  The interest in perovskite nanocrystals (NCs) such as CsPbBr$_3$ for quantum
applications is rapidly raising, as it has been demonstrated that they can
behave as very efficient single photon emitters. The main problem to tackle in
this context is their photo-stability under optical excitation. In this
article, we present a full analysis of the optical and quantum properties of
highly efficient perovskite nanocubes synthesized with an established method,
which is used for the first time to produce quantum emitters, and is shown to
ensure an increased photostability. These emitters exhibit reduced blinking
together with a strong photon antibunching. Remarkably these features are
hardly affected by the increase of the excitation intensity well above the
emission saturation levels. Finally, we achieve for the first time the coupling
of a single perovskite nanocube with a tapered optical nanofiber in order to
aim for a compact integrated single photon source for future applications.
