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In recent years, oxynitride and nitride compounds have attracted much attention as host lattices for phosphors because of their excellent properties, such as non-toxicity, outstanding thermal and chemical stability, broad available range of excitation and emission wavelengths, and high luminescence efficiency upon activation using rare-earth ions.[1–3] For example, bright yellow phosphors comprising Ca-a-SiAlON: Eu2þ and greenemitting phosphors based on b-SiAlON: Eu2þ have been synthesized and used in white light-emitting diode (LED) lamps characterized by high luminous efficiency.[4] However, the production of these materials generally requires high temperatures and pressures.[1–3] In addition, rare-earth ions, such as Eu2þ, Ce3þ, Yb2þ, and Tb3þ, which are required for use as luminescence centers, tend to be very expensive. Therefore, the development of viable methods for the production of oxynitride and nitride phosphor particles without using rare-earth ions at relatively low temperatures under ambient atmospheric pressure is desirable for white LED applications. On the other hand, much effort has been devoted to the preparation of carbon-based boron nitride (BCN) semiconductors for use as phosphors.[5–9] Theoretical studies suggest that it should be possible to use BCN materials to tune the wavelength of emitted light across the visible light spectrum by varying the composition of BCN compounds. BCN compounds are expected to behave as semiconductors with bandgap energies that are tunable by varying the atomic composition, since these materials are thought to be intermediates between graphite and hexagonal-BN …