Transparent Conductive Electrodes Based on Graphene-Related Materials

Transparent conducting electrodes (TCEs) are the most important key component in photovoltaic and display technology. In particular, graphene has been considered as a viable substitute for indium tin oxide (ITO) due to its optical transparency, excellent electrical conductivity, and chemical stability. The outstanding mechanical strength of graphene also provides an opportunity to apply it as a flexible electrode in wearable electronic devices. At the early stage of the development, TCE films that were produced only with graphene or graphene oxide (GO) were mainly reported. However, since then, the hybrid structure of graphene or GO mixed with other TCE materials has been investigated to further improve TCE performance by complementing the shortcomings of each material. This review provides a summary of the fabrication technology and the performance of various TCE films prepared with graphene-related materials, including graphene that is grown by chemical vapor deposition (CVD) and GO or reduced GO (rGO) dispersed solution and their composite with other TCE materials, such as carbon nanotubes, metal nanowires, and other conductive organic/inorganic material. Finally, several representative applications of the graphene-based TCE films are introduced, including solar cells, organic light-emitting diodes (OLEDs), and electrochromic devices.

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Foldable and washable textile-based OLEDs with a multi-functional near-room-temperature encapsulation layer for smart e-textiles

npj Flexible Electronics ◽

10.1038/s41528-021-00112-0 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

So Yeong Jeong ◽

Hye Rin Shim ◽

Yunha Na ◽

Ki Suk Kang ◽

Yongmin Jeon ◽

...

Keyword(s):

Room Temperature ◽

Wearable Electronics ◽

Ambient Conditions ◽

Light Emitting ◽

Stable Operating ◽

Mechanical Durability ◽

Potential Applications ◽

Wearable Electronic ◽

Data Signal ◽

Wearable Electronic Devices

AbstractWearable electronic devices are being developed because of their wide potential applications and user convenience. Among them, wearable organic light emitting diodes (OLEDs) play an important role in visualizing the data signal processed in wearable electronics to humans. In this study, textile-based OLEDs were fabricated and their practical utility was demonstrated. The textile-based OLEDs exhibited a stable operating lifetime under ambient conditions, enough mechanical durability to endure the deformation by the movement of humans, and washability for maintaining its optoelectronic properties even in water condition such as rain, sweat, or washing. In this study, the main technology used to realize this textile-based OLED was multi-functional near-room-temperature encapsulation. The outstanding impermeability of TiO2 film deposited at near-room-temperature was demonstrated. The internal residual stress in the encapsulation layer was controlled, and the device was capped by highly cross-linked hydrophobic polymer film, providing a highly impermeable, mechanically flexible, and waterproof encapsulation.

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Polycarbazole and Its Derivatives: Synthesis and Applications. A Review of the Last 10 Years

Polymers ◽

10.3390/polym12102227 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2227

Author(s):

Fadila Bekkar ◽

Faiza Bettahar ◽

Isabel Moreno ◽

Rachid Meghabar ◽

Mohammed Hamadouche ◽

...

Keyword(s):

Driving Force ◽

Conductive Polymers ◽

Electrochemical Polymerization ◽

Electronic Devices ◽

Light Emitting ◽

Wearable Electronic ◽

Synthetic Routes ◽

Increasing Demand ◽

Synthetic Methodologies ◽

Wearable Electronic Devices

Polycarbazole and its derivatives have been extensively used for the last three decades, although the interest in these materials briefly decreased. However, the increasing demand for conductive polymers for several applications such as light emitting diodes (OLEDs), capacitators or memory devices, among others, has renewed the interest in carbazole-based materials. In this review, the synthetic routes used for the development of carbazole-based polymers have been summarized, reviewing the main synthetic methodologies, namely chemical and electrochemical polymerization. In addition, the applications reported in the last decade for carbazole derivatives are analysed. The emergence of flexible and wearable electronic devices as a part of the internet of the things could be an important driving force to renew the interest on carbazole-based materials, being conductive polymers capable to respond adequately to requirement of these devices.

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Fabrication of Organic Light-Emitting Devices with Indium–Tin-Oxide Anode Prepared by Spray Chemical Vapor Deposition

Japanese Journal of Applied Physics ◽

10.1143/jjap.46.6837 ◽

2007 ◽

Vol 46 (10A) ◽

pp. 6837-6841 ◽

Cited By ~ 3

Author(s):

Shigeyuki Seki ◽

Makoto Wakana ◽

Yoshihiro Kasahara ◽

Yoshiyuki Seki ◽

Takeshi Kondo ◽

...

