Three-Color Passive-Matrix Pixels Using Dye-Diffusion-Patterned Tri-Layer Polymer-Based LED

2001 ◽  
Vol 708 ◽  
Author(s):  
Ke Long ◽  
Florian Pschenitzka ◽  
J. C. Sturm
Keyword(s):  
Leakage Current ◽  
Light Emission ◽  
Layer Structure ◽  
Single Layer ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Reverse Leakage Current ◽  
Dye Diffusion ◽  
Current Rectification ◽  
Doped Polymer

ABSTRACTDry dye-printing and solvent-enhanced dye diffusion were used to locally dope a previously spin-coated poly(9-vinylcarbazole) (PVK) polymer film with different dyes to fabricate side-by-side RGB OLED pixels. To reduce reverse leakage current and raise efficiency, a blanket tris-8-hydroxyquinoline aluminum (Alq) electron transport layer (ETL) was deposited over the polymer layer after the dye diffusion step, along with a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) hole/exciton blocking layer between the Alq and the PVK to ensure all light emission occurred from the doped polymer and not from the Alq. Devices with this tri-layer structure have an extremely low reverse leakage current (rectification ratio of 106 at +/- 10V) and a higher external quantum efficiency (∼1%) than single layer devices. A three-color passive-matrix test array with 300μm x 1mm RGB subpixels was demonstrated with this structure.

Synthesis and Electroluminescence Study of a Novel Copolymer:Poly(Phenylene Vinylene-Co-Quinoline Vinylene)

1997 ◽  
Vol 488 ◽  
Author(s):  
Ramesh K. Kasim ◽  
Bela Derecskei ◽  
Martin Pomerantz ◽  
Ronald L. Elsenbaumer
Keyword(s):  
Indium Tin Oxide ◽  
High Efficiency ◽  
Light Emission ◽  
Chemical Deposition ◽  
Negative Electrode ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Phenylene Vinylene ◽  
Multilayered Structures ◽  
Emission Efficiency

AbstractHigh-efficiency polymer light-emitting diodes (LEDs) are often fabricated using multilayered structures with separate carrier transport and light emission layers. Recently, we reported on the synthesis and electroluminescence (EL) characteristics of poly(2,6-quinoline vinylene) (PQV) and its potential for use as an electron transport layer in poly(phenylene vinylene) (PPV) LEDs. To take advantage of the high emission efficiency of PPV and electron accepting ability of PQV, a copolymer of PPV and PQV, poly(phenylene vinylene-co-quinoline vinylene) (PPVQV) was synthesized via the precursor polymer route and converted to the conjugated form by thermal elimination. When used as the emissive layer with Indium-Tin Oxide (ITO) and aluminum as positive and negative electrodes respectively, PPVQV emitted blue light at an onset electric field of 1.05x 106 V/cm and emission efficiency of 0.08%. Improved efficiencies of the order of 0.15% were obtained when blends of copolymer with PPV were used in conjunction with PPV in a multi-layered structure. Along with copolymer chemical characterization data, results from EL studies on single and multi-layered devices are discussed. We also report on a simple and costeffective chemical deposition of silver for the negative electrode in polymer LEDs.

scholarly journals Improvement in Device Performance and Reliability of Organic Light-Emitting Diodes through Deposition Rate Control

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Shun-Wei Liu ◽  
Chih-Chien Lee ◽  
Yu-Ting Chung ◽  
Jiun-Haw Lee ◽  
Chin-Ti Chen ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Driving Voltage ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Operating Lifetime

We demonstrated a fabrication technique to reduce the driving voltage, increase the current efficiency, and extend the operating lifetime of an organic light-emitting diode (OLED) by simply controlling the deposition rate of bis(10-hydroxybenzo[h]qinolinato) beryllium (Bebq2) used as the emitting layer and the electron-transport layer. In our optimized device, 55 nm of Bebq2was first deposited at a faster deposition rate of 1.3 nm/s, followed by the deposition of a thin Bebq2(5 nm) layer at a slower rate of 0.03 nm/s. The Bebq2layer with the faster deposition rate exhibited higher photoluminescence efficiency and was suitable for use in light emission. The thin Bebq2layer with the slower deposition rate was used to modify the interface between the Bebq2and cathode and hence improve the injection efficiency and lower the driving voltage. The operating lifetime of such a two-step deposition OLED was 1.92 and 4.6 times longer than that of devices with a single deposition rate, that is, 1.3 and 0.03 nm/s cases, respectively.

scholarly journals Single-Layer ZnO Hollow Hemispheres Enable High-Performance Self-Powered Perovskite Photodetector for Optical Communication

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiyan Pan ◽  
Jianqiang Zhang ◽  
Hai Zhou ◽  
Ronghuan Liu ◽  
Dingjun Wu ◽  
...  
Keyword(s):  
Optical Communication ◽  
High Performance ◽  
Carrier Transport ◽  
Dynamic Range ◽  
Incident Light ◽  
Single Layer ◽  
Transport Layer ◽  
Utilization Efficiency ◽  
Electron Transport Layer ◽  
Self Powered

AbstractThe carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light. Herein, we introduced single-layer hollow ZnO hemisphere arrays (ZHAs) behaving light trapping effect as the electron transport layer in perovskite photodetectors (PDs). The single-layer hollow ZHAs can not only reduce the reflection, but also widen the angle of the effective incident light and especially transfer the distribution of the optical field from the ZnO/FTO interface to the perovskite active layer confirmed by the 3D finite-difference time-domain simulation. These merits benefit for the generation, transport and separation of carriers, improving the light utilization efficiency. Finally, our optimized FTO/ZHA/CsPbBr3/carbon structure PDs showed high self-powered performance with a linear dynamic range of 120.3 dB, a detectivity of 4.2 × 1012 Jones, rise/fall time of 13/28 µs and the f−3 dB of up to 28 kHz. Benefiting from the high device performance, the PD was demonstrated to the application in the directional transmission of encrypted files as the signal receiving port with super high accuracy. This work uniquely utilizes the features of high-performance self-powered perovskite PDs in optical communication, paving the path to wide applications of all-inorganic perovskite PDs.

