Room-Temperature Efficient Single-Photon Generation from CdSe/ZnS Nanoplatelets

In the search for materials for quantum information science applications, colloidal semiconductor nanoplatelets (NPLs) have emerged as a highly promising class of materials due to their interesting optical properties, such as narrow emission line widths and fast photoluminescence (PL) lifetimes at room temperature. So far, only a few works focused on the quantum properties of their emission; however, NPLs, with their atomic-scale thickness and one-dimensional quantum confinement, are promising candidates for single-photon sources. Here, we demonstrate room-temperature single-photon emission from core/shell CdSe/ZnS NPLs, which feature an 8 × 20 nm² surface area and 1 nm shell. The limited surface area ensures effective Auger nonradiative recombination, resulting in highly efficient single-photon generation with values of photon purity as low as g⁽²⁾(0) = 0.04. The observed long-period blinking and bleaching typical of such thin shells can be easily reduced by increasing the shell thickness. This work establishes NPLs as single-photon sources that are very well suited for integration into quantum photonic systems.