A nitriding garnet structure cyan emitting phosphor Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 with high efficiency and excellent thermal stability

Abstract

Cyan phosphors with high efficiency and excellent thermal stability are an important part for application in full spectrum illumination. Herein, a series of nitriding cyan emission phosphors Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 with garnet structure are successfully synthesized, their phase purity, crystal structure, morphology, elemental composition and valence state are analyzed in detail, and the results indicate that a small amount of Si3N4 doping does not cause impurity phase. The phosphor has an efficient broadband cyan emission at 493 nm with full width at half maximum (FWHM) of about 95 nm under 411 nm excitation. Impressively, the luminous intensity of the nitriding phosphor is increased by 30%, the internal/external quantum efficiency are increased from 41.63% and 40.01% to 61.93% and 52.13%, and the thermal stability is improved from 75%@150 oC to 85%@150 oC, which is even better than the commercial green phosphor LMS520B (77%@150 oC). Finally, a full-visible-spectrum LED with low correlated color temperature (CCT = 5143 K) and high color rendering index (Ra = 98.3) is fabricated by employing Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 phosphors as cyan emitting component. The results indicate that the nitriding Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 phosphors have potential to act as cyan emission phosphors for full-visible-spectrum LEDs.