| 학회 |
한국재료학회 |
| 학술대회 |
2015년 봄 (05/14 ~ 05/15, 구미코) |
| 권호 |
21권 1호 |
| 발표분야 |
F. 광기능/디스플레이 재료 |
| 제목 |
Effect of Alkali Metal Oxides on Reliability of Phosphor in Glass Encapsulants for White LEDs |
| 초록 |
Reliability issues in solid state lighting devices based on light emitting diodes (LED) is of chief concern as it is a limiting factor to promote these optoelectronic devices for general lighting purposes. Although numerous studies have focused on improving the reliability of high power LED, the mechanisms of degradation and the limitations of packages are not well understood. In this study we have explored the effect of alkali metal oxides i.e. Li2O, Na2O, K2O on reliability/degradation of phosphor in glass (PIG) encapsulants for white LEDs. Glass composition: SiO2-B2O3-ZnO with different alkali oxides and mixed with phosphor was sintered to get PIG. These PIG plates were exposed to extreme conditions like thermal aging at 350oC and 85oC/85RH environment for various holding times. Transmittance loss, luminous loss, and shift in CIE coordinates of PIGs were measured after the subject conditions. Surface features were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. It is found that PIG containing lithium is more stable than others because of the strong L-O bond. PIG with potassium is degraded more under 85oC/85RH than any other. Alkali metals with small ionic radii have better chemical durability. |
| 저자 |
Fauzia Iqbal, Sunil Kim, Hoyong Yie, Hyungsun Kim
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| 소속 |
Inha Univ. |
| 키워드 |
Reliability; 85<SUP>o</SUP>C/85RH; Optical degradation; Thermal aging
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| E-Mail |
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