以二氧化鈦奈米粒子提升白色發光二極體之光取出效率

Enhancement of Light Extraction Efficiency in GaN-Based White Light-Emitting Diodes by using Titanium Dioxide Nano-Particle

吳嘉慶(Chia-Ching Wu)

指導教授 ： 林俊良

崑山科技大學/工程學院/電子工程研究所/碩士(2009年)

摘要

半導體白色發光二極體(LEDs)因具有節能、環保等等諸多優點，被視為是未來固態照明的核心 ; 而提高LED的光取出效率，則被認為是目前的主要關鍵。提高封裝膠體的折射係數，被視為是提高LED光取出效率的有效方法之一。由於二氧化鈦(TiO2)具有較高的折射係數(n=2.8)，因此在本論文中，我們將TiO2奈米粒子摻入封裝LED的矽膠中，提高封裝矽膠的整體平均折射係數，而混合後折射率量測為1.55，以提高LED元件之光取出效率。
輸入電流20 mA，我們發現摻入矽膠之TiO2奈米粒子重量百分比為0.02 wt%時，白色LED之光輸出通量達到3.50流明(lm)、輸出光強度為1780坎德拉(cd)。矽膠未摻雜TiO2之白色LED，其光輸出通量為3.34 lm、輸出光強度為1650 cd。證實了透過在封裝矽膠中摻入合適比例的TiO2奈米粒子，將可使白色LED之光輸出通量與發光強度分別提升4.6%與5.7％。
連續點亮1000小時做壽命測試，我們發現摻雜入矽膠之TiO2奈米粒子與未摻雜，都有相同的電特性。而封裝矽膠中摻入合適比例的TiO2奈米粒子，可提升LED元件壽命。

關鍵字

二氧化太 ； 發光二極體

並列摘要

Semiconductor white light-emitting diodes (LEDs) were regarded as the nucleus of solid-state lighting in the near future, because of energy-saving, environment-friendly and many other advantages; the enhancement in light extraction efficiency of LEDs was considered to be the critical issue at present. Increasing the refractive index of encapsulating gel for package was considered as one of the effective ways to enhance the light extraction efficiency of LEDs. Because the titanium dioxide (TiO2) has high refractive index (n=2.8), therefore, in this thesis, we have doped the TiO2 nano-particles to the silicone of encapsulating gel to increase the overall refractive index of packaging silicone. The refractive index measurement is 1.55, and the light extraction efficiency of LEDs was enhanced.
At 20 mA injection current, the luminous flux and luminous intensity of white LED doped with 0.02 wt% TiO2 nano-particles are 3.5 lumen (lm) and 1.78 candela (cd), respectively. At 20 mA injection current, the luminous flux and luminous intensity of white LED without TiO2 nano-particles dopoing are 3.34 lumen (lm) and 1.65 candela (cd), respectively. Therefore the luminous flux and luminous intensity of white LED were enhanced by 4.6% and 5.7% respectively by doping TiO2 nano-particles in the packaging silicone.
Almost the same electrical characteristics were found for LEDs with/without TiO2 doped in silicone after 1000 hours continued life test.

並列關鍵字

TiO2 ； LED

參考文獻

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