  Achieving pure single-photon emission is essential for a range of quantum
technologies, from optical quantum computing to quantum key distribution to
quantum metrology. Among solid-state quantum emitters, colloidal lead halide
perovskite (LHP) nanocrystals (NCs) have garnered significant attention due to
their interesting structural and optical properties, which make them appealing
single-photon sources (SPSs). However, their practical utilization for quantum
technology applications has been hampered by environment-induced instabilities.
In this study, we fabricate and characterize in a systematic manner Zn-treated
$CsPbBr_3$ colloidal NCs obtained through $Zn^{2+}$ ion doping at the Pb-site,
demonstrating improved stability under dilution and illumination. These doped
NCs exhibit high single-photon purity, reduced blinking on a sub-millisecond
timescale and stability of the bright state for excitation powers well above
the saturation levels. Our findings highlight the potential of this synthesis
approach to optimize the performance of LHP-based SPSs, opening up interesting
prospects for their integration into nanophotonic systems for quantum
technology applications.
