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Abstract:

The synthesis of a new soluble conjugated porphyrin polymer 4 is reported. The MALDI TOF mass spectrum shows the presence of oligomers with up to 13 repeat units and GPC gives a Mn of 53 kDa. The electronic absorption spectra of this polymer exhibit an intense Q band at 800 nm in solution and 853 nm in the solid state, demonstrating a high degree of conjugation. Electroabsorption spectroscopy shows that thin films of 4 have lower resonant third order NLO susceptibility than our previous conjugated porphyrin polymer 2, whereas closed z-scan measurements indicate that the off-resonance real susceptibility, at 1064 nm, is exceptionally large for both polymers (χ⁽³⁾R =-2 × 10^-16 m² V^-2). Open z-scan measurements were also made at 1064 nm, demonstrating that the two polymers exhibit similar nonlinear absorption at this wavelength (β= 1 cm GW^-1 at 0.2 mM concentration).