# Nearly Blinking-Free, High-Purity Single-Photon Emission by Colloidal InP/ZnSe Quantum Dots

## TL;DR

This study demonstrates that colloidal InP/ZnSe quantum dots can serve as high-purity, nearly blinking-free single-photon emitters at room temperature, combining strong photon antibunching with remarkable stability and minimal luminescence intermittency.

## Contribution

The paper reports the synthesis and characterization of InP/ZnSe quantum dots that exhibit high single-photon purity and minimal blinking, advancing their potential for quantum photonics applications.

## Key findings

- Quantum dots show strong photon antibunching due to fast Auger recombination.
- QDs exhibit very good photostability under strong optical excitation.
- They are nearly blinking-free with emission stability comparable to state-of-the-art materials.

## Abstract

Colloidal core/shell InP/ZnSe quantum dots (QDs), recently produced using an improved synthesis method, have a great potential in life-science applications as well as in integrated quantum photonics and quantum information processing as single-photon emitters. Single-particle spectroscopy of 10-nm QDs with 3.2-nm cores reveals strong photon antibunching attributed to fast (70-ps) Auger recombination of multiple excitons. The QDs exhibit very good photostability under strong optical excitation. We demonstrate that the antibunching is preserved when the QDs are excited above the saturation intensity of the fundamental-exciton transition. This result paves the way towards their usage as high-purity on-demand single-photon emitters at room temperature. Unconventionally, despite the strong Auger blockade mechanism, InP/ZnSe QDs also display very little luminescence intermittency ("blinking"), with a simple on/off blinking pattern. The analysis of single-particle luminescence statistics places these InP/ZnSe QDs in the class of nearly blinking-free QDs, with emission stability comparable to state-of-the-art thick-shell and alloyed-interface CdSe/CdS, but with improved single-photon purity.