Emission Control of Perovskite Nanocrystals empowered by Bound States in the Continuum in Dielectric Gratings

To propel the advancement of quantum emitter-based capabilities, the coupling of semiconductor nanocrystals (NCs) with high-quality resonators is gaining traction as a promising platform for amplifying and controlling light-matter interactions. Herein, we demonstrate the modulation of the emission properties of perovskite NCs within the visible spectral region by integrating them with a silicon (Si) grating that sustains symmetry-protected bound states in the continuum. The dielectric metasurface nanostructures, composed of periodic Si bars fabricated via thermal scanning probe lithography, can be precisely manipulated to advance the development of photonic devices operating within the visible range. By adjusting the geometry of the Si bars, we achieve selective enhancement and shaping of specific wavelength ranges within the emission spectrum. Experimental investigation reveals a sixfold enhancement of photoluminescence (PL) attributable to the integration of the Si gratings. Furthermore, the directional emission of NCs is achieved with the help of the angle-dependent properties of the proposed metasurface. The excitation position also provides an additional degree of freedom to manipulate the emission direction of the PL. The enhanced and shaped emission is attributed to light-matter interactions, as further confirmed in transient absorption microscopy spectra. Our switchable emission strategy holds considerable promise for advanced light-emitting devices, with substantial implications for radiation control and optical imaging.