Enhancing monolayer photoluminescence on optical micro/nanofibers for low-threshold lasing.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31803834.
- Also identified by DOI 10.1126/sciadv.aax7398 and PMC identifier 6874480.
- Licence recorded as CC BY-NC.
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Abstract
Although monolayer transition metal dichalcogenides (TMDs) have direct bandgaps, the low room-temperature photoluminescence quantum yields (QYs), especially under high pump intensity, limit their practical applications. Here, we use a simple photoactivation method to enhance the room-temperature QYs of monolayer MoS<sub>2</sub> grown on to silica micro/nanofibers by more than two orders of magnitude in a wide pump dynamic range. The high-density oxygen dangling bonds released from the tapered micro/nanofiber surface are the key to this strong enhancement of QYs. As the pump intensity increases from 10<sup>-1</sup> to 10<sup>4</sup> W cm<sup>-2</sup>, our photoactivated monolayer MoS<sub>2</sub> exhibits QYs from ~30 to 1% while maintaining high environmental stability, allowing direct lasing with greatly reduced thresholds down to 5 W cm<sup>-2</sup>. Our strategy can be extended to other TMDs and offers a solution to the most challenging problem toward the realization of efficient and stable light emitters at room temperature based on these atomically thin materials.