Photophysics, electrochemical properties, and electroluminescence of poly(p-phenylenevinylene) derivatives with 1,3,5-triphenylbenzene or 2,4,6-triphenylpyridine segments along the backbone

The steady-state and time-resolved photoluminescence (PL), electrochemical behavior, and electroluminescence (EL) of didodecyloxy polyp-phenylenevinylene)based polymers that contained along the backbone structure 1,3,5-triphenylbenzene (PC) or 2,4,6-triphenylpyridine (PN) were studied. An intensive green PL broad-band emission with maxima at 516 and 527 nm was observed from thin films of PC and PN polymers, respectively, redshifted in comparison with the PL emission spectra measured in tetrahydrofuran solutions. The PL decay dynamics revealed the existence of more than one excited species, and the decay curves were best described by three-term exponential functions with a dominant lifetime of about 1 ns. The results of time-resolved PL and steady-state PL studies indicated excimer or aggregate formation. Both polymers oxidized irreversibly. A quasireversible reduction was observed in the PN polymer, whereas the PC polymer reduced irreversibly. For PC, slightly higher values of the ionization potential (E-IP) and electron affinity (E-A) were found (E-IP = 5.52 eV, E-A = 2.85 eV) than those for PN (E-IP = 5.37 eV, E-A = 2.77 eV). Light-emitting devices with indium tin oxide hole-injecting and aluminum electron-injecting electrodes were prepared and studied. They emitted green light, and their EL spectra were similar to those of PL thin films. (c) 2005 Wiley Periodicals, Inc.