Time-resolved Fluorescence Decay Study of Hematoporphyrin Derivative

Time-resolved fluorescence decays were first performed on hematoporphyrin derivative laser No.3 in buffer at different micelles concentration. The fluorescence lifetime constants, measured with a time-correlated single photon counting system, could be fitted by two or three exponential components with different relative peak amplitudes depending on the observation wavelength, thus indicating the presence of different emitting molecular species and/or of molecular species in different aggregational states.