Study on the synthesis and third-order nonlinear optical properties of D-A poly-quinacridone optical materials

Quinacridone stands out among many optical materials, because it possesses a large pi-conjugated system, remarkable photothermal stability, excellent semiconductor property, and easy modification at multiple active sites of parent molecule. In this paper, the functionalized D-A poly-quinacridone derivatives have been achieved in good yields via Suzuki cross-coupling reactions, two of polymers, PQA-A and PQA-B, were mainly composed of quinacridone and dicyanovinyl-substituted quinacridone, respectively. The polymers have multiple broad absorption band at a wavelength of 230-600 nm. Polymer PQA-B showed a good photoluminescence quantum yield in the luminescence spectra, which can attributed to the immobilization of dicyanovinyl-substituted quinacridone in the polymer and limited the inversion between its structures. The chi((3)) value of polymer PQA-B was 15.456 x 10(-12) esu, which is up to 5 times than that of monomer material measured by Z-scan technique. PQA-A not only had the large third-order NLO response (chi((3)) = 9.820 x 10(-12) esu), but had the good thermal stability (T-d = 402 degrees C), and these good performances will make it more attractive for applications in integrated NLO devices. Our results can be used to develop an efficient design strategy for NLO materials.