LED용 형광체의 표면개질 및 광학적 특성: Optical properties of the yellow phosphors coated with nano-oxides

by Hye-ri Do (MS Candidate)

Monday Nov 12, 2012, 2:00 PM → 2:30 PM Asia/Seoul

216-1호 (제1과학관)

To enhance the eficiency of the yelow phosphors in the LED, which are (Ba,Sr)2SiO4:Eu2+ andY3Al5O12:Ce(YAG), the phosphors with nano-oxides were coated by a modified sol-gel method. 
Comparisons between the pristine phosphors and the nano-oxides coated phosphors were characterized by the SEM, EDX and PL. The SEM images have confirmed a severe change in surface morphologies of the phosphors after coating with nano-particles. From the EDX data, it has beenfound that the nano-particles as seen in the SEM images are composed of nano-oxides and surface coating of phosphors w ith nano-oxides yielded an increase in the PL intensity. 
To estimate the reliability characteristics of phosphors in the white light LED, the white LED light sources with the pristine and the coated phosphors were fabricated and suffered the aging test for over 1,000 hours. In the aging test, the integration emission ratios of the coated phosphor packed LED have reduced less than that of the pristine phosphor packed LED. The experimental result simply that the surface coating of yellow phosphor with nano-oxide can be an efficient way for improving the efficiency and the reliability of the LED phosphors.

Thesis Advisor: Prof. Sang-Ho Sohn