Temperature dependence of amplified spontaneous emission in conjugated polymers

The photo-luminescence emission of conjugated polymers exhibits a red-shift as the temperature is reduced. The gain curve red-shifts along with the emission and hence, the wavelength for amplified spontaneous emission (ASE) red-shifts on lowering the temperature. A similar, but not as pronounced, red-shift is also observed in optical absorption of these materials. The increased Stokes shift between the absorption and emission leads to lower self-absorption losses and hence to lower thresholds for ASE at lower temperatures.