Fabrication and Characterization of White Light Emission Organic Light-emitting Devices PDF Download
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Author: Han-Jen Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 248
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Book Description
"Organic light emitting devices (OLED) based on small molecule materials capable of white light emission have been fabricated and electrical and optical performance of devices was characterized. The fabricated OLEDs utilize one hole transport material, N, N'-diphenyl-N, N'-bis(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine [TPD], and three light emitting materials including 4, 4'-bis(2, 2'-diphenylvinyl)-1, 1'-biphenyl [DPVBi], Tris-(1-phenylisoquinolinato-N) iridium (III) [Ir(piq)3], and tris-(8-hydroxyquinoline) aluminium [Alq3] to achieve the color blending close to the white light. The overall OLED configuration is in a multi-layer stacking structure. A total of 6 different OLED layer thickness configurations were implemented to investigate the effect of the layer thickness parameters. In one particular configuration, the CIE color coordinates range from (0.357,0.358) at 140.4 cd/m2 to (0.303,0.360) at 1321.7 cd/m2, which indicates adequate color stability in the medium to high luminance range. The luminance value of 1321.7 cd/m2 at the current density of 64.9 mA/cm2 and the operating voltage of 14 V indicates that the device is capable of producing a relatively high level of brightness while operating at relatively low operating voltage and low driving current density." --
Author: Han-Jen Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 248
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Book Description
"Organic light emitting devices (OLED) based on small molecule materials capable of white light emission have been fabricated and electrical and optical performance of devices was characterized. The fabricated OLEDs utilize one hole transport material, N, N'-diphenyl-N, N'-bis(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine [TPD], and three light emitting materials including 4, 4'-bis(2, 2'-diphenylvinyl)-1, 1'-biphenyl [DPVBi], Tris-(1-phenylisoquinolinato-N) iridium (III) [Ir(piq)3], and tris-(8-hydroxyquinoline) aluminium [Alq3] to achieve the color blending close to the white light. The overall OLED configuration is in a multi-layer stacking structure. A total of 6 different OLED layer thickness configurations were implemented to investigate the effect of the layer thickness parameters. In one particular configuration, the CIE color coordinates range from (0.357,0.358) at 140.4 cd/m2 to (0.303,0.360) at 1321.7 cd/m2, which indicates adequate color stability in the medium to high luminance range. The luminance value of 1321.7 cd/m2 at the current density of 64.9 mA/cm2 and the operating voltage of 14 V indicates that the device is capable of producing a relatively high level of brightness while operating at relatively low operating voltage and low driving current density." --
Author: Chi-Hang Cheung
Publisher: Open Dissertation Press
ISBN: 9781361117675
Category : Science
Languages : en
Pages : 124
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Book Description
This dissertation, "Fabrication and Characterization of Microcavity Organic Light Emitting Diodes" by Chi-hang, Cheung, 張智恆, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled FABRICATION AND CHARACTERIZATION OF MICROCAVITY ORGANIC LIGHT EMITTING DIODES Submitted by Cheung Chi Hang for the degree of Master of Philosophy at The University of Hong Kong in December 2005 In recent years, great attention has been devoted to the research in organic light emitting diodes (OLEDs). The main motivation has been the low manufacturing cost of displays on flexible and large area substrates. One significant limitation of OLEDs is the poor color purity, as organic emissive materials usually exhibit broad emission. As a result, microcavity structure can be used to act as a color filter to improve the color purity. In this work, fabrication and detailed characterization of OLEDs and microcavity organic light emitting diodes (MOLEDs) for different organic layer thickness was performed. Layer thickness significantly affects the emission behavior of OLEDs and MOLEDs. In addition to the organic layer thickness, the position of the emission region, i.e. interface between the hole transport and emissive layer, also affects the emission spectra. The device studied consisted of N, N'-di(naphthalene-1-yl)-N, N'-diphenyl -benzidine (NPB) as the hole transport layer and tris(8-hydroxyquinoline) aluminum (Alq ) as the emissive layer. Silver was used as the cathode, while for anode indium tin 3oxide (ITO) coated glass was used for OLEDs, and metal (Cu, Ag, Au) coated quartz was used for MOLEDs. The OLEDs were characterized by electroluminescence and photoluminescence measurements, while MOLEDs were characterized by electroluminescence, photoluminescence, reflection, and