FEMTOSECOND TIME-RESOLVED OPTICAL-RESPONSE OF PHTHALOCYANINE LANGMUIR-BLODGETT-FILM

The mechanism of 2,9,16,23-tetra-heptadecylamido-substituted vanadyl p hthalocyanine Langmuir-Blodgett film was studied with femtosecond lase r pulses. After the excitation into the first electronic excited band, an ultrafast decay due to phonon-exciton coupling greatly affected by temperature was observed. Following this process, exciton-exciton ann ihilation leads to the recovery of the ground state with a decay time of about 10 ps. The Frenkel exciton theory was employed to give a comp lete interpretation of the dynamics. An even slower relaxation was als o observed.