Light Emitting Properties of Poly(2-Fluoro-1,4-Phenylene Vinylene) as Compared with Poly(1,4-Phenylenevinylene)

AbstractLight emitting properties of poly(2-fluoro-l,4-phenylenevinylene) (PFPV) were investigated by using steady-state and time-resolved photoluminescence spectroscopies, EL spectra and current-voltage characteristics. PFPV exhibited a red-shifted structureless emission with higher PL and EL quantum efficiency in comparison with PPV. The time-resolved PL experiments revealed that the shorter wavelength emission is attributable to the free excitons and the longer wavelength emission to the self-trapped excitons. The I-V characteristics of the polymers showed typical diode characteristics and the operating voltages of PPV and PFPV were 6 V and 10 V, respectively. The higher relative EL quantum efficiency of PFPV may be due to the higher PL quantum efficiency and the smaller band offset between the aluminum and the LUMO of the PFPV as compared with that of PPV.