Two-photon excitation properties of a class of novel organic dye chloride

We present the two-photon excited (TPE) upconverted fluorescence and lasing efficiencies of a class of new pyridinium chloride having donor-π-acceptor (D-π-A) structure. Based on the excitation upon 40 ps laser pulses at 1064 nm, the experimental results showed that: the red-shift of TPE fluorescence emission peaks and the TPE fluorescence lifetime were gradually increased with the enhancement of electron-donating capability of the donor. To a certain extent, the enhanced donor would increase the two-photon pumped (TPP) upconversion lasing efficiencies, but the overlong alkyl chains would result in decreased lasing efficiencies. We could obtain TPE fluorescence lifetime of 754 ps, TPP upconversion lasing efficiency of ∼8.4%, and TPA cross-section of 6.14 × 10−49cm4s/photon in these compounds.