Multilayer Structures and Emissive Regions in Organic Thin-Film Electroluminescent Diodes

1995 ◽  
Vol 413 ◽  
Author(s):  
E. Aminaka ◽  
T. Tsutsui
Keyword(s):  
Thin Film ◽  
Single Layer ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Organic Thin Film ◽  
Emission Efficiency ◽  
Narrow Region ◽  
Carrier Recombination ◽  
Emissive Region ◽  
High Emission

ABSTRACTThe relationships between emission quantum efficiency and emissive regions in organic thin-film electroluminescent (EL) devices were studied. As an emissive layer (EML) and an electron transport layer (ETL) material, 9, 10-bis(4-diphenylaminostyryl)anthracene and 1,3- bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)phenylene, respectively, were used. A zone doped with 2,4-bis(4-diethylamino-2-hydroxyphenyl)-1,3-dihydroxycycrobutenediylium dihydroxide was formed in an EML. The relationships between the emission intensities from the dopant and the positions of doped zones gave information on the emissive regions in each EL device. The emissive region in the single-layer (SL) device consisting only of an EML extended over the EML. That in the two-layer device (DL-E) in which an EML was combined with an ETL was located within 10 nm-wide region near the EML/ETL boundary. Moreover, the emission efficiency of the DL-E device was found to be about 20 times as high as that of the SL device. Therefore, it was found that the carrier recombination within the narrow region sufficiently apart from electrodes gave high emission efficiency.

Effects of Varying Geometrical Parameters on Boiling From Microfabricated Enhanced Structures

2003 ◽  
Vol 125 (1) ◽  
pp. 103-109 ◽  
Author(s):  
C. Ramaswamy ◽  
Y. Joshi ◽  
W. Nakayama ◽  
W. B. Johnson
Keyword(s):  
Heat Dissipation ◽  
Layer Structure ◽  
Single Layer ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Geometrical Parameters ◽  
Small Range ◽  
Two Phase ◽  
Wall Superheat

The current study involves two-phase cooling from enhanced structures whose dimensions have been changed systematically using microfabrication techniques. The aim is to optimize the dimensions to maximize the heat transfer. The enhanced structure used in this study consists of a stacked network of interconnecting channels making it highly porous. The effect of varying the pore size, pitch and height on the boiling performance was studied, with fluorocarbon FC-72 as the working fluid. While most of the previous studies on the mechanism of enhanced nucleate boiling have focused on a small range of wall superheats (0–4 K), the present study covers a wider range (as high as 30 K). A larger pore and smaller pitch resulted in higher heat dissipation at all heat fluxes. The effect of stacking multiple layers showed a proportional increase in heat dissipation (with additional layers) in a certain range of wall superheat values only. In the wall superheat range 8–13 K, no appreciable difference was observed between a single layer structure and a three layer structure. A fin effect combined with change in the boiling phenomenon within the sub-surface layers is proposed to explain this effect.

Optimized Al-doped TiO2 gate insulator for metal-oxide-semiconductor capacitor on Ge substrate

2021 ◽  
Author(s):  
Dong Gun Kim ◽  
Cheol Hyun An ◽  
Sanghyeon Kim ◽  
Dae Seon Kwon ◽  
Junil Lim ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Leakage Current ◽  
Tio2 Film ◽  
Single Layer ◽  
Atomic Layer ◽  
Metal Oxide Semiconductor ◽  
Gate Insulator ◽  
Oxide Semiconductor ◽  
High K ◽  
Metal Oxide Semiconductor Capacitor

Atomic layer deposited TiO2- and Al2O3-based high-k gate insulator (GI) were examined for the Ge-based metal-oxide-semiconductor capacitor application. The single-layer TiO2 film showed a too high leakage current to be...

scholarly journals Ultrathin and compact electron transport layer made from novel water-dispersed Fe3O4 nanoparticles to accomplish UV-stable perovskite solar cells

2021 ◽  
Author(s):  
Song Fang ◽  
Bo Chen ◽  
Bangkai Gu ◽  
Linxing Meng ◽  
Hao Lu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Electron Transport ◽  
Perovskite Solar Cells ◽  
Perovskite Solar Cell ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Perovskite Material ◽  
Main Factors ◽  
Induced Decomposition

UV induced decomposition of perovskite material is one of main factors to severely destroy perovskite solar cells for instability. Here we report a UV stable perovskite solar cell with a...

Efficient organic manganese (II) bromide green-light-emitting diodes enabled by manipulating hole and electron transport layer

2021 ◽  
Author(s):  
Hyunsik Im ◽  
Atanu Jana ◽  
Vijaya Gopalan Sree ◽  
QIANKAI BA ◽  
Seong Chan Cho ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Green Light ◽  
Transport Layer ◽  
Lead Free ◽  
Electron Transport Layer ◽  
Flat Panel Displays ◽  
Flat Panel ◽  
Inorganic Hybrid ◽  
Light Emitting ◽  
Light Emitting Devices

Lead-free, non-toxic transition metal-based phosphorescent organic–inorganic hybrid (OIH) compounds are promising for next-generation flat-panel displays and solid-state light-emitting devices. In the present study, we fabricate highly efficient phosphorescent green-light-emitting diodes...

Sign in / Sign up

Export Citation Format

Share Document