Single\nCesium Lead Halide Perovskite Nanocrystals at Low Temperature: Fast\nSingle-Photon Emission, Reduced Blinking, and Exciton Fine Structure

Abstract

Metal-halide\nsemiconductors with perovskite crystal structure are attractive due\nto their facile solution processability, and have recently been harnessed\nvery successfully for high-efficiency photovoltaics and bright light\nsources. Here, we show that at low temperature single colloidal cesium\nlead halide (CsPbX₃, where X = Cl/Br) nanocrystals exhibit\nstable, narrow-band emission with suppressed blinking and small spectral\ndiffusion. Photon antibunching demonstrates unambiguously nonclassical\nsingle-photon emission with radiative decay on the order of 250 ps,\nrepresenting a significant acceleration compared to other common quantum\nemitters. High-resolution spectroscopy provides insight into the complex\nnature of the emission process such as the fine structure and charged\nexciton dynamics.