Fluorescence enhancement of PbS colloidal quantum dots from silicon metasurfaces sustaining bound states in the continuum

PbS colloidal quantum dots (CQDs) can be considered a promising lighting material, but their emission performance is mired by defect sites, strong photo-induced activity, and interaction with the environment. Here, we utilize periodic silicon metasurface sustaining a symmetry-protected bound state in the continuum to enhance the near-infrared emission of PbS CQDs at room temperature. In the experimental investigation, it is observed that the fluorescence of the coated PbS CQDs is enhanced by 10 times by the fabricated metasurface, and the emission peak has a quality factor up to 251 at wavelength 1408 nm. Meanwhile, the potential of this work in sensing is demonstrated by showing that the enhanced emission is disturbed by the introduction of sparse gold nanoparticles. In all, this work confirms that dielectric metasurfaces sustaining bound states in the continuum can be adopted to efficiently improve the emission performance of PbS CQDs which may find various practical applications including on-chip silicon-based optical sources and integrated sensors.