Energy relaxation in phthalocyanine films excited by ultrashort light pulses

Time resolved photobleaching studies of titanyl phthalocyanines with different crystalline structures are reported. Strong photobleaching of the edge components of the complex Q absorption band and much weaker in the center of the band was found to be a general feature of crystalline and amorphous structures. Such behavior was explained by the ultrafast excitation transfer between different molecular species.