“…Phosphors appropriate for practical applications require not only excellent emission capability but also the ability to maintain favorable luminous color at high temperatures. Color purity is the key factor in evaluating phosphor and can be calculated using the following equation: 43
where ( x , y ), ( x i , y i ), and ( x d , y d ) are the CIE coordinates for the phosphor measured at T K, the standard white light, and the dominant wavelength, respectively. The trends in color purity at different temperatures for CI 1− x P:0.05Eu 3+ , CI 1− y P:0.04Sm 3+ , and CI 1− x − y P:0.05Eu 3+ ,0.04Sm 3+ are depicted in Fig.…”