Optical nonlinearities and excited state dynamics of self-assembled cobalt phthalocyanine multilayer films

摘要

An ultrathin composite films containing cobalt phthalocyanine (CoPc) and poly(diallydimethyl ammonium chloride) (PDDA) were fabricated through layer-by-layer assembly technique. The resulting films were characterized by UV-Vis spectroscopy and atomic force microscopy. Their third-order nonlinear optical properties and photo-excitation dynamics were investigated with 20 ps laser pulses at 532 nm. The results demonstrate that the ultrathin films have notable third order optical nonlinearities (chi((3))similar to 4.7 x 10(-9) (esu)) and fast excited-state relaxation (tau similar to 67 +/- 6 ps), indicating their potential applications in future nonlinear optical devices. (C) 2018 Elsevier B.V. All rights reserved.