Single photons, often called flying qubits, have enormous
promise
to realize scalable quantum technologies ranging from an unhackable
communication network to quantum computers. However, finding an ideal
single-photon emitter (SPE) is a great challenge. Recently, two-dimensional
(2D) materials have shown great potential as hosts for SPEs that are
bright and operate under ambient conditions. This Perspective enumerates
the metrics required for an SPE source and highlights that 2D materials,
because of reduced dimensionality, exhibit interesting physical effects
and satisfy several metrics, making them excellent candidates to host
SPEs. The performance of SPE candidates discovered in 2D materials,
hexagonal boron nitride and transition metal dichalcogenides, will
be assessed based on the metrics, and the remaining challenges will
be highlighted. Lastly, strategies to mitigate such challenges by
developing design rules to deterministically create SPE sources will
be presented.