Light Extraction of Organic Light Emitting Diodes by Defective Hexagonal‐Close‐Packed Array

Defective silica sphere arrays having locally hexagonal-closed-packed structure but lack of long range ordering were incorporated into organic light emitting diodes as grating to extract the waveguided light trapped in the indium tin oxide/organic layers and the glass substrate. Using these defective hexagonal-closed-packed gratings for light extraction, broad band lambertian emitters are obtained due to the periodicity broadening and the random orientation in the gratings, resulting in enhancements in current and power efficiencies by a factor of 1.7 and 1.9, respectively.

[1]  Ronald A. Arif,et al.  Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using Si O 2 /polystyrene microlens arrays , 2007 .

[2]  Soon Moon Jeong,et al.  Light extraction from organic light-emitting diodes enhanced by spontaneously formed buckles , 2010 .

[3]  D. Choi,et al.  Corrugated organic light emitting diodes for enhanced light extraction , 2010 .

[4]  Choon‐Gi Choi,et al.  Two‐Dimensional TiO2 Inverse Opal with a Closed Top Surface Structure for Enhanced Light Extraction from Polymer Light‐Emitting Diodes , 2011, Advanced materials.

[5]  Yik-Khoon Ee,et al.  Investigation of the deposition of microsphere monolayers for fabrication of microlens arrays. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[6]  Soon Moon Jeong,et al.  Enhancement of Light Extraction from Organic Light-Emitting Diodes with Two-Dimensional Hexagonally Nanoimprinted Periodic Structures Using Sequential Surface Relief Grating , 2008 .

[7]  Soon Moon Jeong,et al.  Enhancement of normally directed light outcoupling from organic light-emitting diodes using nanoimprinted low-refractive-index layer , 2008 .

[8]  Ifor D. W. Samuel,et al.  Increased Efficiency and Controlled Light Output from a Microstructured Light-Emitting Diode , 2001 .

[9]  Wolfgang Brütting,et al.  Determination of molecular dipole orientation in doped fluorescent organic thin films by photoluminescence measurements , 2010 .

[10]  Stephen R. Forrest,et al.  Enhanced light out-coupling of organic light-emitting devices using embedded low-index grids , 2008 .

[11]  T. Asano,et al.  Optical and Electrical Characteristics of Organic Light-Emitting Diodes with Two-Dimensional Photonic Crystals in Organic/Electrode Layers , 2005 .

[12]  Controlling bucking structure by UV/ozone treatment for light extraction from organic light emitting diodes , 2011 .

[13]  T. Asano,et al.  Organic light-emitting diodes with photonic crystals on glass substrate fabricated by nanoimprint lithography , 2007 .

[14]  Yik-Khoon Ee,et al.  Light Extraction Efficiency and Radiation Patterns of III-Nitride Light-Emitting Diodes With Colloidal Microlens Arrays With Various Aspect Ratios , 2011, IEEE Photonics Journal.

[15]  O. Park,et al.  Control of emission outcoupling in liquid-crystalline fluorescent polymer films , 2007 .

[16]  Masayuki Fujita,et al.  Reduction of operating voltage in organic light-emitting diode by corrugated photonic crystal structure , 2004 .

[17]  Soon Moon Jeong,et al.  Simultaneous Extraction of Indium Tin Oxide/Organic and Substrate Waveguide Modes from Buckled Organic Light Emitting Diodes , 2011 .

[18]  Soon Moon Jeong,et al.  Polarization conversion in surface-plasmon-coupled emission from organic light-emitting diodes using spontaneously formed buckles. , 2011, Advanced materials.

[19]  Michael D. McGehee,et al.  A theoretical and experimental investigation of light extraction from polymer light-emitting diodes , 2005 .

[20]  Peter A. Hobson,et al.  The role of surface plasmons in organic light-emitting diodes , 2002 .

[21]  Shanhui Fan,et al.  Extracting Light from Polymer Light‐Emitting Diodes Using Stamped Bragg Gratings , 2004 .

[22]  Dae-Geun Choi,et al.  Ultraviolet nanoimprinted polymer nanostructure for organic light emitting diode application , 2008 .