We investigated the temperature dependence of the amplified spontaneous emission (ASE) of the β phase of poly(9,9-dioctylfluorene). We show that the ASE threshold increases with temperature of about 1 order of magnitude from 17 μJ cm−2 at 5 K to 206 μJ cm−2 at 300 K due to the thermal activation of uphill energy migration to nonradiative centers that reduces the population inversion for a given excitation density. The temperature increase also changes the luminescence line-shape switching on (around 100 K) the ASE from the C-C interunit stretch vibronic replica at the expense of the phenyl-ring quadrant stretch one.
Temperature dependence of the Amplified Spontaneous Emission of the of Poly(9,9-dioctylfluorene) β-phase
ANNI, Marco;
2008-01-01
Abstract
We investigated the temperature dependence of the amplified spontaneous emission (ASE) of the β phase of poly(9,9-dioctylfluorene). We show that the ASE threshold increases with temperature of about 1 order of magnitude from 17 μJ cm−2 at 5 K to 206 μJ cm−2 at 300 K due to the thermal activation of uphill energy migration to nonradiative centers that reduces the population inversion for a given excitation density. The temperature increase also changes the luminescence line-shape switching on (around 100 K) the ASE from the C-C interunit stretch vibronic replica at the expense of the phenyl-ring quadrant stretch one.File in questo prodotto:
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