 532 and 1064 nm, with significant optical limiting effects. image