Keyword(s):

Chemical Vapor Deposition ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Vapor Deposition ◽

Chemical Vapor ◽

Light Emitting ◽

Light Emitting Devices ◽

Organic Light ◽

Organic Light Emitting Devices ◽

Oxide Anode

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GRAPHENE-BASED TRANSPARENT CONDUCTIVE FILMS

NANO ◽

10.1142/s1793292013300016 ◽

2013 ◽

Vol 08 (03) ◽

pp. 1330001 ◽

Cited By ~ 42

Author(s):

YOUNGBIN LEE ◽

JONG-HYUN AHN

Keyword(s):

Indium Tin Oxide ◽

Optoelectronic Devices ◽

Optical Transmittance ◽

Organic Light Emitting Diodes ◽

Promising Alternative ◽

Light Emitting ◽

Production Methods ◽

Conductive Films ◽

Organic Light ◽

Transparent Conducting Electrodes

Graphene is a promising alternative to indium tin oxide for use in transparent conducting electrodes. We review recent progress in production methods of graphene and its applications in optoelectronic devices such as touch panel screens, organic photovoltaic cells, organic light emitting diodes and thin film transistors. In addition, we discuss important criteria such as optical transmittance, electrical conductivity and work function, which are critical considerations in the integration of graphene conductive films with optoelectronic devices.

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Graphene transparent electrodes grown by rapid chemical vapor deposition with ultrathin indium tin oxide contact layers for GaN light emitting diodes

Applied Physics Letters ◽

10.1063/1.4802798 ◽

2013 ◽

Vol 102 (16) ◽

pp. 162102 ◽

Cited By ~ 34

Author(s):

Xu Kun ◽

Xu Chen ◽

Deng Jun ◽

Zhu Yanxu ◽

Guo Weiling ◽

...

Keyword(s):

Chemical Vapor Deposition ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Vapor Deposition ◽

Light Emitting Diodes ◽

Chemical Vapor ◽

Transparent Electrodes ◽

Light Emitting

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Synthesis of Graphene Films by Chemical Vapor Deposition for Transparent Conducting Electrodes of GaN Light-Emitting Diodes

10.1063/1.3666613 ◽

2011 ◽

Author(s):

Gunho Jo ◽

Minhyeok Choe ◽

Chu-Young Cho ◽

Jin Ho Kim ◽

Woojin Park ◽

...

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Light Emitting Diodes ◽

Chemical Vapor ◽

Light Emitting ◽

Graphene Films ◽

Transparent Conducting ◽

Transparent Conducting Electrodes

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Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes

MRS Proceedings ◽

10.1557/proc-660-jj6.9 ◽

2000 ◽

Vol 660 ◽

Author(s):

Thomas M. Brown ◽

Ian S. Millard ◽

David J. Lacey ◽

Jeremy H. Burroughes ◽

Richard H. Friend ◽

...

Keyword(s):

Indium Tin Oxide ◽

Light Emitting Diodes ◽

Basic Structure ◽

Thin Layers ◽

Carrier Injection ◽

Semiconducting Polymer ◽

Light Emitting ◽

Physical Mechanisms ◽

Organic Solid ◽

Polymer Light Emitting Diodes

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.

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Controlled Injection of Holes into ALQ3 Based Oleds by Means of An Oxidized Transport Layer

MRS Proceedings ◽

10.1557/proc-708-bb3.27 ◽

2001 ◽

Vol 708 ◽

Author(s):

Mathew K. Mathai ◽

Keith A. Higginson ◽

Bing R. Hsieh ◽

Fotios Papadimitrakopoulos

Keyword(s):

Indium Tin Oxide ◽

Oxidative Degradation ◽

Transport Layer ◽

Hole Injection ◽

Carrier Injection ◽

Salt Loading ◽

Light Emitting ◽

Hole Transporting ◽

Intrinsic Degradation ◽

Variable Conductivity

ABSTRACTIn this paper we report a method for tuning the extent of hole injection into the active light emitting tris- (8-hydroxyquinoline) aluminum (Alq3) layer in organic light emitting diodes (OLEDs). This is made possible by modifying the indium tin oxide (ITO) anode with an oxidized transport layer (OTL) comprising a hole transporting polycarbonate of N,N'-bis(3-hydroxymethyl)-N,N'-bis(phenyl) benzidine and diethylene glycol (PC-TPB-DEG) doped with varying concentrations of antimonium hexafluoride salt of N,N,N',N'-tetra-p-tolyl-4,4'-biphenyldiamine (TMTPD+ SbF6-). The conductivity of the OTL can be changed over three orders of magnitude depending on salt loading. The analysis of hole and electron current variations in these devices indicates that optimizing the conductivity of the OTL enables the modulation of hole injection into the Alq3 layer. The bipolar charge transport properties for OLEDs in which the interfacial carrier injection barriers have been minimized, are governed by the conductivities of the respective layers and in this case it is shown that the variable conductivity of the OTL does allow for better control of the same. Accordingly, varying the concentration of holes in the device indicates that beyond an optimum concentration of holes, further hole injection results in the formation of light quenching cationic species and the initiation of oxidative degradation processes in the Alq3 layer, thus accelerating the intrinsic degradation of these devices. The variable conductivity of the OTL can hence be used to minimize the occurrence of these processes.

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