Narrow GREE-Emitting Phosphors
The invention can be used as narrow band green emitting phosphor. Thereported composition can be synthesized via a two-step solid state reaction under normalatmospheric pressure with the second step in a weak reducing condition. The presence of therare-earth ions in the compound allow the material to absorb light in the ultraviolet (UV) to theblue region (≈300 nm to 450 nm) and re-emit the absorbed light. In one example, a bright greenemission in the region (≈492 nm to ≈577nm) of the electromagnetic spectrum . Benefitting from a highly rigid framework structure possesses high photoluminescent quantum yield (PLQY) of 87% and 58% under 400 nmand 450 nm excitation, respectively. This makes the phosphor useful for application in near-UV(∼400 nm) or blue (∼450 nm) LED packages. More importantly, the full width at half maximum(FWHM) of the emission peak is about 64 nm, which is comparable to other commercial narrowgreen emitting phosphor, has an FWHM of 55 nm. Besides narrow emission, the emission of the proposed compound is of excellent thermal stability up to 600 K and a fastemission lifetime. Combining the green source, as theblue source, and K2SiF6: Mn4+ as the red source, generates a wide color gamut covers over 75%National Television System Committee standard (NTSC) in Commission Internationale deL'Eclairage (CIE) 1931 color space. Its highly efficient, narrow green emitting as well as outstanding thermal stability suggests the systemhas greatpotential for industrial applications, such as backlight displaying or general white lighting.
Assistant Professor, Department of Chemistry