Ultrafast Optical Response of Phthalocyanine Langmuir-Blodegett Film

The mechanism of 2, 9, 16, 23- tetra-heptadecylamido substituted vanadyl phthalocyanine Langmuir-Blodegett film was studied with femtosecond laser pulses. An ultrafast decay due to phonon-exciton coupling greatly affected by temperature, and exciton-exciton annihilation leading to the recovery of the ground state (T~lops) and an even slower relaxation were observed.