Laser flash photolysis study of the phase transition effect on the kinetics of triplet-triplet annihilation of tetraphenylporphine inn-decanol

Abstract

The kinetics of triplet-triplet annihilation of tetraphenylporphine (TPP) inn-decanol was studied by nanosecond laser flash photolysis with monitoring of the transient absorption and concomitant delayed fluorescence in the temperature range from 100 to −100°C. The freezing of the solution results in more than tenfold acceleration of the process within the same reaction mechanism. It is supposed that the phase transition is accompanied by the concentration of the TPP molecules in defect regions of the polycrystalline structure of the frozen alcohol. These domains have a homogeneous nature and are characterized by a high molecular mobility.