FDTD Simulation for Extraction Efficiency of Light Emitting Devices
Date Issued
2007
Date
2007
Author(s)
Huang, Yung-Ming
DOI
zh-TW
Abstract
In this thesis, we use three dimensional finite-difference time-domain (FDTD) method to simulate the extraction efficiency of light emitting devices and improve the extraction efficiency by applying photonic crystal structure.
Light wave in light emitting devices, such as organic light-emitting diodes (OLED) or light emitting diodes (LED), is confined when total internal reflection occurs due to difference of refractive index in each layer. We simulate behavior of light in these devices and evaluate the extraction efficiency of each based on FDTD.
The advantages of FDTD are easy derivation and convenience for complex structure design. However, some modification is essential for the metal cathode and inner micro-structures in OLED. We use the Drude model to approximate the light behavior in the metal and evaluate the energy penetrating to air using near-to-far-field transformation and geometric optics. Parallel programming and alternating-direction-implicit difference are also used to improve calculation efficiency since FDTD simulation requires a huge amount of calculation resource.
To enhance the extraction efficiency of OLED, we modify the thickness of layers of OLED and insert the grating structures between the layers. Light is scattered to air due to the grating structure. Finally, we apply photonic crystal structures on LED with different radius-period ratio and thickness. By manipulating the photonic bandgap, light will be coupled to air, resulting in high extraction efficiency.
Subjects
有限時域差分法
有機發光二極體
發光二極體
FDTD
OLED
LED
Type
thesis
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