  High-quality emission centers in two-dimensional materials are promising
components for future photonic and optoelectronic applications. Carbon-enriched
hexagonal boron nitride (hBN:C) layers host atom-like color-center (CC) defects
with strong and robust photoemission up to room temperature. Placing the hBN:C
layers on top of Ag triangle nanoparticles (NPs) accelerate the decay of the CC
defects down to 46 ps from their reference bulk value of 350 ps. The ultrafast
decay is achieved due to the efficient excitation of the plasmon modes of the
Ag NPs by the near field of the CCs. Simulations of the CCs/Ag NP interaction
present that higher Purcell values are expected, although the measured decay of
the CCs is limited by the instrument response. The influence of the NP
thickness to the Purcell factor of the CCs is analyzed. The ultrafast operation
of the CCs in hBN:C layers paves the way for their use in demanding
applications, such as single-photon emitters and quantum devices.