transmission measurements. Time resolved photoluminescence was also performed, and microcavities consisting of only Alq were also characterized to eliminate the effects of NPB emission. It was found that organic layer thickness and interface position significantly affected the emission spectra of both OLEDs and MOLEDs, as expected. However, both types of devices exhibited unexpected behaviors, such as multiple peak emissions and unusual angular dependencies. For OLEDs, up to three emission peaks were resolved for certain thicknesses, and the emission spectra changed significantly with the change of observation angle. For example, device with 65 nm NPB and 153 nm Alq exhibited blueish white emission with CIE coordinates of (0.32, 0.43) at normal incidence, which changed to yellowish white emission with increasing observation angle. For MOLEDs, detailed investigation of the effects of layer thickness interface position, and bottom mirror type (Ag, Au, and Cu with different thickness) was performed. It was found that for several layer thickness combinations, angular emission dependences different from the usual blue shifting with increasing observation angle can be obtained. In some cases, such as MOLEDs with 53 nm NPB, 125 nm Alq, and 25 nm Cu bottom mirror, reduced angular dependence of the emission can be achieved. This device shows dominant yellow and weak near infrared emission peaks, which result in a small change of CIE coordinates with increasing observation angle. In addition, near-infrared emission was achieved from an Alq based microcavity which is very unusual for a green emitting material. MOLEDs with 47 nm NPB, 111 nm Alq, and 80 nm Ag bottom mirror showed strong near-infrared emission ( 750 nm)
Author: Jai Singh
Publisher: BoD – Books on Demand
ISBN: 9535108506
Category : Technology & Engineering
Languages : en
Pages : 246
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Book Description
This book describes the state-of-the-art advancement in the field of organic electroluminescence contributed by many researchers with internationally established expertise in the field. It includes original contributions on the synthesis of suitable organic materials, fabrication of organic light emitting devices (OLEDs) and organic white light emitting devices (WOLEDs), characterization of these devices and some designs for optimal performance. All chapters are self-sufficient in presenting their contents. The cost effective chemical technology offers many exciting possibilities for OLEDs and organic solar cells (OSCs) to be futuristic solutions for lighting and power generation. A common flexible substrate can be used to fabricate OLEDs on one side facing a room and OSCs on the other side facing the sun. The device thus fabricated can generate power in the day time and light a room/house at night. The book covers developments on OLEDs, WOLEDs and briefly on OSCs as well.
Author: Manish Kumar
Publisher: Springer
ISBN: 9789819767434
Category : Science
Languages : en
Pages : 0
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Book Description
This book explores the secrets of white light-emitting materials, shedding light on their fundamental characteristics, fabrication techniques, and potential applications. The book begins by providing an overview of white light emission and its significance in contemporary technology. It then delves into the various types of white light-emitting materials, including phosphors, quantum dots, and organic compounds. The unique properties and mechanisms that enable these materials to emit white light are elucidated, with a focus on the role of energy transfer processes and bandgap engineering. The fabrication methods employed to synthesize white light-emitting materials are discussed, encompassing techniques such as chemical vapor deposition and solution-based methods are presented. The advantages and limitations of each approach are highlighted, along with recent advancements and future prospects. The book also includes the characterization techniques used to assess the optical properties, color rendering indices, and stability of white light-emitting materials, followed by spectroscopic analysis, luminescence measurements, and thermal stability assessments, providing insights into the performance and reliability of these materials. The potential applications of white light-emitting materials are also examined, encompassing fields such as solid-state lighting, displays, and optoelectronic devices. The benefits offered by these materials, such as high color quality, energy efficiency, and tunable emission spectra, are discussed in detail. In conclusion, this book provides a comprehensive overview of white light-emitting materials, offering insights into their fundamental properties, fabrication techniques, and potential applications. The findings presented here contribute to the understanding of these materials and pave the way for future advancements in the field of lighting and display technologies.
