Low Threshold Room Temperature Polariton Lasing from Fluorene‐Based Oligomers

Organic semiconductors possessing tightly bound Frenkel excitons are known to be attractive candidates for demonstrating polariton lasing at room temperature. As can occur without inversion, it is a potential route very low threshold coherent light sources. However, so far, the thresholds of organic lasers have generally been much higher than those photon lasers. Here this problem has addressed by investigating two new molecules with structure combining fluorene and carbazole groups. The materials readily deposited from solution exhibit high photoluminescence quantum yields, absorption coefficients, large radiative decay rates in neat films. Room temperature realized both incident 13.5 9.7 µJ cm−2, corresponding absorbed 3.3 2.2 respectively. These lowest values reported date semiconductor materials, approach typical step-like power dependent blue-shift modes indicates an interplay between different depletion channels exciton reservoir. This work brings practical polaritonic devices future realization electrically driven step closer.