Solution-processed anthracene-based molecular glasses as stable blue-light-emission laser gain media

•We obtain uniform film of anthracene-based molecular glass via solution-processing.•We achieve very low laser threshold from optically pumped DFB laser.•We demonstrate high thermal stability of gain property of the film.•We study the gain properties of the materials with and without fluorine atom.•We show introduced fluorine atom would not drastically affect optical gain properties.

Two asymmetric 9,10-disubstituted anthracene-based, solution-processable, molecular glasses were studied in detail as thin-film laser gain media and were found to demonstrate very low amplified spontaneous emission (ASE) thresholds (0.75–1.1 μJ/pulse). Distributed feedback (DFB) lasers fabricated with these materials by spin coating on top of pre-etched silica one-dimensional (1-D) gratings exhibited a minimum laser threshold of 5.7 nJ per pulse (17.7 μJ cm−2) and maximum slope efficiency of 3.6%. The thermal stability of the gain was also investigated, with ASE observed for thermal annealing at temperatures up to 300 °C without any significant increase in threshold. The high thermal stability and low laser threshold make these materials very promising gain media. Comparison of the two glasses demonstrated that whilst fluorine-substitution significantly lowers the HOMO and LUMO levels it does not dramatically affect the gain. Our results suggest a potential approach for materials synthesis to address the challenge of electrically pumping an organic laser.

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