Design of a Bismuth-Activated Narrow-Band Cyan Phosphor for Use in White Light Emitting Diodes and Field Emission Displays

To overcome the problem that Bi3+-activated phosphors suffer from, it is an urgent need to realize narrow-band light emission of Bi3+-activated phosphors, which not only improves their luminescence characteristics, but also increases their competitiveness with rare earth-activated commercial phosphors. In our work, a novel Bi3+-activated narrow-band cyan phosphor has been achieved in a highly condensed and symmetrical crystal structure of Ca3Lu2Ge3O12, and its full width of half-maximum (fwhm) of the emission band reaches 47 nm. The result indicates that Bi3+-activated Ca3Lu2Ge3O12 is comparative to the commercial green phosphor β-sialon: Eu2+ (fwhm ≈ 55 nm), and its strong excitation band locates at 390 nm, implying that Ca3Lu2Ge3O12: Bi3+ can be well excited by near-ultraviolet (NUV) LED chips. Furthermore, Ca3Lu2Ge3O12: Bi3+ possesses promising cathodoluminescence properties accompanied by good antiaging characteristics. The fascinating PL and CL properties of Ca3Lu2Ge3O12: Bi3+ have been proved to relate to their garnet-type structure; thus, the structure–property relations of Bi3+-activated Ca3Lu2Ge3O12 were discussed in detail in this work, which may provide an effective way for exploring better Bi3+-activated phosphors for use in WLEDs and FEDs.