Photophysics and Triplet-Triplet Annihilation Analysis for Axially Substituted Gallium Phthalocyanine Doped in Solid Matrix

A novel solid matrix doped with tetra-α-(4-tert-butylphenoxy) gallium phthalocyanine (TBP-GaPc) was prepared. Photophysical properties were investigated in order to analyze the effect of triplet—triplet annihilation (TTA) of the phthalocyanine (Pc) both in a solid matrix and in a tetrahydrofuran (THF) solution at different concentrations. The rigid surroundings of the Pc molecules in the solid matrix greatly reduce the aggregation, resulting in much lower probability of the TTA process. With the deductive kinetic models, the rate constant and the percentage of TTA were obtained. In a THF solution, the summation of the first-order exponential decay rate constants k 1 and the apparent rate constants of triplet—triplet annihilation k' 2 is much larger than that in the solid matrix, and the percentages of TTA in THF solutions are much higher (7.74—50.9%) than that in solid matrixes (1.05-6.51 %) from 5.0 × 10 -6 to 1.0 × 10 -3 M. The results of the TTA process and photophysical properties strongly suggest that the Pc doped in the solid matrix will give better optical limiting behaviors than that in liquid solution.