| Popis: |
We present a comparative study on the ultrafast nonlinear optical response of a novel conjugated zinc porphyrin system. The linear optical absorption spectra of these molecules all show the Q‐band and B‐band transitions of the basic porphyrin unit. We have taken spectrally resolved ultrafast pump–probe measurements on monomer, dimer, and polymer solutions, which allows us to compare their excited state dynamics and relate these to their linear optical absorption. The spectra show several common features, but these features have markedly different decay dynamics. The bleaching is preferential in the Q band for the polymer and the B band for the monomer. The polymer Q‐band bleaching shows a two‐component decay, of approximately 700 fs and 170±50 ps time constants in a biexponential fit, which we attribute to both exciton–exciton annihilation and exciton diffusion to recombination centers on the polymer chain. The Q band of the dimer also has a two‐component decay with 13±5 and 1250±70 ps time constants whic... |
