Single-photon emission has been demonstrated in various systems 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15. Single-photon sources are indispensable for photonic quantum information technologies. In fact, g (2)(0) vanishes for perfectly antibunched single photons 2. The autocorrelation function g (2)(0) is considered one of the most basic parameters for characterization of single-photon sources, with its value being <0.5 as a criterion for a quantum emitter in the single-photon regime. In contrast, a single-photon source is a non-classical light source with sub-Poisson statistics, which ensures photons are emitted one by one (i.e., photons are “antibunched”) 1, 2. Photons emitted from coherent or thermal emission sources follow a Poisson or super-Poisson distribution, which means that they inevitably arrive in bunches even when the average emission power is reduced to the single-photon level. A quantitative model is developed to illustrate the carrier injection/recombination dynamics of single-dot electroluminescence. The device structure prevents background electroluminescence while offering efficient single-dot electroluminescence. Such highly suppressed multi-photon-emission probability is attributed to both novel device design and carrier injection/recombination dynamics. The optimal g (2)(0) from single-dot electroluminescence breaks the lower g (2)(0) limit of the corresponding single-dot photoluminescence. The devices generate single photons with near-optimal antibunching at room temperature, i.e., with a second-order temporal correlation function at zero delay ( g (2)(0)) being <0.05 for the best devices without any spectral filtering or background correction. Our solution-processed devices consist of isolated CdSe/CdS core/shell quantum dots sparsely buried in an insulating layer that is sandwiched between electron-transport and hole-transport layers. Here, we report an electrically driven single-photon source based on colloidal quantum dots. Photonic quantum information requires high-purity, easily accessible, and scalable single-photon sources.
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