Spiro-substitution effect of terfluorenes on amplified spontaneous emission and lasing behaviors

In order to investigate the inherent differences between spirofluorenes, two typical spirocycle models, spiro[fluorene-9,9′-xanthene] (SFX) and spirobiflourene (SBF), were chosen to construct four spiro-terfluorenes (DSFX-OSFX, DSBF-OSFX, DOSFX-SFX and DOSFX-SBF) to investigate the effect of spirocycle substitution on photophysical and stimulated emission properties. The terfluorenes have similar absorption and photoluminescence properties. While the DOSFX-SBF film displays the best ASE properties with a threshold of 1.81 μJ cm^-2, the lasing threshold of the 1-D DFB laser based on DOSFX-SBF is lowered to 0.85 μJ cm^-2. These results indicate that the type of spirofluorene has a dramatic influence on stimulated emission properties and spiro terfluorenes have potential applications in organic lasers.