scholarly journals Holographic Fabrication and Optical Property of Graded Photonic Super-Crystals with a Rectangular Unit Super-Cell

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 34 ◽  
Author(s):  
Safaa Hassan ◽  
Oliver Sale ◽  
David Lowell ◽  
Noah Hurley ◽  
Yuankun Lin
Keyword(s):  
Extraction Efficiency ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Interference Lithography ◽  
Light Modulator ◽  
Light Emitting ◽  
Polarization Effects ◽  
Organic Light ◽  
Super Cell ◽  
Phase Engineering

Recently developed graded photonic super-crystals show an enhanced light absorption and light extraction efficiency if they are integrated with a solar cell and an organic light emitting device, respectively. In this paper, we present the holographic fabrication of a graded photonic super-crystal with a rectangular unit super-cell. The spatial light modulator-based pixel-by-pixel phase engineering of the incident laser beam provides a high resolution phase pattern for interference lithography. This also provides a flexible design for the graded photonic super-crystals with a different ratio of length over the width of the rectangular unit super-cell. The light extraction efficiency is simulated for the organic light emitting device, where the cathode is patterned with the graded photonic super-crystal. The high extraction efficiency is maintained for different exposure thresholds during the interference lithography. The desired polarization effects are observed for certain exposure thresholds. The extraction efficiency reaches as high as 75% in the glass substrate.

scholarly journals The Effect of Anisotropy on Light Extraction of Organic Light-Emitting Diodes with Photonic Crystal Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Xu ◽  
Yang Li
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Organic Light Emitting Diodes ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Organic Light ◽  
Triangle Lattice

The light extraction efficiency of organic light-emitting diodes (OLED) is greatly limited due to the difference in refractive indexes between materials of OLED. We fabricated OLED with photonic crystal microstructures in the interface between the glass substrate and the ITO anode. The light extraction efficiency can be improved by utilizing photonic crystals; however, the anisotropy effect of light extraction was clearly observed in experiment. To optimize the device performance, the effect of photonic crystal on both light extraction and angular distribution was investigated using finite-difference time domain (FDTD) method. We simulated the photonic crystals with the structure of square lattice and triangle lattice. We analyzed the improvement of these structures in the light extraction efficiency of the OLED and the influence of arrangement, depth, period, and diameter on anisotropy. The optimized geometric parameters were provided, which will provide the theoretical support for designing the high performance OLED.

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