Engineering and controlling perovskite emissions via optical quasi‐bound‐states‐in‐the‐continuum

Metal halide perovskite quantum dots (PQDs) have emerged as promising materials due to their exceptional photoluminescence (PL) properties. A wide range of applications could benefit from adjustable luminescence properties, while preserving the physical and chemical properties of the PQDs. Therefore, post-synthesis engineering has gained attention recently, involving the use of ion-exchange or external stimuli, such as extreme pressure, magnetic and electric fields. Nevertheless, these methods typically suffer from spectrum broadening, intensity quenching or yield multiple bands. Alternatively, photonic antennas can modify the radiative decay channel of perovskites via the Purcell effect, with the largest wavelength shift being 8 nm to date, at an expense of fivefold intensity loss. Here, this work presents an optical nanoantenna array with polarization-controlled quasi-bound-states-in-the-continuum resonances, which can engineer and shift the photoluminescence wavelength over a ≈39 nm range and confers a 21-fold emission enhancement of FAPbI3 perovskite QDs. The spectrum is engineered in a non-invasive manner via lithographically defined antennas and the pump laser polarization at ambient conditions. This research provides a path toward advanced optoelectronic devices, such as spectrally tailored quantum emitters and lasers.