A facile strategy was developed for the one-step synthesis of S-GQDs with a monolayer-graphene crystal structure. The change of surface chemistry by S-doping resulted in selective and sensitive detection of Pb2+.

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Solid-state quantum emitters play a critical role in the application of quantum information technology. Quantum emitters with high brightness at room temperature can be realized in hBN, and it has become a current research hotspot. However, much of the research up to now only produced quantum emitters at the edges and wrinkles of hBN, which tremendously limited the usage of the quantum emitters. In this work, heavy ions irradiation methods were employed to produce highquality quantum emitters in the middle region of the hBN sample. The quantum emitter production engineering via heavy ions irradiation was systematically investigated. The dependence of irradiated ion type, energy, and fluence, as well as the thickness of the hBN flakes, on the production efficiency of the hBN quantum emitters were analyzed in detail. The characteristics of luminescence of quantum emitters, such as second-order correlation function g (2) (τ), stability, polarization, and saturation, were all compared with different irradiation conditions. In addition, based on the wavelength statistical results of quantum emitters in hBN, the transition energies of various intrinsic point defects in hBN were studied through first-principles calculations to reveal the originations of luminescence. The calculation results indicated that the V N , V B , and B i point defects were possible candidates of the quantum emitter centers. Overall, in this study, according to experimental characterizations, heavy ion irradiation should be an efficient method to produce stable, ultrabright, highly linearly polarized quantum emitters in hBN flakes.