Coupling Efficiency Enhancement in Organic Light-Emitting Devices Using Microlens Array—Theory and Experiment

Peng, H. Benjamin; Ho, Yu‐Hsuan; Yu, Xiaoming; Wong, Man; Kwok, Hoi‐Sing

doi:10.1109/jdt.2005.858944

“…Various approaches for enhancing the optical outcoupling efficiency of bottom emitting OLEDs have been introduced in the literature. Often, the planar substrate/air interface is modified in order to reduce repeated TIR: by using a microlens array [2][3][4] or a large half sphere lens [5] on the substrate surface. Other outcoupling methods try to extract the light trapped in the organic/ITO layers.…”

Section: Introductionmentioning

confidence: 99%

Exceptionally efficient organic light emitting devices using high refractive index substrates

Mladenovski

¹

,

Neyts

²

,

Pavicic³

et al. 2009

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Organic light emitting devices (OLEDs) are now used in commercial cell phones and flat screen displays, but may become even more successful in lighting applications, in which large area, high efficiency, long lifetime and low cost are essential. Due to the relatively high refractive index of the organic layers, conventional planar bottom emitting OLEDs have a low outcoupling efficiency. Various approaches for enhancing the optical outcoupling efficiency of bottom emitting OLEDs have been introduced in the literature. In this paper we demonstrate a green bottom emitting OLED with a record external quantum efficiency (42%) and luminous efficacy (183 lm/W). This OLED is based on a high index substrate and a thick electron transport layer (ETL) which uses electrical doping. The efficient light outcoupling is modeled by optical simulations. 3779-3781 (2003). 10. Y. Sun, and S. R. Forrest, "Enhanced light out-coupling of organic light-emitting devices using embedded lowindex grids," Nat. Photonics 2(8), 483-487 (2008). 11. T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, "Thin-film waveguiding mode light extraction in organic electroluminescent device using high refractive index substrate," J. Appl. Phys. 97(5), 054505 (2005). 12. ©2009 Optical Society of America

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“…56 Both schemes are breaking total internal refractions, in the high index mode by texturing, or in the glass mode with the microlens array. They can be regular periodic structures 51,[53][54][55][56] or randomly roughened surfaces. 52 In periodic structures, light is extracted in the surface plasmon mode or by refracting the ray as classical optics depending on the size, periodicity, and refractive index of the textured surface.…”

Section: Enhanced Light Outcoupling In Light Emitting Devicesmentioning

confidence: 99%

Photonic crystal: energy-related applications

Ye¹,

Joong-Mok²,

Constant³

et al. 2012

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We review recent work on photonic-crystal fabrication using soft-lithography techniques. We consider applications of the resulting structures in energy-related areas such as lighting and solar-energy harvesting. In general, our aim is to introduce the reader to the concepts of photonic crystals, describe their history, development, and fabrication techniques and discuss a selection of energy-related applications. Abstract. We review recent work on photonic-crystal fabrication using soft-lithography techniques. We consider applications of the resulting structures in energy-related areas such as lighting and solar-energy harvesting. In general, our aim is to introduce the reader to the concepts of photonic crystals, describe their history, development, and fabrication techniques and discuss a selection of energy-related applications. Keywords

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“…51 Some of the trapped light is reabsorbed or emitted through edge emission. There have been many efforts to extract the trapped light by texturing the surface on the light emitting side, 52 putting microlens arrays on the other side, 51,[53][54][55] or both. 56 Both schemes are breaking total internal refractions, in the high index mode by texturing, or in the glass mode with the microlens array.…”

Section: Enhanced Light Outcoupling In Light Emitting Devicesmentioning

confidence: 99%

Photonic crystal: energy-related applications

Ye

¹

2012

View full text Add to dashboard Cite

We review recent work on photonic-crystal fabrication using soft-lithography techniques. We consider applications of the resulting structures in energy-related areas such as lighting and solar-energy harvesting. In general, our aim is to introduce the reader to the concepts of photonic crystals, describe their history, development, and fabrication techniques and discuss a selection of energy-related applications. Abstract. We review recent work on photonic-crystal fabrication using soft-lithography techniques. We consider applications of the resulting structures in energy-related areas such as lighting and solar-energy harvesting. In general, our aim is to introduce the reader to the concepts of photonic crystals, describe their history, development, and fabrication techniques and discuss a selection of energy-related applications. Keywords

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Coupling Efficiency Enhancement in Organic Light-Emitting Devices Using Microlens Array—Theory and Experiment

Cited by 110 publications

References 18 publications

Exceptionally efficient organic light emitting devices using high refractive index substrates

Exceptionally efficient organic light emitting devices using high refractive index substrates

Photonic crystal: energy-related applications

Photonic crystal: energy-related applications

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