Evaluating the moisture resistance of Y3Al5O12: Ce3+ phosphor used in high power white LED packaging. (June 2021) - Yuan, Weiyi
Abstract: Owing to its low cost and high efficiency, the blue light-emitting diode (LED) chip covered with the Y3 Al5 O12 :Ce 3+ (YAG) phosphor has become a mainstream technology of high power white LED packaging. However, phosphors are often susceptible to degradation under high-temperature and high-humidity conditions, which directly affects the optical and color stability of the white LED package. In this study, the moisture resistance of YAG phosphor was evaluated through both a short-term water-immersion test and long-term aging tests, i.e. 85 °C&85% Relative Humidity (RH) test and high-temperature and saturated humidity test. The phosphor hydrolysis mechanism was then revealed by characterizing the phosphor emission spectrum, photothermal property, crystal structure, micromorphology, and chemical element composition. Highlights: The water-immersion test with in-situ electrical conductivity monitoring is conducted on YAG phosphor. YAG phosphor exhibits stable luminescence performance and crystal structure under long-term aging high moisture aging tests. YAG phosphor particle's surface roughness and self-heating effect are slightly enhanced after aging.