Author:
Publisher:
ISBN:
Category : Optoelectronic devices
Languages : en
Pages : 818
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Book Description
Author: Inamuddin
Publisher: John Wiley & Sons
ISBN: 1119654653
Category : Technology & Engineering
Languages : en
Pages : 288
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Book Description
Polymers for Light-Emitting Devices and Displays provides an in-depth overview of fabrication methods and unique properties of polymeric semiconductors, and their potential applications for LEDs including organic electronics, displays, and optoelectronics. Some of the chapter subjects include: • The newest polymeric materials and processes beyond the classical structure of PLED • Conjugated polymers and their application in the light-emitting diodes (OLEDs & PLEDs) as optoelectronic devices. • The novel work carried out on electrospun nanofibers used for LEDs. • The roles of diversified architectures, layers, components, and their structural modifications in determining efficiencies and parameters of PLEDs as high-performance devices. • Polymer liquid crystal devices (PLCs), their synthesis, and applications in various liquid crystal devices (LCs) and displays. • Reviews the state-of-art of materials and technologies to manufacture hybrid white light-emitting diodes based on inorganic light sources and organic wavelength converters.
Author: Inamuddin
Publisher: John Wiley & Sons
ISBN: 1119654602
Category : Technology & Engineering
Languages : en
Pages : 288
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Book Description
Polymers for Light-Emitting Devices and Displays provides an in-depth overview of fabrication methods and unique properties of polymeric semiconductors, and their potential applications for LEDs including organic electronics, displays, and optoelectronics. Some of the chapter subjects include: • The newest polymeric materials and processes beyond the classical structure of PLED • Conjugated polymers and their application in the light-emitting diodes (OLEDs & PLEDs) as optoelectronic devices. • The novel work carried out on electrospun nanofibers used for LEDs. • The roles of diversified architectures, layers, components, and their structural modifications in determining efficiencies and parameters of PLEDs as high-performance devices. • Polymer liquid crystal devices (PLCs), their synthesis, and applications in various liquid crystal devices (LCs) and displays. • Reviews the state-of-art of materials and technologies to manufacture hybrid white light-emitting diodes based on inorganic light sources and organic wavelength converters.
Author: Laxman Singh
Publisher: CRC Press
ISBN: 1000953033
Category : Science
Languages : en
Pages : 292
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Book Description
The book Organic Light Emitting Diode (OLED) Toward Smart Lighting and Displays Technologies, edited by Laxman Singh, Rituraj Dubey, and Prof. R. N. Rai, strives to address the multiple aspects of OLEDs and their applications in developing smart lightings and displays. OLEDs have been used in almost all kinds of digital displays like those of mobile phones, laptops, tablets, phablets, TVs, etc., due to their outstanding features, including superior color quality, low cost, wide viewing angle, easy fabrication, mercury-free manufacture, tenability, stretchability, flexibility, etc. Investigations related to the synthesis of new organic materials and fabrication techniques have inspired us to write this book, which will fulfil the desire and thirst of OLEDs-based researchers. Features • Nanolithographic techniques used and the challenges involved. • Printing technology for fabrication. • Designing of hybrid perovskites. • Stretchable and flexible materials used. • Metal–dielectric composites and efficiency of organic semiconductor via molecular doping for OLEDs applications. • Organic small molecule materials and display technologies involved. • New generation of organic materials with respect to photophysical approach. • Mixed valence π-conjugated coordination polymers used. • Electroluminescent polymer used. • Blue fluorescent and phosphorescent organic materials used. In comparison to other books available related to similar topics, this book aims at those audiences who are looking for a single source for a comprehensive understanding of strategies and their challenges with respect to material fabrication of OLEDs. This book covers the pace and productivity at a uniform level in each chapter with respect to the audiences, from doctoral student to postdoctoral researchers or from postdoctoral researchers to multidisciplinary field researchers with a background in physics, chemistry, materials science, and engineering, who are already working with organic materials and their applications.
Author:
Publisher:
ISBN:
Category : Electroluminescent devices
Languages : en
Pages : 386
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Book Description
Author: T.D. Subash
Publisher: CRC Press
ISBN: 1000889831
Category : Science
Languages : en
Pages : 222
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Book Description
This book covers a comprehensive range of topics on the physical mechanisms of LEDs (light emitting diodes), scattering effects, challenges in fabrication and efficient enhancement techniques in organic and inorganic LEDs. It deals with various reliability issues in organic/inorganic LEDs like trapping and scattering effects, packaging failures, efficiency droops, irradiation effects, thermal degradation mechanisms, and thermal degradation processes. Features: Provides insights into the improvement of performance and reliability of LEDs Highlights the optical power improvement mechanisms in LEDs Covers the challenges in fabrication and packaging of LEDs Discusses pertinent failures and degradation mechanisms Includes droop minimization techniques This book is aimed at researchers and graduate students in LEDs, illumination engineering, optoelectronics, and polymer/organic materials.
