A new blue-emitting conjugated polycarbazoles: Low threshold of amplified spontaneous emission and charge-transporting properties

• Low threshold amplified spontaneous emission was observed from a new polycarbazoles (OCZ).
• Hole mobility of the OCZ was measured by time-of-flight technology.
• OCZ can be used as gain media in polymer lasers.

We report a detailed study of optical gain and charge transport properties of a new fluorescent conjugated polycarbazole (OCZ). OCZ has a bulky side chain of 4-[tris-(4-octyloxyphenyl)methyl]phenyl which contributes to its high fluorescence quantum yield. Amplified spontaneous emission (ASE) with a low threshold value of 6 kW cm−2 and a high net gain co-efficiency up to 47 cm−1 was observed from the OCZ based waveguides. Further, the hole mobility values of the OCZ films was found to be the order of 10−5 cm2 V−1 s−1 for different film thicknesses. These results show that the introduction of the big side chain is beneficial for the fluorescence efficiency of the polycarbazoles polymer without sacrificing the charge mobility.

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