Room-Temperature, Highly Pure Single-Photon Sources from All-Inorganic Lead Halide Perovskite Quantum Dots.

Zhu, Chenglian; Marczak, Malwina; Feld, Leon; Boehme, Simon C; Bernasconi, Caterina; Moskalenko, Anastasiia; Cherniukh, Ihor; Dirin, Dmitry et al. · Nano Lett · 2022

basic_science · Level V

Where this comes from

Abstract

Attaining pure single-photon emission is key for many quantum technologies, from optical quantum computing to quantum key distribution and quantum imaging. The past 20 years have seen the development of several solid-state quantum emitters, but most of them require highly sophisticated techniques (e.g., ultrahigh vacuum growth methods and cryostats for low-temperature operation). The system complexity may be significantly reduced by employing quantum emitters capable of working at room temperature. Here, we present a systematic study across ∼170 photostable single CsPbX<sub>3</sub> (X: Br and I) colloidal quantum dots (QDs) of different sizes and compositions, unveiling that increasing quantum confinement is an effective strategy for maximizing single-photon purity due to the suppressed biexciton quantum yield. Leveraging the latter, we achieve 98% single-photon purity (<i>g</i><sup>(2)</sup>(0) as low as 2%) from a cavity-free, nonresonantly excited single 6.6 nm CsPbI<sub>3</sub> QDs, showcasing the great potential of CsPbX<sub>3</sub> QDs as room-temperature highly pure single-photon sources for quantum technologies.