Amplified spontaneous emission in α-phase and β-phase polyfluorene waveguides

Amplified spontaneous emission (ASE) of α- and β-phase poly(9,9-dioctylfluorene) (F8) based waveguides has been studied and ASE wavelengths have been determined as 451 nm and 468 nm, respectively. β-phase waveguides are found to be with higher net gain and lower light propagation loss as compared to α-phase waveguides. Such important improvement of ASE properties, making β-phase waveguides superior over α-phase counterparts is shown to be achieved at the expense of higher refractive index and photoluminescence quantum efficiency of β-phase F8.