Photoluminescent and electrochemical properties of novel copoly(aryl ether)s with isolated fluorophores

Two, novel copoly(aryl ether)s (P1 and P2) consisting of alternate, isolated electron- and hole-transporting fluorophores were synthesized and characterized. Furthermore, we investigated the optical, photoluminescent (PL), and electrochemical properties of copoly(aryl ether)s P1-P5. The PL spectra of these polymers in film states showed maximum peaks around 420-498 nm. However, compared with the PL spectra of corresponding model compounds M1-M5, the emissions of P1 and P2 were compositions of the two isolated fluorophores, and that of P3 was dominated by the fluorophores with a longer emissive wavelength via the energy transfer. The formation of an interchain interaction in P4 and P5 was also observed. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of these copolymers were measured by cyclic voltammetry. Both the electron and hole affinities could be enhanced simultaneously because of the introduction of isolated hole-transporting naphthalene (or fluorene) and electron-transporting bis-1,3,4-oxadiazole segments. The single-layer devices (Al/polymer/indium tin oxide) of P1, P2, and P4 revealed blue or blue-green electroluminescence, but that of P3 emitted yellow light because of the excimer emission.