Perovskite colloidal quantum dots (CQDs) enable a solution-processed approach toward lasers, simultaneously providing tunable wavelength, high quantum efficiency, large absorption cross-section, and long Auger lifetimes. However, broad-band single-mode lasers based on such CQDs have been proven to be challenging. Here we report broad-band single-mode lasers from solution-processed CsPbX3 (X = Cl, Br, I) CQDs based on a high-quality zinc oxide microrod hexagonal whispering-gallery microcavity. A typical single-mode laser with ultra-narrow linewidth (B0.21 nm, quality factor B3000) at 11.7 mJ cm_2 was obtained at 636 nm based on the conformal deposition of CsPb(Br0.5I0.5)3 CQDs on an individual hexagonal zinc oxide microrod cavity with a radius of about B776 nm. Moreover, by tuning the halogen ratio, synthesis temperature and the size of the zinc oxide microrods, broad-band tunable single-mode lasers are obtained across the entire visible spectrum from 417 nm to 723 nm. These results represent a significant step towards easy solution-processed broad-band tunable single-mode lasers.
Bibliographical noteKAUST Repository Item: Exported on 2020-11-04
Acknowledgements: This work was supported financially by the National Natural Science Foundation of China (61875256, 61675219). H. Dong acknowledges the Nature Science Foundation of Shanghai (20JC1414605). Thank the University of Chinese Academy of Sciences (UCAS) Joint PhD Training Program. Thank prof. Edward Ted Sargent for the help of SEM and EDS.