Controlled Alignment of Nanowires for Transparent Conductive Films: Methods and Applications

Background: Nanowires (NWs) have received extensive attention as the candidate materials for transparent conductive films (TCFs) in recent years. To date, the aligned nanowire (NW)-based TCFs with the same arrangement direction have shown superior characteristics to their random counterparts in applications. Objective: To fully develop the potential of NW TCFs in devices and provide inspiration for the development of subsequent NW alignment processes, this review summarizes state-of-the-art alignment techniques and emphasizes their mechanisms in detail from multiple perspectives. Methods: According to the mechanism of NW alignment, this review divides these techniques into seven categories, i.e., the assisted assembly of fluid flow, meniscus, pressure, template, electromagnetic field, contact and strain, and analyzes the characteristics of these techniques. Moreover, by briefly enumerating the applications of aligned NW films in solar cells, organic light-emitting diodes, and touch screens, the superiority of aligned NW films over random NW films is also addressed. Results: Contact-assisted assembly exhibits the best arrangement effect, reaching a 98.6% alignment degree within ±1°. Under the same conditions, shorter NWs show better alignment in several cases. The combination of various assembly techniques is also an effective means to improve the alignment effect. Conclusion: There is still room for improvement in the precise control of NW position, density and orientation in a simple, efficient and compatible process. Therefore, follow-up research work is needed to conquer these problems. Moreover, a process that can realize NW alignment and film patterning simultaneously is also a desirable scheme for fabricating personalized devices.

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Enhanced Electroluminescence of CdSe/ZnS Quantum Dot Light–emitting Diodes with Phosphorescent Donors

MRS Proceedings ◽

10.1557/opl.2011.1401 ◽

2011 ◽

Vol 1348 ◽

Author(s):

Yiqiang Zhang ◽

X. A. Cao

Keyword(s):

Energy Transfer ◽

Light Emitting Diodes ◽

Organic Dyes ◽

Effective Means ◽

Organic Light Emitting Diodes ◽

Exciton Energy ◽

Light Emitting ◽

Precise Control ◽

Organic Light ◽

Good Agreement

ABSTRACTWe demonstrated the enhancement of electroluminescence (EL) from green CdSe/ZnS QDs in hybrid QD/organic light-emitting diodes (QD-LEDs) by employing blue phosphorescent dyes Bis(4,6-difluorophenylpyridinato-N,C2)picolinatoiridium (FIrpic) as efficient exciton harvesters and energy transfer donors. Precise control of the concentration of the FIrpic donors doped in a 4,4’-N, N’-dicarbazole-biphenyl (CBP) host and their distance from the QD layer led to complete triplet exciton energy transfer and EL enhancement by a factor of 2.5. The Förster distance between FIrpic molecules and green CdSe/ZnS QDs was determined to be ∼ 8 nm, which is in a good agreement with the value calculated using the Förster model. Our study shows that integrating colloidal QDs with phosphorescent organic dyes provides an effective means for improving the quantum efficiency of QD-based hybrid LEDs.

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Annealing Effect on Small Molecules Blend Organic Light-Emitting Diodes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.795.110 ◽

2013 ◽

Vol 795 ◽

pp. 110-114 ◽

Cited By ~ 1

Author(s):

Mohd Arif Mohd Sarjidan ◽

Siti Hajar Basri ◽

W.H. Abd Majid

Keyword(s):

Light Emitting Diode ◽

Research Work ◽

Annealing Process ◽

Organic Light Emitting Diodes ◽

Ternary Blend ◽

Light Emitting ◽

Emissive Layer ◽

Organic Light Emitting Diode ◽

Organic Light ◽

Coating Method

This research work investigates the influence of the annealing process upon the performance of photo-emissive layer of organic light-emitting diode (OLED). The photo-emissive layer consists of a ternary blend of N, N-diphenyl-N,N-bis (3-methylphenyl)-(1,1-biphenyl)-4,4-diamine (TPD), 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) and tris-8-hydroxyquinoline (Alq3), to produce TPD:PBD:Alq3 (at 1:1:1 ratio) blend thin films, in which the material solutions are deposited onto clean substrate via spin-coating method. The samples were annealed at 100°C in 10, 20 and 30 minute of time in an open-air condition. The results reveal that the annealing process at 10 minutes produces an optimum performance of the ternary OLED.

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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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Enhanced Performance in Polymer Light Emmiting Diode by Using Ultra-thin Conductive Films as the Buffer Layer

Communications in Physics ◽

10.15625/0868-3166/24/3s1/5071 ◽

2014 ◽

Vol 24 (3S1) ◽

pp. 7-12 ◽

Cited By ~ 1

Author(s):

Nguyen Phuong Hoai Nam

Keyword(s):

Buffer Layer ◽

High Efficiency ◽

Organic Light Emitting Diodes ◽

Buffer Layers ◽

Nanocomposite Films ◽

Light Emitting ◽

Conductive Films ◽

Organic Light ◽

Nano Crystal ◽

Carbon Nano Tube

The ultra-thin nanocomposite films based on the nano-crystal TiO$_{2}$ (TiO$_{2}$-nc) or multi-walled carbon nano-tube (MWCNTs) were prepared and used as the buffer layers in the fabrication of the organic light-emitting diodes (OLEDs). The injection efficiency of the hole and electron was improved by inserting an ultra-thin buffer layer between the electrodes and emissive layer. The turn-on voltage of the device with the buffer layers was lowered from 4 to 2.5V, and the current density was increased from 0.3 to 0.7~mA/mm$^{2}$, in comparison with the device without such a buffer layer. These devices showed a high efficiency and good stability.

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Organic Light Emitting Diodes - Innovative Light Sources

Light & Engineering ◽

10.33383/2018-157 ◽

2019 ◽

pp. 101-107

Author(s):

Sergei A. Stakharny

Keyword(s):

Light Source ◽

Organic Light Emitting Diodes ◽

Organic Leds ◽

Light Sources ◽

High Quality ◽

Light Emitting ◽

Organic Light ◽

Lighting Systems ◽

Physical Principles ◽

Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

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