Broad-band lead halide perovskite quantum dot single-mode lasers
Perovskite colloidal quantum dots (CQDs) enable the solution-processed approach toward laser, 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 proven to be challenging. Here we report broad-band single-mode lasers from solution-processed CsPbX3 (X=Cl, Br, I) CQDs based on high-quality zinc oxide microrod hexagonal whispering-gallery microcavity. A typical single-mode laser with ultra-narrow linewidth (~ 0.21 nm, quality factor ~ 3000) at 11.7 μJ.cm-2 was obtained at 636 nm based on the conformal deposition of CsPb(BrxI1-x)3 CQDs on an individual hexagonal zinc oxide microrod cavity with radius size about ~ 776 nm. Moreover, by tuning the halogen ratio, synthesized 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.