Copoly(aryl ether)s with electron-transporting 2,7-bis(3-(trifluoromethyl)phenyl)-9,9-dihexylfluorene segments: Synthesis, optical, and electrochemical properties

Abstract: We prepared and characterized three new copoly(aryl ether)s (P1–P3) consisting of alternate electron-transporting 2,7-bis(3-(trifluoromethyl)phenyl)-9,9-dihexylfluorene and hole-transporting fluorophores (P1: 3,6-distyryl-N-2-ethylhexylcarbazole; P2: 2,7-distyryl-9,9-dihexylfluorene; P3: 1,4-distyryl-2,5-dihexylbenzene) separated by ether spacers. The copolymers were soluble in common organic solvents such as chloroform, NMP, and 1,1,2,2-tetrachloroethane and exhibited good thermal stability with T ds higher than 360°C. Optical properties of P1–P3 were investigated by comparing their absorption and photoluminescence spectra with those of compositional model compounds M1–M4. The emissions of P1–P3 are originated from both fluorophores (P1) or dominated by fluorophores with longer emissive wavelength via efficient energy transfer (P2 and P3). Cyclic voltammetric investigations confirm that incorporation of isolated hole- and electron-transporting segments leads to simultaneous enhancement of electron and hole affinity in these copoly(aryl ether)s. The HOMO and LUMO energy levels of P1–P3 are −5.15, −5.28, −5.17 and −3.04, −3.06, −3.08eV, respectively, and double-layer light emitting diodes of P1–P3 reveal emission maxima around 450–500nm. [Copyright &y& Elsevier]