The Q absorption band of the excited triplet phthalocyanine dimer

The lowest excited triplet (T1) state of tri-tert-butylpyridinotribenzotetraazaporphinatozinc (ZnPcPy) has been investigated using transient absorption and phosphorescence measurements. The excited-state absorption spectrum of the self-assembled dimer ((ZnPcPy)2) exhibits two sharp absorption bands (658 and 694 nm) in the Q band region, in addition to triplet-triplet absorption at 500 nm. This is the first observation of the Q band of the T1 phthalocyanine dimer.