Nonlinear absorption properties of PPyPyV polymer

Abstract We design and synthesize a highly soluble poly(pyridopyrazine vinylene) (denoted as PPyPyV) attaching 4-(4-tert-butyl-phenoxy)phenyl, which made good solubility, as a n-type, low band-gap semiconducting polymer. The optical band-gap was found to be ∼1.83 eV. The nonlinear absorption of PPyPyV dissolved in THF was investigated by the open aperture Z-scan technique with the various wavelength of nanosecond pulses. For two resonant wavelengths, 620 and 640 nm, the increase in the normalized transmittance observed the saturable absorption (SA) effect. On the contrary, for two nonresonant wavelengths, 690 and 730 nm, the increase in the normalized transmittance due to the reverse saturable absorption (RSA) effect was observed.