Enhanced Photoluminescence of Halide Perovskite Nanocrystals Mediated by a Higher-Order Topological Metasurface

Halide perovskite nanocrystals are a family of nanomaterials with a high prospect for use in light-emitting devices, lasers, and quantum optics, which makes their integration into photonic circuits highly desirable. On the other hand, recently discovered higher-order topological insulators offer rich potential for disorder-robust light confinement due to topological protection over an extended range of dimensionalities. Here, we demonstrate coupling of halide perovskite nanocrystals to higher-order zero-dimensional states confined to the corners of a topological metasurface. Namely, we integrate a silicon-based kagome lattice supporting various topologically protected states with a layer of perovskite nanocrystals with the emission wavelength precisely tuned to the required wavelength via anion exchange reaction. By measuring the photoluminescence spectra of perovskite nanocrystals, we reveal a significant enhancement at the frequency of zero-dimensional topological corner states, thus highlighting the interplay of topological physics and the Purcell effect. We further support our findings by the time-resolved photoluminescence measurements.